Stability Studies of Agrifood Reference Materials Under Different Conditions of Storage by Near-Infrared Spectroscopy

Abstract

Reference materials (RM) play an increasingly important role for laboratories. The aim of this work is to compare different conditions of storage and assess the stability of agrifood external reference materials (ERM). These materials could be used as tools by laboratories notably for their quality control procedure. However, as the other RM, their stability must be assessed during stability studies. The determination of the limiting date of stability (LDS), defined as the period during which analytes called marker of stability are still considered as stable, is used on this purpose. The influences of the environmental factor were tested by the application of full experimental designs with two tested environmental factors: the temperature (storage at +4 °C or +20 ± 10 °C) and the composition of the atmosphere (absence or presence of gases in the packaging). Thus, the setting under vacuum increases clearly the stability for the studied analyte. Almost all ERM stored in the best conditions have a determined LDS higher than those stored in current condition of storage. Indeed, the bread wheat ERM LDS is higher than the current storage of 24 months