Synthesis and study of a sorbent for HPLC based on a copolymer of styrene and divinylbenzene modified with gold nanoparticles
Abstract
A new sorbent (CSD-Au-lipoic acid-lysine) for HPLC based on a styrene-divinylbenzene copolymer (CSD) was obtained by adsorption of gold nanoparticles (GNPs) on its surface, followed by modification of lipoic acid grafted with lysine. Self-assembled monolayers are readily formed by the reaction between sulfur, which lipoic acid contains, and gold surfaces. Low-temperature nitrogen adsorption, diffuse reflection spectroscopy,
scanning electron microscopy were used to examine the physical and chemical properties of CSDAu-lipoic acid-lysine, as well as sorbents with lipoic acid-modified GNPs and L-cysteine- modified GNPs (CSD-Au-L-cysteine).
The hydrophobicity of CSD-Au-lipoic acid-lysine, CSD-Au-L-cysteine and unmodified CSD was estimated by the retention of aromatic compounds on the laboratory-made columns with these sorbents. The retention of these non-polar compounds was quite large, but differed slightly for three columns. It can be assumed that the hydrophobic properties of sorbents are determined predominantly by the polymer matrix.
The chromatographic behavior of profens and β-blockers on the obtained sorbents was studied depending on the composition of the mobile phase - the nature of the buffer solution, its concentration and pH, the proportion of organic solvent and its nature. It was established that significant retention factors for both groups of substances are observed using the mixture of acetonitrile and buffer solution as the eluent. Herewith profens are kept longer with a lower content of organic solvent, and β-blockers, on the contrary. Hydrophobic interactions play a significant role in the retention of the studied compounds. The order of elution ofprofens correlates with their hydrophobicity indices logP, logD. This dependence is traced to a lesser extent for β-blockers, due to the additional interactions. It was found that profens, which are organic acids with a pK value of 3.74 - 5.3, are better retained and separated at a pH close to four, since as the pH rises, they dissociate into the carboxyl group and logD decreases. The best chromatographic parameters for β-blockers, which are bases, are obtained at a pH close to seven, since their pKa take values from 8.8 to 9.7. Thus, the reversed-phase retention mechanism predominantly is realized for profens on the studied sorbents, while for β-blockers, it is impossible to distinguish the main influence of one interaction, that is, a complex retention mechanism is implemented.
Downloads
References
2. Palmer C.P., McCarney J.P., Electrophoresis, 2004, Vol. 25, pp. 4086-4094.
3. Moliner-Martinez Y., Cardenas S., Simonet B. M., Valcarcel M., Electrophoresis, 2009,Vol. 30, pp. 169-175. DOI: 10.1002/elps.200800314
4. Nesterenko E.P., Nesterenko P.N., Connolly D. et al., Analyst, 2013, Vol. 138, pp. 4229-4254. DOI: 10.1039/C3AN00508A
5. Ananieva I.A., Elfimova Ya.A., Mazhuga A.G., Rudakovskaya P.G. et al., Sorbtsionnye i khromatograficheskie protsessy, 2011, Vol. 11, No 3, pp. 281-291.
6. Qu Q., Peng S., Mangelings D., Hu X., Yan C., Electrophoresis, 2010, Vol. 31, pp. 556-562. DOI: 10.1002/elps.200900375
7. Liu F.K., Wei G.T., Cheng F.C., Chin. J. Chem. Soc., 2003, Vol. 50, pp. 931-937.
8. Shapovalova E.N., Ananieva I.A., Elfimova Ya.A., Grinyova L.A. et al., Bulletin of the Moscow university. Chemistry series, 2012, Vol. 53, No 2, pp. 108-114.
9. Elfimova Ya.A., Pichugina D.A., Anan’eva I.A., Mazhuga A.G. et al., Journal of Physical Chemistry A, 2012, Vol. 86, No 10, pp. 1623- 1629. DOI: 10.1134/S0036024412100081
10. Elfimova Ya.A., Ananieva I.A., Mazhuga A.G., Shpigun O.A., Zavodskaya laboratoriya. Diagnostika materialov, 2012, Vol. 78, No 6. pp. 20-27.
11. Mahouche-Chergui S., Guerrouache M., Carbonnier B., Chehimi M.M., Colloids and Surfaces A: Physicochem. Eng. Aspects, 2013, Vol. 439, pp. 43-68. DOI:10.1016/j.colsurfa.2013.04.013.
12. Turkevich J., Stevenson P.C., Hillier J., Discuss. Faraday Soc., 1951, Vol. 11, pp. 55-75.
13. Rudakovsky P.G. Diss. cand. chem. science. M., 2015, 185 p.
14. Polyakova Ya.A. Diss. cand. chem. science, M., 2013, 190 p.
15. Amendola V., Meneghetti M., Stener M., Guo Y. et al., Comprehensive Analytical Chemistry, 2014, Vol. 66, pp. 81-152.
16. Dolgonosov A.M., Rudakov O.B., Prudkovsky A.G. Kolonochnaya analiticheskaya hromatografiya: praktika, teoriya, modelirovanie.. SPb., Lan’ Publ., 2015. 468 p.
