千瓦级微波等离子体质谱仪研究水体中锰元素

为了使微波等离子体电离源更好地用于分析水溶液中金属元素，本研究基于改进型千瓦级微波等离子体（KMP）电离源耦合线性离子阱质谱仪（LTQ MS），在新型进样系统（Nafion H2SO4）下，研究水体中锰元素的质谱行为。锰元素的千瓦级微波等离子体质谱（KMP MS）特征谱图不同于传统的电感耦合等离子体（ICP MS）获得的特征信号，这可能有助于金属元素分析。使用KMP LTQ MS法分析水体中锰的络合物阴离子，证实锰的络合物阴离子是由流经KMP源中心管的水溶液在等离子体火焰中电离产生的，如NO3-。此外，解释了主要离子在多步碰撞诱导解离过程中特征碎片的形式，并在优化的条件下，使用锰的络合物阴离子二级质谱特征离子评估锰的检测限（LOD）为033 μg/L，线性动态范围涵盖至少2个数量级，在0~100 μg/L之间。因KMP源无Ar背景干扰，未来可将其与四极杆质谱结合，能够为水质检测提供新方法。

Study of Manganese in Water by Kilowatt-Microwave Plasma Mass Spectrometry

Due to the unique ionization properties of microwave plasma, it can be used as an ion source for atmospheric pressure mass spectrometry, both for the analysis of organic small molecules and the detection of inorganic metallic elements. To improve the performance of microwave plasma ionization sources for the analysis of metallic elements in aqueous solutions, the mass spectrometric behaviour of manganese (Mn) in kilowatt microwave plasma mass spectrometry (KMP-MS) with a novel injection system (Nafion H2SO4) was investigated. The KMP MS characteristic spectra of Mn had new features that were significantly different from the characteristic signals obtained by traditional inductively coupled plasma (ICP-MS), which might be useful for the detection of metal elements. The complex anions of Mn in water were analyzed using the KMP LTQ MS, confirming that these complex anions were produced by aqueous solutions flowing through the KMP central tube in a plasma flame, such as NO3-. In addition, the form of the major ions was explained during multi-step collision induced dissociation. The limit of detection (LOD) of Mn was 0.33 μg/L under the optimized conditions using its secondary mass spectrometric characteristic ions, while the linear dynamic range covered at least two orders of magnitude (0 100 μg/L). This method is suitable for analysis of metal elements in water and Mn ions in real samples. Because there is no Ar background interference in KMP source, the combination of the KMP source and quadrupole mass spectrometry will provide a new powerful analytical tool for multi element detection in areas, such as environmental pollution, criminal investigation, and geological exploration.