STUDY ON METHOD VALIDATION FOR THE DETERMINATION OF HEXAVALENT CHROMIUM IN CEMENT

The accreditation requirements of ISO / IEC 17025 [1] among other things, are the use of validated procedures. Last year, this requirement has become imperative for accredited laboratories, because of rules stated by RENAR the accreditation body for testing and calibration laboratories in our country. This paper describes the results obtained and steps taken to obtain calibration curves and method validation for two areas of concentrations of soluble hexavalent chromium, namely: the range stipulated by EN 196-10 standard and the range of cement samples with low chromium content. Steps taken to check the two cases were the following: making determinations for obtaining experimental calibration curves verifying the calibration curves for two types of cement, that is usual and reduced samples performing 10 determinations in the first calibration point for obtaining the standard deviation making uncertainty calculations for the two areas validation method in the two cases. The experimental results were obtained by using a spectrophotometer type SPECORD 205 of Analytik Jena.