Abstract Optimisation and validation of a novel isotope dilution gas chromatography mass spectrometry (GC–MS) method for determination of inorganic chloride (Cl−) in crude oils is presented. The use of stable isotope dilution calibration approach decreases losses and biases and it is considered a higher order measurement approach. Samples were diluted with a 1:1 blend of isopropyl alcohol : toluene with 5% water, mixed with 37Cl− internal standard, water extracted and derivatized with triethyloxonium tetrafluoroborate at room temperature. This reagent converted Cl− into stable ethyl chloride (EtCl) which was detected by headspace GC–MS. A limit of quantitation of 100 µg kg−1 and limit of detection of 30 µg kg−1 were observed in crude oil samples when initial dilution was not required. The performance of this novel method was compared with combustion ion chromatography, ion chromatography with conductivity detection after microwave-induced combustion, and ASTM D3230 method on a set of medium and heavy crude oil samples. Despite the challenges of the measurement, a reasonable level of agreement was observed among methods over the range of 0.38 ± 0.02 to 993 ± 103 mg kg−1 of Cl−. Presented headspace GC–MS method proved to be suitable for analysis of all types of crude oils samples with an excellent reproducibility (RSD

中文翻译：

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使用同位素稀释 GC-MS 测定原油中的氯化物：一项比较研究

摘要 介绍了一种用于测定原油中无机氯化物 (Cl−) 的新型同位素稀释气相色谱质谱 (GC-MS) 方法的优化和验证。稳定同位素稀释校准方法的使用减少了损失和偏差，它被认为是一种更高阶的测量方法。样品用异丙醇：甲苯和 5% 水的 1:1 混合物稀释，与 37Cl− 内标混合，在室温下用水萃取并用四​​氟硼酸三乙基氧鎓衍生。该试剂将 Cl− 转化为稳定的氯乙烷 (EtCl)，由顶空 GC-MS 检测。当不需要初始稀释时，在原油样品中观察到 100 µg kg-1 的定量限和 30 µg kg-1 的检测限。将这种新方法的性能与燃烧离子色谱法、微波诱导燃烧后电导检测离子色谱法和 ASTM D3230 方法在一组中重原油样品上进行了比较。尽管测量存在挑战，但在 0.38 ± 0.02 至 993 ± 103 mg kg-1 Cl- 范围内的方法之间观察到了合理的一致性水平。所提出的顶空 GC-MS 方法被证明适用于分析所有类型的原油样品，并具有出色的重现性 (RSD) 02 至 993 ± 103 mg kg-1 Cl-。所提出的顶空 GC-MS 方法被证明适用于分析所有类型的原油样品，并具有出色的重现性 (RSD) 02 至 993 ± 103 mg kg-1 Cl-。所提出的顶空 GC-MS 方法被证明适用于分析所有类型的原油样品，并具有出色的重现性 (RSD)