ERM-BC211 - Arsenic in rice

The starting material, which had been checked for its arsenic species was purchased and  supplied by the University of Aberdeen. The rice was milled, sieved, dried, homogenised,  filled in vials and sterilised.  Between unit-inhomogeneity was quantified and stability during dispatch and storage was  assessed in accordance with ISO Guide 35:2006 [2]. Within-unit inhomogeneity was  quantified to determine the minimum sample intake.  The material was characterised by an intercomparison among laboratories of demonstrated  competence and adhering to ISO/IEC 17025. Technically invalid results were removed but  no outlier was eliminated on statistical grounds only.  Uncertainties of the certified values were estimated in compliance with ISO/IEC Guide 98-3,  Guide to the Expression of Uncertainty in Measurement (GUM) [3] and they include  contributions from possible between-unit inhomogeneity, instability and characterisation.  The material is intended for quality control and assessment of method performance.  Moreover, it can be used for validation purposes and trueness determination. The CRM is  available in glass bottles containing 10 g of dried rice powder closed under argon  atmosphere. The minimum amount of sample to be used for total arsenic and dimethylarsinic  acid is 50 mg. The minimum amount of sample to be used for the sum of arsenite and  arsenate is 100 mg.  The CRM has been accepted as European Reference Material (ERM) after peer evaluation  by the partners of the European Reference Materials consortium. 

Keywords: Biological material, Plant material, Foodstuff, Agricultural food product, speciation analysis , arsenic speciation