Evaluation of Hg species after culinary treatments of fish

- Critical evaluation of influence of culinary treatments on mercury species in fish.
- Dependence on the type of cooking procedure for losses of mercury species in fish.
- Feasibility of selected extraction method for further determination of Hg species by LC-CVG-ICP-MS.

The present study aimed to evaluate possible conversion or loss of Hg species (Hg2+ and CH3Hg+) during different culinary treatments of six fish species. Four cooking procedures (uncooked, boiling, frying and roasting) and the influence of three commonly used cooking conditions (no spices, with salt, and with salt and lemon juice) were also evaluated for each treatment, creating a total of 12 types of culinary treatment for each fish species. Oil and water used during cooking procedures and the used spices like salt and lemon were analyzed to assure a close mass balance of total Hg. After each culinary treatment, samples were immediately freeze-dried. Mercury species were identified and quantified by liquid chromatography-chemical vapor generation-inductively coupled plasma mass spectrometry. No significant conversion of Hg species was observed with any of the evaluated cooking treatments. On the other hand, an overall loss of up to 33% of Hg species was observed after frying. Most of the Hg lost during the cooking procedure came from CH3Hg+.