Institute for National Measurements Standards, National Research Council Canada, Ottawa, Ontario, Canada, K1A 0R6.
Anal Chem. 2009 Dec 1;81(23):9834-9. doi: 10.1021/ac901778n.
The present work describes the mass spectrometric detection of organometallic compounds following their atmospheric pressure ionization using a commercial direct analysis in real time (DART) ion source. Several organometallic compounds of As, Fe, Hg, Pb, Se, and Sn were examined, and their corresponding mass spectra as well as induced fragmentation patterns were recorded. Gas phase sampling of the pure organometallic compounds or their solutions prepared in toluene generated temporally stable signals. For the majority of the compounds, the molecular ion or protonated molecule was detected; noticeable exceptions are the tetra-substituted compounds for which their less-substituted species dominated. The organometallic species were used as model compounds for a systematic investigation of the impact of operating parameters of the DART source, including gas temperature and electrode voltages. In general, results have shown that powering the electrodes designed to remove ions from the DART gas stream results in a reduction in signal intensity for most of the compounds investigated, suggesting that charged species from the plasma play an important role in the ionization process of the test analytes.
本工作描述了使用商业常压直接分析实时（DART）离子源对金属有机化合物进行质谱检测。考察了几种砷、铁、汞、铅、硒和锡的金属有机化合物，并记录了它们相应的质谱和诱导裂解模式。对纯金属有机化合物或在甲苯中制备的溶液进行气相采样可产生稳定的时间信号。对于大多数化合物，检测到分子离子或质子化分子；明显的例外是四取代化合物，其中它们的较少取代的物种占主导地位。这些金属有机化合物被用作模型化合物，对 DART 源操作参数的影响进行了系统研究，包括气体温度和电极电压。一般来说，结果表明，为从 DART 气流中去除离子而给电极供电会导致大多数所研究化合物的信号强度降低，这表明等离子体中的带电物质在测试分析物的电离过程中发挥了重要作用。
