Analysis of 5-vinyl-1,3-oxazolidine-2-thione in complex matrices at ppb level

5-Vinyl-1,3-oxazolidine-2-thione (5-VOT) is a goitrogenic compound released by enzymatic degradation of progoitrin, the most important glucosinolate o ccurring in rapeseed meal. This paper describes an analytical method for de termining the 5-VOT in complex matrices. The method proposed by Quinsac et al. [J. Assoc. Off. Anal. Chem., 75(3) (1992) 529] has been improved by mod ification of the extraction conditions and the purification steps. The extr action of 5-VOT is performed with hot acid buffer. The first purification s tep is achieved by solid-phase chromatography (C-18). The second purificati on step of 5-VOT is carried out by complexation with phenyl mercury acetate in cyclohexane and, afterwards, by decomplexation using an aqueous solutio n of sodium thiosulfate. These reactions move 5-VOT from an aqueous to an o rganic medium, and then back again to the aqueous phase. This Procedure ens ures a high purification efficiency. The precise quantification of 5-VOT is completed in 12 min by reverse-phase liquid chromatography (C18), using an isocratic elution with an ultraviolet detector and with synthetic 4,4-dime thyl-1,3-oxazolidine-2-thione as internal standard. Using this modified met hod, 5-VOT can be determined in different matrices such as rapeseed meal, a nimal diets, muscle, several organs (thyroid, liver, kidney and lung) and b iological fluids (plasma and milk). The quantification limit of 5-VOT in th e sample is of 1 ppb (1 mu g kg(-1)), the recovery rate of 5-VOT is about 9 0% and the repeatability is over 97%. (C) 1999 Elsevier Science B.V. All ri ghts reserved.