过量酸性铬蓝K隐色光度法测定铜的研究

The Spectrophotometric Determination of Micro Amounts of Copper by Hiding Colour of the Excessive Acid Chrome Blue K

在pH 4.0的微酸性介质中,酸性铬蓝K同Cu^(2+)形成稳定的红色络合物,用H_2O_2为隐色剂可以隐去过量显色剂的颜色,消除高色度背景的影响。络合物的最大吸收波长为540nm,摩尔吸光系数为1.6×10~4L·mol^(-1)·cm^(-1),Cu量在0～1.4μg/ml范围服从比尔定律。方法已应用于测定矿样中的Cu。

Copper ( Ⅱ ) reacts with acid chrome blue K to form a stable complex in HAc-NaAc buffer(pH 4. 0). The precision and sensitivity are increased by hiding the background colour of the excessive colour reagent with H2O2. The maximum absorption is at 540nm. The molar absorptivity is 1. 6× 104 L·mol-1·cm-1. Beer's law is obeyed in the range 0~1. 4μg/ml of copper. The method has been applied to the determination of micro amounts of copper in ores with satisfactory results.