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.