Heikes D L
J Assoc Off Anal Chem. 1987 Mar-Apr;70(2):215-26.
A method developed for the determination of ethylene dibromide in table-ready foods has been modified and expanded to include 7 other volatile halocarbons and carbon disulfide. Samples are stirred with water and purged with nitrogen for 0.5 h in a water bath at 100 degrees C. The analytes collected on a duplex trap composed of Tenax TA and XAD-4 resin are eluted with hexane and determined by gas chromatography with electron capture detection or Hall electrolytic conductivity detection. Flame photometric detection in the sulfur mode is used to determine carbon disulfide. Thick-film, wide-bore capillary columns are used exclusively in both the determination and confirmation of the halogenated analytes. The higher levels of analytes are also confirmed by full scan gas chromatography mass spectrometry (GC/MS). Samples are analyzed for carbon disulfide, methylene chloride, chloroform, 1,2-dichloroethane, methyl chloroform, carbon tetrachloride, trichloroethylene, 1,2-dibromoethane, and tetrachloroethylene. Initially, 19 table-ready foods from the Food and Drug Administration's Total Diet Study were analyzed by this method. A limited survey of those food items exhibiting high levels of analytes was conducted. Samples exhibited levels up to 3300 ppb (methyl chloroform in Parmesan cheese). Recoveries of all 9 analytes from fortified samples ranged from 83 to 104%. Chromatograms from this purge and trap method are clean, enabling quantitation levels of low parts per billion and sub-parts per billion to be achieved for the halogenated analytes. The quantitation limit for carbon disulfide is 12 ppb. Two compounds found in drinking water were identified by GC/MS as bromodichloromethane and chlorodibromomethane. Drinking water from several cities was analyzed for these trihalomethanes as well as for bromoform. Levels of up to 17 ppb bromodichloromethane were found. Recoveries ranged from 96 to 103%.
一种用于测定即食食品中1,2 - 二溴乙烷的方法已得到改进和扩展，以涵盖其他7种挥发性卤代烃和二硫化碳。将样品与水混合搅拌，并在100℃水浴中用氮气吹扫0.5小时。收集在由Tenax TA和XAD - 4树脂组成的双联捕集阱上的分析物用己烷洗脱，并通过带有电子捕获检测或霍尔电解电导检测的气相色谱法进行测定。采用硫模式的火焰光度检测法测定二硫化碳。在卤代分析物的测定和确证中均专门使用厚膜、宽口径毛细管柱。较高含量的分析物也通过全扫描气相色谱 - 质谱联用（GC/MS）进行确证。对样品分析二硫化碳、二氯甲烷、氯仿、1,2 - 二氯乙烷、三氯乙烷、四氯化碳、三氯乙烯、1,2 - 二溴乙烷和四氯乙烯。最初，采用该方法对食品药品监督管理局总膳食研究中的19种即食食品进行了分析。对那些显示出高含量分析物的食品项目进行了有限的调查。样品中分析物含量高达3300 ppb（帕尔马干酪中的三氯乙烷）。强化样品中所有9种分析物的回收率在83%至104%之间。这种吹扫捕集方法得到的色谱图很干净，使得卤代分析物能够达到十亿分率低含量和十亿分率以下含量的定量水平。二硫化碳的定量限为12 ppb。通过GC/MS鉴定出饮用水中存在的两种化合物为溴二氯甲烷和氯二溴甲烷。对几个城市的饮用水分析了这些三卤甲烷以及溴仿。发现溴二氯甲烷含量高达17 ppb。回收率在96%至103%之间。
