串联质谱中子离子相对强度稳定性的研究

采用串联质谱的多反应监测模式,在最佳碰撞能量条件下,监测同一物质的4对母-子离子对,计算不同子离子的相对强度,并比较了该值在甲醇标准溶液与血清基质中的差异.实验结果表明,在不同浓度条件下,5种代表生物碱的子离子相对强度的相对标准偏差小于6%,血清基质与甲醇标准溶液之间的相对偏差小于4.5%,这说明在最佳碰撞能量条件下,同一物质子离子相对强度与待测物的浓度和所处基质无直接关系.同时发现,在最佳碰撞能量条件下,子离子相对强度具有稳定性,这为复杂基质中的快速定性提供了可能性.

Research on the Stability of Relative Strength of Sub-ion in ESI-MS-MS Analysis

The work presents an electrospray tandem mass spectrometric(ESI-MS-MS) method capable of validating the stability of the product ion ratios of alkaloids at the optimal collision energy(OCE). The mass spectrometer was operated in MS-MS multiple reaction monitoring(MRM) mode, monitoring four reactions of one alkaloid. The product ion ratios are specific and reproducible(relative standard deviation: <6%, the percent deviation between two different matrixes: <4.5%). This unreported result shows the ion ratios at OCE are stable and independent of the analyte concentration and matrix. This described method can be used in the qualitative analysis in the complex matrix.