在pH 6.35 的乙酸盐缓冲介质中并加入氟化物作为掩蔽剂,铜(Ⅱ)与二溴茜素紫(DBAV)生成二元配合物Cu(DBAV)2,利用光谱修正法表征配合物的分子结构.选择吸收光谱峰谷波长607,548 nm为工作波长,测定显色溶液及空白的吸光度A607 nm,A548 nm及A′607 nm,A′548 nm.计算光吸收比差值(ΔAr).当铜离子浓度在0.15 mg·L-1以内与ΔAr值之间呈线性关系,方法的检出限(3σ)为2.5 μg·L-1.分别对长江及黄浦江水样中痕量铜(Ⅱ)进行了测定,结果与电感耦合等离子体原子发射光谱法的测定结果相符,方法的回收率在100%~108%之间.

In an acetate buffer medium of pH 6.35,a binary coordination complex of Cu(DBAV)2 was formed by the reaction of Cu(Ⅱ) with dibromo alizarin violet (DBAV),and its molecular structure was characterized by the spectral correction method. Wavelengths of the crest and trough in the absorption spectrum of the coordination complex were found at 607 nm and 548 nm respectively. Values of absorbance of the colored complex solution and the blank solution were measure at both wavelengths (recorded as A607 nm,A548 nm and A′607 nm and A′548 nm) and value of difference of absorption ratio (ΔAr) was calculated. Linear relationship between values of ΔAr and concentration of Cu(Ⅱ) ion was found in the range within 0.15 mg·L-1,and the detection limit (3σ) found was 2.5 μg·L-1. The proposed method was used in the determination of trace amount of copper(Ⅱ) in surface water taken from Yangtze River and Huangpu River,giving results in consistency with the results found by ICP-AES method,and the values of recovery found were ranged from 100% to 108%.