Simultaneously determination of methyl and inorganic mercury in fish species by cold vapour generation atomic absorption spectrometry

► Simultaneous non-chromatographic determination of methyl and inorganic mercury species in fish. ► Microwave assisted alkaline dissolution method was used for extraction of ethyl and inorganic mercury. ► Stannous chloride and sodium tetrahydroborate used as reducing agents for both mercury species. ► The effects of inert gas flow rate, oxidizing reagent, potassium persulphate and reductant were optimised. A simple and rapid non-chromatographic method was developed to determine methylmercury (MeHg) and inorganic mercury (iHg) levels in muscles tissues of 10 freshwater fish species. The MeHg and iHg were determined by cold vapour atomic absorption spectrometry after alkaline wet digestion of samples. The digested samples were reduced sequentially with stannous chloride and sodium tetrahydroborate for iHg and MeHg, respectively. Parameters such as carrier gas flow rate (argon), volume of oxidizing and potassium persulphate solutions were investigated in detail. The accuracy of the technique was evaluated by using certified reference material (DORM-2) and spiking the both Hg species in muscles tissue of a fish. The limits of detection were 0.117 and 0.133μg kg−1 for MeHg and iHg, respectively. The concentrations of MeHg and iHg in muscles tissues of ten fish species were found in the range of (28.4–56.3) and (3.01–8.11)μg kg−1, respectively.