Fast-LC determination of 1-methyl-1H-tetrazole-5-thiol in human plasma with column-switching sample clean-up

A simple, fast and sensitive method for the quantitative determination of 1-methyl-1H-tetrazole-5-thiol using HPLC is reported. Samples are deproteinated by plasma water filtration and injected into a HPLC system capable of column switching and backflushing the analytical column. The limit of quantitation was determined to be 70 ng ml −1 and the limit of detection 22 ng ml −1. Between-day precision (expressed as percent coefficient of variation of standard curve slopes was ±3.5% with a range of within-day percent coefficient of variations from 0.28 to 1.4%. Recovery and precision of spiked control samples was 96 ± 7% over a concentration range of 630–6300 ng ml −1.