CALIBRATION OF ION SPRAY MASS-SPECTRA USING CLUSTER IONS
CALIBRATION OF ION SPRAY MASS-SPECTRA USING CLUSTER IONS
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DOI：
10.1002/oms.1210270603
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发表时间：
1992-06-01
期刊：
影响因子：
--
通讯作者：
BOYD, RK
中科院分区：
文献类型：
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作者：
ANACLETO, JF;PLEASANCE, S;BOYD, RK
将碱金属盐乙腈水溶液流动注射到流向离子喷雾针的液体中，形成团簇离子，即可实现离子喷雾质谱学的质量校正。从而将污染源污染减少到最低限度。对于四极质谱计，碘化钠在不理想的光谱复杂性和校正质谱峰之间的间距之间提供了理想的折衷，这些峰之间的距离足够接近，以至于内插误差可以忽略不计。当需要更近的距离时，质子化水团簇可提供高达约1000 m/z的出色校准。如果需要更高的质量范围和大量的标准峰，混合碱金属碘化物溶液确实可以提供预期的光谱，但在较高的m/z值时强度较差。对于液质联用(LC/MS)，可以在不改变流动相的情况下通过柱后流动注射碳酸铯溶液来检查质量校准，因为碳酸盐阴离子被流动相酸改进剂的阴离子完全置换，导致没有混合簇合物。金属盐校准剂的另一个优点是可用于大气压电离源的各种调谐参数，既适用于大分子蛋白质的相对分子质量测定，也适用于小分析物的LC/MS测定。
Mass calibration for ion spray mass spectrometry can be achieved by using cluster ions formed by flow injection of solutions of alkali metal salts in aqueous acetonitrile into the liquid flowing to the ion spray needle. Source contamination is thereby reduced to a minimum. For quadrupole mass analyzers, sodium iodide provides an ideal compromise between undesirable spectral complexity and spacings between calibrant mass peaks sufficiently close that interpolation errors are negligible. When much closer spacings are required, protonated water clusters provide an excellent calibration up to about m/z 1000. If higher mass ranges are required with a large number of calibrant peaks, a solution of mixed alkali metal iodides does provide the expected spectra but intensities are poor at higher m/z values. For liquid chromatography with on-line mass spectrometry (LC/MS) the mass calibration may be checked without changing the mobile phase by post-column flow injection of a cesium carbonate solution, since the carbonate anion is wholly displaced by the anion of the mobile phase acid modifier, resulting in no mixed clusters. The metal salt calibrants have the additional advantage of being useful over a wide range of tuning parameters in the atmospheric pressure ionization source, covering those appropriate to both relative molecular mass determinations of large proteins and to LC/MS of small analyte species.