Development, characterization and certification of QS-CRM-23: A multi-element quinoa seed powder certified reference material for food composition analysis

This study reports the development, characterization, and certification of QS-CRM-23 , the first Moroccan quinoa seed powder Certified Reference Material (CRM) intended for reliable multi-element food composition analysis. Quinoa seeds collected from the Rehamna and Berrechid regions were processed under ISO 17034:2016 requirements, including drying, milling, sieving, homogenization, and bottling to ensure material uniformity. Homogeneity and stability assessments were performed according to ISO 33405:2024 using one-way ANOVA and linear regression models. Macronutrients and micronutrients (N, P, K, Ca, Mg, Cu, Mn, Fe, Zn, B) were quantified using validated ICP-OES and Kjeldahl methods. Certified values were established through an interlaboratory comparison involving eight ISO/IEC 17025-accredited laboratories and calculated in accordance with ISO 13528:2022 Algorithm A. QS-CRM-23 exhibited excellent within- and between-bottle homogeneity and demonstrated long-term (ambient, 24 months) and short-term (50 °C, 24 days) stability. All certified property values were assigned with expanded uncertainties (k = 2) below 15%. QS-CRM-23 provides a robust metrological tool to support calibration, method validation, and proficiency testing in food and nutritional analysis laboratories. Its availability contributes to improving data comparability, traceability, and measurement reliability in agro-food composition studies. • QS-CRM-23 is the first Moroccan quinoa seed powder Certified Reference Material. • Produced in accordance with ISO 17034, with homogeneity and stability assessed following ISO 33405:2024. • Macro- and micronutrients were determined using validated ICP-OES and Kjeldahl methods. • Certified values were assigned through an interlaboratory study applying ISO 13528 Algorithm A. • All certified analytes exhibit expanded uncertainties (k = 2) below 15%. • QS-CRM-23 provides a reliable metrological tool for calibration, method validation, and proficiency testing in food analysis