曙红B分光光度法测定痕量铋(Ⅲ)
来源期刊：冶金分析2010年第7期
论文作者：凌立新 王林
文章页码：58 - 61
关键词：曙红B； 催化动力学光度法； 铋(Ⅲ)； 水体
Key words：eosin B； catalytic kinetic spectrophotometry； bismuth (Ⅲ)； water body
摘 要：在硫酸介质中,铋(Ⅲ)对碘酸钾氧化生物染料曙红B的褪色反应有强烈催化作用,据此建立了测定痕量铋(Ⅲ)的催化动力学方法。反应最优实验条件:在25 mL测定体积中,2.0×10-3 mol/L曙红B用量为1.2 mL,1.0×10-2 mol/L碘酸钾用量为1.5 mL,反应温度为90℃。在优化条件下,体系催化反应和非催化反应的吸光度变化值(ΔA)与铋(Ⅲ)质量浓度在0~0.18μg/mL范围内呈良好线性关系。方法检出限为8.04×10-7 g/L,表观速率常数为2.97×10-4 s-1,表观活化能为36.74 kJ/mol。对0.06 g/mL Bi(Ⅲ)标准溶液进行11次平行测定,其相对标准偏差为2.7%。本法已用于水体中痕量铋(Ⅲ)的测定,相对标准偏差(n=6)为2.8%~3.2%,与原子吸收光谱法进行了对照,结果一致。
Abstract: In sulphuric acid medium,bismuth(Ⅲ) had strong catalytic action on the fading reaction of biological dye eosin B oxidized by potassium iodate.Based on this,the catalytic kinetic determination of trace bismuth(Ⅲ) was established.The optimal experimental conditions were obtained: for 25 mL of solution,the dosage of eosin B(2.0×10-3 mol/L) was 1.2 mL,the dosage of potassium iodate(1.0×10-2 mol/L) was 1.5 mL and the reaction temperature was 90 ℃.The absorbency change (ΔA) of catalytic reaction and non-catalytic reaction showed good linear relationship with the mass concentration of bismuth(Ⅲ) in the range of 0-0.18 μg/mL.The detection limit of this method was 8.04×10-7 g/L,the apparent reaction rate constant was 2.97×10-4 s-1,and the apparent activation energy was 36.74 kJ/mol.The standard solution of bismuth(Ⅲ) (0.06 g/mL) was determined for 11 times,and the relative standard deviation(RSD) was 2.7 %.The proposed method was applied to the determination of trace bismuth(Ⅲ) in water body with the relative standard deviation of 2.8%-3.2%,and the results were consistent with those obtained by atomic absorption spectrometry.
