新显色剂1-(4-硝基苯基)-3-(5-氯吡啶)三氮烯的合成及其与镉的显色反应

Synthesis of 1-(4-nitrophenyl)-3-(5-chloropyridyl)-triazene and its color reaction with cadmium

报道了1-(4-硝基苯基)-3-(5-氯吡啶)三氮烯(NPCPDT)的合成及其与镉的显色反应研究.在Triton X-100的存在下,pH 11.5的Na2B4O7-NaOH缓冲溶液中,该试剂能与镉发生显色反应,镉与NPCPDT形成摩尔比为1:3的黄色配合物,在440 nm处有一最大吸收,在535 nm处有一最大负吸收.以440 nm为参比波长,535 nm为测量波长进行双波长测定,表观摩尔吸光系数为2.68×105L·mol-1·cm-1,镉的质量浓度在0～0.48μg/mL范围内符合比尔定律.用拟定方法测定废水和环境水样中的微量镉.

This paper reported the synthesis of a new re- gent 1-（ 4-nitrophenyl ）-3-（ 5-chloropyridyl ）-triazene （NPCPDT） and the color reaction of NPCPDT with cad- mium. In the presence of the surfactant Triton X-100 and in the medium of Na2B4O7-NaOH pH 11.5, the reagent forms a yellow complex with cadmium in the molar ratio of 1：3. The apparent molar absorptivity is 2.68×10^5L·mol^-1·cm^-1 by double wavelength spectrophotometry. The measuring wavelength is 4-40 nm and the reference wavelength is 535 nm. Beer＇s law is obeyed in the range of 0 - 12μg/25 mL. The method has been applied to the direct determination of cadmium in practical samples and waster water with satisfactory results.