Identification of Historical Colourantsby Mass Spectrometry

Volodymyr Pauk

under the supervision of prof. Lemr

18.05.2012 by V.Pauk Palacky University in OlomoucFaculty of Science

Department of Anlalytical Chemistry

Olomouc 2012Ref. [1]

Outline

1. Introduction

2. Experimental

3. Results

4. Conclusion

18.05.2012 by V.Pauk

Introduction1. Identification of colourants:

• restoration• evaluation• approximate dating

2. ‘The Legend’

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Partial views of ‘Crucifixion’, St. Šebestian church on St. Hill in Mikulov

a b c

Ref. [2]

Introduction3. Prussian Blue vs Indigo

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Ref. [3, 4, 5]

Prussian blue Indigo• dark-blue shade

• small shaped particles• high tinting strength

•highly insoluble in water and organic solvents

Synthetic,18th century, Berlin18th – 19th century

Natural, plant originAntique times – 19th century(replaced by synthetic dye)

Fe4[Fe(CN)6]3

Iron (III) hexacyanoferrate (II)

Indigotine

ExperimentalEquipment: Micromass Q-TOF Premier, Z-spray ESI source, negative mode; Acquity UPLC system; Elma S40H ultrasound bath, 0.45 µm filters.

Sample preparation:

Eq. 1 Fe4[Fe(CN)6]3 + NaOH → Fe(OH)3↓ + Na4[Fe(CN)6]

Eq. 2

Data acquisition and processing: m/z 133.95 (Prussian blue), m/z 263.08 (indigotin), Mass lynx v. 4.0 (Waters Laboratory Informatics)QC Expert v. 3.2 (TriloByte LTD.)

18.05.2012 by V.Pauk

a) and b) FIA mass-chronograms of Prussian blue and indigo; curves I, II, and III respond to 100, 1000 and 5000 ng/mL , respectively;integrated peak areas for 5000 ng/mL are shown;

18.05.2012 by V.Pauk Results

c) MS spectrum of Prussian blue

d) MS spectrum of indigo

Linear calibration up to 5000 ng/mL

Traces of Prussian blue in samples !!!LOD: 10 ng/mL,

47 pg absoluteLOD: 12 ng/mL, 59 pg absolute

Developed method:•successful in analysis of real samples•fast•sensitive•no chromatographic separation

Application:Fast screening of Prussian blue and indigo in historical and art objects

18.05.2012 by V.Pauk Conclusion

References[1] Reproduction of Peter Paul Rubens - La découverte de la pourpre available on

http://no.wikipedia.org/wiki/Fil:Peter_Paul_Rubens__La_d%C3%A9couverte_de_la_pourpre.JPG.

[2] Partial photos of the painting of ‘Crucifixion’, St. Šebestian church on St. Hill in Mikulov, Czech Republic, available on http://breclavsky.denik.cz/multimedia/galerie/2328622.html?section=1,1.

[3] Kirby, J.; Saunders, D. Fading and colour change of Prussian blue: methods of manufacture and the influence of extenders. National Gallery Technical Bulletin (London), 2004, 25: 73 – 99.

[4] Bartoll, J. The early use of prussian blue in paintings. 9th International Conference on NDT of Art, Jerusalem Israel, 25–30 May 2008.

[5] Bechtold, T.; Mussac, R. Handbook of natural colorants. Wiley, 2009, 412 p.

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Thank You for attention

18.05.2012 by V.Pauk