Determination of Four Arsenic Forms in Sediments by Liquid Chromatography Atomic Fluorescence Spectroscopy
A method for simultaneous and rapid analysis of four different forms of arsenic in sediments,namely AS(Ⅲ),DMA,MMA,and AS(Ⅴ),was established based on liquid chromatography atomic fluorescence spectroscopy.The optimization of the extraction agent showed that 1.0 mol/L phosphoric acid and 0.5 mol/L ascorbic acid 10 mL were effective in extracting different forms of arsenic.The extraction method was optimized,and the results showed that the extraction rate was higher after 30 min of microwave extraction at 80℃.Comparing the recovery rates of samples before and after purification with the extraction solution,it was found that the C18 solid-phase column can avoid the adsorption loss of the target compound.Four different forms of arsenic had good correlation within a certain linear range,with correlation coefficients greater than 0.999.The detection limit of the method was from 0.018 to 0.083 mg/kg.The recovery rate of sample spiking was from 70.5％to 95.9％,and the relative standard deviation(RSD,n=6)was from 3.2％to 9.0％.The actual sediment samples were mainly composed of inorganic arsenic,and the content of AS(Ⅴ)was higher than that of AS(Ⅲ).The detection limit,precision,and accuracy of this method all meeted the analysis requirements,which could provide technical support for ensuring water environment quality and safety.
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