Determination of mercury in fish by cold vapor atomic absorption spectrophotometry using a multicommuted flow injection analysis system

A flow system was developed for the determination of total mercury concentration in fish samples by cold vapor atomic absorption spectrophotometry (CVAAS), based on the multicommuted flow injection analysis (MCFIA) approach. The system uses independently controlled solenoid valves for the introduction of reagents and samples. When not injected, solutions were recirculating to the reservoir bottles, in this way reducing the waste produced by the analytical system and also the sample consumption. Results were compared to those obtained by the reference flow injection procedure. Accuracy was also assessed by recovery studies using a certified reference material as well as spiked samples; recovery percentages in the range of 90.7% to 99.8% were found. The repeatability of the method was better than 6.0% (RSD, n = 10). A limit of detection of 4.8 mu g of mercury per kg of fresh fish sample was achieved. The total waste produced was reduced to 30% of that from the reference flow injection CVAAS procedure.