Abstract

A non-targeted method for analyzing petroleum hydrocarbons in soil was established by extracting a wide range of PAC compounds using a model system. Here, sand was spiked with a heavy crude oil, which simulated a hydrocarbon contaminated soil of low soil organic matter (SOM). Soxhlet and supercritical fluid extraction (SFE) was optimized for PAXHs analysis in soil. A concept of using multidimensional ionization for ultrahigh resolution mass spectrometry was employed for detection using electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photo ionization (APPI) for the analysis of polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic heterocycles. Fourier transform mass spectrometry (FT-MS) with its ultrahigh mass resolution and high mass accuracy enables an unambiguous assignment of the detected ions obtained from different ionization methods, which provides a secure and comprehensive view of contaminants in soil on a molecular level. Over 95% of the spiked crude oil could be recovered by Soxhlet extraction using toluene, dichloromethane and acetone:n-hexane (1:1, v:v). In comparison, when using SFE with supercritical CO₂ the recovery was only about 50% but showed more polar compounds. Detailed analyses showed that besides 16 PAHs, a wide range with more than 10,000 PAXHs could also be successfully extracted.

摘要

通过使用模型系统提取各种 PAC 化合物，建立了一种分析土壤中石油烃的非靶向方法。在这里，沙子中掺入了重质原油，模拟了低土壤有机质 (SOM) 的碳氢化合物污染土壤。索氏和超临界流体萃取 (SFE) 针对土壤中的 PAXH 分析进行了优化。使用电喷雾电离 (ESI)、大气压化学电离 (APCI) 和大气压光电离 (APPI) 来分析多环芳烃 (PAH) 和多环芳烃，采用多维电离进行超高分辨率质谱检测杂环。傅里叶变换质谱 (FT-MS) 具有超高的质量分辨率和高质量的准确度，可以明确分配从不同电离方法中获得的检测离子，从而在分子水平上提供安全和全面的土壤污染物视图。通过使用甲苯、二氯甲烷和丙酮的索氏萃取可以回收超过 95% 的加标原油：正己烷(1:1, v:v )。相比之下，当使用具有超临界 CO ₂的 SFE 时，回收率仅为 50% 左右，但显示出更多的极性化合物。详细分析表明，除了 16 种 PAHs 外，还可以成功提取超过 10,000 种 PAXHs。