PREFACE

Every aspect of human activity is closely connected with the natural environment. Whether or not we are aware, or care, every day each of us interacts with and affects our environment. The rapid development of technology, especially at the end of 20th century, has increased enormously man's ability to produce goods which, in turn, have enhanced his standard of living. On the other hand, this development has also generated a secondary phenomenon, the environment pollution. Such effect led to deterioration of life quality. Thus, improvement of the life quality owing to innovative technologies caused negative effects for the environment.

In order to keep the balance between technology development and main components of the man's environment the appropriate technologies should be used which appear to be a powerful force for the improvement of the environment. The relevant activities for upgrading the quality of ground water, drinking water, soil and air have to be developed. The environmental changes affect also the human health. Only few chemical compounds present in the human close surrounding may be considered as beneficial for health. The majority of them act harmfully on humans, even in minimal doses. They occur in our environmental media - air, water and soil and that is why we observe the increasing efforts devoted to the human environmental protection. One of the most important factors in this field are the possibilities and results of modern chemical analyses of pollutants in biological fluids to maintain human health.

Water is one of the most important components of our environment. Nowadays, the drinking water is becoming more and more scarce, but our demand for water is becoming greater and greater. A very important problem is concerned with the rising levels of nutrients such as nitrates and phosphates in the surface water. Their presence has caused a serious deterioration in the water quality of many rivers, lakes and reservoirs. Therefore the attention has to be given to the removal of nutrients originating from sewages and fertilizers by adsorption methods, ion-exchange and relevant biotechnological techniques. Phosphorous and its compounds dissolved in the ground waters are responsible for the eutrophication in the closed water system, especially in lakes and highly enclosed bays where water is stagnant. Slag media, wasted by - products from steel industries, are effective adsorbents for phosphorous and its compounds.

The earth atmosphere along with water, is the main component of our environment. One essential cause of pollution of the air is the tendency to decrease the cost of manufacturing goods by the use of contaminated raw materials without purifying or enriching them before their application. A preliminary desulfurization of coal is still rare. When air is used as a source of

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oxygen, nitrogen in the air is a diluent which, after the oxygen consumption, is discharged into the atmosphere together with other impurities. Dusts and smogs are another group of air contaminants. The modern technologies should restrict emissions of carbon dioxide to prevent from increasing the amount of heat being dispersed into the atmosphere. This increase, leading to a change of climate, is the greenhouse effect. The other fundamental problem is connected with the removal of volatile organic chloride (VOC) compounds from ground water and recovery of chlorofluorocarbons (CFCs), which are still used in refrigeration and cooling systems. Emission control of ozone depletion by CFCs is very urgent.

The pressure on industry to decrease the emission of various pollutants into the environment is increasing. A broad range of methods is available and developed to control and remove both natural and anthropogenic, municipal, agricultural and other pollutants. In relation to the price/performance, adsorption technologies are the most important techniques to overcome the degradation of environmental quality. They play a significant role both in environmental and human health control and in prevention from global warming and ozone layer depletion. The neccessity to reduce the ozone depletion gases like CFCs and the demand for primary energy diversification in the air conditioning sector, are the main reasons for the increasing interest in adsorption devices considered as alternative to the traditional compressor heat pumps in the cooling systems. Adsorption processes are the ,,heart" of several safety energy technologies which can find suitable applications in the domestic sectors as reversible heat pumps, and in the industrial sectors as refrigerating systems and heat trasnformers using industrial waste heat as the primary energy source. They can also be used for technologies to be applied in the transportation sectors, for automobile air conditioning or for food preservation in trucks. The adsorption dessicant dehumidification technology is also emerging as an alternative to vapour compression systems for cooling and conditioning air for a space. Dessicant base systems can improve indoor air quality and remove air pollutants due to their coadsorption by the dessicant materials. Moreover, a number of microorganisms are removed or killed by the dessicant. Other problems are production of drinking water, removal of anthropogenic pollutants from air, soil and water as well as removal of microorganisms from the indoor air and other important tasks to solve in terms of adsorption technologies. Adsorption can also be expected to play a significant role in the environmental control and life supporting systems or planetary bases, where sorbents may be used to process the habitat air or to recover useful substances from the local environments. Another environmental dilemma deals with the removal of thermal SOx and NOx from hot combustion gases. The above mentioned problems may be solved by advanced adsorption techniques. Among them, the rapid pressure swing adsorption (PSA) methods are very efficient for solving both global and local environmental issues. By the term of global environmental problem is meant emission of ozone depletion gases like CFCs, VOC and emission of green-house gases (CO2, CH4, N20, etc.), but the term local environmental problem deals with flue gas recovery (SOx and NOx),

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solvent vapour fractionation and solvent vapour recovery, wastewater treatment and drinking water production. Other environmental issues concern the industrial solid aerosols, which are the incomplete combustion products. They are harmful as precursors to the synthesis of strong toxins, carcinogenes and mutagenes. Automobiles contribute substantially to man-made hydrocarbon emissions. A new type of activated carbon filtres for the application in Evaporative Loss Central Devices (ELCD) were developed by NORIT. Automobiles had to pass the so-called SHED emission test, which was legislated in Europe in 1992.

Adsorption of metals into living or dead cells has been termed biosorption. Biosorption dealing with the metal - microbe interactions include both terrestrial and marine environments. Biosorption by the sea bacteria plays a significant role in detoxification of heavy metals in the aqueous systems. The literature on the influence of biosorption in metal crystal formation is rather scant. The subject of microbe participation in nucleation and halite crystal growth is important with regard to the influence of cell surface layer (S-layer) components on the crystal habit.

As follows from the above considerations, the subject of utility of modern adsorption technologies has enormous environmental, economic and legal importance and constitutes a serious challenge with the prospects for further intense development. Likwise to volume I which contains the most important industrial applications of adsorption, this volume includes the chapters written by authoritative specialists on the broad spectrum of environmental topics to find a way for intense anthropogenic activities to coexist with the natural environment. Some of the topics presented in this volume were mentioned above. However, I would like to highlight a wide spectrum of themes referring to the environmental analysis and environmental control, molecular modelling of both sorbents and adsorption environmentally friendly processes, new trends in applications of colloidal science for protecting soil systems, purification and production of drinking water, water and ground water treatment, new environmental adsorbents for removal of pollutants from waste waters and sewages, selective sorbents for hot combustion gases, some corrosion aspects and ecological adsorption of heating and cooling pumps.

This book is divided into two volumes, consisting of chapters arranged in a consistent order, though some chapters could be connected with the industrial (volume I) or environmental (volume II) fields. In order to highlight for readers all topics and considerations each volume of the monograph comprises the complete contents and the complete list of authors, but ncludes its own subject index only. It should be emphasized that all contributions were subjected to a rigorous review process, with almost all papers receiving two reviews from a panel of approximately fifty reviewers.

The presented chapters give not only brief current knowledge about the studied problems, but are also a source of topical literature on it. Thus each chapter constitutes an excellent literature guide for a given topic and encourages

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the potential reader to get to know a problem in detail and for further specialistic studies. At the end of the volume the comprehensive bibliography on adsorptive separations, environmental applications, PSA, parametric pumping, ion-exchange and chromatography is presented which includes the period 1967-1997.All the articles give both the scientific background of the phenomena discussed and indicate practical aspects to a great extent. Consequently, this monograph is addressed to a large group of research workers both in academic institutions and industrial laboratories, whose professional activities are related to widely understood surface environmental problems, including environmental analysis, environmental catalysis and biocatalysis,modern adsorption ecologically- friendlly technologies, etc. This book is meant also for students of graduate and postgraduate courses.

I am aware, that the panorama of the researches presented is incomplete.On the other hand, I believe that this monograph is a substantial step presenting the current trends and the state of the art. I would like to express my warmest thanks to all the contributors for their efforts to develop the topical environmental fields of great importance. Finally, I wish acknowledge the great help I had my wife, Mrs. Iwona D@rowska, during all stages of the growth of the monograph.Her patience, encouragment and support made it possible to appear this book in present form.

Lublin, September, 1998. A.Dqbrowski (ed.)

Complete L is t o f Authors

1. A lexandratos S.D. Department of Chemistry, University of Tennessee at Knoxville, Knoxville, TN 37996-1600, USA

2. Andrushkova O.V. Department of Total and Bioorganic Chemistry, Novosibirsk Medical Institute, Krasny Prospekt 52, Novosibirsk 630091, Russia

3. Baldini F. Instituto di Ricerca sulle Onde Elettromagnetiche ,,Nello Carrara", CNR, Via Panciatichi 64, 50127 Firenze, Italy

4. Bandosz T.J. Department of Chemistry, City College of New York, New York, NY 10031, USA

5. Blom J. Tauw Milieu P.O.Box 133, 7400 AC Deventer, The Netherlands

6. Bl~dek J. Institute of Chemistry, Military University of Technology, Kaliskiego 2, 01-489 Warsaw, Poland

7. Boere J.A. NORIT N.V., Research & Development, Nijverheidsweg - Noord 72, P.O.Box 105, 3800 AC Amersfoort, The Netherlands

8. Bogillo V.I. Institute of Surface Chemistry, National Academy of Sciences, Prospekt Nauki 31, 252022 Kiev, Ukraine

9. Bracc iS. Centro di Studio sulle Cause di Deperimento e Metodi di Conservazione Opere d'Arte, CNR, Via G.Capponi 9, 50121 Firenze, Italy

10. Billow M. The BOC Group Gases Technical Center, 100 Mountain Ave., Murray Hill, NJ 07974, USA

11. Buczek B. Faculty of Fuels and Energy, University of Mining and Metallurgy, 30-059 Cracow, Poland

12. Burke M. University of Arizona, Old Chemistry Bldg., Tucson, AZ 85721, USA

13. Cacciola G. National Council of Research, Institute for Research on Chemical Methods and Processes for Energy Storage and Transformation, S.Lucia sopra Contesse, 98126 Messina, Italy

14. Carey T.R. Radian International, LLC, 8501 N.Mopac Blvd., Austin, TX 78759, USA

15. Cerofolini G.F. SGS-THOMSON Microelectronics, 20041 Agrate MI, Italy

16. Chang R. Electric Power Research Institute, 3412 Hillview Ave., Palo Alto, CA 94403, USA

17. Chen J. Georgia Institute of Technology, School of Civil and Environmental Engineering, Atlanta, GA 30332-0512, USA

18. Chen S. Illinois State Geological Survey, 615 E. Peabody Dr. Champaign, IL 61820, USA

19. Dabou X. Chemical Process Engineering Laboratory, Department of Chemical Engineering, Aristotle University of Thessaloniki and Chemical Process Engineering Research Institute, PO Box 1520, Thessaloniki 54006, Greece

20. Dal lBauman L.A. NASA Johnson Space Center, Houston, TX 77058, USA

21. D~browski A. Faculty of Chemistry, M.Curie-Sktodowska University, 20031 Lublin, Poland

22. Deka R.C. India Catalysis Division, National Chemical Laboratory, Pune - 411008, India

23. Deng S.G. USA Department of Chemical Engineering, University of Cincinnati, Cincinnati, Ohio 45221, USA

24. Dobrowolski R. Faculty of Chemistry, M.Curie-Sklodowska University, 20031 Lublin, Poland

25. Domingo-Garcia M. Grupo de InvestigaciSn en Carbones, Dpto. de Quimica Inorganica, Fac. de Ciencias, Universidad de Granada, 18071 Granada, Spain

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26. Dybko A. Department of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland

27. Fadoni M. Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, 20133 Milan, Italy

28. Fernandez-Mora les I. Grupo de InvestigaciSn en Carbones, Dpto. de Quimica Inorganica, Fac. de Ciencias, Universidad de Granada, 18071 Granada, Spain

29. F inn J.E. NASA Ames Research Center, Moffett Field CA, USA

30. F leming H. Cochrane Inc., 800 3 nd Avenue, King of Prussia, 19406 PA, USA

31. Ghosh T.K. Particulate Systems Research Center, Nuclear Engineering Program, E 2434 Engineering Building East, University of Missouri-Columbia, Columbia, MO 65211, USA

32. Ghzaoui A.E1. UM II LAMMI ESA 5079, Case 015, Place Eugene Bataillon, 34095 Montpellier Cedex 5, France

33. Golden T.C. Air Products and Chemicals, Inc., 7201 Hamilton Boulevard, Allentown, PA 18195-1501, USA

34. Groszek A.J. MICROSCAL LTD, 79 Southern Row, London W 10 5 AL, UK

35. Haukka S. Microchemistry Ltd., P.O.Box 132, FIN-02631 Espoo, Finland

36. Hei jman S.G.J. KIWA Research and Consultancy, P.O.Box 1072, 3430 BB Nieuwegein, The Netherlands

37. Hines A.L. Honda of America Mfg.Inc., 24 000 Honda Parkway, Marysville, OH 43040, USA

38. Hopman R. KIWA Research and Consultancy, P.O.Box 1072, 3430 BB Nieuwegein, The Netherlands

39. Horvath G. University of Veszprem, H-8201 Veszprem, P.O.Box 158, Egyetem u.10, Hungary

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40. Hsi H-C. University of Illinois, Environmental Enegineering Program, 205 N.Mathews Ave., Urbana, IL 61801, USA

41. Hubicki Z. Faculty of Chemistry, M.Curie-Sktodowska University, 20031 Lublin, Poland

42. Isupov V.P. Institute of Solid State Chemistry and Raw Mineral Processing Kutateladze-18, 630128, Novosibirsk, Russia

43. Iverson I. Department of Chemistry, University of Nevada, Reno, NV 89557, USA

44. Izmailova V.N. Moscow State University, Department Colloid Chemistry, Vorob'evy Gory, 119899 Moscow, Russia

45. Jakowicz A. Faculty of Chemistry, M.Curie-Sklodowska University, 20031 Lublin, Poland

46. Janusz W. Faculty of Chemistry, M.Curie-Sktodowska University, 20031 Lublin, Poland

47. Kalvoda R. J.Heyrovsky Inst.Phys.Chem., Czech Acad. Scis, Dolejskova 3, 18223 Prague 8, Czech Republic

48. Kaneko K. Chiba University, Department of Chemistry, Faculty of Science, 1-33 Yayoi, Inage, Chiba 263, Japan

49. Kanellopoulos N. Institute of Physical Chemistry NCSR ,,DEMOKRITOS", Aghia Paraskevi Attikis, GR- 153 10, Athenes, Greece

50. Kikkinides E.S. Institute of Physical Chemistry NCSR ,,DEMOKRITOS", Aghia Paraskevi Attikis, GR- 153 10, Athenes, Greece

51. Kir ichienko O.A. Institute of Solid State Chemistry, SB RAS, Kutateladze 18, Novosibirsk 630128, Russia

52. Kleut D.v.d. NORIT N.V., Research & Development, Nijverheidsweg - Noord 72, P.O.Box 105, 3800 AC Amersfoort, The Netherlands

53. Kobal I. Department of Physical and Environmental Chemistry, J.Stefan Institute, 61000 Ljubljana, Slovenia

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54. Kotsupalo N.P. Ekostar - Nautech Company, B.Chmielnitsky 2, 630075 Novosibirsk, Russia

55. Krebs K.-F. Merck KGaA, LAB CHROM Synthese, D-64271 Darmstadt, Germany

56. Kubo M. Department of Molecular Chemistry and Engineering, Faculty of Engineering, Tohoku University, Sendai 980-77, Japan

57. Lakomaa E.-L. Neste Oy, Technology Center, P.O.Box 310, FIN-06101 Porvoo, Finland

58. Lemcoff N.O. The BOC Group, 100 Mountain Avenue, Murray Hill, NJ 07974, USA

59. Lin Y.S. USA Department of Chemical Engineering, University of Cincinnati, Cincinnati, Ohio 45221, USA

60. Liu Y. Department of Chemical Engineering, Swearingen Engineering Center, University of South Carolina, Columbia, SC 29208, USA

61. Long R. Department of Chemical Engineering, The University of Michigan, Ann Arbor, Michigan 48109-2136, USA

62. Lopez-Cortes A. Center for Biological Research, P.O. Box 128, La Paz 23000, BCS, Mexico

63. Lopez-Garzon F.J. Grupo de Investigaci6n en Carbones, Dpto. de Quimica Inorganica, Fac. de Ciencias, Universidad de Granada, 18071 Granada, Spain

64. Lucarelli L. ThermoQuest Italy S.p.A., Strada Rivoltana, 20090 Rodano (Milan), Italy

65. Luo R.G. Department of Chemical Engineering, Chemistry and Environmental Science, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982, USA

66. Lutz W. Holzmarktstrasse 73, D-10179 Berlin, Germany

67. Lodyga A. Fertilizers Research Institute, 24110 Putawy, Poland

68. Lukaszewski Z. Poznafl University of Technology, Institute of Chemistry and Technical Electrochemistry, Piotrowo 3, 60-965 Poznafl, Poland

69. MacDowall J.D. NORIT United Kingdom Ltd., Clydesmill Place, Cambuslang Industrial Estate, Glasgow G32 8RF, Scotland

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70. Matyska M. Department of Chemistry, San Jose State University, San Jose, CA 95192 USA

71. Matijevic E. Center for Advanced Materials Processing, Clarkson University, P.O.Box 5814, Potsdam, New York 13699-5814, USA

72. Meda L. EniChem - Istituto Guido Donegani, 28100 Novara NO, Italy

73. Menzeres L.T. Ekostar - Nautech Company, B.Chmielnitsky 2, 630075 Novosibirsk, Russia

74. Meyer K. Bundesanstalt ffir Materialforschung und -prfifung (BAM), Zweiggelande Adlershof, Rudower Chaussee 5, D-12489 Berlin, Germany

75. Mitropoulos A.Ch. Institute of Physical Chemistry NCSR ,,DEMOKRITOS", Aghia Paraskevi Attikis, GR- 153 10, Athenes, Greece

76. Miyamoto A. Department of Molecular Chemistry and Engineering, Faculty of Engineering, Tohoku University, Sendai 980-77, Japan

77. Mizukami K. Department of Molecular Chemistry and Engineering, Faculty of Engineering, Tohoku University, Sendai 980-77, Japan

78. Moon H. Department of Chemical Technology, Chonnam National University, Kwangju 500-757, Korea

79. Moreno-Castilla C. Grupo de Investigaci6n en Carbones, Dpto. de Quimica Inorganica, Fac. de Ciencias, Universidad de Granada, 18071 Granada, Spain

80. Neffe S. Institute of Chemistry, Military University of Technology, Kaliskiego 2, 01-489 Warsaw, Poland

81. Nemudry A.P. Institute of Solid State Chemistry and Raw Mineral Processing, Kutateladze-18, 630128, Novosibirsk, Russia

82. Nijdam D. Tauw Milieu, P.O.Box 133, 7400 AC Deventer, The Netherlands

83. Ochoa J.L. Center for Biological Research, P.O.Box 128, La Paz 23000, BCS, Mexico

84. Pan G. Department of Earth Sciences, University of Leeds, Leeds LS2 9JT, UK

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85. Par tyka S. UM II LAMMI ESA 5079, Case 015, Place Eugene Bataillon, 34095 Montpellier Cedex 5, France

86. Patel D.C. Department of Chemical Engineering, Chemistry and Environmental Science, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982, USA

87. Pesek J. Department of Chemistry, San Jose State University, San Jose, CA 95192, USA

88. Pokrovskiy V.A. Institute of Surface Chemistry, National Academy of Sciences, Prospekt Nauki 31, 252022 Kiev, Ukraine

89. Raisglid M. University of Arizona, Old Chemistry Bldg., Tucson, AZ 85721, USA

90. Ramarao B.V. Syracuse University, Faculty of Paper Science and Engineering and Engineering, SUNY, College of Environmental Science and Forestry, Syracuse, NY 13210, USA

91. Rao M.B. Air Products and Chemicals, Inc., 7201 Hamilton Boulevard, Allentown, PA 18195-1501, USA

92. Ray M.S. Department of Chemical Engineering, Curtin University of Technology, GPO Box U1987, Perth 6845, Western Australia

93. Reimerink W.M.T.M. NORIT N.V., Research & Development, Nijverheidsweg - Noord 72, P.O.Box 105, 3800 Ac Amersfoort, The Netherlands

94. Restuccia G. National Council of Research, Institute for Research on Chemical Methods and Processes for Energy Storage and Transformation, S.Lucia sopra Contesse, 98126 Messina, Italy

95. Richardson C.F. Radian International, LLC, 8501 N.Mopac Blvd., Austin, TX 78759, USA

96. Ripperger K.P. Department of Chemistry, University of Tennessee at Knoxville, Knoxville, TN 37996-1600, USA

97. Ritter J.A. University of South Carolina, Department of Chemical Engineering, Swearingen Engineering Center, Columbia, South Carolina 29208, USA

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98. Robens E. Institut ffir Anorganische Chemie und Analytische Chemie der J.Gutenberg-Universitat D-55099 Mainz, Germany

99. Rodrigues A.E. Laboratory of Separation and Reaction Engineering, University of Porto, 4099 Porto Codex, Portugal

100. Rood M. University of Illinois, Environmental Engineering Program, 205 N.Mathews Ave., Urbana, IL 61801, USA

101. Rosenhoover W. CONSOL, 4000 Brownsville Rd., Library, PA 15129, USA

102. Rostam-Abadi M. Illinois State Geological Survey, 615 E. Peabody Dr. Champaign, IL 61820, USA

103. Rule J. College of Sciences, Old Dominion University, Norfolk, VA 23529-0163, USA

104. Saba J. Faculty of Chemistry, M.Curie-Sklodowska University, 20031 Lublin, Poland

105. Sakellaropoulos G.P. Chemical Process Engineering Laboratory, Department of Chemical Engineering, Aristotle University of Thessaloniki and Chemical Process Engineering Research Institute, PO Box 1520, Thessaloniki 54006, Greece

106. Samaras P. Chemical Process Engineering Laboratory, Department of Chemical Engineering, Aristotle University of Thessaloniki and Chemical Process Engineering Research Institute, P.O. Box 1520, Thessaloniki 54006, Greece

107. Sh in tan i H. National Institute of Hygienic Sciences, 18-1 Kamiyoga 1-Chome, Setagaya-ku, Tokyo 158, Japan

108. Silva da F.A. Laboratory of Separation and Reaction Engineering, University of Porto, 4099 Porto Codex, Portugal

109. Silva J.A.C. Laboratory of Separation and Reaction Engineering, University of Porto, 4099 Porto Codex, Portugal

110. Sircar S. Air Products and Chemicals, Inc., 7201 Hamilton Boulevard, Allentown, PA 18195-1501, USA

111. Sivasanker S. Catalysis Division, National Chemical Laboratory, Pune - 411008, India

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112. Stubos A.K. Institute of Nuclear Technology and Radiation Protection, NCSR ,,DEMOKRITOS", 15310 Aghia Paraskevi Attikis, GR-15310, Athenes, Greece

113. Subramanian D. University of South Carolina, Department of Chemical Engineering, Swearingen Engineering Center, Columbia, South Carolina 29208, USA

114. Suckow M. Fachhochschule Lausitz, Grossenhainer Strasse, D-01968 Senftenberg, Germany

115. Suntola T. Microchemistry Ltd., P.O.Box 132, FIN-02631 Espoo, Finland

116. Suzuki M. Institute of Industrial Science, University of Tokyo, 7-221 Roppongi, Minato-ku, Tokyo 106, Japan

117. Szczypa J. Faculty of Chemistry, M.Curie-Sktodowska University, 20031 Lublin, Poland

118. Sykut K. Faculty of Chemistry, M.Curie-Sklodowska University, 20031 Lublin, Poland

119. Swi~ttkowski A. Institute of Chemistry, Military Technical Academy, Kaliskiego 2, 01-489 Warsaw, Poland

120. Takaba H. Department of Molecular Chemistry and Engineering, Faculty of Engineering, Tohoku University, Sendai 980-77, Japan

121. Tam-Chang S.-W. Department of Chemistry, University of Nevada, Reno, NV 89557, USA

122. Tarasevich Yu.I. Institute of Colloid Chemistry and Chemistry of Water, 42 Vernadsky avenue, Kiev 252680, Ukraine

123. TSth J. Hungarian Academy of Sciences, Research Laboratory for Mining Chemistry, 3515 Miskolc-Egyetemvaros, P.O. Box 2, Hungary

124. Tzevelekos K.P. Institute of Physical Chemistry NCSR ,,DEMOKRITOS", Aghia Paraskevi Attikis, GR-153 10, Athenes, Greece

125. Unger K.K. Institut ffir Anorganische Chemic und Analytische Chemic der J.Gutenberg-Universitat, D-55099 Mainz, Germany

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126. Ushakov V.A. Institute of Solid State Chemistry, SB RAS, Kutateladze 18, Novosibirsk 630128, Russia

127. Vansant E.F. Laboratory of Inorganic Chemistry, University of Antwerpen (U.I.A.), Universiteitsplein 1, 2610 Wilrijk, Belgium

128. Vetrivel R. Catalysis Division, National Chemical Laboratory, Pune - 411008, India

129. Vigneswaran S. University of Technology, Sydney, Faculty of Engineering, Building 2, Level 5 P.O.Box 123 Broadway, NSW 2007, Australia

130. Waghmode S.B. Catalysis Division, National Chemical Laboratory, Pune - 411008, India

131. Wr6blewski W. Department of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland

132. Yampolskaya G.P. Moscow State University, Department Colloid Chemistry, Vorob'evy Gory, 119899 Moscow, Russia

133. Yang R.T. Department of Chemical Engineering, The University of Michigan, Ann Arbor, Michigan 48109-2136, USA

134. Y iacoumi S. Georgia Institute of Technology, School of Civil and Environmental Engineering, Atlanta, GA 30332-0512, USA

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Contents of Volume I

Preface v

Complete List of Authors IX

Fundamentals of Adsorption 1. Adsorption - its development and applications for practical purposes

(A.D@rowski) 3 2. Industrial carbon adsorbents (A.Swi~tkowski) 69 3. Standarization of sorption measurements and reference materials for

dispersed and porous solids (E.Robens, K.-F.Krebs, K.Meyer, K.K.Unger) 95 4. Spectroscopic characterization of chemically modified oxide surfaces

(J.Pesek, M.Matyska) 117 5. Advances in characterisation of adsorbents by flow adsorption

microcalorimetry (A.J.Groszek) 143 6. Temperature programmed desorption, reduction, oxidation and flow

chemisorption for the characterisation of heterogeneous catalysts. Theoretical aspects, instrumentation and applications (M.Fadoni, L.Lucarelli) 177

7. Adsorption with soft adsorbents and adsorbates. Theory and practice (G.F.Cerofolini, L.Meda, T.J.Bandosz) 227

Application in Industry 1. Advanced technical tools for the solution of high capacity adsorption

separation (G.Horvath, M.Suzuki) 275 2. The mutual transformation of hydrogen sulphide and carbonyl sulphide

and its role for gas desulphurization processes with zeolitic molecular sieve sorbents (M.B(ilow, W.Lutz, M.Suckow) 301

3. Nitrogen separation from air by pressure swing adsorption (N.O.Lemcoff) 347 4. Methodology of gas adsorption process design. Separation of

propane/propylene and rgiso- paraffins mixtures (Jose A.C.Silva, F.Avelino da Silva, Alirio E.Rodrigues) 371

5. Fractionation of air by zeolites (S.Sircar, M.B.Rao, T.C.Golden) 395 6. Production, characterization and applications of carbon molecular sieves

from a high ash Greek lignite (P.Samaras, X.Dabou, G.P.Sakellaropoulos) 425 7. Development of carbon-based adsorbents for removal of mercury

emissions from coal combustion flue gas (M.Rostam-Abadi, H-C.Hsi, S.Chen, M.Rood, R.Chang, T.R.Carey, C.F.Richardson, W.Rosenhoover) 459

8. Sorption properties of gas/coal systems, degasification of coal seams (J.TSth) 485

9. The influence of properties within particles of active carbons on selected adsorption processes (B.Buczek) 507

Adsorption and its Applications in Industry and Environmental Protection Studies in Surface Science and Catalysis, Vol. 120 A. Dabrowski (Editor) 9 1998 Elsevier Science B.V. All rights reserved.

Environmental pollutants and application of the adsorption phenomena for their analyses

J. Btadek and S. Neffe

Institute of Chemistry, Military University of Technology, 00-908 Warsaw, Kaliskiego St., 2, Poland

1. INTRODUCTION

Human activity is now altering the global environment on an unprecedented scale and thus contributes to the environmental change affecting human health. Only few of chemical compounds present in direct human surrounding may be considered as beneficial for health; the majority of them act harmfully on humans, even in minimal doses. They occur in all environmental media (air, water and soil) and that is why we observe the increasing attention to the environmental protection. One of the most important factors in this field are the results of chemical analysis of pollutants. It is obvious that only reliable analytical data obtained during monitoring can be a base for environmental protection activities.

The term monitoring means systematic and planned collection of analytical activities realised in any space to define the quality of air, water and soil. Volatile organic compounds, pesticides, polycyclic aromatic hydrocarbons, polycyclic aromatic heterocycles, phenols, polychlorinated biphenyls, organotins, chemical warfare agents and inorganic pollutants belong to the most important environmental pollutants. The need of monitoring leads to the development of independent branch of instrumental analysis - environmental analysis. It is a discrete, and sophisticated branch of instrumental analysis which concerns the treatment of environmental samples from their sampling to receiving the final result of analysis. The fundamental requirement of environmental analysis is for a fast, modern and reliable methodology, especially as the data produced are increasingly drawn upon as the decisive basis for regulatory measures. Consequently, specific conditions need to be fulfilled for the detection of pollutants in trace and ultra-trace quantities, within a short time and with a high degree of precision.

To define the analytical process, Skoog and co-workers [1] mention the following steps: selecting method of sampling, obtaining representative samples, preparing laboratory samples, defining replicate samples, dissolving samples,

eliminating interference and measuring features of analyses. The aims of these activities are: 9 making the sample suitable physical parameters, removing interference and

transferring the analytes to matrix being compatible with analytical technique; liquid, gas, solid phase and supercritical fluid extraction is usually applied for transferring analytes directly from samples into media being subjected to final instrumental analysis, as well as to liberate analytes trapped on sorbents during preconcentration steps;

9 cleaning-up the analytical samples and analytes enrichment; liquid-liquid partitioning, solid phase extraction, preparative column and thin layer chromatography are usually applied as clean-up and preconcentration techniques,

9 separation of sample components to obtain the chemical individuals; in environmental analyses the partition of analysed mixtures is most often realised by chromatographic methods,

9 detection, identification and quantitation; detectors which are parts of chromatographic apparatus or can co-operate with them in on-line mode are predominantly used. There are many various methods of sampling, sample preparation and

analyses, which warrant correctness of obtained analytical results. Extraction, chemisorption, absorption, adsorption, distillation or freezing are used in them inter alia. Features and applications of these methods are presented in numerous compilations and monographs. In this elaboration we present only these techniques in which phenomena of adsorption are used. They are applied mainly to the sampling of pollutants in fluid, sample preparation and such analytical techniques, which warrant separation of components of analysed mixture (mainly chromatographic techniques of analyses). In these processes compounds of interest are selectively removed from the bulk sample matrix, preconcentrated, cleaned-up~ separated into individual substances and analysed.

2. SHORT CHARACTERISTIC OF MONITORED SUBSTANCES

The term environmental pollution means any physical, chemical, or biological change disturbing ecological equilibrium in the environment. It may be a result of random, accidental events, emission of certain pollutants due to activity of nature itself, or human activities. As a result of the activity of nature, natural pollutants are emitted into atmosphere; human activity leads to the emission of pollutants called anthropogenic pollutants. Natural and anthropogenic pollutants emitted from a given source are called primary pollutants. A number of primary pollutants can undergo some changes due to reactions with other pollutants, as well as with some components of the environment. In this way, new compounds, often of higher toxicity, can be formed. They are called secondary pollutants. Primary as well as secondary pollutants occur in all of the environment media:

atmosphere, hydrosphere, and soil. The following groups of substances are considered as the most important environmental pollutants: 9 Volatile organic compounds. Volatile organic compounds (VOCs), originating

from anthropogenic sources, are the monocyclic aromatic hydrocarbons and the volatile chlorinated hydrocarbons. Both groups of compounds are considered as priority pollutants; they are present in all parts of the environment. Monocyclic aromatic hydrocarbons are mainly emitted by industrial processes and combustion of fossil fuels, while chlorinated hydrocarbons are widely applied as solvents for dry cleaning, as degreasing agents in metal industries or as fumigants [2]. Due to their lipophilic properties, they can be taken up in lipophilic matrices. Uptake of xenobiotic VOCs in plants used for human nutrition (vegetables and fruits), results in an exposure of man through the food chain, next to a direct exposure to air pollutants through inhalation. VOCs are also the most frequently encountered contaminants at hazardous waste sites.

9 Pesticides comprise a group of compounds that are given great attention in environmental studies. They are introduced into environment due to wilful human activity; economic production in the cultivation of vegetables and fruits, as well as in agriculture, can not be achieved without pesticides. Pesticides belong to different chemical groups of compounds; the most important of them are: organophosphorous, organochloride, carbamate, triazine compounds and chlorophenoxy acids. With respect to the biological activity they are classified as insecticides, herbicides and fungicides. Well known compounds such as DDT, lindane or aldrin belong to the organochloride group which, in the past, was widely used all over the world. Although their manufacture and application are now largely prohibited, they can still, due to their persistence, be found in the soil, in animals, plants and food products. Pesticides are poisons; some of them or their degradation products also demonstrate carcinogenic potential and teratogenic activity. They are present in all parts of the environment.

9 Polycyclic aromatic hydrocarbons (PAHs) are compounds whose molecules can contain 2-13 aromatic rings arranged in linear, cluster, or angular shapes. They may contain some number of alkyl substituents. PAHs arouse much interest mainly due to their carcinogenic and mutagenic properties. They are widespread environmental contaminants emitted from a variety of sources, including industrial combustion and discharge of fossil fuels, residential heating, or motor vehicle exhaust. In processes of monitoring, PAHs have been measured in a variety of environmental matrices including air, water, soil, sediments and tissue samples.

9 Polycyclic aromatic heterocycles. In the environment, carbon atoms in PAHs rings can be substituted with oxygen, sulphur, or nitrogen atoms. In this way polycyclic aromatic heterocycles are formed, and they usually occur together with PAHs. The most dangerous of these, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans, are by-products formed during the

manufacture of chlorophenols and related products; other sources include the pulp and paper industry and accidental fires that release polychlorinated biphenyls. Dibenzotiophene and some of its methyl-substituted compounds are persistent residues in sea environment after oil accidents. In the natural environment, polychlorinated thianthrenes and polychlorinated dibenzothiophenes also exist. As with their oxygen analogues, they are hazardous substances. Azaarenes, mainly benz(c)acridine and many of its related compounds, have been shown to exhibit carcinogenic activity. Nitro- related compounds are mutagenic and carcinogenic. Polycyclic aromatic heterocycles are continually found in many natural and environmental samples.

9 Pheno ls form a group of aromatic compounds with one or more hydroxyl groups. Phenols and substituted phenols are products of manufacturing processes used in plastics, dyes, drugs, antioxidants, and pesticides industries. They pose the serious danger to the environment, especially when they enter the food chain as water pollutants. Even at very low concentration phenols affect the taste and odour of fishes and drinking water. Because of this, many phenol derivatives (mainly nitrophenols and chlorophenols, which are also poisons) are considered as priority pollutants of the environment.

9 Po lych lor inated b iphenyls (PCBs) are a group of compounds derived from biphenyl by substituting one to ten hydrogen atoms with chlorine. There are 209 possible PCB configurations. They have extensive application because of high chemical and thermal stability, low or no flammability, low vapour pressure at ambient temperature and high permeability. PCBs are utilised alone or in mixtures as heat-transfer fluids, dielectrics for capacitors and transformers, hydraulic fluids, lubricants, additives in plastics and dyes, etc. PCBs are different in their physical and chemical properties as well as toxic potencies; some of them are inducers of drug-metabolising enzymes also being able to affect various physiological processes such as reproduction, carcinogenesis or embryonic development.

9 Organot ins . These compounds have been widely used as biocides incorporated in antifouling paints, and are accumulated by the biota, especially by filtrating organisms. The organotins are much more toxic than inorganic tin. Contamination of the marine environment by organotins has been well documented. Tributyltin is the most often used organotin compound, followed by triphenyltin. In water these substances can be step-wise decomposed to less substituted and down to inorganic tin, absorbed by lipid fraction of organisms or adsorbed onto particulate matter.

9 Chemica l warfare agents. The need of the monitoring on the presence of these substances in the environment results not only from the need of the verification of the Chemical Weapon Convention [3] but also because certain chemical warfare agents can be spread in the environment as the old or abandoned chemical warfare agents. Out of this group of compounds organophosphorous (O-ethyl S-2-diisopropylaminoethyl methyl phosphono-

thiolate, O-pinacolyl methylphosphono-fluoridate, etc.) and bis(2-chloroethyl) sulfide (mustard gas), tris(2-chloroethyl) amine (nitrogen gas), 10-chloro-5,10- dihydrophenarsazine (adamsite) have importance due to their toxicity or persistence in the environment.

9 Explosives. 2,4,6-trinitrotoluene (TNT) is known first of all as an explosive, but it appears that this compound and its degradation products have been found as contaminants in water and soil. TNT and its degradation products have been identified in the blood and urine of the explosives manufacturing plants personnel. Because of the mutagenity of these compounds, environmental t reatment of TNT and its degradation products (2- and 4-monoamino- dinitrotoluenes as well as 2,4- and 2,6-diaminonitrotoluenes) is an important issue.

9 Inorganic po l lutants . Among inorganic environmental pollutants aerosols, heavy metals, radionuclides and some anions are monitored. Aerosol or particulate matter refer to any substance, except pure water, that exists as a liquid or solid in the atmosphere under normal conditions and is in microscopic or submicroscopic size. Even non-toxic aerosols are harmful; they can cause eye or throat irritation, bronchitis or lung damage. Heavy metals (mainly As, Cd, Cr, Cu, Se, Ni, Mo, Hg and Pb) can pose serious threats to the human health even at very low concentrations in air and water. For instance, lead causes damage of brain, mercury affects several areas of the brain, as well as the kidneys and bowels, arsenic causes cancer etc. After pollution of soil they can be incorporated into the food cycle via vegetables or, alternatively, be washed towards surface or underground water. Farming, industrial and urban activities are most often mentioned as pollution sources of heavy metals. The radioactivity in environment originates from both natural sources and human activities. The latter include operations concerned with the nuclear fuel cycles, from mining to reprocessing, medical uses etc. Radionuclides cause cancer. The common anions, such as cyanides (CN-), halides (Br-, CI-, F-) or the oxy-ions (SO3-, 304-, NO2-or NO3-) are monitored mainly in water and wastewaters. When listing the most important environmental pollutants it is impossible to

forget industrial gases such as SO2, NOx, CO2, etc., which are emitted in huge quantities to the atmosphere. First two of them cause respiratory illness and lung damage. They also cause the acid rains which are responsible for corrosion of metals, acidification of soil and surface waters, as well as degradation of forests. NO2 and CO2 are, like as CH4, tropospheric 03 and chlorofluorocarbons, greenhouse gases. These gases absorb in the spectral range where thermal energy radiated from the earth is at a maximum. All of them, analogically as above mentioned organic and non-organic pollutants must be systematically monitored.

3. ADSORPT ION IN SAMPLING AND SAMPLE PREPARATION

Basic feature which distinguishes environmental analysis is the need of sampling and sample preparation of substances existing in matrix on trace levels. Monitoring of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans can be a good example of such needs. Because of high toxicity the level of quantitation of these substances equals 10 -~2 g/kg; it is also important that these substances usually exist in natural environment in neighbourhood of other organic chlorine compounds whose concentration can be twice or three times higher. So to cope with the demands of environmental analyses such as techniques of sampling, sample preparation and analyses, which have proper ability to separation, high sensitivity, good selectivity, ability to generate reliable identification data should be applied. Adsorption phenomena play an important, if not decisive, role in many of these processes.

3.1. Sampl ing The term sampling is used for the description of the process by which a

representative fraction of matrix is acquired. In environmental analyses various sampling techniques (and equipment submitting them) are used; adsorption phenomena are usually applied for the sampling of air, surface water and wastewater; in these processes sampling is realised together with the enrichment of analytes. Owing to the adsorption processes compounds of interest are selectively removed from the bulk sample matrix and preconcentrated (an enrichment factor of 103-107 can be usually obtained).

There are two main groups of sampling and preconcentration methods of air samples: passive and aspirative (denudatic or dynamic) [4]. The idea of passive method is diffusion or permeation of analytes to the trapped medium surface. Analytes which are present in the nearest surrounding of the enriching device (dosimeter) are transferred due to the molecular diffusion forces towards the semipermeable membrane and are penetrating through it. Phenomena of absorption, chemisorption and adsorption are used in aspirative methods. Passive samplers are suitable for large scale measurements. As they do not require pumping of air during sampling they can be employed at virtually every location. Passive samplers can be sent by mail and stored before and after sampling for periods of several months. On the other hand, passive samplers require at least 24-hour exposure and therefore cannot be used for short-term sampling.

Aspirative denudatic method of preconcentration consist in a junction of a forced gas stream flow and diffusive transfer of analytes in the direction of denuder wall which acts as an analyte trap. The advantage of denudating techniques is the possibility of differentiation of so called physical speciation of analytes, it means differentiation between gaseous and aerosol form of preconcentrated substances. Aspirative dynamic enrichment is the oldest method of air sampling. It allows to determine the time weighted average concentration or short term exposure level. Absorption in liquid solutions, freezing out in

cryogenic traps and adsorption belongs to these methods. Adsorption aspirative dynamic methods are used to separate the volatile and non-volatile organic pollutants. The applied techniques differ from each other in volume of sample, shape of sorbent container, and first of all in dissimilarity of used sorbents (usually they are carbonaceous, inorganic or polymeric sorbents). The scheme of the set for sampling and preconcentration of atmospheric air pollutants on adsorbent is presented in Figure la. In Figure lb the crossection of adsorption tube is shown.

1 5

6 7

8 r

Figure la. The set for collecting samples. 1-probe, 2- adsorption tube, 3- filter, 4-capillary tubes 5-vacuum-gauge, 6-flow controller, 7-pressure reducing valve, 8-vacuum pump. Reprinted from [4].

1 2 .~/3 #y5. ~_.#6#'L.~ 8 1

Figure lb. Adsorption tube. 1-plastic caps, 2-fused ends of tube (they are broken before using), 3-glass sorption tube, 4- spring, 5-glass wool, 6-adsorbent layer, 7-polyurethane plug, 8-adsorbent protective layer. Reprinted from [4].

Among carbon sorbents active carbons and carbon molecular sieves with specific surface area between 600 and 1200 me/g, and relatively high adsorption

10

capacity for most organic compounds are used. For specific non-polar analytes graphitized carbon blacks with a small specific surface area are used. Disadvantage of carbon adsorbents is an irreversible adsorption of many analytes and substantial variability of adsorption properties between different batches of the same product. Detailed description of application of carbon adsorbents in analyses of organic environmental pollutants is presented in work of Matiskowa and Skrabakov~ [5].

Among the inorganic sorbents, silica is the most widely used. Chromatographic silica is amorphous, porous solid which can be prepared in a wide range of surface areas and average pore diameters. Variation of solution pH during the acid gelation of sodium silicate yields silica with surface areas varying from about 200 m2/g (pH ~ 10) to 800 m2/g (pH < 4). Silica may be treated as a typical polar adsorbent. The raw material for the production of chromatographic alumina (aluminium oxides) are different aluminium hydroxides, e.g. hydrargillite. Like silica, alumina can be regarded as a typical polar adsorbent, and sample separation order on alumina and silica is generally similar. The presence of carbon-carbon double bonds in a pollutant molecule generally increases adsorption energy on alumina more than on silica. Aromatic hydrocarbons which contain different numbers of aromatic carbon atoms are much better separated on alumina than on silica. Adsorption sites are used for the selective adsorption of unsaturated or polar molecules onto a hydroxylated silica surface. Three distinct site types can be recognised on the alumina surface: acidic or positive field sites, basic or proton acceptor sites and electron acceptor (charge transfer) sites [6]. Each of these is important in the adsorption of certain samples on alumina. Florisil is co-precipitate of silica and magnesia and this is why the retention and separation on its surface is generally intermediate between alumina and silica. Inorganic adsorbents have a high adsorption capability, even to polar and volatile organic compounds. This property is limited in the case of moisture samples (adsorption of water vapours cause the deactivation of adsorption centres and lowers the retention of analytes).

Porous polymers and co-polymers are the most universal group of adsorbents used for sampling of air; they are synthesised in the processes of the bead polymerisation. A suitable selection of cross-linking polymers and other polymerisation parameters allows to control polymerisation processes. Therefore it is possible to obtain adsorbents with desirable specific surface area, porosity and polarity (for example Tenax | Porapak | Chromosorb | or XAD| Tenax is a porous polymer based on 2,6-diphenyl-p-phenylene oxide. The high thermal stability and its compatibility with alcohols, amines, amides, acids and bases together with good recovery characteristics make Tenax very suitable as sorbent medium in air and water analysis [7]. Porapak is a series of cross-linked porous polymers, for example divinylbenzene/ethylene glycol dimethacrylate (Porapak N). That sorbent is used for preconcentration of many substances [8]. Porapaks have the following polarity: N>S>P>Q, T>R. Chromosorbs or XAD are produced by copolymerising monofunctional monomers with bifunctional monomers. For

11

instance Chromosorb 102 is a styrene/divinylbenzene copolymer with specific surface area in the range of 300-400 m2/g; the surface is non-polar. Chromosorb 108 is moderately polar acrylic ester resin with the specific surface area between 100 and 200 m2/g. They are also commonly used for air sampling and preconcentration of analytes [9, 10]. Disadvantage of polymeric adsorbents is their sensibility to oxidative action of ozone or chlorine.

Among the adsorption methods applied for isolating analytes from liquid matrixes (mainly from water) and for their preconcentration, practical importance has the solid phase extraction (SPE) technique. The idea of this technique consists in retention of analytes from a large sample volume on a small bed of adsorbent (placed in cartridge or shaped in the disk form), and following elution of analytes, with a small volume of solvent. The selection of appropriate parameters of adsorbents and solvents is the basic condition for successful employment of this method. Details on the SPE are presented in chapter 23, vol. 2 of this book.

An alternative to the SPE, solvent-free sampling technique is a solid phase microextraction [SPME]. Typically, a fused-silica fibre, which is coated with a thin layer of polymeric stationary phase, is used to extract analytes from fluid (for analysis the retained analytes are thermally desorbed). The application of the SPME for sampling of polycyclic aromatic hydrocarbons [PAHs] from aqueous samples is presented in the work of Yu Liu et al. [11]. The porous layer coatings were prepared by the use of silica particles (5 ~m diameter) bonded with phenyl, Cs, and monomeric or polymeric Cls stationary phases. It was proved that several factors affected the selectivity for extraction of PAHs, including functional group in the bonded phase, and phase type (monomeric or polymeric). The distribution coefficients of PAHs in the porous layer increased with an increasing number of carbon atoms. A greater selectivity towards solute molecular size and shape were obtained using a polymeric Cls porous layer. The effect of solution ionic strength on recovery was also investigated.

There are many papers describing the testing of usefulness of various adsorbents for fluid sampling [12, 13]. Adsorption capacity for the defined groups of the analytes, breakthrough capacity and influence of adsorbent bed length, as well as enrichment conditions on these parameters were investigated. The recovery of analytes by their thermal or liquid desorption is an essential element of such investigations.

3.2. Sample preparation Only few analytical methods provide the possibility for examination of samples

in their original state, without preliminary preparation. In case of the environmental analysis such examinations are in practice almost impossible. Complexity of environmental samples is the reason why analytical processes are very difficult and usually multistages. Analytes need to be determined at extremely low concentrations over a wide polarity range, and frequently there is little or no information about the analysed sample. This is why the sample

12

preparation is the most important and often the most difficult step of analysis in environmental studies.

The experiment described by Falcon et al. [14] can be a very good example of complications of sample preparation process. They developed the procedure for trace enrichment of benzo(a)pyrene in extracts of smoked food products. All steps of this analysis are presented in Figure 2. As it was mentioned above, the

[ Lyophilization [

[ Ultrasound I

I 50 ml hexane extract I

] Centrifugation I

[ Supernatant !

I Concentration to 5 ml

I ] Silica purification

[ Extraction DMSO [

30 ml DMSO extract I

[ C- 18 purification [

[ Hexane evaporation I

] Filtration I I

[ HPLC [

25/15/10 ml hexane (lh)

Elution 10 ml hexane

15/10/5 ml DMSO (5 min)

75 ml water

Elution 5 ml hexane

1 ml acetonitryle

Figure 2. Flow-chart summarising treatment sample prior to the HPLC analysis of benzo(a)pyrene. Reprinted from [ 13].

13

transfer of analytes to matrix being compatible with analytical technique, usually by means of liquid, gas or supercritical fluids extraction, is one of the steps of sample preparation process. Unfortunately, in this process very undesirable substances (interferences) penetrate to the matrix. This is why a cleaning-up of analytical samples, connected usually with preconcetration of analytes, is a very essential step of environmental analyses. Among the adsorption methods, preparative column chromatography and thin layer chromatography are commonly used. Aluminium oxide, cellulose powder or microcrystalline cellulose, silica, diatomaceous earth (Kieselguhr), polyamide and Florisil | are employed in column or layer preparation.

Nowadays, a large variety of chemicaly bonded stationary phases are applied. Such phases are prepared by anchoring specific organic moieties to inorganic oxides (mainly silica), under defined reaction conditions. Organic moieties can be attached to the silica by mono-, di-, or trifunctional silane reaction. After derivatisation of the silica substrate to yield a bonded phase, a network of so- called structure elements can be distinguished at the silica surface. This includes organic moieties bound to the surface, like cyano-, NH2-, phenyl-, octyl-, or octadecyl groups. The residual silanols, approximately 50% of the originally present silanols, have different properties as they consist of lone, vicinal and geminal groups. Consequently, besides the attached organic ligands, also the residual silanols play an important role in the final properties of the chemically bonded stationary phases.

Carlsson and Ostman [15] presented a method for the isolation of polycyclic aromatic nitrogen heterocyclic (PANHs) compounds from complex sample matrix. They are known to be mutagenic and /or carcinogenic. PANHs with a single endocyclic nitrogen heteroatoms can be divided into two classes: acridines (containing a pyridine ring) and carbazoles (containing a pyrrole ring). They were isolated and separated as carbazole and acridine type PANHs with an absolute recovery in the range between 79-98%. The open column chromatography was used as an initial step for isolating a PANH fraction. By applying a normal-phase liquid chromatography using a dimethylaminopropyl silica stationary phase and utilising back-flush technique it was possible to separate the PANHs fraction into two fractions containing acridine type and carbazole type PANHs respectively. The method applied on a sample of solvent refined coal heavy distillate; acridines and carbazoles were identified by gas chromatography (GC).

Rimmer's and co-workers work [16] is a good example of application of high- resolution gel permeation chromatographic clean-up technique (prior to GC). The method for the determination of phenoxy acid herbicides in vegetable samples was presented. Macerated samples were extracted with acetone, filtered and acidified; the herbicides were then partitioned into dichloromethane, cleaned-up using high-resolution gel permeation chromatography before undergoing rapid and efficient methylation using trimethyl-silyldiazomethane. The resultant methyl esters were than selectively and sensitively analysed by GC/MS

14

technique. The procedure has been applied for grass samples spiked with four phenoxy acid herbicides: 2,4-D, dichlorprop, MCPA and mecroprop.

Environmental monitoring is often realised by using the non-direct methods; in such investigations the results of contamination, e.g. presence of pollutants or products of their transformation in food are determined. For example milk; being at one of the highest levels of the tropic chain and due to its lipophilic nature, milk has been usually studied as an indicator of the bioconcentration process of environmentally persistent organic micropollutants. Di Muccio and co-workers [17] developed a rapid procedure that allows a single step selective extraction and clean-up of organophosphate pesticide residues from milk, dispersed on solid matrix diatomaceous material into disposable cartridges by means of light petroleum saturated with acetonitrile and ethanol. Recovery experiments were carried out on homogenised commercial milk spiked with solutions of 24 pesticides. Bernal and co-workers [18] presented a method for determination of vinclozolin (agrochemical fungicide) in honey and bee larvae. LL or SPE extraction techniques were used and two clean-up procedures (chromatography on Florisil or Cls column) were assayed after the solvent extraction. A clean-up method for organochloride compounds in fatty samples based on normal-phase liquid chromatography is described in work of van der Hoff et al. [19]. The use of liquid chromatography column packed with silica enables complete fat/organochloride pesticide separation in total fraction volume of 12 ml and results in a fully automated clean-up procedure.

Adsorption phenomena in the soil sampling and sample preparation is rarely applied; it is used mainly to the clean-up of extracts.

4. TIIE CHROMATOGRAPHIC METHODS

The detection and determination of pollutants in complex environmental systems by conventional and biochemical methods is difficult and time- consuming, and the results are often doubtful. These methods are now being systematically replaced by instrumental analytical methods, among which adsorption procedures play an imporatan role; crucial meaning have the chromatographic methods.

The idea of all chromatographic methods is the partition of components of analysed mixture between two phases. One of these phases is stationary; the second is the mobile phase which moves along the stationary phase. Gas, liquid or supercritical fluid can be the mobile phase; the separation techniques which use these phases are called respectively: gas chromatography (GC), liquid chromatography (LC) and supercritical fluid chromatography (SFC). A solid or liquid can be the stationary phase; in the first case it is adsorption chromatography (GSC), in the second one - partitioning chromatography (GLC). If the stationary phase is in a column we call it column chromatography (GC or High Performance Liquid Chromatography - HPLC). In the case when adsorbent

15

is spread on a solid carrier plate in the form of thin layer and attached to it we call it thin-layer chromatography (TLC). In every case the separation is achieved by repeating distribution of analytes between two phases of given chromatographic system.

In the column chromatography the compounds are eluted with the mobile phase to a detector (universal or selective), which produces a signal proportional to the amount of a particular substance in this phase. The proper choice of column, injection technique and temperature program will ensure the separation of interesting substances from the background ones. Good separation efficiency is one of the most critical parameters for reliable identification of pollutants by a detector. Pollutants can be identified by means of the absolute or relative retention times; a very useful parameter of identification is also retention index. Quantitation can be realised by internal or external standards. In cases of environmental analyses very frequently compounds cannot be separated from each other. These problems can often be solved by chromatographic technique utilising two or more columns. In multicolumn chromatography the columns may have widely varying measurements and separation characteristics. The columns may be connected either off-line or, nowadays much more often, on-line technique.

Volatile or semi-volatile environmental pollutants which are the subject of monitoring are usually analysed by GC. In this technique sensitive and selective detectors such as the electron capture detector (ECD) or the mass spectrometer (MS) are used. They enable identification and quantitation of trace components in complex mixtures. HPLC has been recommended for the analyses of thermally labile, non-volatile and highly polar compounds. Application of high performance adsorbents in TLC and sophisticated equipment (apparatus for automatically spotting and developing chromatograms, scanning densitometry) caused, that present instrumental TLC can compete with the HPLC in terms of analytical efficiency, sensitivity, and precision. Other chromatographic methods such as SCFC and capillary electromigration have been currently developed but for the time being their application in environmental analysis is limited.

The studies on applications of chromatographic methods for environmental investigation can be classified on the criteria of goals of experiments. According to this criterion they can be divided into three groups. These ones which refer to the monitoring are represented the most frequently. The reports which can be entitled "behaviour" are relatively numerous too. They refer to behaviour (in term of resolution possibilities) of pollutants in various chromatographic systems. The third group consists of the works in which physical and chemical properties of pollutants, i.e. their mobility, bioaccumulation, biotransformation etc. are examined.

4.1. High Performance Liquid Chromatography High Performance Liquid Chromatography (HPLC) is a form of column liquid

chromatography. In this technique the mobile phase is pumped through the

15

packed column at high pressure and therefore HPLC is also called High Pressure Liquid Chromatography. Columns are made of stainless steel tubes 10-, 20 cm long and internal diameters (I.D.) of a few millimetres. Depending on the type of interaction between stationary phase, mobile phase and a sample, following separation mechanisms can take place: adsorption, partition, ion exchange, ion- pair and size exclusion.

In adsorption liquid chromatography mainly silica and (rarely) aluminium oxide, cellulose and polyamide are used as stationary phases. The separated molecules are reversibly bonded to the solid surface by dipole-dipole interactions. Because the strength of interaction is different for different molecules, residence time at the stationary phase varies for different compounds; thus, separation can be achieved. This technique is used mainly for resolution of polar, non-ionic substances; in environmental analyses it is used occasionally.

In the case of liquid- liquid partition chromatography stationary phases (liquids) can coat a support or can be chemically bonded to that support. Distribution mechanism is called partitioning because separation is based on the use of relative solubility differences of the sample in the two phases (in fact the separation is also achieved through the adsorption by non-protected silanol groups). In the normal phase (NP) liquid-liquid partition chromatography, the stationary phase is more polar than the mobile phase, in the reversed phase (RP) liquid-liquid partition chromatography, the mobile phase is more polar than stationary phase. The NP liquid-liquid partition chromatography is used for separation of very polar organic substances, while the RP chromatography (nowadays more popular technique) is used for the non-polar or weakly polar compounds.

An example of using the liquid-liquid partition chromatography for the environmental analyses can be the above mentioned work of FalcSn et al. [14]. They used a HPLC-fluorescent detection method for the determination of benzo[a]pyrene in the enriched extract of the smoked food products. It should be stressed that the determination of polycyclic aromatic hydrocarbons (PAHs) by HPLC requires separation columns of high selectivity and efficiency. Reupert and co-workers [20] proposed a method for the separation of PAHs by the application of PAH 16-Plus column under optimal operating conditions. A very good separation of 16 PAHs was obtained (Figure 3).

Liquid-liquid partition chromatography is often employed in the analysis of pesticides. The analysis of pesticide residues in the environment is of great current interest due to the possible risks that may arise from the exposure of humans and animals to such agents. From among the latest papers concerning that problem the special issue of Journal of Chromatography "Chromatography and Electrophoresis in Environmental Analysis: Pesticide Residues" is worthy to notice [21]. A good example of taking advantage of liquid-liquid partition HPLC can be the paper by Somsen and co-workers [22]. Precolumn packed with Cls (Polygosil) material for the enrichment of herbicides was combined on-line with the column liquid chromatography and Fourier-transform infrared spectrometry.

17

100 -

80 -

60-

40

20

O-

9

11

11213

I I I I

0 10 20 30 40

Time, min

Figure 3. HPLC chromatogram of 10 ~tl PAHs standard (EPA) in CH3CN; concentration of individual substances 90 pg/~tl. Emission signals. Column- Bakerbond PAH 16-Plus; mobile phase H20 - CH3CN (gradient elution). 1-naphthalene, 2-acenaphthene, 3-fluorene, 4-phenanthrene, 5-anthracene, 6-fluoranthene, 7-pyrene, 8-benzo [a] anthracene, 9-chrysene, 10-benzo[e]pyrene, 11-benzo[b]fluoranthene, 12-benzo[k]fluoranthene, 13-benzo[a]pyrene, 14-dibenzo[a,h]anthracene, 15-benzo[g,h,i] perylene, 16-indeno[ 1,2,3oc,d]pyrene. Reprinted from [20].

The isocratic separation was carried out on a 200x2.1 mm I.D. C18 column (Rosil) using acetonitrile-phosphate buffer (40:60) as eluent. The method was based on post-column on-line liquid-liquid extraction and solvent elimination, followed by Fourier-transform infrared spectroscopy. The feasibility of the complete system was demonstrated by analysing river water spiked with triazines and phenylureas at the ~g/1 level. Identifiable spectra were obtained for all analytes. The authors showed that on-line trace enrichment in combination with column liquid chromatography and Fourier-transform infrared detector offers a selective method for the characterisation of moderately polar analytes such as phenylureas and triazines in water samples.

In the analysis of pesticides the degradation products also have to be determined because these products will often possess such activities as the parent pesticides. One ought to emphasise that the analysis of pesticide degradation in environmental samples is often difficult to perform due to the different polarities and lower concentrations of the degradation products relative to the parent compounds. Taking into account these difficulties Rollang, Beck-Westermeyer and Hage [23] applied the RP liquid-liquid partition chromatography and the high performance immunoaffinity chromatography for determining the degradation products of the herbicide atrazine in water. A high performance

18

immunoaffinity chromatography column containing anti-triazine antibodies was first used to extract the degradation products of interest from samples, followed by the on-line separation of the retained components on C18 analytical column. The limits of detection for hydroxyatriazine, deethylatriazine and deisopropylatriazine were 20-30 ng/1. Usefulness of this method was demonstrated in the analysis of both river water and groundwater samples.

Rapid methods for the isolation and determination of alkylphenols from crude oils with the use of partitioning chromatography were described by Bennett et al. [24]. Determinations were performed by RP liquid-liquid partition HPLC. The authors have proved that the method affords rapid and accurate quantitation of phenol, cresols, dimethylphenols and is suitable for screening large number of samples. They illustrated the methods with two petroleum geochemical examples: determination of the partition coefficients of alkylphenols in oil/brine systems under high pressure and temperature conditions.

Leira, Botana and Cela [25] applied an effect of differences in the retention capacity and selectivity of C18 and graphitized carbon column to resolve complex mixtures of non-flavonoid polyphenols (Table 1). Separation of mixture components was accomplished in a single switching operation by using mobile phase of the same composition but a different eluting strength in both separation steps. The elution conditions used in both columns were simplified by means of simulation software in order to obtain multiple fractions. The potential of this technique was realised by resolving a mixture of 38 very similar species (Figure 4).

AU

2.5

2 .0 - -

1 .5 - -

1.0 - -

0.5

0.0

@

II Ii. I TM , ]

I jl !1 iI A I I I-- - - - l i fl it t ,A ,ll ,,!i, | i I I I I I 1 Pl if i I I I Iii I I II I I I I II i I I i [I II li I

V 7 VI

Q v i i I I I I

i I I I I I

!AN_ ' ' I I ~.~_ ~. I I I I

0 5 10 15 20

Minutes

Figure 4. Chromatogram of 38 non-flavonoid polyphenols. Reprinted from [25].

19

Table 1 Listing of the non-flavonoid species studied; key numbers match the spectrum labels in the figures, and heart-cut groups the labels in Figure 4

Key Compound Heart-cut number Group

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38

3-Hydroxybenzoic acid III 4-Hydroxybenzoic acid II 2,4 Dihydroxybenzoic acid (~-resorcylic acid) II 2,5 Dihydroxibenzoic acid (gentisic acid) II 2,6 Dihydroxybenzoic acid (7-resorcylic acid) I 3,4 Dihydroxybenzenzoic acid (protocatechuic acid) I 3,3 Dihydroxybenzoic acid (a-resorcylic acid) I 3,4,5-Trihydroxybenzoic acid (gallic acid) 4-Hydroxy-3-methoxybenzoic acid (vanillic acid) III 3-Hydroxy-4-methoxybenzoic acid (isovanillic acid) III 4-Hydroxy-3,5-dimethoxybenzoic acid (syringic acid IV 2,4 Dimethoxybenzoic acid 2,6 Dimethoxybenzoic acid IV 3,4-Dimethoxybenzoic acid V 3,5- Dimethoxybenzoic acid VII 2-Hydroxycinnamic acid (o-coumaric acid) VI 3-Hydroxycinnamic acid (o-coumaric acid) V 4-Hydroxycinnamic acid (p-coumaric acid) 3,4-Dihydroxycinnamic acid (caffeic acid) III 4-Hydroxy-3-methoxycinnamic acid (ferulic acid) V 3,5-Dimethoxy-4-hydroxycinnamic acid (sinapic acid) V 3,4,5-Trimethoxycinnamic acid VII 2-Hydroxybenzaldehyde (salicyl aldehyde) V 3- Hydroxybenzaldehyde III 4-Hydroxybenzaldehyde III 2,5-Dihydroxybenzaldehyde III 3,4-Dihydroxybenzaldehyde(protocatechialdehyde) III 3,5-Dimethoxy-4-hydroxybenzaldehyde 2-Hydroxy-3-methoxybenzaldehyde (o-vanillin) V 4-Hydroxy-3-methoxybenzaldehyde (vanillin) IV 3-Hydroxy-4-methoxybenzaldehyde (isovanillin) IV 2,4-Dimethoxybenzaldehyde 3,4-Dimethoxybenzaldehyde (veratraldehyde) V 3,5-Dimethoxybenzaldehyde VII 3-Methoxybenzaldehyde (m.-anisaldehyde) VI 4- Methoxybenzaldehyde (p-anisaldehyde) VI 3,4,5-Trimethoxybenzaldehyde VI Chlorogenic acid II

Reprinted from [25].

20

Ion-exchange chromatography is a separation procedure in which ions of similar charges are separated by elution from a column packed with a finely divided resin. The stationary phase consists of acidic or basic functional groups bonded to the surface of the polymer matrix. Charged species present in the mobile phase are attracted to appropriate functional groups in the ion exchanger and separated. Mixtures of bases and acids can be separated by this technique. The stationary phases used in ion-pair chromatography are the same as in RP chromatography. Ionic organic compounds (e.g. C7H15803- - heptane sulfonic ion for bases or Bu2N - tetrabutyl ammonium ion for acids), which form the ion-pair with the analysed sample component of opposite charge, are added to the mobile phase. This ion-pair is a salt, which behaves chromatographically like a non-ionic organic molecule that can be separated by RP chromatography. These methods found only limited application in environmental analysis. D. Krochmal and A. Kalina [26] proved that coupling the ion-exchange chromatography with active or passive sampling of air pollutants gives the possibility of simultaneous determination of sulphur dioxide and nitrogen dioxide. Both gases can be quantitatively absorbed in aqueous solution of triethanolamine and subsequently determined with ion chromatography as sulphates and nitrates. Absorbing solutions were analysed with a single column ion chromatograph equipped with a packed column.

Size-exclusion chromatography is a powerful technique applicable for separation of high-molecular-weight pollutants. Packing material for size- exclusion chromatography consists of a small silica or polymer particles containing network of uniform pores into which solute and solvent molecules can diffuse. In the chromatographic process molecules are effectively trapped in pores and removed by the flowing mobile phase. The compounds with higher molecular weight cannot penetrate into the pores and are retained to a less extend than smaller ones. Some of size-exclusion packing materials are hydrophilic and are used with aqueous mobile phase (gel filtration); others are hydrophobic and are used with non-polar, organic solvents (gel permeation). In environmental analyses size-exclusion chromatography is used for sample clean-up and fractionation. For example, gel permeation chromatography is a standard technique for the isolation of herbicides and fungicides from samples that contain high-molecular-weight interferences, such as solid waste extract, oil or fats [16].

In the case of environmental analyses information about pollutants may be obtained not only from environmental matrix. Kabzifiski [27] proposed a new analytical method for the quantitative determination of metallothioneins protein in human body fluids and tissues, in order to determine the level of environmental and industrial exposition to heavy metals. For metallothioneins isolation covalent affinity chromatography with thiol-disulfide interchange was applied, which is a modern technique of separation of high affinity, good repeatibly and reproducibility, allowing specific isolation of the thiolproteins and metallothiolproteins. Fundamentals of indirect determination of the contents of metallothioneins protein were worked out throughout estimation of the

21

quantities of metals bound with metallothionein protein and adsorbed on covalent affinity chromatography gel as on the solid-phase extraction support during a separating process.

4.2. Gas chromatography The term gas chromatography (GC) is used to denote the chromatographic

techniques in which the mobile phase is a gas (the carrier gas, mostly N2, H2, Ar or He). The stationary phase is placed in the column; it may be a porous solid (GSC-gas solid chromatography, adsorption chromatography) or viscous liquid (GLC-gas liquid chromatography, partition chromatography). In both cases the transport of components of analysed mixtures (adsorbates, analytes) is realised exclusively in the gas phase, separation - exclusively in the stationary phase. The time of passing of particular analytes through the stationary phase and the frequency of interactions of analytes with this phase are the decisive factors in the separation process. In case of GSC separation occurs because of differences in the adsorption equlibria between the gaseous components of the sample and the solid surface of the stationary phase. In case of GLC, in contrast to HPLC, there is no interaction between the mobile phase and the analyte.

Glass, metal (copper, aluminium, stainless steel) or Teflon tubes long 2-3 m and I.D. 2-4 mm are used for making the packed columns to GC. Open tubular columns (capillary columns) are of two basic types: wall coated open tubular (WCOT) and support coated open tubular (SCOT). WCOT is the traditional capillary column made of glass or stainless steel. The liquid phase is applied as a continuous thin film on the inside walls of the tube. The newest WCOT are fused silica open tubular columns (FSOT). This is a very small outer diameter thin wall column that is inherently a straight tube but is flexible enough to be coiled to diameters c.a. 20 cm. FSOT are drawn from specially purified silica that contains minimal amounts of metal oxides. Compared to packed column these capillaries show inert surfaces and higher reproducibility with at last equal separation efficiencies. PLOT (porous layer open tubular) column is similar to a SCOT except for the fact, that the support material is responsible for the separation through the adsorption process. In a PLOT columns there is no coating liquid phases.

There are two basic types of packing materials employed in GC. The first type is porous materials used in GSC. The second type are the support materials which are covered with a layer of liquid phase used in GLC. The adsorption properties and selectivity of adsorbents applied in GSC depend first of all on the chemical composition and geometrical structure of their surface. There are several kinds of attractive adsorbate-adsorbent interactions occurring during the separation of mixturecomponents. The most important interactions are: dispersion or London forces, electrostatic forces, induction forces and specific interaction (mainly charge-transfer, which occur between one component with n- bonding electrons and showing small ionisation energy and the second component showing high electron affinity). Among dozens of different solids which have been

22

used in adsorption chromatography only few adsorbent types have wide application today. Non-organic adsorbents such as silica, aluminium oxide or Florisil and polymeric adsorbents type of Tenax, Chromosorb or Porapak belong to the porous packings (which do not need to be coated with stationary phases). They can directly be used for adsorption chromatography. The carbonaceous adsorbents are today used in gas adsorption chromatography rather occasionally.

In case of GLC the stationary phase is a liquid (often rubber-like), it is immobilised on the surface of a solid support by adsorption or by chemical bonding. Liquid stationary phases are applied both in packed and capillary columns. Packed columns are completely filled with a packing, liquid stationary phases coating an inert support such as diatomite (Kieselguhr), rarely Teflon or glass spheres. Capillary columns do not require a support because their inert walls are coated with the stationary phases. The most important feature of liquid stationary phase is its polarity. The very popular non-polar phases are Squalane (hexamethyltetracosane) and Apolane-87 (24,14-diethyl-19,29-dioctadecylhapta- tetracontane). Squalane is used as reference for determination of polarity of other liquid phases in packed column.

Apolane-87 is high temperature standard phase used in capillary chromatography. In environmental analyses semipolar phases are used most often. That group of phases is mainly represented by Silicones. Depending on the kind of substituent in oxosilanes chain (dimethyl-, phenyl-, trifluoropropyl-, cyano- etc.), the weak-, medium- and strong polar phases can be prepared. Polygethylenelycol is an example of strong-polar phase. Among specific liquid phases a family of polysiloxane stationary phases (Chirasil), developed for the separation of optical enantiomers, has a great practical importance. Chemicaly bonded phases used in GLC are identical as twere used in HPLC.

Barrefors et al. [28] showed that furan and alkylfurans might be selectively analysed on PLOT (aluminium oxide) columns, since other oxygen-containing compounds are normally not eluted. Furan, 2-methylfuran, 3-methylfuran, 2,5-dimethylfuran and the five isomeric C6 alkylfurans, two C7 and three C6-C7 alkenylfurans were determined by adsorbent sampling and GC/MS technique. Separation on PLOT column is presented on Figure 5. Furan elutes after isoprene and cyclopentadiene in the same region as minor pentadienes and branched hexanes. Several minor C6 and C7 furans appear.in the chromatographic range before and after methylbenzene. The purpose of this study was to characterise volatile furans in birdwood smoke which may be of interest with respect to human exposure and as indoor and outdoor wood-smoke tracers in studies of air pollutants.

An analytical method to determine highly volatile saturated aldehydes, degradation products of lipid peroxidation, was developed for the capillary GC [29]. The carbonyl compounds were derivatized quantitatively with 2-hydrazinobenzothiazole at room temperature to form their corresponding water-insoluble hydrazones. The derivatives were extracted and detected with high selectivity (Figure 6) by high-resolution GC with nitrogen-phosphorous

23

m

C

k

9

0 I I~I

5

9

10 20 -1

4~ min 200~ isothermal

m

3O L . | v ,

Figure 5. Gas chromatographic separation on aluminium oxide column of prominent furans, alkadienes. Reprinted from [28].

34 ISTD,

21

5

6

1 - Methanal 2- Ethanal 3 - Propanal 4- Butanal 5 - Isopentanal 6- Pentanal

7 - Hexanal

I I I I

0 5 l 0 15 Time (min)

Figure 6. Typical gas chromatogram of the 2-hydrazinobenzothiazole-derivative aldehydes. ISTD- internal standard: 2,4 pentanedione-2-hydrazinobenzothiazole-derivative. Reprinted from [29].

24

detection due to their high nitrogen content. Analyte concentration, pH and type of extraction technique (LLE and SPE) were studied to determine optimal recovery conditions. The method was applied to the analysis of the volatile aldehydes generated during the thermal oxidation of olive oil at 220~

Begerov and co-workers [30] applied the screen method for the simultaneous determination of 28 volatile organic compounds in the indoor and outdoor air at environmental concentrations. Using passive (sorption-diffusive) samplers, the volatile organic compounds were adsorbed onto charcoal during a four-week sampling period and subsequently desorbed with carbon disulphide. The eluate was split via an Y-connector and led onto two capillary columns of different polarity switched in parallel. This dual column configuration provides additional information about the volatile organic compound components and can be obtained for verification purpose. Detection was in both cases performed by connecting each column with a non-destructive electron-capture detector and a flame ionisation detector switched in series. The procedure has been successfully applied in the context of a large field study to measure outdoor air concentration in three areas with different traffic density (Figure 7). It is applicable to indoor air measurements in a similar manner.

a) b)

7 0.275]--~

0.345 1 4 11 0.265

0.305 13

0.305 2 5 10 17 0.255

1516 3 1 0.245, , .- 0.285 8 14 / ," - -"""

6 r " 18 . . - ' " 0.265 " "

0.245 , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , 5 10 15 20 25 30 35 40

Time (min)

Figure 7. Typical gas chromatograms of an indoor air sample obtained by flame ionisation detection. (a) more polar column, (b) less polar column. Reprinted from [30].

Lobiafiski et al. [31] studied the potential of the microwave-induced plasma atomic emission detector for capillary GC (GC/AED) as a tool for the specification of organotin compounds in environmental samples. The operational variables are optimised for chromatographic resolution and detection limits. A comprehensive

25

method for the determination of mono-, di-, tri-, and some tetraalkylated organotin compounds in water and sediments by GC/AED was developed. Ionic organotin compounds were extracted as diethyl dithiocarbamates into pentane and, after its evaporation, dissolved in a small volume of octane and derivatized by pentylmagnesium bromide to give the solution suitable for gas chromatography.

The phenoxy acids were first introduced as herbicides in the late 1940s. They have found widespread usage in the post-emergence control of annual and perennial broad leafed weeds cereals and grasses. Functioning as synthetic plant growth regulators these herbicides accumulate in the roots and stems of the plants. A method for the determination of phenoxy acid herbicides in vegetation samples is described among other things in the work of Rimmer and co-workers [32]. Macerated samples were extracted with acetone. After filtration and acidification they were introduced into dichloromethane. The herbicides were than cleaned-up using high-resolution gel permeation chromatography.

Analysis of PCB normally includes extensive sample clean-up and preconcentration followed by high resolution capillary GC either with electron capture or mass-selective detection. Although both techniques provide the high sensitivity required for PCB investigations, quantitative analysis is complicated by structural variations of detectors-response factors. The quantitative aspect of GC with atomic emission detection (GC/AED) used for the analysis of PCB is presented in work of Bjergaard et al. [33]. Since Cl-responses were almost independent on the PCB structure, individual PCBs were quantitated with an acc