In this study, we focus on isolation and fractionation strategies by solid phase extraction (SPE) for a broad range of environmentally related organic acids. These emerging potential contaminants are primary degradation products of spilled petrogenic compounds but little attention has been given to their environmental analysis and risk assessment. Three mixed-mode anion exchange sorbents possessing various backbone polarities were compared with respect to the extraction and fractionation efficiency. Quantitative analysis was obtained using an optimized and validated LC-MS method. We demonstrated the importance of reasonable ion source settings for highest sensitivity of individual carboxylic acids. Furthermore, fractionation of carboxylic acids into aliphatic and aromatic fractions by SPE was achieved by step-wise elution. Best performance regarding the isolation of low-concentration acids (sub μg L-1 level) in complex samples was attributed to Strata XA and is caused by high secondary hydrophobic interactions in addition to the ionic interactions. Isolation and fractionation of acid spiked diesel-spilled harbor water (22 μg L-1 spike level) revealed recoveries >80% for all tested carboxylic acids and low carry-overs of neutral petroleum compounds. We conclude that the isolation and fractionation of acidic degradation products by SPE is a powerful tool to investigate this new class of contaminants in relation to identification and ecological risk assessments.

中文翻译：

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用于酸性油降解产物分离和分馏的 SPE-LC-MS 研究

在这项研究中，我们专注于通过固相萃取 (SPE) 对各种与环境相关的有机酸进行分离和分馏策略。这些新出现的潜在污染物是溢出的石油化合物的主要降解产物，但很少有人关注它们的环境分析和风险评估。比较了三种具有不同骨架极性的混合模式阴离子交换吸附剂的萃取和分馏效率。使用优化和验证的 LC-MS 方法进行定量分析。我们证明了合理的离子源设置对于单个羧酸的最高灵敏度的重要性。此外，通过逐步洗脱实现了通过 SPE 将羧酸分馏为脂肪族和芳香族馏分。在复杂样品中分离低浓度酸（亚微克 L-1 水平）的最佳性能归功于 Strata XA，除离子相互作用外，还由高次要疏水相互作用引起。加标柴油的港口水（22 μg L-1 加标水平）的分离和分馏表明，所有测试羧酸的回收率 >80%，中性石油化合物的残留量低。我们得出的结论是，通过 SPE 对酸性降解产物的分离和分馏是研究与鉴定和生态风险评估相关的新型污染物的有力工具。加标柴油的港口水（22 μg L-1 加标水平）的分离和分馏表明，所有测试羧酸的回收率 >80%，中性石油化合物的残留量低。我们得出的结论是，通过 SPE 对酸性降解产物的分离和分馏是研究与鉴定和生态风险评估相关的新型污染物的有力工具。加标柴油的港口水（22 μg L-1 加标水平）的分离和分馏表明，所有测试羧酸的回收率 >80%，中性石油化合物的残留量低。我们得出的结论是，通过 SPE 对酸性降解产物的分离和分馏是研究与鉴定和生态风险评估相关的新型污染物的有力工具。