【摘要】 在HCl介质中及65℃加热条件下,痕量Ni(Ⅱ)对溴酸钾氧化甲基蓝褪色的反应具有灵敏的阻抑作用。研究了最佳实验条件,建立了阻抑动力学光度法测定痕量Ni(Ⅱ)的新光度分析方法。在602 nm处,非阻抑反应吸光度(A0)与阻抑反应的吸光度(A)的差值ΔA与Ni(Ⅱ)的质量浓度ρ在0.10~1.50μg/25 mL范围内呈良好的线性关系。检出限为2.44×10-10g/mL。测定了动力学参数,Ni(Ⅱ)为一级反应,总反应为准一级反应。反应表观速率常数为3.750×10-4/s,表观活化能为47.19 kJ/mol。该方法用于含钒生铁和低合金钢中痕量Ni(Ⅱ)的测定,测定值与推荐值一致,回收率为98%~102%。更多还原

【Abstract】 The fading reaction of methylene blue when methylene blue was oxidized by potassium brominates can be easily inhibited by trace nickel(Ⅱ) in HCl medium under 65 ℃ heating conditions.The optimum experimental conditions were studied,and a new inhibitory kinetic spectrophotometry method of trace nickel(Ⅱ) determination was established.The absorbency difference ΔA between non-inhibitory reaction(absorbency A0) and inhibitory reaction(absorbency A) remained good linear relationship with the mass concentration(ρ) of nickel(Ⅱ) in the range of 0.10-1.50 μg/25mL at 602 nm.The detection limit was 2.44×10-10 g/mL,and kinetic parameters were determined which showed that the reaction was the first order reaction to nickel(Ⅱ) and pseudo first order reaction to the total reaction.The apparent ratio constant of the reaction was 3.750×10-4 /s and the apparent activation energy was 47.19 kJ/mol.The method was also applied to the determination of trace nickel(Ⅱ) in vanadium iron and low alloy steel with the recovery of 98%-102%,and the results were consistent with the certified value.更多还原