茜素红褪色动力学光度法测定痕量钴

Catalytic Kinetic Spectrophotometric Determination of Trace Cobalt (Ⅱ) by Alizarin Red Fading

在pH8．0的氨-氯化铵介质中，以聚氧乙烯醚-200（PEG-200）为活化剂，Co（Ⅱ）催化溴酸钾氧化茜素红褪色，建立了动力学光度法测定痕量Co（Ⅱ）的新方法。该方法检出限为2．0×10^-7g／L；线性范围0．01—0．21μg／50mL；最大相对标准偏差为4．3％。该法用于湖水及生产排水的测定，结果满意；加标回收率在96．0—105．0％。

A rapid, simple and sensitive kinetic spoetrophotometric method was presented for the determination of cobalt （Ⅱ）. The method was based on the oxidation fading of alizarin red by KBrO3 with polyethylene glycol-200（PEC-200） as activation agent and cobalt （Ⅱ） as catalyst in a medium of NH3 · H2O - NH4Cl. The reactions can be monitored spoctrophotometrically by measuring the absorbance at 516 nm. The results show that the detection limit of the method is 2.0 × 10^-7 g/L,the linear range is between 0.01 - 0.21 μg/50 mL, the relative standard deviation is 4.3%. It has been used to determine trace cobalt（Ⅱ） in water with satisfactory results, the recovery of standard addition is 96.0% - 105.0%.