1 Center for Environmental Measurement and Modeling, Environmental Protection Agency, Athens, GA, 30605, USA. mosley.jonathan@epa.gov.
2 Chemical Sciences Division, National Institute of Standards and Technology (NIST), Charleston, SC, 29412, USA.
3 IROA Technologies, Chapel Hill, NC, USA.
4 Centre for Metabolomics Research, Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK.
5 Neonatal Research Group, Health Research Institute La Fe, 46026, Valencia, Spain.
6 Life Sciences Mass Spectrometry Division, Bruker UK Limited, Coventry, CV4 8HZ, UK.
7 National Phenome Centre & Division of Systems Medicine, Department of Metabolism, Digestion & Reproduction, Imperial College London, London, W12 0NN, UK.
8 BIOMIC_Auth, Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Aristotle University Thessaloniki, 57001, Thermi, Greece.
9 Eastern Laboratory, Office of Public Health Science (OPHS), Food Safety and Inspection Service (FSIS), Department of Agriculture (USDA), Athens, GA, 30605, USA.
10 Department of Chemistry and Biochemistry, Concordia University, Montreal, QC, H4B 1R6, Canada.
11 Division of Systems Medicine, Department of Metabolism Department of Metabolism, Digestion and Reproduction, Imperial College, London, W12 0NN, UK.
12 Office of Nutrition Research, Office of the Director, Division of Program Coordination, Planning, and Strategic Initiatives, National Institutes of Health, Bethesda, MD, USA.

Background: Quality assurance (QA) and quality control (QC) practices are key tenets that facilitate study and data quality across all applications of untargeted metabolomics. These important practices will strengthen this field and accelerate its success. The Best Practices Working Group (WG) within the Metabolomics Quality Assurance and Quality Control Consortium (mQACC) focuses on community use of QA/QC practices and protocols and aims to identify, catalogue, harmonize, and disseminate current best practices in untargeted metabolomics through community-driven activities.

Aim of review: A present goal of the Best Practices WG is to develop a working strategy, or roadmap, that guides the actions of practitioners and progress in the field. The framework in which mQACC operates promotes the harmonization and dissemination of current best QA/QC practice guidance and encourages widespread adoption of these essential QA/QC activities for liquid chromatography-mass spectrometry.

Key scientific concepts of review: Community engagement and QA/QC information gathering activities have been occurring through conference workshops, virtual and in-person interactive forum discussions, and community surveys. Seven principal QC stages prioritized by internal discussions of the Best Practices WG have received participant input, feedback and discussion. We outline these stages, each involving a multitude of activities, as the framework for identifying QA/QC best practices. The ultimate planned product of these endeavors is a "living guidance" document of current QA/QC best practices for untargeted metabolomics that will grow and change with the evolution of the field.