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zjandzq金虫 (正式写手)
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翻译两段话（药分）希望专业点，呵呵
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Cross-talk refers to different forms of instrumental phe- nomena which compromise the selectivity of a TQMS mass analyzer. Two types of cross-talk exist. The first source is a blen- ding of adjacent SRMtransitions attributed to the slower rate of scanning product ions out of the collision cell (Q2) relative to the response rate of the detector. This effect is most pronounced when consecutive SRM transitions monitor the same product ion m/z . The second cross-talk results from fragmentation within the ion source (in-source CID) giving rise to multiple sources for the precursor ion selected by Q1. Two approaches have been reported to study ME. In the first approach, a solution of the analyte is constantly infused into the eluent from the column via post-column tee connection using a syringe pump. The continuous post-column infusion pro- duces constant signals in the detector, unless compounds that elute from the column suppress or enhance ionization, which would lead to a decreased or increased detector response, res- pectively . The second approach with a comprehensive strategy has been recently published byMatuszewski et al. This paper provides excellent guidance on how to perform and evaluate studies on ME in LC–MS/MS analysis. |
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zjandzq(金币+8,VIP+0):谢谢了！ 4-24 17:14
zjandzq(金币+8,VIP+0):谢谢了！ 4-24 17:14
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有两种TQ质谱仪。 第一种离子源 SRM transition 的混合物。该SRM transition，归因于碰撞单元Q2出来的子离子的扫描速率相对于检测器响应速率较低。 当用连续的SRM transitions检测相同子离子的m/z时，该影响是显著的。 第二种cross-talk是在离子源发生裂解的结果,为Q1选择的母离子增加了多重离子源。 有两种用来研究ME的方法都被报道过了。 第一种方法是，被分析的样品溶液通常用针泵连接到柱后三通被灌注到从分离柱出来的洗脱液中。 连续的柱后灌流会在检测器中产生恒定的信号。除非从分离柱洗脱出来的化合物抑制或者增强了离子化，那么就会导致检测响应的减少或增加。 第二种方法是目前由Matuszewski et al 发表的一种综合的技术。 该文很好地指导了如何运用ME 作LC-MS/MS分析以及对这些研究做出评价。 |
2楼2009-04-24 07:49:50