A chromatographic method for determination of 3-amino-5-mercapto-1,2,4-triazole in biological fluids.
Depree GJ; Siegel PD
Toxicologist 2001 Mar; 60(1):53
The chemical, 3-amino-5-mercapto-1,2,4-triazole (AMT) is used in the manufacture of the pesticide, flumetsulam. Analysis of AMT in biological fluids requires a sensitive and selective analytical method. Direct quantitation of AMT using HPLC coupled with UV detection was found to be unsuitable due to poor sensitivity and retention of AMT on reverse phase materials. Detection of AMT at 215 nm resulted in a limit of detection of approximately 900 pmole and a linear working range of 5000-83000 pmole. AMT is not suitable for GC analysis due to its high boiling point. To overcome these limitations a HPLC-fluorescent method was devised which takes advantage of the free thiol present in AMT. The free thiol was conjugated to the probe, monobromobimane (MBB), resulting in a highly fluorescent species. The AMT-MBB derivative can be analyzed directly or further purified by solid phase C18 extraction (SPE). Excellent recovery was observed when the SPE column was eluted with acetonitrile or methanol. The samples were analyzed by reverse phase (C18) HPLC using a binary mobile phase gradient of acetonitrile/water. The limit of detection of AMT-MBB was approximately 10 pmole with a normal linear working range of 86-4300 pmole. Preliminary work has demonstrated that biological samples containing low levels of AMT may be concentrated by SPE. This fluorescent HPLC method should be applicable for the determination of AMT in biological fluids from toxicokinetic studies and may have potential industrial hygiene application.
Chromatographic analysis; Fluids; Pesticides; Pesticides and agricultural chemicals; Analytical methods; Sensitivity testing; Biological factors; Sampling; Industrial hygiene
The Toxicologist. Society of Toxicology 40th Annual Meeting, March 25-29, 2001, San Francisco, California