热解吸收-冷原子荧光光谱法测定水泥中痕量汞

将热解吸收技术应用于冷原子荧光光谱法测定水泥样品中痕量汞含量。采用自制的石英管加热550℃处理样品,用0.01mol·L-1高锰酸钾溶液作为吸收液吸收释放出的汞蒸气,用盐酸羟胺还原过量的高锰酸钾后直接进样测定。试验中优化了仪器的工作参数和试验条件。分析中采用载气及屏蔽气的流量依次为400mL.min-1及1 000mL.min-1。荧光强度与汞的质量浓度在2μg·L-1以内呈线性关系,方法的检出限(3σ)为0.020μg·L-1。应用此法分析土壤标准样品(GBW 07405),测定值(0.30μg.g-1)与证书值(0.29±0.03μg.g-1)相符;方法用于测定水泥中汞含量,加标回收率在97.0%～107.0%之间,相对标准偏差(n=5)在0.7%～4.1%之间。

CV-AFS Determination of Trace Amount of Mercury in Cement with Pretreatment of Sample by Pyrolytic Absorption

Pyrolytic and absorption technique was applied to the CV-AFS determination of mercury in cement.The samples were heated in a self-made quartz tube at 550 ℃,the Hg vapour released was absorbed in 0.01 mol·L-1 KMnO4 solution and excess of KMnO4 was reduced by hydroxylamine hydrochloride solution,and then mercury was determined in the solution directly.Flow-rates of 400 mL·min-1 for carrier gas and 1 000 mL·min-1 for shielding gas were taken in the analysis.Linear relationship between the fluorescence intensity and mass concentration of Hg found was in the range within 2 μg·L-1,with detection limit(3σ) of 0.020 μg·L-1.Result of average value of Hg(0.30 μg·g-1) determined in a CRM(GBW 07405) was in consistency with the certified value(0.29±0.03 μg·g-1).The proposed method was applied to the analysis of samples of cement,giving values of recovery and RSD′s(n=5) in the ranges of 97.0%-107.0% and 0.7%-4.1% respectively.