目的 建立DMA-80直接测汞仪快速测定农村环境土壤中总汞含量的方法。方法 土壤样品经风干后,粉碎研磨,过100目(孔径0.149 mm)尼龙筛,称取一定质量的样品置于石英样品舟内,样品经干燥、分解、催化、汞齐化富集,生成的汞蒸汽由氧气导入光学池,在波长253.7 nm处检测,用标准曲线法,依据朗伯-比耳定律进行定量。同时,采用原子荧光法平行测定。结果 DMA-80直接测汞仪快速测定方法,干燥温度选择300 ℃,分解温度选择650 ℃,进样量选择0.1000 g时,可获得准确的分析结果。在最佳实验条件下,测定了土壤标准物质,测定值与标准值一致,测定值的相对标准偏差依次为2.53%和1.13%,方法的线性范围为0~30 ng和 0~600 ng,线性相关系数分别为0.9991和0.9997,检出限为0.1080 ng/g,加标回收率在93.6%～115.8%之间;10份土壤样品分别采用DMA-80直接测汞仪快速测定法和原子荧光法测定土壤中的汞含量,结果表明两种方法分析结果差异无统计学意义(W⁺=36,拒绝域为{W⁺≤8}U{W⁺≥47})。结论 该方法稳定可靠,操作简单高效、准确度和重复性好,可用于农村环境土壤中总汞的测定。

Objective To establish a method for rapid determination of total mercury in rural environmental soil sample by DMA-80 direct mercury analyzer. Methods After air drying,the soil samples were crushed and ground,passed through a 100 mesh (aperture 0.149 mm) nylon sieve,weighed and placed in a quartz sample boat.After drying,decomposition,catalysis and mercury homogenization and enrichment,the generated mercury vapor was introduced into the optical cell by oxygen,detected at the wavelength of 253.7 nm,and quantified by standard curve method according to Lambert Beer law.At the same time,atomic fluorescence spectrometry was used for parallel determination. Results When DMA-80 direct mercury analyzer was used for rapid determination,the drying temperature was 300 ℃,the decomposition temperature was 650 ℃,and the injection volume was 0.1000 g,accurate analysis results could be obtained.Under the best experimental conditions,the soil reference materials were determined,and the measured values were consistent with the standard values.The relative standard deviations of the measured values were 2.53% and 1.13%,respectively.The linear range of the method was 0~30 ng and 0~600 ng,the linear correlation coefficients were 0.999 1 and 0.999 7,the detection limit was 0.1080 ng / g,and the recovery rate of spiked standard was 93.6%~115.8%.The contents of mercury in 10 soil samples were determined by DMA-80 direct mercury analyzer and atomic fluorescence spectrometry,respectively.The results showed that there was no statistical difference between the two methods (W⁺=36,the rejection domain was {W⁺≤ 8} u {W⁺≥ 47}). Conclusion The method is stable,reliable,simple,efficient,accurate and repeatable,and can be used for the determination of total mercury in rural environmental soil.