Determination of total mercury in fish and sea products by direct thermal decomposition atomic absorption spectrometry

• Published in: Food chemistry Vol. 166; pp. 432 - 441
• Main Authors: Panichev, N.A., Panicheva, S.E.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2015
• Subjects: Analyzers; Animals; Comparative measurements; Concentration (composition); Criteria; CVAAS; Direct thermal decomposition of fish; Fish; Fish and seafood analysis; Fishes - metabolism; Markets; Mercury; Mercury (metal); Mercury - analysis; RA-915+ mercury analyzer; Seafood; Seafood - analysis; Spectrophotometry, Atomic - methods; Thermal decomposition; INW, Russia; CVAAS; RA-915+ mercury analyzer; Comparative measurements; Mercury; Fish and seafood analysis; Direct thermal decomposition of fish; RA-915(+) mercury analyzer
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2014.06.032

•A method of direct thermal decomposition for Hg measurement in raw samples of fish was developed.•Samples of wet fish were analysed without any chemical pretreatment.•There were no losses of Hg during analysis of wet and dry fish samples.•The concentration of Hg in most fishes from Tshwane market (Pretoria, South Africa) was found to be within safety limits. A Zeeman Mercury analyzer Model RA-915+ (Lumex, St. Petersburg, Russia), based on the direct thermal evaporation of Hg from solid samples was used for developing a method for the determination of Hg in fish and other seafood. The method does not require any chemical pretreatment of samples. This greatly simplifies the analytical procedure and minimises potential sources of contamination. The limit of detection (3s criteria) and limit of quantification (10s criteria) for the determination of Hg in wet fish samples with a mass of 250mg was found to be 0.6ngg−1 and 2.0ngg−1, respectively. Time taken for the analysis of one sample is about 3min. The accuracy of the method was confirmed by the analysis of certified reference materials of different types and by comparative analysis of fish samples using the accepted method of cold vapour generation. Excellent correspondence to the certified values was obtained. It was found that the mercury concentration in most fish species purchased from the Tshwane fish market were below the 0.5mgkg−1 (500ngg−1), wet weight, recommended by the FAO/WHO. It was also found that the direct thermal decomposition method for the determination of mercury is a more environmentally friendly alternative since it does not generate chemical waste.