SPSFAM Heavy Metals ERP Book

AOAC FIRST ACTION 2015.01

MULTI LABORATORY TEST

RESULTS Raw Data

Results received from the participating laboratories were paired, according to assigned blind duplicate number and recorded in the AOAC International Inter- laboratory Study Workbooks according to the instructions provided. Individual worksheets were created for each study material and analyte. The statistical results were calculated according the worksheet and included all participant results. All numeric data was included in the statistical calculations, non-numeric data was excluded and not included in the calculations. Non-numeric data included results reported as less than (<) the LOQ or where results were reported as Not Reported (NR). Results excluded as outliers either from statistical tests or not meeting the SMPR recovery requirements are marked with an asterisk (*). This allows for the reporting of the result while excluding the value from the statistical calculation. The individual spreadsheets were saved and named according to MLT sample number, study material and analyte. The worksheets have been embedded as an attachment to this report in Annex G. The raw data and the statistical report, including RSD(r), RSD(R) and HORRAT from the Study Workbooks was tabulated into a combined multitab spreadsheet. Additionally SMPR performance requirements were added and highlighted for comparison. A tab for Trueness recovery was also added to compare recoveries with available reference values. The worksheet is embedded as an attachment to this report in Annex G. The individual tables for discussion are grouped according to study material, raw data, precision and trueness and are displayed in the discussion section below. The MLT samples consisted of SRM2384 Baking Chocolate, SRM 1946 Lake Superior Fish Tissue, ERM-BD 150 Milk Powder, Apple Juice Concentrate, SRM 1568b Rice Flour, Infant Formula QC Material and Apple Juice Concentrate Spike. Unfortunately the Apple Juice Concentrate spike sample was not sent to the participants due to an error in processing the study materials. Apple Juice Concentrate was mistakenly sent instead. SRM 2384 Baking Chocolate All thirteen participating laboratories reported results for SRM 2384 Baking Chocolate including the four Heavy Metal analytes, Arsenic, Cadmium, Mercury and Lead. One lab was unable to report results for study sample 4, the results are designated as NR. The raw data, precision and trueness data are shown in the tables below. Arsenic: Lab 9 results were excluded as outliers from the precision determination along with Lab 2 and 10 for < LOQ and Lab 11 NR result. The 10 labs used for the precision determination reported a RSD(r) value of 8.97 and a RSD(R) value of 23.6. Both precision results meet the requirements of the SMPR. Cadmium: Lab 11 results were excluded as an outlier from the precision determination along with the NR result from Lab 11. The 12 labs used for the

Discussion

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