Plasma persistence of 2-aminothiazoline-4-carboxylic acid in rat system determined by liquid chromatography tandem mass spectrometry

2-Aminothiazoline-4-carboxylic acid (ATCA) was intravenously injected to rats in order to investigate its plasma distribution. ATCA was extracted from plasma samples by solid phase extraction (SPE) and molecularly imprinted polymer stir bar sorption extraction (MIP-SBSE). Detection and quantification of ATCA were achieved by using liquid chromatography–tandem mass spectrometry (LC–MS/MS). It was found that the intravenously injected ATCA concentration quickly decreased to half within 2.5 h in the rat system. However, after 2.5 h, the concentration of ATCA in plasma stayed constant at least 5 folds above the endogenous ATCA level for more then 48 h. This finding can be used for evaluating ATCA's diagnostic and forensic value as a biomarker for cyanide exposure.

► ATCA persistence was determined after injecting it directly to the blood stream.
► ATCA concentration in blood decreased to half within 2.5 h in the rat system.
► After the initial loss, ATCA level stayed constant (700 ng/ml) over 48 h.
► Endogenous ATCA level in blood was found 141 ng/ml.
► The role of ATCA as a biomarker for CN exposure needs more future investigations.