Food Control 121 (2021) 107579 Available online 29 August 2020 0956-7135/© 2020 Elsevier Ltd. All rights reserved. Method optimization and validation for multi-class residue analysis in turmeric Britt Maestroni a, * , Natalia Besil b, c , Sofía Rezende a, b , Ying Liang a , Natalia Gerez c , Nuwan Karunarathna a, d , Marivil Islam a , Horacio Heinzen b, c , Andrew Cannavan a , MaríaVer´ onica Cesio a, c a Food and Environmental Protection Laboratory, Joint FAO/IAEA Division of Nuclear Applications in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Wagramerstrasse 5, A-1400, Vienna, Austria b Grupo de An´ alisis de Compuestos Traza (GACT). Departamento de Química del Litoral. Facultad de Química. CENUR Litoral Norte. Universidad de la República. Ruta 3, Km 363, 60000, Paysandú, Uruguay c GACT. C´ atedra de Farmacognosia y Productos Naturales. Facultad de Química. Universidad de la República, General Flores 2124, 11800, Montevideo, Uruguay d Department of Veterinary Public Health and Pharmacology, Faculty of Veterinary Medicine and Animal Science, University of Peradeniya, Peradeniya 20400, Sri Lanka A R T I C L E INFO Keywords: Spices Turmeric Multi-class method optimization Method validation Gas and liquid chromatography coupled to tandem mass spectrometry Interlaboratory comparison ABSTRACT Turmeric (Curcuma longa L.) is an economically important food and medicinal plant that grows in tropical and subtropical regions consumed worldwide. Turmeric is a diffcult matrix for residue/contaminant analysis due to the high content of potentially interfering polyphenols (curcuminoids) and essential oils with physicochemical properties similar to target analytes. To solve this problem, a simple and straightforward sample preparation protocol based on ethyl acetate extraction and dispersive solid phase clean-up, followed by gas and liquid chromatography coupled to tandem mass spectrometry analysis, was optimized and validated, after selecting a representative blank material using gas chromatography coupled to ion mobility spectrometry and multivariate data analysis. Method validation was performed according to Codex guidelines for 67 pesticide residues, including 12 persistent organic pollutants, 4 afatoxins and 3 dyes at 0.01, 0.02 and 0.05 mg kg 1 level. Re- coveries ranged between 60 and 120%, with relative standard deviations for repeatability and reproducibility below 20% and 32% respectively. Method performance was tested collaboratively between laboratories in Austria and Uruguay which helped proving the robustness of the methodology. The method was applied to the analysis of commercial samples and chlorpyrifos was detected in most of them. The novelty of the work relies in the optimization and validation of a multiclass method that allows analysis of four types of organic residues/contaminants, of paramount importance for food safety, using a single sample preparation step followed by gas and liquid chromatography coupled to tandem mass spectrometry determination. 1. Introduction Herbs and spices have been used worldwide throughout human history as ingredients in food, teas and medicines due to their favors and their pharmacological, biological and antimicrobial properties. Most are commercially produced and generally traded as powders or milled leaves, barks or roots. Due their high value, spices are important to the economy of countries that produce and export them. As a result of the growing demand for spices, agricultural cultivation has become increasingly intensive. To ensure optimum crop yields, agrochemicals are frequently applied, unless the product is declared as organic. The crops, before or after harvest, may be fumigated or treated to prevent insect and fungal infestation (Food and Agriculture Organization of the United Nations (FAO), 2004). The chemicals used may not always be authorized for use on the spice plants or, although allowed, may be misused and the residues found at higher levels than the maximum residue limits. Turmeric (Curcuma longa L.) is an economically important food and medicinal spice plant that grows primarily in tropical and sub-tropical regions. The consumption of turmeric is forecast to increase * Corresponding author. E-mail address: B.M.Maestroni@iaea.org (B. Maestroni). Contents lists available at ScienceDirect Food Control journal homepage: www.elsevier.com/locate/foodcont https://doi.org/10.1016/j.foodcont.2020.107579 Received 16 July 2020; Received in revised form 21 August 2020; Accepted 24 August 2020