Determination of Total Mercury in Selected Seafood Samples Using Cold Vapor Atomic Absorption Spectrometry (CVAAS)

Abstract

Mercury (Hg) is a persistent environmental contaminant that can accumulate in aquatic organisms and enter the human diet through seafood consumption. Monitoring total mercury concentrations in seafood is therefore important for food-safety assessment and environmental surveillance. This study aimed to determine and compare total mercury concentrations in selected seafood samples, including squid, prawn, fresh fish (mackerel), and canned fish, using cold vapor atomic absorption spectrometry (CVAAS) following microwave-assisted acid digestion. The analytical procedure was also assessed in terms of calibration linearity, recovery, and repeatability. Homogenized seafood samples (approximately 0.20 g) were digested with concentrated nitric acid using a closed-vessel microwave digestion system. Mercury was measured using a NIC RA-3000 Mercury Analyzer, with the standard addition method used to minimize matrix effects. The calibration curves demonstrated good linearity, with coefficients of determination (R²) ranging from 0.9883 to 0.9956. The measured total mercury concentrations were 1.74 ppb in squid, 1.22 ppb in prawn, 5.69 ppb in fresh fish, and 6.92 ppb in canned fish. Recovery values ranged from 65% to 102%, while repeatability assessment for canned fish produced an RSD of 5.57%. Total mercury concentrations varied among the investigated seafood samples, with the highest measured value in canned fish and the lowest in prawn. However, the limited sampling design prevents statistical generalization, and the higher value in canned fish cannot be attributed to canning. Further studies should include larger representative samples, independent biological replicates, comprehensive analytical validation, and mercury speciation to better evaluate contamination and potential dietary exposure.