Validation of an analytical method for the determination of cadmium, lead and mercury in fish and fishery resources by graphite furnace and Cold Vapor Atomic Absorption Spectrometry

Abstract

This paper describes the validation of analytical methods for the determination of heavy metals in fish and fishery resources by microwave assisted digestion method followed by Graphite Furnace Atomic Absorption Spectrometry (GFAAS) and Cold Vapor Atomic Absorption Spectrometry (CVAAS). Method parameters such as linearity, repeatability, reproducibility, and accuracy were determined; whereas, detection limit, quantification limit and measurement of uncertainty were calculated. The proposed method was linear over the concentration ranges of 0.0002–0.0010 mg/L (Cd), 0.0010–0.0100 mg/L (Pb) and 0.0010–0.0160 mg/L (Hg). The coefficient of determination (R 2 ) acquired were higher than 0.998. Mean recoveries obtained after fortification of standard concentration for all metals ranged from 77 to 108% with a precision not exceeding 7.72% relative standard deviation (RSD). The computed limit of detection (LOD) and limit of quantification (LOQ) for Cd, Pb and Hg passed the criteria set by Commission Regulation (EU) No 836/2011. The relative expanded uncertainty was estimated at less than 11.68, 9.98 and 8.96% for Cd, Pb and Hg, respectively. Participation to proficiency test was conducted to further assess the performance of this method. The z-score obtained in the test performance were −0.5 for Cd, 0.1 for Pb and 0.2 for Hg. Overall, the proposed method was deemed satisfactory and effective for the determination of heavy metals in fish and fishery resources.