2-CHLORO-1-METHYLQUINOLINIUM TETRAFLUOROBORATE AS AN EFFECTIVE AND THIOL SPECIFIC UV-TAGGING REAGENT FOR LIQUID CHROMATOGRAPHY

Abstract

A new, highly reactive, and thiol specific derivatization reagent for liquid chromatographic analysis has been developed. The reagent, 2-chloro-1-methylquinolinium tetrafluoroborate, reacts instantaneously with hydrophilic thiols in water under mild conditions. The 2-S-quinolinium derivatives, resulting from this reaction, are stable thioethers exhibiting well defined absorption maximum at 348 nm and molar absorptivity coefficient about 2 × 10[4] Bald, E., Sypniewski, S., Drzewoski, J. and Stepień, J. 1996. Chromatogr. B, 681: 283[Crossref], [PubMed] , [Google Scholar] L mol −1cm−1. It is shown that under reversed-phase high performance liquid chromatography conditions with gradient elution, six thiols possessing different functional groups, can be baseline separated and quantified within 4 min in one analytical run. The lower limits of detection and quantitation of the analytes (20 μL injection volume) are within 0.3–1.5 pmol and 0.5–4.0 pmol, respectively. The assays are linear in the range of 0.025–8 nmol/mL with correlation coefficients values close to 0.9999. Synthesis of 2-chloro-1-methylquinolinium tetrafluoroborate, as well as isolation of the 2-S-quinolinium derivative of one model thiol, are described.