A.V. Pento – Ph.D.(Phys.-Math.), Senior Research Scientist, 
GPI RAS (Moscow)
E-mail: pentan@mail.ru

I.I. Kuzmin – Junior Research Scientist, 
Vernadsky Institute of Geochemistry and Analytical Chemistry (Moscow)
E-mail: kuzmin.ilya.92@gmail.com

A.R. Mukhamatnurova – Post-graduate Student, 
National Research Nuclear University «MEPhI» (Moscow)
E-mail: alisson94@mail.ru

A laser mass spectrometer reflectron for two-pulse two-frequency mode implementation in SALDI (Surface Assisted Laser Desorption and Ionization) is described in details. Experimental results for desorption of ions of organic compounds by 351 nm and 263 nm pulsed laser radiation are presented.
A laser mass spectrometer reflectron for two-pulse two-frequency mode implementation in SALDI (Surface Assisted Laser Desorption and Ionization) is described in details. 523 nm, 351 nm and 263 nm pulsed laser radiation can be used for desorption of ions. A SALDI-active layer is being produced on a surface of crystalline silicon inside the vacuum chamber of the mass-spectrometer under pulsed laser irradiation. Gas-phase analyte deposition on the emitter active surface can be performed inside the chamber of the mass spectrometer. Experimental results for desorption of ions of organic compounds by 351 nm and 263 nm pulsed laser radiation are presented.

1. Aleksandrov M.L., Gall L.N., Krasnov N.V., Nikolaev V.I., Shkurov V.A. Ekstraktsiya ionov iz rastvorov pri atmosfernom davlenii – novyi metod mass-spektrometricheskogo analiza. DAN SSSR. 1984. T. 277. № 2. S. 379−383.
2. Fenn J.B., Mann M., Meng C.K., Wong S.F., Whitehouse C.M. Electrospray ionization for mass spectrometry of large biomolecules. Science. 1989. V. 246. № 4926. P. 64−71.
3. Karas M., Bahr U., Hillenkamp F. UV laser matrix desorption/ionization mass spectrometry of proteins in the 100.000 dalton range. International Journal of Mass Spectrometry and Ion Processes. 1989. V. 92. P. 231−242.
4. Nelson R.W., Dogruel D., Williams P. Detection of human IgM at m/z ~ 1 MDa. Rapid Communications in Mass Spectrometry. 1995. V. 9. № 7. P. 625−625.
5. Murray Kermit K., Boyd Robert K., Eberlin Marcos N., Langley G.J., Li L., Naito Y. Definitions of terms relating to mass spectrometry (IUPAC Recommendations 2013). Editor. 2013. P. 1515.
6. Wei J., Buriak J.M., Siuzdak G. Desorption-ionization mass spectrometry on porous silicon. Nature. 1999. V. 399. № 6733. P. 243−246.
7. Korte A.R., Morris N.J., Vertes A. High Throughput Complementary Analysis and Quantitation of Metabolites by MALDI- and Silicon Nanopost Array-Laser Desorption/Ionization-Mass Spectrometry. Analytical Chemistry. 2019.10.1021/acs.analchem.8b05074.
8. Chen Y., Vertes A. Adjustable fragmentation in laser desorption/ionization from laser-induced silicon microcolumn arrays. Anal. Chem. 2006. V. 78. № 16. P. 5835−5844.
9. Alimpiev S., Grechnikov A., Sunner J., Karavanskii V., Simanovsky Y., Zhabin S., Nikiforov S. On the role of defects and surface chemistry for surface-assisted laser desorption ionization from silicon. J. Chem. Phys. 2008. V. 128. № 1. P. 014711−014719.
10. Zhabin S.N., Pento A.V., Grechnikov A.A., Borodkov A.S., Sartakov B.G., Simanovsky Y.O., Nikiforov S.M., Alimpiev S.S. On the role of laser irradiation in the processes of laser desorption/ionisation from silicon surfaces. Quantum Electronics. 2011. V. 41. № 9. P. 835−842.
11. Pat. RF № 2426191. 2011. Sposob formirovaniya emittera ionov dlya lazernoi desorbtsii-ionizatsii khimicheskikh soedinenii. Grechnikov A.A., Alimpiev S.S., Nikiforov S.M., Simanovskii Ya.O.
12. Liu P.L., Yen R., Bloembergen N., Hodgson R.T. Picosecond laser-induced melting and resolidification morphology on Si. Applied Physics Letters. 1979. V. 34. № 12. P. 864−866.
13. Wiley W.C., McLaren I.H. Time-of-Flight Mass Spectrometer with Improved Resolution. Review of Scientific Instruments. 1955. V. 26. № 12. P. 1150−1157.
14. Belay A., Ture K., Redi M., Asfaw A. Measurement of caffeine in coffee beans with UV/vis spectrometer. Food chemistry. 2008. V. 108. № 1. P. 310−315.
15. Bahrami H., Tabrizchi M., Farrokhpour H. Protonation of caffeine: A theoretical and experimental study. Chemical Physics. 2013. V.415. P. 222−227.
16. Proton Affinity Evaluation, NIST Chemistry WebBook, NIST Standard Reference Database. Edited by P.J. Linstrom and W.G. Mallard. Hunter E.P., Lias S.G. Gaithersburg: National Institute of Standards and Technology. 2005. 243 p.
17. Berton M., Mello R., Acerete R., González Núñez M.E. Photolysis of Tertiary Amines in the Presence of CO2: The Paths to Formic Acid, α-Amino Acids and 1, 2-Diamines. The Journal of organic chemistry. 2017. V. 83. № 1. P. 96−103.
18. Iweibo I., Oderinde R.A., Faniran J.A. Electronic absorption spectra and structures of aniline and its 4-chloro, pentafluoro and pentachloro derivatives. Spectrochimica Acta Part A: Molecular Spectroscopy. 1982. V. 38. № 1. P. 1−7.