Determination of mercury and methylmercury in seafood by ion chromatography using photo-induced chemical vapor generation atomic fluorescence spectrometric detection

A novel method based on photo-induced chemical vapor generation (CVG) as interface to on-line coupled Hg-cysteine ion chromatograpy (IC) with atomic fluorescence spectrometry (AFS) was developed for rapid determination of methylmercury (MHg) in seafood. Separation of inorganic mercury (Hg2+) and methylmercury(CH3Hg+) was accomplished on a Hamilton PRP X-200 polymer-based exchange column with a mobile of 3% acetonitrile, 1% (w/w) L-cysteine and 20 mmol L− 1 pyridine and 160 mmol L− 1 formic acid, at pH 2.4 within 7 min. Once separated, both species are reduced by formic acid in mobile phase under UV radiation to convert Hg0 on-line, which is subsequently swept (by argon carrier gas) into an atomic fluorescence spectrometry (AFS) for measurement. Under the optimized experiment conditions, the detection limits (as Hg), based on three times the standard deviation of a standard solution, were found to be 0.1 ng mL− 1 for mercury and 0.08 ng mL− 1 for methylmercury, with an injection volume of 100 μL. The developed method was validated by determination of certified reference material DORM-2 and was further applied in determination of seafood samples.