A new highly reactive, and thiol specific derivatization reagent for liquid
chromatographic analysis has been developed. The reagent, 2-chloro-1-methy
lquinolinium tetrafluoroburate, reacts instantaneously with hydrophilic thi
ols in water under mild conditions. The 2-S-quinolinium derivatives, result
ing from this reaction, are stable thioethers exhibiting well defined absor
ption maximum at 348 nm and molar absorptivity coefficient about 2 x 10(4)
L mol(-1) cm(-1). It is shown that under reversed-phase high performance li
quid chromatography conditions with gradient elution, six thiols possessing
different functional groups, can be baseline separated and quantified with
in 4 min in one analytical run.
The lower limits of detection and quantitation of the analytes (20 muL inje
ction volume) are within 0.3-1.5 pmol and 0.5-4.0 pmol, respectively. The a
ssays are linear in the range of 0.025-8 nmol/mL with correlation coefficie
nts values close to 0.9999.
Synthesis of 2-chloro-1-methylquinolinium tetrafluoroborate, as well as iso
lation of the 2-S-quinolinium derivative of one model thiol, are described.