desorption ionization analysis of nano film products for ... film... · desorption ionization...

1
Overview Two NanoFilm Products (NFPs) were analysed using two different desorption ionization techniques, Nano Assisted Laser Desoption Ionization (NALDI) and Tranmission Mode Desorption Electrospray Ionization (TM-DESI). Both methods worked well and the NFPs were found to contain hydrolysates and condensates of organo-functionalised silanes. Above:Silanes and siloxanes in NFP 1 (floor coating). Below: Silanes and siloxanes in NFP 2 (tile coating) NALDI NALDI is a new type of ionization technique for MALDI-type instruments comprising targets of inorganic nano structures coated with a hydrophobic, organic layer that facilitates sample deposition and Laser Desorption Ionization (LDI) performance (1). They absorb laser energy causing LDI without need for a matrix. Thus analysis of small molecules (e.g.100-2000 Da) deposited upon the target is possible without matrix interference. TM-DESI TM-DESI is an alternative mode of operation for DESI analysis (2). An electrospray is transmitted through a sampling mesh (e.g. Polypropylene) at 0° angle between spray tip, sample mesh and capillary inlet. Before analysis, the sample is applied to the sample mesh from where it is desorbed by the spray during analysis. This is a simpler approach than traditional DESI for the analysis of liquid samples, since the number of variables to be optimized are reduced. Water dropplets on coated surfaces Above: TM-DESI spectrum of NFP 1 (floor coating) Below: TM-DESI spectrum of NFP 2 (tile coating) Above: NALDI spectrum of NFP 1 (floor coating) Below: NALDI spectrum of NFP 2 (tile coating) References (1) Daniels RH, Dikler S, Li E, Stacey C. Break Free of the Matrix: Sensitive and Rapid Analysis of Small Molecules Using Nanostructured Surfaces and LDI-TOF Mass Spectrometry. Journal of the Association for Laboratory Automation 2008 Dec;13(6):314-21. (2) Chipuk JE, Brodbelt JS. Transmission Mode Desorption Electrospray Ionization. Journal of the American Society for Mass Spectrometry 2008 Nov;19(11):1612-20. Experimental NALDI NFP was diluted 10 times with 2-propanol (NFP 1) or ethanol (NFP 2) and a small amount (few crystals in 10 ml) of NaTFA was added. 1-2 μl of the resulting solution was applied to the NALDI target and allowed to dry at room temperature. Analysis was carried out on a Bruker Autoflex II MALDI-TOF. The mass accuracy was better than 10 ppm for the analysis NFP 1 and better than 30 ppm for the analysis of NFP 2. TM-DESI A 3 x 3 cm polypropylene mesh (open space: 297 μm) was dipped into undiluted NFP and then analysed directly hereafter. A solution of methanol/water 1:1 with 1 % formic acid and a few crystals of ammonium acetate was used as electrospray solvent at flow rates of 5-10 μl/min. Nitrogen was used as nebulization gas at a pressure of 10 Bar. The electrospray voltage was -4.5 kV applied to MS inlet capillary which was kept at 250 °C. The TM- DESI experiments were carried out on a Bruker micrOTOF-Q instrument equipped with an in-house built DESI source. The mass accuracy was better than 1.5 ppm. In case of NFP 2, addition of NaTFA improved signal intensity by a factor 2-3. The ions observed in NALDI analysis of the NFPs were therefore all sodium adducts; NFP 1 mainly yielded ions which had eliminated HF as a neutral loss, + [(M-HF)+Na] , while NFP 2 yielded both + + [M+Na] and [(M+Na)Na] ions. In TM-DESI analysis of NFP 1, ammonia + adducts, [M+NH ] , were more abundant 4 than both the sodium adduct and the quasi molecular ions. Addition of a small amount of ammonium acetate to the electrospray solvent increased the signal intensity by at least 100 times. + TM-DESI of NFP 2 resulted in [M+H] ions regardless of the addition of ammonia acetate. Conclusions Both NALDI and TM-DESI are suitable for analysis of NFPs based on functionalised silanes. NALDI yielded more information on the polysiloxanes; this is probably due to film formation on NALDI target taking place by condensation reactions. Addition of salts were critical for the ionization efficiency in both methods. The demonstrated usefulness of desorption ionization methods for NFP analysis, form the basis for future studies of the film formation process. Both NALDI and TM-DESI analysis of the NFPs showed the silanes and siloxanes of 1H,1H,2H,2H-perfluorooctyltriisopropoxysilane (NFP 1) and hexadecyltriethoxysilane (NFP 2) with different degrees of hydrolyzation and condensation. The mass accuracy in NALDI and especially TM-DESI experiments enabled determination of sum formulas which, in combination with MS/MS experiments, facilitated the identification. NALDI showed the silanes and their polysiloxanes for both products; up to tetrasiloxanes for NFP 1 and up to decasiloxanes for NFP 2, while TM-DESI showed trisiloxanes for NFP 1 and disiloxanes for NFP 2. Addition of NaTFA was found to be critical for the NALDI analysis of NFP 1. Desorption ionization analysis of nano film products for surface coating: A comparison of NALDI and TM-DESI 1 2 2 1 Asger W. Nørgaard , Christian Janfelt , Frants R. Lauritsen and Peder Wolkoff 1) National Research Centre for the Working Environment, Copenhagen, Denmark 2) Faculty of Pharmaceutical Sciences, University of Copenhagen, Denmark [email protected] Introduction NanoFilm Products (NFPs) are a relatively new type of consumer products for surface coating e.g. bathroom tiles, floors, textiles etc. The products are sprayed onto a surface, whereupon a thin coating is formed during evaporation of the solvent. This coating induces non-stick and in some cases self cleaning properties to the treated surface. In this study, two products, NFP 1 (floor coating) and NFP 2 (tile coating), were selected for analysis by two desorption ionization techniques, Nano Assisted Laser Desorption Ionization (NALDI) and Transmission Mode Desorption Electrospray Ionization (TM-DESI). Both methods are simple to use and require a minimum of sample preparation. The two methods were compared and the results are presented below. Hydrolysates and condensates of 1H,1H,2H,2H-perfluorooctyltriisopropoxysilane NALDI: [(M-HF)+Na] + at m/z 555.091 TM-DESI: [M+H] + at m/z 553.1429 Si OC 3 H 7 H 7 C 3 O C 8 H 4 F 13 OC 3 H 7 Si O Si OH F 13 H 4 C 8 OC 3 H 7 OC 3 H 7 OC 3 H 7 C 8 H 4 F 13 Si O Si OC 3 H 7 F 13 H 4 C 8 OC 3 H 7 O OC 3 H 7 C 8 H 4 F 13 Si H 7 C 3 O C 8 H 4 F 13 OC 3 H 7 OC H F CHF F Si O Si 3 7 13 H 4 C 8 O O OC 3 H 7 8 4 13 Si O C 8 H 4 F 13 OC 3 H 7 Si 13 H 4 C 8 OC 3 H 7 n Si O O O C 8 H 4 F 13 X X X X = H, C 3 H 7 or C 8 H 4 F 13 O 2 Si-Y where Y = H or C 3 H 7 General formula: [(M-HF)+Na] + at m/z 963.098 OCHCHF Si O Si 3 7 F 13 H 4 C 8 OC 3 H 7 OC 3 H 7 OC 3 H 7 8 4 13 Silane Disiloxane NALDI: [M+NH 4 ] + at m/z 1020.2033 TM-DESI: Trisiloxane NALDI: [(M-HF)+Na] + at m/z 1455.183 TM-DESI: [M+NH 4 ] + at m/z 1470.2357 Tetrasiloxane NALDI: [(M-HF)+Na] + at m/z 1803.064 Hydrolysates and condensates of 1H,1H,2H,2H-perfluorooctyltriisopropoxysilane NALDI: [(M-HF)+Na] + at m/z 555.091 TM-DESI: [M+H] + at m/z 553.1429 Si OC 3 H 7 H 7 C 3 O C 8 H 4 F 13 OC 3 H 7 Si OC 3 H 7 H 7 C 3 O C 8 H 4 F 13 OC 3 H 7 Si O Si OH F 13 H 4 C 8 OC 3 H 7 OC 3 H 7 OC 3 H 7 C 8 H 4 F 13 Si O Si OH F 13 H 4 C 8 OC 3 H 7 OC 3 H 7 OC 3 H 7 C 8 H 4 F 13 Si O Si OC 3 H 7 F 13 H 4 C 8 OC 3 H 7 O OC 3 H 7 C 8 H 4 F 13 Si H 7 C 3 O C 8 H 4 F 13 OC 3 H 7 Si O Si OC 3 H 7 F 13 H 4 C 8 OC 3 H 7 O OC 3 H 7 C 8 H 4 F 13 Si H 7 C 3 O C 8 H 4 F 13 OC 3 H 7 OC H F CHF F Si O Si 3 7 13 H 4 C 8 O O OC 3 H 7 8 4 13 Si O C 8 H 4 F 13 OC 3 H 7 Si 13 H 4 C 8 OC 3 H 7 OC H F CHF F Si O Si 3 7 13 H 4 C 8 O O OC 3 H 7 8 4 13 Si O C 8 H 4 F 13 OC 3 H 7 Si 13 H 4 C 8 OC 3 H 7 Si O Si 3 7 13 H 4 C 8 O O OC 3 H 7 8 4 13 Si O C 8 H 4 F 13 OC 3 H 7 Si 13 H 4 C 8 OC 3 H 7 n Si O O O C 8 H 4 F 13 X X X X = H, C 3 H 7 or C 8 H 4 F 13 O 2 Si-Y where Y = H or C 3 H 7 General formula: n Si O O O C 8 H 4 F 13 X X X X = H, C 3 H 7 or C 8 H 4 F 13 O 2 Si-Y where Y = H or C 3 H 7 General formula: Si O O O C 8 H 4 F 13 X X X X = H, C 3 H 7 or C 8 H 4 F 13 O 2 Si-Y where Y = H or C 3 H 7 Si O O O C 8 H 4 F 13 X X X X = H, C 3 H 7 or C 8 H 4 F 13 O 2 Si-Y where Y = H or C 3 H 7 General formula: [(M-HF)+Na] + at m/z 963.098 OCHCHF Si O Si 3 7 F 13 H 4 C 8 OC 3 H 7 OC 3 H 7 OC 3 H 7 8 4 13 Si O Si 3 7 F 13 H 4 C 8 OC 3 H 7 OC 3 H 7 OC 3 H 7 8 4 13 Silane Disiloxane NALDI: [M+NH 4 ] + at m/z 1020.2033 TM-DESI: Trisiloxane NALDI: [(M-HF)+Na] + at m/z 1455.183 TM-DESI: [M+NH 4 ] + at m/z 1470.2357 Tetrasiloxane NALDI: [(M-HF)+Na] + at m/z 1803.064 Hydrolysates and condensates of hexadecyltriethoxysilane Si O O O C 16 H 33 X X X n X = H, C 2 H 5 orC 16 H 33 O 2 Si-Y where Y = H or C 2 H 5 General formula: Si O Si OH H 33 C 16 OC 2 H 5 O OC 2 H 5 C 16 H 33 Si H 5 C 2 O C 16 H 33 OH Si O Si OH H 33 C 16 OC 2 H 5 OC 2 H 5 OC 2 H 5 C 16 H 33 Si OC 2 H 5 H 5 C 2 O C 16 H 33 OC 2 H 5 [(M+Na] + at m/z 383.303 Silane Disiloxane Trisiloxane Tetrasiloxane Si OC 2 H 5 HO C 16 H 33 OC 2 H 5 NALDI: TM-DESI: [M+H] + at m/z 389.3447 NALDI: [(M+Na] + at m/z 697.566 TM-DESI: [M+H] + at m/z 675.5760 NALDI: [(M+Na] + at m/z 983.776 NALDI: [(M+Na] + at m/z 1241.910 S i O S i O H 3 3 C 1 6 O C 2 H 5 O O H C 1 6 H 3 3 S i H 5 C 2 O C 1 6 H 3 3 O H S i H O O H C 1 6 H 3 3 Hydrolysates and condensates of hexadecyltriethoxysilane Si O O O C 16 H 33 X X X n X = H, C 2 H 5 orC 16 H 33 O 2 Si-Y where Y = H or C 2 H 5 General formula: Si O O O C 16 H 33 X X X n X = H, C 2 H 5 orC 16 H 33 O 2 Si-Y where Y = H or C 2 H 5 Si O O O C 16 H 33 X X X n X = H, C 2 H 5 orC 16 H 33 O 2 Si-Y where Y = H or C 2 H 5 General formula: Si O Si OH H 33 C 16 OC 2 H 5 O OC 2 H 5 C 16 H 33 Si H 5 C 2 O C 16 H 33 OH Si O Si OH H 33 C 16 OC 2 H 5 OC 2 H 5 OC 2 H 5 C 16 H 33 Si OC 2 H 5 H 5 C 2 O C 16 H 33 OC 2 H 5 [(M+Na] + at m/z 383.303 Silane Disiloxane Trisiloxane Tetrasiloxane Si OC 2 H 5 HO C 16 H 33 OC 2 H 5 NALDI: TM-DESI: [M+H] + at m/z 389.3447 NALDI: [(M+Na] + at m/z 697.566 TM-DESI: [M+H] + at m/z 675.5760 NALDI: [(M+Na] + at m/z 983.776 NALDI: [(M+Na] + at m/z 1241.910 S i O S i O H 3 3 C 1 6 O C 2 H 5 O O H C 1 6 H 3 3 S i H 5 C 2 O C 1 6 H 3 3 O H S i H O O H C 1 6 H 3 3 Si O Si OH H 33 C 16 OC 2 H 5 O OC 2 H 5 C 16 H 33 Si H 5 C 2 O C 16 H 33 OH Si O Si OH H 33 C 16 OC 2 H 5 O OC 2 H 5 C 16 H 33 Si H 5 C 2 O C 16 H 33 OH Si O Si OH H 33 C 16 OC 2 H 5 OC 2 H 5 OC 2 H 5 C 16 H 33 Si O Si OH H 33 C 16 OC 2 H 5 OC 2 H 5 OC 2 H 5 C 16 H 33 Si OC 2 H 5 H 5 C 2 O C 16 H 33 OC 2 H 5 Si OC 2 H 5 H 5 C 2 O C 16 H 33 OC 2 H 5 [(M+Na] + at m/z 383.303 Silane Disiloxane Trisiloxane Tetrasiloxane Si OC 2 H 5 HO C 16 H 33 OC 2 H 5 Si OC 2 H 5 HO C 16 H 33 OC 2 H 5 NALDI: TM-DESI: [M+H] + at m/z 389.3447 NALDI: [(M+Na] + at m/z 697.566 TM-DESI: [M+H] + at m/z 675.5760 NALDI: [(M+Na] + at m/z 983.776 NALDI: [(M+Na] + at m/z 1241.910 S i O S i O H 3 3 C 1 6 O C 2 H 5 O O H C 1 6 H 3 3 S i H 5 C 2 O C 1 6 H 3 3 O H S i H O O H C 1 6 H 3 3 333.2834 361.3129 389.3447 675.5760 647.5445 0 1 2 3 4 5 6 100 200 300 400 500 600 m/z x10 4 Intens. [a.u.] Disiloxanes Silanes 411.3249 [M 1 +Na] + [M 1 +H] + [M 2 +H] + [M 3 +Na] + 333.2834 361.3129 389.3447 675.5760 647.5445 0 1 2 3 4 5 6 100 200 300 400 500 600 m/z x10 4 Intens. [a.u.] 333.2834 361.3129 389.3447 675.5760 647.5445 0 1 2 3 4 5 6 100 200 300 400 500 600 m/z x10 4 Intens. [a.u.] Disiloxanes Silanes 411.3249 [M 1 +Na] + [M 1 +H] + [M 2 +H] + [M 3 +Na] + Polypropylene mesh MS-inlet (-4.5 kV) Sprayer angle fixed at 0º Grounded sprayer TM-DESI on a Bruker micrOTOF-Q instrument Results 449.390 1455.183 963.098 1353.080 555.091 1803.064 685.467 2188.989 2935.669 0 1 2 3 4 x10 4 Intens. [a.u.] 500 1000 1500 2000 2500 3000 m/z 1455.183 1353.080 1433.200 1413.129 1311.028 1391.149 1475.258 1331.088 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1250 1300 1350 1400 1450 Silanes Disiloxanes Trisiloxanes Tetrasiloxanes [M 1 +Na] + [(M 1 -HF)+Na] + [M 2 +Na] + [(M 2 -HF)+Na] + [(M 3 -HF)+Na] + [(M 4 -HF)+Na] + Trisiloxanes 449.390 1455.183 963.098 1353.080 555.091 1803.064 685.467 2188.989 2935.669 0 1 2 3 4 x10 4 Intens. [a.u.] 500 1000 1500 2000 2500 3000 m/z 1455.183 1353.080 1433.200 1413.129 1311.028 1391.149 1475.258 1331.088 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1250 1300 1350 1400 1450 449.390 1455.183 963.098 1353.080 555.091 1803.064 685.467 2188.989 2935.669 0 1 2 3 4 x10 4 Intens. [a.u.] 500 1000 1500 2000 2500 3000 m/z 449.390 1455.183 963.098 1353.080 555.091 1803.064 685.467 2188.989 2935.669 0 1 2 3 4 x10 4 Intens. [a.u.] 500 1000 1500 2000 2500 3000 m/z 1455.183 1353.080 1433.200 1413.129 1311.028 1391.149 1475.258 1331.088 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1250 1300 1350 1400 1450 1455.183 1353.080 1433.200 1413.129 1311.028 1391.149 1475.258 1331.088 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1250 1300 1350 1400 1450 Silanes Disiloxanes Trisiloxanes Tetrasiloxanes [M 1 +Na] + [(M 1 -HF)+Na] + [M 2 +Na] + [(M 2 -HF)+Na] + [(M 3 -HF)+Na] + [(M 4 -HF)+Na] + Trisiloxanes 697.566 430.931 983.776 1241.910 1528.020 1814.083 2101.103 2387.088 2673.054 2986.989 0.0 0.5 1.0 1.5 2.0 2.5 x10 4 Intens. [a.u.] 500 1000 1500 2000 2500 3000 m/z 697.566 669.533 725.598 641.498 691.512 719.545 0.0 0.5 1.0 1.5 620 640 660 680 700 720 383.303 Silanes Disiloxanes Trisiloxanes Tetra Penta Hexa Hepta Octa Nona Deca Trisiloxanes [M 1 +Na] + [(M 2 +Na)Na] + [(M 3 +Na)Na] + [M 2 +Na] + [M 3 +Na] + [M 4 +Na] + 697.566 430.931 983.776 1241.910 1528.020 1814.083 2101.103 2387.088 2673.054 2986.989 0.0 0.5 1.0 1.5 2.0 2.5 x10 4 Intens. [a.u.] 500 1000 1500 2000 2500 3000 m/z 697.566 669.533 725.598 641.498 691.512 719.545 0.0 0.5 1.0 1.5 620 640 660 680 700 720 383.303 697.566 430.931 983.776 1241.910 1528.020 1814.083 2101.103 2387.088 2673.054 2986.989 0.0 0.5 1.0 1.5 2.0 2.5 x10 4 Intens. [a.u.] 500 1000 1500 2000 2500 3000 m/z 697.566 669.533 725.598 641.498 691.512 719.545 0.0 0.5 1.0 1.5 620 640 660 680 700 720 669.533 725.598 641.498 691.512 719.545 0.0 0.5 1.0 1.5 620 640 660 680 700 720 383.303 Silanes Disiloxanes Trisiloxanes Tetra Penta Hexa Hepta Octa Nona Deca Trisiloxanes [M 1 +Na] + [(M 2 +Na)Na] + [(M 3 +Na)Na] + [M 2 +Na] + [M 3 +Na] + [M 4 +Na] + 469.0489 1020.2033 1428.1904 0.0 0.5 1.0 1.5 200 400 600 800 1000 1200 1400 m/z x10 4 Intens. [a.u.] 961.1275 978.1544 1003.1771 1020.2033 0.0 0.5 1.0 1.5 950 960 970 980 990 1000 1010 1020 Silanes Disiloxanes Disiloxanes Trisiloxanes [M 1 +NH 4 ] + [M 1 +H] + [M 2 +H] + [M 2 +NH 4 ] + 469.0489 1020.2033 1428.1904 0.0 0.5 1.0 1.5 200 400 600 800 1000 1200 1400 m/z x10 4 Intens. [a.u.] 469.0489 1020.2033 1428.1904 0.0 0.5 1.0 1.5 200 400 600 800 1000 1200 1400 m/z x10 4 Intens. [a.u.] 961.1275 978.1544 1003.1771 1020.2033 0.0 0.5 1.0 1.5 950 960 970 980 990 1000 1010 1020 961.1275 978.1544 1003.1771 1020.2033 0.0 0.5 1.0 1.5 950 960 970 980 990 1000 1010 1020 Silanes Disiloxanes Disiloxanes Trisiloxanes [M 1 +NH 4 ] + [M 1 +H] + [M 2 +H] + [M 2 +NH 4 ] +

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Page 1: Desorption ionization analysis of nano film products for ... film... · Desorption ionization analysis of nano film products for surface coating: A comparison of NALDI and TM-DESI

OverviewTwo NanoFilm Products (NFPs) were analysed using two different desorption ionization techniques, Nano Assisted Laser Desoption Ionization (NALDI) and Tranmission Mode Desorption Electrospray Ionization (TM-DESI). Both methods worked well and the NFPs were found to contain hydrolysates and condensates of organo-functionalised silanes.

Above:Silanes and siloxanes in NFP 1 (floor coating).Below: Silanes and siloxanes in NFP 2 (tile coating)

NALDINALDI is a new type of ionization technique for MALDI-type instruments comprising targets of inorganic nano structures coated with a hydrophobic, organic layer that facilitates sample deposition and Laser Desorption Ionization (LDI) performance (1). They absorb laser energy causing LDI without need for a matrix. Thus analysis of small molecules (e.g.100-2000 Da) deposited upon the target is possible without matrix interference.

TM-DESITM-DESI is an alternative mode of operation for DESI analysis (2). An electrospray is transmitted through a sampling mesh (e.g. Polypropylene) at 0° angle between spray tip, sample mesh and capillary inlet. Before analysis, the sample is applied to the sample mesh from where it is desorbed by the spray during analysis. This is a simpler approach than traditional DESI for the analysis of liquid samples, since the number of variables to be optimized are reduced.

Water dropplets on coated surfaces

Above: TM-DESI spectrum of NFP 1 (floor coating)Below: TM-DESI spectrum of NFP 2 (tile coating)

Above: NALDI spectrum of NFP 1 (floor coating)Below: NALDI spectrum of NFP 2 (tile coating)

References(1) Daniels RH, Dikler S, Li E, Stacey C. Break Free of the Matrix:

Sensitive and Rapid Analysis of Small Molecules Using Nanostructured Surfaces and LDI-TOF Mass Spectrometry. Journal of the Association for Laboratory Automation 2008 Dec;13(6):314-21.

(2) Chipuk JE, Brodbelt JS. Transmission Mode Desorption Electrospray Ionization. Journal of the American Society for Mass Spectrometry 2008 Nov;19(11):1612-20.

ExperimentalNALDI NFP was diluted 10 times with 2-propanol (NFP 1) or ethanol (NFP 2) and a small amount (few crystals in 10 ml) of NaTFA was added. 1-2 µl of the resulting solution was applied to the NALDI target and allowed to dry at room temperature. Analysis was carried out on a Bruker Autoflex II MALDI-TOF. The mass accuracy was better than 10 ppm for the analysis NFP 1 and better than 30 ppm for the analysis of NFP 2.

TM-DESIA 3 x 3 cm polypropylene mesh (open space: 297 µm) was dipped into undiluted NFP and then analysed directly hereafter. A solution of methanol/water 1:1 with 1 % formic acid and a few crystals of ammonium acetate was used as electrospray solvent at flow rates of 5-10 µl/min. Nitrogen was used as nebulization gas at a pressure of 10 Bar. The electrospray voltage was -4.5 kV applied to MS inlet capillary which was kept at 250 °C. The TM-DESI experiments were carried out on a Bruker micrOTOF-Q instrument equipped with an in-house built DESI source. The mass accuracy was better than 1.5 ppm.

In case of NFP 2, addition of NaTFA improved signal intensity by a factor 2-3. The ions observed in NALDI analysis of the NFPs were therefore all sodium adducts; NFP 1 mainly yielded ions which had eliminated HF as a neutral loss,

+[(M-HF)+Na] , while NFP 2 yielded both + + [M+Na] and [(M+Na)Na] ions.

•In TM-DESI analysis of NFP 1, ammonia +adducts, [M+NH ] , were more abundant 4

than both the sodium adduct and the quasi molecular ions. Addition of a small amount of ammonium acetate to the electrospray solvent increased the signal intensity by at least 100 times.

+•TM-DESI of NFP 2 resulted in [M+H] ions regardless of the addition of ammonia acetate.

Conclusions•Both NALDI and TM-DESI are suitable for analysis of NFPs based on functionalised silanes.

•NALDI yielded more information on the polysiloxanes; this is probably due to film formation on NALDI target taking place by condensation reactions.

•Addition of salts were critical for the ionization efficiency in both methods.

•The demonstrated usefulness of desorption ionization methods for NFP analysis, form the basis for future studies of the film formation process.

•Both NALDI and TM-DESI analysis of the NFPs showed the silanes and siloxanes of 1H,1H,2H,2H-perfluorooctyltriisopropoxysilane (NFP 1) and hexadecyltriethoxysilane (NFP 2) with different degrees of hydrolyzation and condensation.

•The mass accuracy in NALDI and especially TM-DESI experiments enabled determination of sum formulas which, in combination with MS/MS experiments, facilitated the identification.

•NALDI showed the silanes and their polysiloxanes for both products; up to tetrasiloxanes for NFP 1 and up to decasiloxanes for NFP 2, while TM-DESI showed trisiloxanes for NFP 1 and disiloxanes for NFP 2.

•Addition of NaTFA was found to be critical for the NALDI analysis of NFP 1.

Desorption ionization analysis of nano film products for surface coating: A comparison of NALDI and TM-DESI

1 2 2 1Asger W. Nørgaard , Christian Janfelt , Frants R. Lauritsen and Peder Wolkoff 1) National Research Centre for the Working Environment, Copenhagen, Denmark

2) Faculty of Pharmaceutical Sciences, University of Copenhagen, [email protected]

IntroductionNanoFilm Products (NFPs) are a relatively new type of consumer products for surface coating e.g. bathroom tiles, floors, textiles etc. The products are sprayed onto a surface, whereupon a thin coating is formed during evaporation of the solvent. This coating induces non-stick and in some cases self cleaning properties to the treated surface. In this study, two products, NFP 1 (floor coating) and NFP 2 (tile coating), were selected for analysis by two desorption ionization techniques, Nano Assisted Laser Desorption Ionization (NALDI) and Transmission Mode Desorption Electrospray Ionization (TM-DESI). Both methods are simple to use and require a minimum of sample preparation. The two methods were compared and the results are presented below.

Hydrolysates and condensates of 1H,1H,2H,2H-perfluorooctyltriisopropoxysilane

NALDI: [(M-HF)+Na]+ at m/z 555.091TM-DESI: [M+H]+ at m/z 553.1429

Si

OC3H7

H7C3O

C8H4F13

OC3H7Si O Si

OH

F13H4C8

OC3H7 OC3H7

OC3H7

C8H4F13

Si O Si

OC3H7

F13H4C8

OC3H7 O

OC3H7

C8H4F13

SiH7C3O

C8H4F13

OC3H7

OC H

F

C H F

F

Si O Si

3 7

13H4C8

O O

OC3H7

8 4 13

SiO

C8H4F13

OC3H7Si13H4C8

OC3H7

n

Si OO

O

C8H4F13

X

X X

X = H, C3H7 or C8H4F13O2Si-Y where Y = H or C3H7

General formula:

[(M-HF)+Na]+ at m/z 963.098

OC H C H F

Si O Si

3 7

F13H4C8

OC3H7 OC3H7

OC3H7

8 4 13

Silane DisiloxaneNALDI:

[M+NH4]+ at m/z 1020.2033

TM-DESI:

Trisiloxane

NALDI: [(M-HF)+Na]+ at m/z 1455.183TM-DESI: [M+NH4]+ at m/z 1470.2357

Tetrasiloxane

NALDI: [(M-HF)+Na]+ at m/z 1803.064

Hydrolysates and condensates of 1H,1H,2H,2H-perfluorooctyltriisopropoxysilane

NALDI: [(M-HF)+Na]+ at m/z 555.091TM-DESI: [M+H]+ at m/z 553.1429

Si

OC3H7

H7C3O

C8H4F13

OC3H7Si

OC3H7

H7C3O

C8H4F13

OC3H7Si O Si

OH

F13H4C8

OC3H7 OC3H7

OC3H7

C8H4F13

Si O Si

OH

F13H4C8

OC3H7 OC3H7

OC3H7

C8H4F13

Si O Si

OC3H7

F13H4C8

OC3H7 O

OC3H7

C8H4F13

SiH7C3O

C8H4F13

OC3H7

Si O Si

OC3H7

F13H4C8

OC3H7 O

OC3H7

C8H4F13

SiH7C3O

C8H4F13

OC3H7

OC H

F

C H F

F

Si O Si

3 7

13H4C8

O O

OC3H7

8 4 13

SiO

C8H4F13

OC3H7Si13H4C8

OC3H7

OC H

F

C H F

F

Si O Si

3 7

13H4C8

O O

OC3H7

8 4 13

SiO

C8H4F13

OC3H7Si13H4C8

OC3H7

Si O Si

3 7

13H4C8

O O

OC3H7

8 4 13

SiO

C8H4F13

OC3H7Si13H4C8

OC3H7

n

Si OO

O

C8H4F13

X

X X

X = H, C3H7 or C8H4F13O2Si-Y where Y = H or C3H7

General formula:

n

Si OO

O

C8H4F13

X

X X

X = H, C3H7 or C8H4F13O2Si-Y where Y = H or C3H7

General formula: Si OO

O

C8H4F13

X

X X

X = H, C3H7 or C8H4F13O2Si-Y where Y = H or C3H7

Si OO

O

C8H4F13

X

X X

X = H, C3H7 or C8H4F13O2Si-Y where Y = H or C3H7

General formula:

[(M-HF)+Na]+ at m/z 963.098

OC H C H F

Si O Si

3 7

F13H4C8

OC3H7 OC3H7

OC3H7

8 4 13

Si O Si

3 7

F13H4C8

OC3H7 OC3H7

OC3H7

8 4 13

Silane DisiloxaneNALDI:

[M+NH4]+ at m/z 1020.2033

TM-DESI:

Trisiloxane

NALDI: [(M-HF)+Na]+ at m/z 1455.183TM-DESI: [M+NH4]+ at m/z 1470.2357

Tetrasiloxane

NALDI: [(M-HF)+Na]+ at m/z 1803.064

Hydrolysates and condensates of hexadecyltriethoxysilane

Si O

O

O

C16H33

X

X

X

n

X = H, C2H5 or C16H33O2Si-Y where Y = H or C2H5

General formula:

Si O Si

OH

H33C16

OC2H5 O

OC2H5

C16H33

SiH5C2O

C16H33

OH

Si O Si

OH

H33C16

OC2H5 OC2H5

OC2H5

C16H33

Si

OC2H5

H5C2O

C16H33

OC2H5

[(M+Na]+ at m/z 383.303

Silane Disiloxane

Trisiloxane Tetrasiloxane

Si

OC2H5

HO

C16H33

OC2H5

NALDI:

TM-DESI: [M+H]+ at m/z 389.3447 NALDI: [(M+Na]+ at m/z 697.566TM-DESI: [M+H]+ at m/z 675.5760

NALDI: [(M+Na]+ at m/z 983.776 NALDI: [(M+Na]+ at m/z 1241.910

S i O S i

O

H 3 3 C 1 6

O C 2 H 5O

O H

C 1 6 H 3 3

S iH 5 C 2 O

C 1 6 H 3 3

O H

S iH O O H

C 1 6 H 3 3

Hydrolysates and condensates of hexadecyltriethoxysilane

Si O

O

O

C16H33

X

X

X

n

X = H, C2H5 or C16H33O2Si-Y where Y = H or C2H5

General formula: Si O

O

O

C16H33

X

X

X

n

X = H, C2H5 or C16H33O2Si-Y where Y = H or C2H5

Si O

O

O

C16H33

X

X

X

n

X = H, C2H5 or C16H33O2Si-Y where Y = H or C2H5

General formula:

Si O Si

OH

H33C16

OC2H5 O

OC2H5

C16H33

SiH5C2O

C16H33

OH

Si O Si

OH

H33C16

OC2H5 OC2H5

OC2H5

C16H33

Si

OC2H5

H5C2O

C16H33

OC2H5

[(M+Na]+ at m/z 383.303

Silane Disiloxane

Trisiloxane Tetrasiloxane

Si

OC2H5

HO

C16H33

OC2H5

NALDI:

TM-DESI: [M+H]+ at m/z 389.3447 NALDI: [(M+Na]+ at m/z 697.566TM-DESI: [M+H]+ at m/z 675.5760

NALDI: [(M+Na]+ at m/z 983.776 NALDI: [(M+Na]+ at m/z 1241.910

S i O S i

O

H 3 3 C 1 6

O C 2 H 5O

O H

C 1 6 H 3 3

S iH 5 C 2 O

C 1 6 H 3 3

O H

S iH O O H

C 1 6 H 3 3

Si O Si

OH

H33C16

OC2H5 O

OC2H5

C16H33

SiH5C2O

C16H33

OH

Si O Si

OH

H33C16

OC2H5 O

OC2H5

C16H33

SiH5C2O

C16H33

OH

Si O Si

OH

H33C16

OC2H5 OC2H5

OC2H5

C16H33

Si O Si

OH

H33C16

OC2H5 OC2H5

OC2H5

C16H33

Si

OC2H5

H5C2O

C16H33

OC2H5Si

OC2H5

H5C2O

C16H33

OC2H5

[(M+Na]+ at m/z 383.303

Silane Disiloxane

Trisiloxane Tetrasiloxane

Si

OC2H5

HO

C16H33

OC2H5Si

OC2H5

HO

C16H33

OC2H5

NALDI:

TM-DESI: [M+H]+ at m/z 389.3447 NALDI: [(M+Na]+ at m/z 697.566TM-DESI: [M+H]+ at m/z 675.5760

NALDI: [(M+Na]+ at m/z 983.776 NALDI: [(M+Na]+ at m/z 1241.910

S i O S i

O

H 3 3 C 1 6

O C 2 H 5O

O H

C 1 6 H 3 3

S iH 5 C 2 O

C 1 6 H 3 3

O H

S iH O O H

C 1 6 H 3 3

333.2834

361.3129

389.3447

675.5760

647.5445

0

1

2

3

4

5

6

100 200 300 400 500 600 m/z

x104

Inte

ns

.[a

.u.]

Disiloxanes

Silanes

411.3249

[M1+Na]+

[M1+H]+

[M2+H]+

[M3+Na]+

333.2834

361.3129

389.3447

675.5760

647.5445

0

1

2

3

4

5

6

100 200 300 400 500 600 m/z

x104

Inte

ns

.[a

.u.]

333.2834

361.3129

389.3447

675.5760

647.5445

0

1

2

3

4

5

6

100 200 300 400 500 600 m/z

x104

Inte

ns

.[a

.u.]

Disiloxanes

Silanes

411.3249

[M1+Na]+

[M1+H]+

[M2+H]+

[M3+Na]+

Polypropylene mesh

MS-inlet (-4.5 kV)

Sprayer angle fixed at 0º

Grounded sprayer

TM-DESI on a Bruker micrOTOF-Q instrument

Results

449.390

1455.183

963.098

1353.080

555.091

1803.064

685.467 2188.989 2935.6690

1

2

3

4

x104

Inte

ns.

[a.u

.]

500 1000 1500 2000 2500 3000m/z

1455.183

1353.080

1433.200

1413.1291311.028

1391.149 1475.2581331.0880.00

0.25

0.50

0.75

1.00

1.25

1.50

1250 1300 1350 1400 1450

Silanes

Disiloxanes

Trisiloxanes

Tetrasiloxanes

[M1+Na]+

[(M1-HF)+Na]+

[M2+Na]+

[(M2-HF)+Na]+

[(M3-HF)+Na]+

[(M4-HF)+Na]+

Trisiloxanes

449.390

1455.183

963.098

1353.080

555.091

1803.064

685.467 2188.989 2935.6690

1

2

3

4

x104

Inte

ns.

[a.u

.]

500 1000 1500 2000 2500 3000m/z

1455.183

1353.080

1433.200

1413.1291311.028

1391.149 1475.2581331.0880.00

0.25

0.50

0.75

1.00

1.25

1.50

1250 1300 1350 1400 1450

449.390

1455.183

963.098

1353.080

555.091

1803.064

685.467 2188.989 2935.6690

1

2

3

4

x104

Inte

ns.

[a.u

.]

500 1000 1500 2000 2500 3000m/z

449.390

1455.183

963.098

1353.080

555.091

1803.064

685.467 2188.989 2935.6690

1

2

3

4

x104

Inte

ns.

[a.u

.]

500 1000 1500 2000 2500 3000m/z

1455.183

1353.080

1433.200

1413.1291311.028

1391.149 1475.2581331.0880.00

0.25

0.50

0.75

1.00

1.25

1.50

1250 1300 1350 1400 1450

1455.183

1353.080

1433.200

1413.1291311.028

1391.149 1475.2581331.0880.00

0.25

0.50

0.75

1.00

1.25

1.50

1250 1300 1350 1400 1450

Silanes

Disiloxanes

Trisiloxanes

Tetrasiloxanes

[M1+Na]+

[(M1-HF)+Na]+

[M2+Na]+

[(M2-HF)+Na]+

[(M3-HF)+Na]+

[(M4-HF)+Na]+

Trisiloxanes

697.566

430.931

983.7761241.910

1528.020

1814.083

2101.103

2387.0882673.054

2986.989

0.0

0.5

1.0

1.5

2.0

2.5

x104

Inte

ns.[a

.u.]

500 1000 1500 2000 2500 3000m/z

697.566

669.533

725.598

641.498691.512 719.545

0.0

0.5

1.0

1.5

620 640 660 680 700 720

383.303Silanes

Disiloxanes

TrisiloxanesTetra

Penta

Hexa

Hepta

OctaNona Deca

Trisiloxanes

[M1+Na]+

[(M2+Na)Na]+[(M3+Na)Na]+

[M2+Na]+

[M3+Na]+

[M4+Na]+

697.566

430.931

983.7761241.910

1528.020

1814.083

2101.103

2387.0882673.054

2986.989

0.0

0.5

1.0

1.5

2.0

2.5

x104

Inte

ns.[a

.u.]

500 1000 1500 2000 2500 3000m/z

697.566

669.533

725.598

641.498691.512 719.545

0.0

0.5

1.0

1.5

620 640 660 680 700 720

383.303

697.566

430.931

983.7761241.910

1528.020

1814.083

2101.103

2387.0882673.054

2986.989

0.0

0.5

1.0

1.5

2.0

2.5

x104

Inte

ns.[a

.u.]

500 1000 1500 2000 2500 3000m/z

697.566

669.533

725.598

641.498691.512 719.545

0.0

0.5

1.0

1.5

620 640 660 680 700 720

669.533

725.598

641.498691.512 719.545

0.0

0.5

1.0

1.5

620 640 660 680 700 720

383.303Silanes

Disiloxanes

TrisiloxanesTetra

Penta

Hexa

Hepta

OctaNona Deca

Trisiloxanes

[M1+Na]+

[(M2+Na)Na]+[(M3+Na)Na]+

[M2+Na]+

[M3+Na]+

[M4+Na]+

469.0489

1020.2033

1428.1904

0.0

0.5

1.0

1.5

200 400 600 800 1000 1200 1400 m/z

x104

Inte

ns.

[a.u

.]

961.1275

978.1544

1003.1771

1020.2033

0.0

0.5

1.0

1.5

950 960 970 980 990 1000 1010 1020

Silanes

DisiloxanesDisiloxanes

Trisiloxanes

[M1+NH4]+

[M1+H]+

[M2+H]+

[M2+NH4]+

469.0489

1020.2033

1428.1904

0.0

0.5

1.0

1.5

200 400 600 800 1000 1200 1400 m/z

x104

Inte

ns.

[a.u

.]

469.0489

1020.2033

1428.1904

0.0

0.5

1.0

1.5

200 400 600 800 1000 1200 1400 m/z

x104

Inte

ns.

[a.u

.]

961.1275

978.1544

1003.1771

1020.2033

0.0

0.5

1.0

1.5

950 960 970 980 990 1000 1010 1020

961.1275

978.1544

1003.1771

1020.2033

0.0

0.5

1.0

1.5

950 960 970 980 990 1000 1010 1020

Silanes

DisiloxanesDisiloxanes

Trisiloxanes

[M1+NH4]+

[M1+H]+

[M2+H]+

[M2+NH4]+