El-Haj B M, Al-Amri A M, Hassan M H, Bin-Khadem R K, Al-Hadi A A
Sharjah Police Forensic Science Laboratory, Emirate of Sharjah, United Arab Emirates.
J Anal Toxicol. 2000 Sep;24(6):390-4. doi: 10.1093/jat/24.6.390.
The interference of some substances with the gas chromatography-flame ionization detection and gas chromatography-Fourier transform infrared detection of toluene and ethylbenzene in volatile substance abuse poses problems. A gas chromatography-mass spectrometry (GC-MS) method that will overcome such interference has been developed for the detection of toluene and/or ethylbenzene in the headspace of preparations and products containing these substances and in the headspace of blood samples in the cases of volatile substance abuse. The method is based on converting toluene to benzoic acid via the formation of benzotrichloride. The latter compound was obtained upon the reaction of toluene with chlorine gas under direct sunlight conditions. In the presence of water, benzotrichloride was converted to benzoic acid. Ethylbenzene was converted to benzoic acid and two phenylethanols via the formation of side chain chloro-substituted phenylethanes followed by reaction with water. The chloro-substituted phenylethanes were obtained by the reaction of ethylbenzene with chlorine under direct sunlight conditions. The benzoic acid resulting from toluene and/or ethylbenzene and the two phenylethanols resulting from ethylbenzene were detected by GC-MS as their trimethylsilyl (TMS) derivatives. For the method to be viable for the detection of volatile substance abuse, the chlorination reactions were effected in the gaseous state.
在挥发性物质滥用检测中，某些物质对甲苯和乙苯的气相色谱 - 火焰离子化检测及气相色谱 - 傅里叶变换红外检测产生干扰，带来了问题。现已开发出一种气相色谱 - 质谱联用（GC - MS）方法，用于检测含有这些物质的制剂和产品顶空以及挥发性物质滥用案例中血样顶空中的甲苯和/或乙苯，该方法可克服此类干扰。该方法基于通过生成三氯甲苯将甲苯转化为苯甲酸。后者是在阳光直射条件下甲苯与氯气反应得到的。在有水存在的情况下，三氯甲苯转化为苯甲酸。乙苯通过生成侧链氯代苯乙烷，随后与水反应，转化为苯甲酸和两种苯乙醇。氯代苯乙烷是在阳光直射条件下乙苯与氯气反应得到的。由甲苯和/或乙苯产生的苯甲酸以及由乙苯产生的两种苯乙醇，通过气相色谱 - 质谱联用检测其作为三甲基硅烷基（TMS）衍生物的形式。为使该方法适用于挥发性物质滥用的检测，氯化反应在气态下进行。
