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    火焰原子吸收光谱法测定钒基合金中铬的含量

    Determination of Chromium in Vanadium Alloys by Flame Atomic Absorption Spectrometry

    • 摘要: 应用火焰原子吸收光谱法(FAAS)测定钒基合金(V-Cr-Ti三元合金)中铬的含量。取样0.100 0 g,用硫酸(1+1)溶液5 mL及硝酸2 mL加热溶解后蒸发至冒硫酸烟。冷却后移至100 mL容量瓶中,加水定容。分取适量样品溶液(其中含Cr约为0.1~0.5 mg)置于另一100 mL容量瓶中,加入20 g·L-1硫酸钾溶液10 mL(作为对共存元素V和Ti的抗干扰试剂,同时起到增敏作用明显提高信号强度),加水定容为100.0 mL(溶液中含硫酸<0.5%),按仪器工作条件测定溶液中铬的含量。在优化的试验条件下,铬的质量浓度在1.00~5.00 mg·L-1内与相应的吸光度之间呈线性关系。应用此方法测定了实际样品中铬的含量,测定值的相对标准偏差(n=6)为0.64%,以实际样品为基体,按照标准加入法在2个浓度水平上进行回收试验,测得回收率的平均值为97.1%。

       

      Abstract: FAAS was applied to the determination of Cr in a vanadium based alloy, a ternary componental alloy of V, Cr and Ti. 0.100 0 g of the alloy sample was taken and dissolved in 5 mL of H2SO4 (1+1) and 2 mL of HNO3 by heating, then evaporated to fumes of sulfuric acid. After cooling, the solution was diluted to 100.0 mL with water in a volumetric flask. An aliquot containing chromium approximately in the range of 0.1-0.5 mg was taken and transferred to a 100 mL volumetric flask, and its volume was made up to 100.0 mL with water after adding 10 mL of 20 g·L-1 K2SO4 solution, which was added as an anti-interfering reagent to overcome the interferences from the coexisting V and Ti ions as well as a sensitizing reagent to raise the signal intensity. Chromium content of the sample solution was then determined by FAAS. Under the optimum condition, linear relationship between values of absorbancy and the corresponding mass concentration of Cr was obtained in the range of 1.00-5.00 mg·L-1. A substantial V based alloy was analyzed by the proposed method, and value of RSD (n=6) found for chromium was 0.64%. Using V-Cr-Ti alloy as matrix, recovery was tested by adding chromium standard solution at 2 concentration levels, average value of recovery found was 97.1%.

       

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