Performance of the Wet Oxidation Unit of the HPLC Isotope Ratio Mass Spectrometry System for Halogenated Compounds
Performance of the Wet Oxidation Unit of the HPLC Isotope Ratio Mass Spectrometry System for Halogenated Compounds
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DOI：
10.1021/ac501174d
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发表时间：
2014-08-05
影响因子：
7.4
通讯作者：
Richnow, Hans Hermann
中科院分区：
文献类型：
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作者：
Gilevska, Tetyana;Gehre, Matthias;Richnow, Hans Hermann
研究了液相色谱-同位素比值质谱联用技术（LC-IRMS）对极性卤代化合物的分析性能。用卤代乙酸和卤代芳香族化合物测试了该体系的氧化能力。选择乙酸（AA）作为完全氧化的参比化合物，并在摩尔基础上与其他分析物的氧化进行比较。用元素分析仪（EA）获得的校准δ C-13值验证同位素值。获得了一氯、二氯、氟化和三溴乙酸以及苯胺、苯酚、苯、溴苯、氯苯、1，2-二氯苯、2，4，6-三氯苯酚、五氟苯酚和硝基苯的正确同位素值。三氯乙酸（TCA）和三氟乙酸（TFA）的不完全氧化导致与AA相比更低的回收率（分别为37%和24%），并且导致与用EA获得的值相比的同位素偏移（TCA Δ Δ C-13（EA/LC-IRMS）= 8.8%，TFA Δ Δ C-13（EA/LC-IRMS）= 6.0份每千份）。通过在反应器中更长的反应时间和硫酸根浓度的增加来改善氧化并不导致δ C-13分析所需的TCA和TFA的完全燃烧。据我们所知，这是第一次用LC-IRMS系统研究这种高度氯化的化合物。这项工作提供了信息的方法开发的LC-IRMS方法的卤代污染物，被称为对公众健康和环境的潜在威胁。
The performance of liquid chromatography-isotope ratio mass spectrometry (LC-IRMS) for polar halogenated compounds was evaluated. Oxidation capacity of the system was tested with halogenated acetic acids and halogenated aromatic compounds. Acetic acid (AA) was selected as a reference compound for complete oxidation and compared on the molar basis to the oxidation of other analytes. The isotope values were proofed with calibrated delta C-13 values obtained with an elemental analyzer (EA). Correct isotope values were obtained for mono- and dichlorinated, fluorinated, and tribrominated acetic acids and also for aniline, phenol, benzene, bromobenzene, chlorobenzene, 1,2-dichlorobenzene, 2,4,6-trichlorophenol, pentafluorophenol, and nitrobenzene. Incomplete oxidation of trichloroacetic acid (TCA) and trifluoroacetic acid (TFA) resulted in lower recovery compared to AA (37% and 24%, respectively) and in isotopic shift compared to values obtained with EA (TCA Delta delta C-13(EA/LC-IRMS) = 8.8%o, TFA Delta delta C-13(EA/LC-IRMS) = 6.0 parts per thousand). Improvement of oxidation by longer reaction time in the reactor and increase in the concentration of sulfate radicals did not lead to complete combustion of TCA and TFA needed for delta C-13 analysis. To the best of our knowledge, this is the first time such highly chlorinated compounds were studied with the LC-IRMS system. This work provides information for method development of LC-IRMS methods for halogenated contaminants that are known as potential threats to public health and the environment.