HOKLAS Method Validation Technical Criteria: Quantification of Arsenic, Cadmium, Mercury and Lead in Foods Objective: Develop a method validation for quantifying arsenic, cadmium, mercury and lead in food. The standard method is BS EN 15763:2009 and BS EN 13805:2002. The method validation steps follow the ISO/IEC 17025:2005 standard. General information on method validation in ISO 17015: Definition of method validation. According to ISO 1702 [1], validation is the confirmation by examination and provision of objective evidence that the particular requirements of an intended use are met. It can be classified into three main parts: specific intended use, objective evidence and confirmation. The meaning of the specific intended use is that it is necessary to know why we need to test the analyst. Common reasons are that the chemical is toxic to humans or has a harmful effect on animals or the environment. After identifying the reason for method validation, we need to perform method validation studies in different method validation settings. For example, detection limits recovery and uncertainty. The final step is to use the method validation result to compare it with the information obtained from the customer's requirements. The result must also meet the requirements of the standards. Method validation is very important for the application of the method. It can determine the performance characteristics of the method and verify whether they meet the requirements of the specific intended use. There are four advantages for method validation. The first is that it can help the laboratory ensure that the method can meet accreditation requirements. For example, if the laboratory must have HOKAS certification, the validation of the method is done in the middle of paper......the equation of the R value Figure 4: the example of the RStdconc value (mg/l) Answer Answer found by cal. curve Residual1 2.7 3 -0.32 5.7 5 0.74 9.2 9 0.26 12.4 13 -0.6Figure 5: the example of Response Residual PlotFigure 6: The definition of the detection limitFigure 7: The result of the inter-laboratory study of CRM-Tort-2 Figure 8: The IDL of each analysis in the standard method Reference: 1. ISO/IEC 17025:2005 “Quality manual/compliant procedure” cl. 5.4.5.12. ISO/IEC 17025:2005 “Quality manual/compliant procedure” cl. 5.4.5.2 and note 13. http://mathbits.com/MathBits/TISection/Statistics2/correlation.htm4. IOS 5725 “Accuracy (correctness and precision) of measurement methods and results” Parts 2 to 5: 19945. ISO/IEC Guide 43-1 “Proficiency testing by interlaboratory comparisons -- Part 1: Development and operation of measurement programs aptitude tests” 1997