一种H酸衍生物新试剂的合成并用于铜(Ⅱ)离子的显色反应

Synthesis of a New Azo Reagent of H-acid Derivative and Its Use in the Color Reaction with Cupric Ion

以H酸钠盐和4-氨基苯磺酸为主要反应物,制备了偶氮类试剂7-（4-磺酸基苯偶氮）-8-羟基-1-氨基-3,6-萘二磺酸（简称SPAHANS）。采用红外光谱法、紫外-可见分光光度法和元素分析法对SPAHANS的组成及结构作了检测。研究了该试剂与铜（Ⅱ）的显色反应。在pH 4.5的乙酸-乙酸钠缓冲体系中,在40-65℃加热5 min后,铜（Ⅱ）和SPAHANS反应生成配合比为1∶2的棕褐色配合物,在其最大吸收波长510 nm处的摩尔吸光率为1.6×105L.mol-1.cm-1。铜（Ⅱ）量在0.22-3.0 mg.L-1范围内服从比耳定律。方法的检出限（3s/k）为5.6×10-2mg.L-1,取质量浓度为1.0 mg.L-1铜（Ⅱ）标准溶液,同时测定9次,测得相对标准偏差为0.17%。

A new azo reagent,7-（4-sulfophenylazo）-8-hydroxy-1-amino-3,6-naphthalene disulfonic acid（SPAHANS）,was synthesized by the reaction of diazonium compound of 4-aminobenzene sulfonic with H acid in 0.25 mol·L-1 Na2CO3 solution of pH 9.0.Molecular composition and structure of SPAHANS were determined by FT-IRS,UV-VIS spectrophotometry and elementary analysis.It was found that in an acetate buffer medium of pH 4.5 and heated at 40-65 ℃ for 5 min,a stable coordination complex（Cu2＋∶R=1∶2） was formed by the reaction of SPAHANS with cupric ion,having the absorption maximum at 510 nm.Linear relationship between values of absorbance and concentration of Cu2＋-ion was obtained in the range of 0.22-3.0 mg·L-1.Detection limit（3s/k） found was 5.6×10-2mg·L-1.The molar absorptivity of the color system was found to be 1.6×105L·mol-1·cm-1.Test for precision was made with standard Cu2＋ solution of 1.0 mg·L-1 for 9 determinations,giving value of RSD 0.17%.