Determination Of Methylmercury In Biological Samples By Domestic Microwave-assisted Extraction And Capillary Gas Chromatography

The toxity of mercury was closely correlated with its speciation,of which methyl-mercury was the most toxic and the main form existing in biological samples. The study on the separation and collection of methyl-mercury, and the technique for determination of methyl-mercury was of great importance. An economic method was introduced in this paper, employing domestic microwave-assisted extraction of methyl-mercury from biological samples and capillary gas-chromatography for the determination, based on related theory on microwave-assisted extraction and capillary gas-chromatography.Parameters of domestic GC7890 capillary gas-chromatography, affecting the determination of methyl-mercury, including the injection volume,the retention time, the flowrate of carrier gas and supporting gas,and the temperature of input, column, and ECD, were discussed and optimized: input temperature—200℃, columntemperature—160℃, ECDtemperature—200℃, flowrate of carrier gas—60mL/min, supporting gas—30mL/min, injection volume—2μL. Under optimized condition, the retention time of methyl-mercury was about 1.094min. In the variation from 0 to 1.0μg/mL, signals show good linearity with the concentration of merthyl-mercury. The detection limit was 0.09μg/mL.Paramters of microwave, affecting the extraction, including microwave extracting time, the volume of L-cysteine as extracting reagent,and the volume of HC1 and benzene in counterextraction were discussed and optimized: Microwave extracting time—5min, L-cysteine—12mL, volume of HC1—4mL,and benzene—5mL.Under optimized condition, the extraction rate was satisfactory.The new method was applied to practical determination of methyl-mercury extracted from biological samples. The results showed that the recovery rate and precision were satisfactory, and the method was suitable for practical use,and of great value.