Determination of Total Mercury in Food Samples by DMA-80 Direct Mercury Analyzer
With the release of the new National Standard GB 5009.17-2021,the direct sampling method is used as the sec-ond method in the detection of mercury in food.In order to validate the direct sampling method,the application of DMA-80 direct mercury analyzer in the determination of total mercury in different matrix samples was studied in this paper.The accu-racy and stability of the method were verified by the multi-matrix and multi-level recovery experiment,precision experi-ment,quality control sample determination and atomic fluorescence spectrometry comparison experiment.The results show that the method had a good linear relationship in the range of standard curves of low and high concentrations of 0-30 ng and 40-600 ng(R2=1.000 0;R2=l.000 0);The recoveries of different samples ranged from 72.0%to 109%.When the sample size is 0.10 g,the detection limit is 0.000 12 mg/kg;Meet the national standard method detection limit(0.000 2 mg/kg)re-quirements.The quality control samples were determined many times,and the results were all in the characteristic value range.The results of FAPAS comparison show that the direct sampling method is more close to the median value of the labo-ratory comparison.In a word,direct determination of mercury does not need pre-treatment,low detection limit,good stabili-ty,accurate results,simple and rapid operation,suitable for all kinds of food analysis of total mercury.