1 London Research and Development Centre, Agriculture and Agri-Food Canada, 1391 Sandford Street, London, Ontario N5 V 4T3, Canada.
2 Metrology, National Research Council Canada, 1411 Oxford Street, Halifax, Nova Scotia, B3H 3Z1, Canada.
3 Agassiz Research and Development Centre, Agriculture and Agri-Food Canada, 6947 Lougheed Hwy., Agassiz, British Columbia V0 M 1A2, Canada.
4 Calgary Laboratory, Canadian Food Inspection Agency, 3650 36th Street NW, Calgary, Alberta T2 L 2L1, Canada.
5 Unit Food Hygiene and Technology, Centre for Food Science and Veterinary Public Health, Clinical Department for Farm Animals and Food System Science, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria.
6 Magan Centre of Applied Mycology, Faculty of Engineering and Applied Sciences, Cranfield University, Cranfield, Bedford MK43 0AL, United Kingdom.
7 Campus Heymans, Department of Bioanalysis, Centre of Excellence in Mycotoxicology & Public Health, Ghent University, Ottergemsesteenweg, 460, 9000 Ghent, Belgium.
8 Department of Chemistry and Biochemistry, Concordia University, 7141 Sherbrooke Street West, Montréal, Québec H4B 1R6, Canada.
9 Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada.
10 Department of Food and Drug, University of Parma, Parco Area delle Scienze 27/A, 43125 Parma, Italy.
11 Department of Food Chemistry and Toxicology, University of Vienna, Währingerstraße 38, A-1090 Vienna, Austria.
12 Grain Research Laboratory, Canadian Grain Commission, 1404-303 Main Street, Winnipeg, Manitoba R3C 3G7, Canada.
13 Guelph Research and Development Center- Agriculture and Agri-Food Canada, 93 Stone Road West, Guelph, Ontario N1 G 5C9, Canada.
14 Institute of Bioanalytics and Agro-Metabolomics Department of Agrobiotechnology (IFA-Tulln) University of Natural Resources and Life Sciences, Vienna, Konrad Lorenz Straße 20, 3430 Tulln, Austria.
15 Institute of Food Chemistry, Universität Münster, Corrensstraße 45, 48149 Muenster, Germany.
16 Institute of Sciences of Food Production, National Research Council, Amendola 122/O 70126 Bari, Italy.
17 Laboratory of Pharmacology and Toxicology, Department of Pathobiology, Pharmacology and Zoological Medicine, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
18 Morden Research and Development Centre, Agriculture and Agri-Food Canada, 101 Rout, Unit 100, Morden, Manitoba R6 M 1Y5, Canada.
19 National Research Council Canada, Metrology, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada.
20 Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, Ontario, K1A 0C6, Canada.
21 Center for Food Safety and Applied Nutrition, US Food and Drug Administration, 5001 Campus Drive, College Park, Maryland 20740, USA.
22 Veterinary Diagnostic Laboratory, Iowa State University, 1850 Christensen Drive, Ames, Iowa 50011-1134, USA.
23 London Research and Development Centre, Agriculture and Agri-Food Canada, 1391 Sandford Street, London, Ontario N5 V 4T3, Canada. Electronic address: mark.sumarah@agr.gc.ca.

Monitoring for mycotoxins in food or feed matrices is necessary to ensure the safety and security of global food systems. Due to a lack of standardized methods and individual laboratory priorities, most institutions have developed their own methods for mycotoxin determinations. Given the diversity of mycotoxin chemical structures and physicochemical properties, searching databases, and comparing data between institutions is complicated. We previously introduced incorporating a retention index (RI) system into liquid chromatography mass spectrometry (LC-MS) based mycotoxin determinations. To validate this concept, we designed an interlaboratory study where each participating laboratory was sent N-alkylpyridinium-3-sulfonates (NAPS) RI standards, and 36 mycotoxin standards for analysis using their pre-optimized LC-MS methods. Data from 44 analytical methods were submitted from 24 laboratories representing various manufacturer platforms, LC columns, and mobile phase compositions. Mycotoxin retention times (t_R) were converted to RI values based on their elution relative to the NAPS standards. Trichothecenes (deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol) showed t_R consistency (± 20-50 RI units, 1-5 % median RI) regardless of mobile phase or type of chromatography column in this study. For the remaining mycotoxins tested, the RI values were strongly impacted by the mobile phase composition and column chemistry. The ability to predict t_R was evaluated based on the median RI mycotoxin values and the NAPS t_R. These values were corrected using Tanimoto coefficients to investigate whether structurally similar compounds could be used as anchors to further improve accuracy. This study demonstrated the power of employing an RI system for mycotoxin determinations, further enhancing the confidence of identifications.