Determination of Total Mercury in Seafood and Other Protein-Rich Products

Abstract

Abstract A previously developed wet-digestion method for the determination of total mercury in plants by cold vapor atomic absorption spectroscopy (CVAAS) was extended to the analysis of seafood and other products rich in proteins. Oxidation of matrixes is accomplished by K2Cr2O7 in the presence of diluted H2SO4; a simple air condenser is used to reflux vapors released from the boiling mixture. The original procedure (A) and 2 modifications (B and C), which differ with respect to the mode of acidification and/or digestion time and the types of condensers used, were compared for precision and accuracy by means of National Institute of Standards and Technology Research Material 50 Albacore Tuna and proved to be reliable (Hg present, 0.95 ± 0.1 μg/g; Hg found, 0.97 ± 0.029 μg/g [A], 0.98 ± 0.018 μg/g [B], and 0.94 ± 0.025 μg/g [C]). The modified procedures were tested further in Hg recovery experiments on a variety of biological matrixes with different spiking substances and again showed good analytical characteristics (overall average recoveries = 98 ± 5.1 % for seafood and 100 ± 3.6% for protein-rich baby foods)