Concerns about the environmental impact of shale energy exploration (i.e., hydraulic fracturing and other well stimulation techniques) have risen due to its rapid expansion in the United States and other countries. Soils in shale basins engaged in unconventional oil and gas development can become contaminated by volatile organic compounds (VOCs), such as benzene, toluene, ethylbenzene, and xylenes (BTEX) through mishandling of chemical additives, products, and/or waste fluids. In this study, room temperature ionic liquids (RTILs) were evaluated as solvents in an effort to increase sensitivity and to reduce and normalize matrix effects associated with varying soil compositions during analysis. Headspace gas chromatography mass spectrometry (HS-GC-MS) experiments demonstrated that hydrophilic RTILs 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM][ESO4], 1-ethyl-3-methylimidazolium diethyl phosphate [EMIM][DEP], and tris(2-hydroxyethyl) methylammonium methylsulfate [MTEOA][MeOSO3] normalized the response for BTEX compounds between 2 different soils, sandy loam and sandy clay loam. Furthermore, the optimization of the HS equilibration time to 30 min resulted in the reduction of matrix effects in certified reference soils of sand, clay, and loam textures. Limits of detection and limits of quantification were in the sub- to mid- pg g-1 level in soil. For determination at 1 g of certified BTEX reference soil, the relative standard deviation was within 10% and percent recoveries were above 80% for toluene, ethylbenzene, and xylenes. This method reduces the need to characterize and matrix-match soil texture for calibration purposes. It also reduces the analysis time and increases precision and accuracy for the quantification of BTEX in variable soil matrices relative to standard methods.

中文翻译：

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在静态顶空气相色谱质谱法中使用室温离子液体共溶剂无基质效应测定可变土壤成分中的 BTEX

由于页岩能源勘探（即水力压裂和其他油井增产技术）在美国和其他国家的快速扩张，人们对其环境影响的担忧有所增加。从事非常规油气开发的页岩盆地中的土壤可能会因化学添加剂、产品和/或废液处理不当而受到挥发性有机化合物 (VOC) 的污染，例如苯、甲苯、乙苯和二甲苯 (BTEX)。在这项研究中，室温离子液体 (RTIL) 被评估为溶剂，以提高灵敏度并减少和标准化与分析过程中不同土壤成分相关的基质效应。顶空气相色谱质谱 (HS-GC-MS) 实验表明亲水性 RTILs 1-乙基-3-甲基咪唑乙基硫酸盐 [EMIM][ESO4]、1-乙基-3-甲基咪唑鎓二乙基磷酸酯 [EMIM][DEP] 和三（2-羟乙基）甲基硫酸甲酯铵 [MTEOA][MeOSO3] 标准化了两种不同土壤（砂质壤土和砂质粘壤土）之间 BTEX 化合物的响应。此外，将 H2S 平衡时间优化为 30 分钟，导致在沙、粘土和壤土质地的认证参考土壤中的基质效应降低。检测限和定量限在土壤中的亚至中 pg g-1 水平。对于 1 g 经认证的 BTEX 参考土壤的测定，甲苯、乙苯和二甲苯的相对标准偏差在 10% 以内，回收率高于 80%。这种方法减少了为校准目的而表征和矩阵匹配土壤质地的需要。相对于标准方法，它还减少了分析时间并提高了可变土壤基质中 BTEX 定量的精确度和准确度。