Validation of an in-house measurement procedure for determination of selected priority hazardous substances in water and estimation of measurement uncertainty

Abstract

© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. This study investigates measurement procedure validation for the determination of hexachlorobenzene, pentachlorobenzene and trifluralin as priority hazardous pesticides in water with suspended solids < 12 mg/L by liquid–liquid extraction with hexane and gas chromatography with electron capture detector analysis. Two water matrices were used: synthetic matrix and a natural matrix—Danube surface water. Limit of detection was in the range 2.2 ng/L–3.9 ng/L. Trueness expressed as recovery was determined at pesticide concentrations of 20 ng/L and 50 ng/L in both water matrices. The intermediate precision was determined as relative standard deviations (RSD) and represents an agreement between replicates. Trueness was 72 %–121 % with RSD < 20 %. Expanded uncertainty of measurement was similar for all compounds (33.3 %–37.5 %) with a 95 % confidence level, for coverage factor k = 2. The validity of the measurement procedure was confirmed by participation in a PT Scheme with satisfactory |z|-score smaller than 2. Based on these results, it can be concluded that this low-cost measurement procedure is fit for the intended use measurements.