Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy.
Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy.
J Chromatogr A. 2021 Mar 15;1640:461963. doi: 10.1016/j.chroma.2021.461963. Epub 2021 Feb 1.
Historically, retention parameters were reliably used as identification criterion in chromatographic analytical systems. However, pure analytical standards are necessary to determine the retention behaviour of a given compound. In recent decades, mass spectrometer (MS) became the detector of choice to obtain structural information on unknown peaks, thanks to the elucidation of fragments, often arisen from the loss of specific functional groups. The cost and the level of experience of the operators is surely higher compared to the use of retention data. Therefore, the aim of the present review is to describe the efforts in the introduction of the Linear Retention Index (LRI) in routine, interlaboratory applicable identification procedures. The requirements and the main challenges will be discussed, even compared to gas chromatography methods, in which LRI is stably used for identification purposes, usually in combination with MS spectral libraries. The higher number of LC-amenable molecules and the wide range of LC mobile phase compositions make the building of universal LRI database a very challenging task. The limitations encountered in the past decades are reported, together with new proposals in order to overcome such issues.
从历史上看，保留参数被可靠地用作色谱分析系统中的鉴定标准。然而，为了确定给定化合物的保留行为，需要使用纯分析标准品。在最近几十年中，质谱仪（MS）成为获得未知峰结构信息的首选检测器，这要归功于碎片的阐明，这些碎片通常是由于特定功能基团的丢失而产生的。与使用保留数据相比，其成本和操作人员的经验水平肯定更高。因此，本综述的目的是描述在引入线性保留指数（LRI）方面的努力，以便在常规、可在不同实验室间应用的鉴定程序中使用。将讨论其要求和主要挑战，即使与气相色谱法相比，LRI 也被稳定地用于鉴定目的，通常与 MS 光谱库结合使用。LC 可处理的分子数量更多，LC 流动相组成范围更广，这使得构建通用 LRI 数据库成为一项极具挑战性的任务。报告了过去几十年中遇到的局限性，以及为克服这些问题而提出的新建议。
