Performance characteristics of a rapid method for iodine determination in milk / Szybka metoda oznaczania jodu w mleku – walidacja i akredytacja zgodnie z normą ISO/IEC 17025:2005

The repeatability and within-laboratory reproducibility were tested on 72 samples. The most important validation parameters were determined, including the components of uncertainty. The results of the analyses were compared with reference values. The repeatability and within-laboratory reproducibility of the method did not exceed 8% and 10%, respectively. The limit of quantification (LOQ) in the milk sample solution was 14 μg/L. The working range of the calibration curve was 7 to 200 μg/L. The uncertainty of the method (P≤0.05), which accounts for the errors of within-laboratory reproducibility, recovery and standard purity as well as the errors of volumetric glassware, was (%) 17.8 and 22.8 (n = 2 and n = 1), respectively. The coefficient of variation for repeatability should also be determined during routine analysis; it should not exceed the repeatability limit of 16%. The method has sufficient reliability, as confirmed by the validation results. The procedure is rapid, simple and has a low LOQ. The method was accredited according to ISO/IEC 17025:2005 international standard.