氨基乙酸邻苯甲酸-溴化十六烷基吡啶荧光猝灭体系检测痕量铜

DETERMINATION OF TRACE AMOUNTS OF COPPER BY ITS QUENCHING EFFECT ON THE FLUORESCENCE OF GLYCINE-o-BENZOIC ACID IN THE PRESENCE OF CPB

研究了荧光猝灭法测定痕量铜的方法。在溴化十六烷基吡啶存在下,氨基乙酸邻苯甲酸可以和铜形成稳定的配合物,此配合物可以使配体荧光定量猝灭。反应的适宜酸度为pH5.0～6.0,最大发射波长λem为427nm,表观摩尔吸光系数ε=5.56×104L·mol-1·cm-1,Cu(Ⅱ)含量在0.2～12.8μg/10ml范围内符合比耳定律,相关系数为0.9999。应用于铝合金样品中痕量铜的测定,结果满意。

It was found that the fluorescence emitted by glycine-o-benzoic acid (λ_(ex)=351nm, λ_(em)=427nm) was quenched by the presence of trace amounts of Cu(Ⅱ) in an acetate buffer medium of pH 5～6, through the formation of a stable complex with mole ratio of (R∶Cu) 1 to 1. The quenching effect was further intensified by the presence of CPB. Linear relationship between the magnitude of weakening of the fluorescence intensity (ΔF) and the concentration of Cu(Ⅱ) was found in the range of 0.2～12.8μg of Cu(Ⅱ) per 10ml of solution giving a correlation coefficient value of 0.999 9. The apparent molar absorptivity was found to be 5.56×10~4L·mol^(-1)·cm^(-1). This method has been used satisfactorily in the analysis of aluminum alloys.