Determination Of Trace Mercury In Water By UV-PVG-ICP-MS

As a highly toxic element,mercury poses a serious threat to human health.The mercury content in the natural water body is ng/L class,which is not only difficult to measure,but also easily disturbed in the measurement process.The main research content of this paper is to establish a UV-PVG-ICP-MS method for the determination of trace mercury,using sodium diethyldithiocarbamate(DDTC)modified C18 solid phase extraction secondary enrichment of mercury in water not only improves the retention efficiency of mercury,but also reduces the influence of the sample matrix on the accurate determination of analytes.The method has been successfully applied to the determination of trace mercury in tap water and industrial wastewater,and can detect wet digestion of aquatic product samples.The specific work and conclusions are as follows:(1)A method for the determination of trace mercury in water by using a solid-phase extraction based ultraviolet photochemical vapor generator and inductively coupled plasma mass spectrometry was established.Experiments were conducted on the elution time of mercury,the concentration of mercaptoethanol in the eluent,the carrier gas flow rate,and the working conditions of the detector.The optimal experimental conditions were determined.The optimal experimental conditions were as follows: the elution time of mercury was 160 s,the concentration of mercaptoethanol in the eluate was 0.1%,and the carrier gas flow rate was 800 mL/min.Mercury peak area is in a good linear relationship with mercury concentration in the range of 20-200 ng/L.The regression equation of the working curve is Y=4872.8 X-17098,the correlation coefficient is 0.9985,and the precision RSD<5%(n=7).(2)Under the optimal experimental conditions,tap water samples,industrial wastewater samples and biological reference samples were determined.The detection limit of the method was 0.92 ng/L,and the recoveries of the samples were between 94% and104%.Standard reference prawn GBW10050 and tuna IAEA 436 were found to match the recommended values.The results show that the UV photochemical vapor generation and inductively coupled plasma mass spectrometry system can be used for the determination of trace mercury in water,and can be applied to the detection of trace mercury in aquatic products after wet digestion.The method has the advantages of simplicity,low detection limit and relative greenness.(3)Based on the existing experiments,the extended application of ultraviolet photochemical generator and inductively coupled plasma mass spectrometry was studied.It mainly includes the impact of the detection system on the determination results of different sample matrices and the impact on the response degree of mercury,methyl mercury and ethyl mercury.The experimental results show that mercury in the combined system is severely disturbed by the matrix.For different mercury forms,the signals generated by the combined system are also different.The mercury response signal is about 3 times that of methylmercury,about 2 times that of ethyl mercury,and it may be that the mercury forms have been converted during the detection process.