Derivatization of ethylenethiourea with m-trifluoromethylbenzyl chloride for analysis by electron-capture gas chromatography

Application of gas chromatography-mass spectrometry for the determination of urinary ethylenethiourea in humans

“…Due to scarce volatility of ETU, the first step toward this technique was the identification of a suitable derivative, useful for GC analysis. Although in literature several derivatization protocols were proposed for GC analysis of ETU [23][24][25][26][27][28][29], our interest was focused on the use of silylating agents that could react with both the functional groups present in ETU: the secondary amide nitrogens and the sulfur of the thiocarbonyl moiety. Moreover, reaction mixture containing silylating agents did not need a purification step before introduction in the chromatographic column.…”

Residue Reviews

“…Autio (1983) achieved high sensitivity and selectivity for the determination of N,N'-dimethylimidazolidine-2-thione using selected ion monitoring (Section III d). King (1977), Nitz et al (1982), and Newsome (1972) also used M.S. for the confirmation of identity of the gas chromatographic peaks measured in their determinations.…”

“…Various alkyl halides have been employed, including I-bromobutane (Onley and Yip 1971, Haines and Adler 1973, Watts et al 1974, Onley et al 1977, Pease and Holt 1977, benzyl chloride (Newsome 1972, Nash 1974, Pecka et al 1975, Onji et al 1979), o-chlorobenzyl chloride (Nash 1975), and m-trifluoromethylbenzyl chloride (King 1977). In some of the methods a second derivatization step was used to attach a multi-halogenated compound such as the pentafluorobenzoyl group (Nash 1974 and, the trifluoroacetyl group (Newsome 1972, Pecka et al 1975, and King 1977, or the methane sulphonyl group (Onji et al 1979) on to the nitrogen of the imidazoline ring. This second derivatization serves two purposes, firstly as a further confirmation of identity of the ETU and secondly to increase the response of the compound to the electron-capture detector.…”

“…The residues in winter-grown lettuce 91 and 63 days after a treatment at the recommended rates carried out 11 and 39 days after planting ranged from 0.06 to less than 0.01 mg/kg. King (1977) then developed a further variation by reacting ETU with mtrifluoromethylbenzyl chloride in the same way as benzyl chloride. The resulting S-(m-trifluoromethylbenzyl) derivative could be determined by GLC at levels (0.01 mg/kg) similar to Newsome's trifluoroacetylated S-benzyl derivative but without the need for a second derivatization sequence.…”

An Improved Method for Residue Analysis of Ethylenethiourea in Vegetables by High-performance Liquid Chromatography

“…13) The primary method was based on a gas chromatographic (GLC) determination of derivatized ETU such as S-butyl, S-benzyl-Ntrifluoroacetyl, S-benzyl-N-pentafluorobenzoyl and S-(m-trifluoromethylbenzyl) derivatives. [14][15][16][17] HPLCgrade methanol was obtained from Wako Pure Chemical Ind., Ltd., Osaka, Japan. All the other reagents were of analytical grade.…”