The certification of different mass fractions of DAS-40278-9 in maize seed powder : certified reference materials ERM-BF433a, ERM-BF433b, ERM-BF433c and ERM-BF433d

This report describes the production of a set of Certified Reference Materials (CRMs) ERM-BF433a, b, c and d, matrix materials certified for their DAS-40278-9 mass fractions. The material has been produced following ISO Guide 34:2009 [1]. Genetically modified (GM) seeds of the maize event DAS-40278-9 and of a non-GM maize variety were ground to obtain GM and non-GM base powders. Gravimetric mixtures of non-GM and GM maize powder were prepared by dry-mixing. Between unit-heterogeneity has been quantified and stability during dispatch and storage have been assessed in accordance with ISO Guide 35:2006 [2]. The certified value was obtained from the gravimetric preparations, taking into account the purity of the base materials and their respective water mass fraction. The certified values were confirmed by event-specific real-time PCR as independent verification method (measurements within the scope of accreditation to ISO/IEC 17025:2005 [3]). Uncertainties of the certified values were calculated in compliance with the Guide to the Expression of Uncertainty in Measurement (GUM) [4] and include uncertainties related to possible heterogeneity, instability, and characterisation. The materials are intended for the calibration or quality control of DAS-40278-9 maize identification and quantification methods. As any reference material, they can also be used for control charts or validation studies. The CRMs are available in glass vials containing at least 1 g of dried maize seed powder, closed under argon atmosphere. The minimum amount of sample to be used is 200 mg. The CRM has been accepted as European Reference Material (ERM®) after peer evaluation by the partners of the European Reference Materials consortium.