新显色剂BCTZACA光度法测定镍的研究

Spectrophotometric Determination of Nickel with 2,7-bi(5-carboxy-1,3,4-triazolylazo)-chromotropic Acid

研究了新显色剂2,7-双(5-羧基-1,3,4-三氮唑偶氮-变色酸(简称BCTZACA)与镍的显色反应条件。结果表明,在pH7.0HAc-NaAc介质中,新显色剂BCTZACA与Ni(II)形成稳定的紫色络合物,络合物的λmax=558nm,络合物的表观摩尔吸光系数ε=2.57×104L/(mol.cm)。Ni(II)在(0—1.6)mg/L范围内符合比尔定律。所拟方法直接用于镁合金和铝合金样品中微量镍的测定,结果满意。

The conditions of color reaction of a new reagent 2,7 - bi （5 - carboxy - 1,3,4 - triazolylazo） - chromotropie acid （BCTZACA） with nickel（Ⅱ） were presented. The results showed that the new color reagent reacts with nickel （Ⅱ） to form a stable purple complex in the buffer solution of HAc - NaAc（ pHT. 0）. The apparent molar absorbance is 2.57 × 10^4 L/（ mol. cm） at λmax = 558nm. Beer＇ s law is obeyed in concentration range of （0 - 1.6） mg/L for Ni（Ⅱ）. The proposed method has been applied to the spectrophotometric determination of trace nickel in magnesium and alumunium alloys with satisfactory results.