N-Alkylpyridinium sulfonates for retention time indexing in reversed-phase-liquid chromatography-mass spectrometry-based metabolomics.

Content Provider	Europe PMC
Author	Stoffel, Rainer Quilliam, Michael A. Hardt, Normand Fridstrom, Anders Witting, Michael
Abstract	Chromatographic retention time information is valuable, orthogonal information to MS and MS/MS data that can be used in metabolite identification. However, while comparison of MS data between different instruments is possible to a certain degree, retention times (RTs) can vary extensively, even when nominally the same phase system is used. Different factors such as column dead volumes, system extra column volume, and gradient dwell volume can influence absolute retention times. Retention time indexing (RTI), routinely employed in gas chromatography (e.g., Kovats index), allows compensation for deviations in experimental conditions. Different systems have been reported for RTI in liquid chromatography, but none of them have been applied to metabolomics to the same extent as they have with GC. Recently, a more universal RTI system has been reported based on a homologous series of N-alkylpyridinium sulfonates (NAPS). These reference standards ionize in both positive and negative ionization modes and are UV-active. We demonstrate the NAPS can be used for retention time indexing in reversed-phase-liquid chromatography-mass spectrometry (RP-LC–MS)–based metabolomics. Having measured >500 metabolite standards and varying flow rate and column dimension, we show that conversion of RT to retention indices (RI) substantially improves comparability of retention information and enables to use of RI for metabolite annotation and identification.Graphical AbstractSupplementary InformationThe online version contains supplementary material available at 10.1007/s00216-021-03828-0.
ISSN	16182642
Journal	Analytical and Bioanalytical Chemistry
Volume Number	414
PubMed Central reference number	PMC9482907
Issue Number	25
PubMed reference number	34907452
e-ISSN	16182650
DOI	10.1007/s00216-021-03828-0
Language	English
Publisher	Springer Berlin Heidelberg
Publisher Date	2021-12-15
Publisher Place	Berlin/Heidelberg
Access Restriction	Open
Rights License	Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. © The Author(s) 2021
Subject Keyword	Metabolomics Retention time indexing Reversed-phase Metabolite annotation
Content Type	Text
Resource Type	Article
Subject	Analytical Chemistry Biochemistry