双波长双指示剂催化光度法同时测定锰和铜

摘要

研究了在pH4．5的HAc-NaAc缓冲溶液介质中，利用痕量铜和锰同时催化高碘酸钾氧化亚甲基蓝和罗丹明B的褪色的指示反应，分别在660nrn和540nm波长下测量催化体系和非催化体系的吸光度，建立了双指示剂、双波长催化动力学光度法下测定痕量铜和锰的新方法。在最佳实验条件下，用固定时间法，测得的铜和锰线性范围分别为：0．0050～0．025μg／mL，0．0010~0．020μg／mL；检出限分别为：3．3×10^-10g／mL，7．6×10^-11g／mL。该法操作简单，灵敏度高，选择性好，可用于实际样品头发和大米中痕量铜和锰的测定，结果令人满意。%A new dual-wavelength single-indicator catalytic kinetic spectrophotometric method for the determination of trace Cu（II） and Mn（II） in HAc-NaAc（pH4. 5） buffer solution medium was studied. The method was based on the Cu（II）and Mn（II）catalyzing oxidation of methythlene blue and rhodamine B by potassium periodate. The ab- sorbance of catalytic and uncatalytic systems was measured at 660nm and 540nm. Under the optimum conditions, the linear range of the determination of trace Cu（II） and Mn（II） were 0. 0050~0. 025μg/mL and 0. 0010~ 0. 020μg/mL. The detection limits were 3.3 ×10^-10g/mL and 7. 6 ×10^-11g/mL respectively. The method was simple, high sensitivity, and good selectivity, the method was applied to the determination of trace Cu（II） and Mn （II） in hair and rice with satisfactory results.