Use of liquid chromatography/tandem mass spectrometry to detect distinctive indicators of in situ RDX transformation in contaminated groundwater
Use of liquid chromatography/tandem mass spectrometry to detect distinctive indicators of in situ RDX transformation in contaminated groundwater
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DOI：
10.1021/es0157696
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发表时间：
2002-05-01
影响因子：
11.4
通讯作者：
Tiemeier, K
中科院分区：
文献类型：
--
作者：
Beller, HR;Tiemeier, K
监测自然衰减的一个重要因素是在地下水中检测到污染物降解或转化的独特产物。在这项研究中，在爱荷华州陆军弹药厂受污染的地下水中检测到了三种不同的炸药黑索今(六氢-1，3，5-三硝基-1，3，5-三嗪)，产品是MNX、(hexahydro-1-nitroso-3，5-dinitro-1，3，5-triazine)，、DNX、(hexahydro-1，3-dinitroso-5-nitro-1，3，5-triazine)，和TnX(六氢-1，3，5-三硝基-1，3，5-三嗪)。这些化合物是黑索金转化的有力指标，原因有几个： (A)它们具有独特的化学特征，表明它们是黑索金的子产物，(B)它们没有已知的商业、工业或自然来源，以及(C)它们在实验室研究中被很好地记录为厌氧黑索金代谢物。采用LC/MS/MS(液/质/质)联用仪进行分析，选择性反应监测，用[RING-U-15N]RDX进行内标定量。验证试验表明，LC/MS/MS方法具有良好的灵敏度(检出限约为0.1μg/L)、准确度和精密度。在所有RDX浓度约为1μg/L(分析的55个样品中的25个)的地下水样品中检测到的产物的浓度从接近检测下限到430μg/L不等，MNX是三种亚硝基取代产物中典型的最丰富的；产物的浓度很少超过RDX浓度的4mol%，尽管它们的浓度高达26mol%(Tnx)。评估了RDX、MNX、DNX和TNX的地理和时间分布。LC/MS/MS在任何样品中均未检测到黑索今环裂解产物亚甲基二硝胺(检出限约为0.6−4μg/L)。利用高选择性分析方法(LC/MS/MS)对地下水中的MNX、DNX和TNX分布进行广泛的现场表征具有重要意义，因为人们对受污染含水层中RDX的内在转化知之甚少。
An important element of monitored natural attenuation is the detection in groundwater of distinctive products of pollutant degradation or transformation. In this study, three distinctive products of the explosive RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) were detected in contaminated groundwater from the Iowa Army Ammunition Plant; the products were MNX (hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine), DNX (hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine), and TNX (hexahydro-1,3,5-trinitroso-1,3,5-triazine). These compounds are powerful indicators of RDX transformation for several reasons: (a) they have unique chemical features that reveal their origin as RDX daughter products, (b) they have no known commercial, industrial, or natural sources, and (c) they are well documented as anaerobic RDX metabolites in laboratory studies. The products were analyzed by LC/MS/MS (liquid chromatography/mass spectrometry/mass spectrometry) with selected reaction monitoring and internal standard quantification using [ring-U-15N]RDX. Validation tests showed the novel LC/MS/MS method to be of favorable sensitivity (detection limits ca. 0.1 μg/L), accuracy, and precision. The products, which were detected in all groundwater samples with RDX concentrations of > ca. 1 μg/L (25 out of 55 samples analyzed), were present at concentrations ranging from near the detection limit to 430 μg/L. MNX was the typically the most abundant of the three nitroso-substituted products; concentrations of the products seldom exceeded 4 mol % of the RDX concentration, although they ranged as high as 26 mol % (TNX). Geographic and temporal distributions of RDX, MNX, DNX, and TNX were assessed. A degradation product resulting from RDX ring cleavage, methylenedinitramine, was not detected by LC/MS/MS in any sample (detection limit ca. 0.6−4 μg/L). This extensive field characterization of MNX, DNX, and TNX distributions in groundwater by a highly selective analytical method (LC/MS/MS) is significant because very little is known about the occurrence of intrinsic RDX transformation in contaminated aquifers.