# Polar microcystins or arginine methyl ester can serve as sensitive reference materials for system suitability tests in untargeted metabolomics using reversed-phase LC-MS: A case study

## TL;DR

The paper suggests using polar microcystins or arginine methyl ester as reference materials to improve quality control in LC-MS metabolomics.

## Contribution

The study introduces new reference materials for system suitability tests in untargeted metabolomics.

## Key findings

- Polar microcystins and arginine methyl ester are effective for LC-MS system suitability tests.
- Current C18 RP column performance may be insufficient despite passing standard tests.
- Incorporating these RMs improves QA procedures in metabolomics.

## Abstract

LC-MS system suitability test (SST) is crucial for reliable data acquisition especially in untargeted metabolomics.

Identification of best reference materials (RMs) to improve best quality assurance (QA) and quality control (QC) practices.

Investigations were performed using a C18 reversed-phase (RP) column LC-MS approach.

Targeted cyanotoxin analysis revealed a performance loss of the used C18 RP column although the SST confirmed a fit for purpose instrument which prompted to test several additional RMs.

QA procedures for LC-MS can be improved by incorporating polar microcystins or arginine methyl ester as RMs for SST.

The online version contains supplementary material available at 10.1007/s11306-026-02413-9.