Development and comparison of methods using MS scan and selective ion monitoring modes for a wide range of airborne VOCs
Development and comparison of methods using MS scan and selective ion monitoring modes for a wide range of airborne VOCs
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DOI：
10.1039/b607042f
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发表时间：
2006-01-01
影响因子：
--
通讯作者：
Chernyak, Sergei
中科院分区：
文献类型：
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作者：
Jia, Chunrong;Batterman, Stuart;Chernyak, Sergei
吸附剂采样结合热解吸、气相色谱和质谱分析（TD/GC/MS）为挥发性有机化合物（VOC）提供了许多优势，因此在许多应用中得到越来越多的应用。对于环境样品和其他复杂混合物，MS检测器通常以扫描模式操作，以帮助识别共洗脱化合物。然而，扫描模式不能实现最佳灵敏度，因此可能无法检测到低浓度的化合物。本文开发并评估了一种更灵敏的TD/GC/MS方法，使用选择性离子监测（SIM），适用于环境和室内空气中发现的VOC混合物的应用。根据毒性和流行情况，选择了94种VOCs（包括萜烯类、芳香族、卤代和脂肪族化合物）作为目标化合物。开发了两种分析方法：一种传统的全扫描方法，离子从29到270 m/z;和SIM方法，使用16个时间窗口和不同的离子选择的化合物在每个窗口。两种方法使用相同的Tenax GR吸附剂采样管、TD和GC参数以及目标和限定离子。实验室测试确定校准，方法检测限（MDLs），精密度，回收率和储存稳定性。现场测试比较了扫描和SIM模式分析的室内空气在51所房子和室外空气在41个站点的重复样本。统计分析包括误差/精密度模型的开发。实验室测试表明，大多数化合物表现出出色的精度（浓度超过0.5 mg m（-3）时< 10%），良好的线性，扫描和SIM模式的校准几乎相同，动态范围宽（高达1500 mg m（-3）），1个月后的储存损失可忽略不计（7种化合物显示中度损失）。SIM模式的MDL范围为0.004至0.27 mg m（-3），与扫描模式相比有适度（1.1至22倍）改善。然而，在现场测试中，SIM方法检测到的化合物明显更多（例如，例如，在一个实施例中，苯乙烯和氯仿）。误差模型适合大多数化合物，并允许定量。在选定的范围内纠正错误。总的来说，虽然新的SIM方法开发起来有些耗时，但它提供了更高的灵敏度，并保持了传统扫描方法的高选择性。
Adsorbent sampling with analysis by thermal desorption, gas chromatography and mass spectrometry ( TD/GC/MS) offers many advantages for volatile organic compounds ( VOCs) and thus is increasingly used in many applications. For environmental samples and other complex mixtures, the MS detector typically is operated in the scan mode to aid identification of co-eluting compounds. However, scan mode does not achieve the optimal sensitivity, thus compounds occurring at low concentrations may not be detected. This paper develops and evaluates the application of a more sensitive TD/GC/MS method using selective ion monitoring ( SIM) that is applicable to VOC mixtures found in ambient and indoor air. Based on toxicity and prevalence, 94 VOCs ( including terpenes, aromatic, halogenated and aliphatic compounds) were selected as target compounds. Two analytical methods were developed: a conventional full scan method for ions from 29 to 270 m/z; and a SIM method using 16 time windows and different ions selected for the compounds in each window. Both methods used the same Tenax GR adsorbent sampling tubes, TD and GC parameters, and target and qualifier ions. Laboratory tests determined calibrations, method detection limits ( MDLs), precisions, recoveries and storage stability. Field tests compared scan and SIM mode analyses for duplicate samples of indoor air in 51 houses and outdoor air at 41 sites. Statistical analyses included the development of error/precision models. The laboratory tests showed that most compounds demonstrated excellent precision ( < 10% for concentrations exceeding similar to 0.5 mg m(-3)), good linearity, near identical calibrations for scan and SIM modes, a wide dynamic range ( up to 1500 mg m(-3)), and negligible storage losses after 1 month ( 7 compounds showed moderate losses). SIM mode MDLs ranged from 0.004 to 0.27 mg m(-3), representing a modest ( 1.1 to 22-fold) improvement compared to scan mode. However, in field tests the SIM method detected significantly more compounds ( e. g., styrene and chloroform). Error models fit most compounds and allow quanti. cation of errors at selected percentiles. Overall, while the new SIM method is somewhat time-consuming to develop, it offers greater sensitivity and maintains the high selectivity of traditional scan methods.