Certification of different mass fractions of DP202216 in maize seed powder : ERM®-BF444a and ERM®-BF444b

ERM®-BF444a and ERM®-BF444b are matrix materials certified for the mass fraction of DP202216 maize (unique identifier DP-2Ø2216-6), produced within the scope of accreditation to ISO 17034:2016 [1]. Genetically modified (GM) maize seeds of the DP202216 event and seeds from a non-GM maize variety were milled, sieved and dried to obtain GM and non-GM seed powders of similar particle size distribution. The certified reference materials (CRMs) are available in glass vials containing at least 1 g of dried maize powder, which were sealed under an atmosphere of argon. The purity of the non-GM and GM maize seeds and the respective maize powders was quantified. Between unit homogeneity, stability during transport and storage were assessed in accordance with ISO Guide 35:2017 [2]. The minimum sample size for one measurement is 200 mg. The certified values were obtained, taking into account the genetic purity of the base materials with respect to the DP202216 maize event. The certified values were verified by event-specific quantitative polymerase chain reaction (qPCR), measured within the scope of accreditation to ISO/IEC 17025:2017 [3]. Uncertainties of the certified values were calculated in accordance with ISO 17034:2016 [1] and ISO Guide 35:2017 [2] and include uncertainties related to the characterisation, based on the genetic purity assessment. The materials are intended for calibration, quality control and assessment of method performance of the event-specific qPCR method for DP202216 maize. Before release of the CRMs, the certification project was subjected to peer-review involving internal experts.