The certification of reference materials of dry-mixed maize powder with different mass fractions of MIR604 maize : set of certified reference materials ERM-BF423a, ERM-BF423b, ERM-BF423c, ERM-BF423d

This report describes the preparation and certification of dry-mixed maize powder Certified Reference Materials (CRMs) with different mass fractions of genetically modified (GM) MIR604 maize powder (CRMs ERM-BF423a, ERM-BF423b, ERM-BF423c and ERM-BF423d). The CRMs were processed in 2005 and certified in 2006 by the European Commission, Directorate General Joint Research Centre, the Institute for Reference Materials and Measurements (IRMM), Geel, Belgium. Seeds of non-modified maize and MIR604 maize, supplied by Syngenta Crop Protection AG (Basel, CH), were rinsed with demineralised water, drained and dried at 30 °C in order to minimise dust contamination from other crops. After a two step grinding process, transforming the seeds into a non-modified maize powder and a MIR604 GM maize powder, mixtures of the two materials were gravimetrically prepared and homogenised by turbula- and dry-mixing. The GM seeds used are hybrids and heterozygous for the transgene. The CRMs are intended for the quality control or calibration of methods for the detection and quantification of genetically modified food and feed. The MIR604 mass fractions of ERM-BF423 were verified with the help of an event specific real-time polymerase chain reaction (rt-PCR) method. The CRMs are available in glass bottles containing 1 g of maize powder closed under argon atmosphere.