LC–MS/MS has been the dominant analytical technology for quantitative bioanalysis of drugs and metabolites for more than two decades. Despite this, a very fundamental question like how much separation is required for LC–MS/MS quantitative bioanalysis of drugs and metabolites has not been adequately addressed. Some think that no or only very limited separation is necessary thanks to the unparalleled selectivity offered by tandem mass spectrometry. Others think that the more separation, the better, because of the potential detrimental impact of matrix effect (ion suppression or enhancement). Still others just use a rule-of-thumb approach by keeping the adjusted retention/capacity factor always between 2 and 5. The purpose of this article is to address this fundamental question through rational thinking together with various real case examples drawn from regulated bioanalytical laboratories.

在过去的二十多年中，LC-MS / MS一直是用于药物和代谢物定量生物分析的主要分析技术。尽管如此，还没有充分解决一个非常基本的问题，例如需要对LC-MS / MS进行药物和代谢物定量生物分析进行多少分离。有人认为，由于串联质谱提供了无与伦比的选择性，因此没有必要或只有非常有限的分离是必要的。其他人则认为，分离越多越好，因为基质效应（离子抑制或增强）的潜在有害影响。还有一些人只是使用经验法则，将调整后的保留/容量系数始终保持在2到5之间。