Identification of possible technical problems in determination of the major inorganic constituents of brown-rice flour by evaluating proficiency test results

Abstract

To support skill upgrading in analysis of inorganic constituents of environmental and food samples, the National Metrology Institute of Japan (NMIJ) and the National Food Research Institute (NFRI) have organized a proficiency test (PT) of determination of Mn, Fe, Cu, Zn, As, and Cd in brown-rice flour based on the international standard (ISO/IEC 17043:2010). One hundred and thirty-three sets of reports were assessed by use of the E(n)-number and z-score approaches in accordance with ISO/IEC 17043 and the international harmonized protocol for PT. The PT results and analytical procedures, reported in detail, were reviewed, and possible technical reasons for questionable or unsatisfactory results are discussed.

Difference between Consensus Value of Participants' Results and Isotope-Dilution Mass Spectrometric Results in Proficiency Testing for Pesticide Residues in Husked Wheat

“…4 In addition, participating in PT assists participants to locate technical areas that require improvement. 5,6 Consequently, PT has been routinely carried out by numerous providers in a wide variety of chemical quantitation fields, including the analysis of pesticide residues in food. [7][8][9] In 2012, the National Metrology Institute of Japan (NMIJ) initiated a new PT program for the analysis of pesticide residues in food samples.…”