Determination of ethylenethiourea residues in apples

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

“…For example, Onley and Yip (1971) stated "We could not analyze ETU by direct GLC because the peak tailed even when several liquid phases were tried and other GLC parameters were changed." Similarly Haines and Adler (1973) experienced the same difficulty, Newsome (1972) found "the unmodified compound unsuitable for GLC," and very recently Matisova et al (1984) using capillary column GLC have reported that "The direct analysis of highly polar ETU at trace concentrations was found to be difficult owing to the adsorption of ETU, in spite of the use of capillaries with different modes of surface treatment, producing unsymmetrical peaks." Despite these apparent difficulties a number of papers describing the direct analysis of ETU using GLC with a number of different detectors have been published.…”

“…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.…”

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.…”