新显色剂分光光度法测定氯化十六烷基吡啶

Spectrophotometric Determination of Cetylpyridinium Chloride with Bibromocarbaxylbenzenediazoaminoazobenzene

研究了新显色剂二溴羧基苯基重氮氨基偶氮苯与阳离子表面活性剂氯化十六烷基吡啶(CPC)的显色反应.结果表明,在1.0 mol/L NaOH介质中,显色剂与CPC发生灵敏的显色反应,形成1∶2的紫红色缔合物,其最大吸收波λmax＝580 nm,表观摩尔系数ε＝3.7×104 L·mol-1·cm-1,CPC的含量在0～80 μg/25ml范围内遵守比尔定律.据此建立了水中微量的CPC光度测定新方法.在EDTA存在下,显色反应具有良好的选择性,可直接用于自来水样的分析.

A novel spectrophotometric method for the determination of cetylpyridinium chloride(CPC)with dibromocarbaxylbenzenediazoaminoazobenzene is developed. In the medium of 1.0 mol/L sodiumhydroxide,CPC reacts with dibromocarbaxylbenzenediazoaminoazobenzene to form violet red 1∶2 complex of ion association in the presence of TritonX-100.This complex of ion association exhibits an absorption maximum at 580 nm with an apparent molar absorptivity of 3.7×10~4 L·mol~(-1_·cm~(-1_. Beer's law is obeyed of CPC in the concentration rang of 0~80 μg per 25 ml of solution. The proposed method based on the above colour reaction is simple and rapid, and toxic organic solvents are not used. It has been applied to the determination of trace CPC in tap water with satisfactory result.