Application of sol-gel method in poly(ethyleneglycol) coating to multicapillary columns
Abstract
Polyglycols are referred to the most frequently used stationary phases (SP) in gas chromatography due to its high specificity to polar & polarized sorbates. However they have some typical shortcomings, limiting their wider application, such as: a narrow temperature range, instability in oxidation, limited operating time, etc. One of the ways to improve the field-performance data of poly(ethylene glycol) (PEG) capillary columns provides the use of sol-gel technology based on hydrolysis products of alkoxysilanes. During the sol-gel reactions on a surface of capillaries a layer polysilicic acid is being formed. This layer consists of the stationary phase molecules with the covalent bonds partially formed. As a result it becomes non-extractable to provide for the columns high thermal stability and operational sustainability. The multicapillary PEG columns with Carbowax 20M™ also have the shortcomings typical for polyglycols. The study investigates the opportunity of PEG coating to the multicapillary columns with the sol-gel method being used to improve its field-performance data.
In the current study there are direct multi-channeled tubes made of C89-1 type glass (with a capillary ID about 40 um) used as a raw material. The precursor used for the coating of the SP is prepared according to the sol-gel technology from tetraethoxysilane, trifluoroacetic acid as a catalyst and methylene chloride containing Carbowax 20M. The sol-gel to be ready the mixture was kept at room temperature for some time, then it was diluted by chloroform. Prepared solution was used to coat the SP to the multicapillary columns by the static low pressure method.
At the time of sol-gel being ready from 24 to 36 hours during the coating there are high-efficient MCC with the immobilized SP as a result (3000-4200 theoretical plates for the sorbates with the retention factor k > 10 and the length ≈ 0,25 m). The chromatographic characteristics of such columns were close to the ones, made by basic technology. During for more or less time of sol-gel being ready the gas chromatography columns with less selectivity or less degree of immobilization are made as a result.
The study of sol-gel MCCs characteristics revealed its increased thermal stability as it work out at 240°C during 20 hours relatively unchanged, while the others made by basic technology degrade in 3 hours. In addition, the investigated MCCs demonstrate low bleeding.
So, during the coating of SP Carbowax 20M to multicapillary tubes with the sol-gel method being used there are high efficient MCCs with the stationary phase with an immobilized coat. The immobilization degree of stationary phase with the optimal time of 24-36 h. for sol-gel is being ready accounts for 80-92%. The columns characterized by increased thermal stability and reduced bleeding than the ones obtained by the basic technology. Apparently, this result caused by the stable three-dimensional organic-inorganic polymer formed from the PEG along with the products of hydrolysis of tetraethoxysilane
Downloads
References
2. Korol' A.N. Nepodvizhnye fazy v gazozhidkostnoi khromatografi. Moscow, Khimiya, 1985, 240 p.
3. Evans M.B., Smith J.E., J. Chromatogr., 1968, Vol. 36, pp. 489-503.
4. Yancey J.A., J. Chromatogr. Sci., 1994, Vol. 32, No 9, pp. 403-413.
5. Barry E.F. Columns: Packed and Capillary; Column Selection in Gas Chromatography: Modern practice of gas chromatography. 4th ed. Edit. Grob R.L., Barry E.F., Wiley, 2004, pp. 148-164
6. Yancey J. A., J. Chromatogr. Sci., 1985, Vol. 23, No 8, pp. 370-377.
7. Ciganek M.; Dressler M.; Teply J. J., Chromatogr., 1991, Vol. 588, pp. 225-230.
8. Keller R. A., Bate R., Costa, B., Forman P. J., Chromatogr., 1962, Vol. 8, pp.157-177.
9. Conder, J., Fruitwala N., Shingari, K., J., Chromatogr., 1983, Vol. 269, pp.171-178.
10. Borek V., Hubacek J., Rehakova V., Chem. Listy, 1985, Vol. 79, p. 364.
11. Blomberg L. G., J. Microcol. Sep., 1990, Vol. 2, pp. 62-68.
12. Mukhina V.P., Berezkin V.G., Levin Ya.A., Russian chemical reviews, 1998, Vol. 67, № 12. pp. 1164-1174.
13. Guo Y., Colon L.A., Anal. Chem., 1995, Vol. 67, pp. 2511-2516.
14. Wang D., Chong S.L., Malik A., Anal. Chem., 1997, Vol. 69, pp. 4566-4576.
15. Hayes J.D., Malik A., J. Chromatogr. B., 1977, Vol. 695, pp. 3-13.
16. Rodrıguez S.A., Colon L.A., Chem. Mater., 1999, Vol. 11, pp.754-762.
17. Kiridena W., Poole C.F., Koziol W.W., Analyst., 2002, Vol. 127, pp. 1608–1613.
18. Shende C., Kabir A., Townsend E., Malik A., Anal. Chem., 2003, Vol. 75, No 14, pp. 3518-3530.
19. Malik A., Kabir A., Shende C. Patent USA, no. 2007/0062874, 2007.
20. Gu X., Wang Y., Zhang X., Chromatogr., 2005, Vol. 62, No 9/10, pp. 483-491.
22. Technical article: The importance of low bleed columns for GC-MS. URL: http://www.sge.com/uploads/0a/ea/0aeaf7d5c0ae608bbdf5a0ac81c6f100/TA-0063-C.pdf (accessed 30 March 2017)
23. Malik A., Kabir A., Shende C. Patent USA, no. 8685240, 2014.
24. Multicapillary Columns for the Fast Gas Chromatography. URL: http://mcc-chrom.com/ (accessed 30 March 2017)
25. SUPELCO catalog 2000: Chromatography Products for Analysis and Purification. Sigma-Aldrich Co., USA, 2000, p. 38.
26. Naumenko I. I, Soboleva V. K., Sorbtsionnye i khromatograficheskie protsessy (Russ.), 2016, Vol. 16, No. 5, pp. 591-599.
27 Naumenko I. I., Efimenko A. P., Baldin M.N., Gruznov V.M., Sensors & Systems, 2013, No.11, pp. 51-55.
28. Efimenko A. P., Naumenko I. I, Soboleva V. K., Russian J. Phys. Chem., 2007, Vol. 81, No. 3, pp. 488-492.
29. Efimenko A. P., Naumenko I. I., Soboleva V. K. Sprintery v gazovoi khromatografii – polikapillyarnye khromatograficheskie kolonki: Khromatografiya vo blago Rossii. Moscow, Granitsa, 2007, pp. 634-648.
