分光光度法测定水样中偶氮染料刚果红

Spectrophotometry method for the determination of bisazo dye congo red in water samples

采用可见光分光光度法对水溶液中刚果红的测定条件进行探讨,分别考察了溶液p H、水浴温度、无水乙醇、恒温时间以及钙镁铝离子对其测定的影响。同时,用紫外吸收光谱研究不同p H和钙镁铝离子等因素对刚果红溶液光谱学性质的影响。研究结果表明:在测定波长为500 nm,用5 m L氯化铵-氨水反冲溶液将溶液p H调节到6~11之间,加入无水乙醇15 m L,在303 K水浴中恒温10 min后检测,乙二胺四乙酸二钠、柠檬酸三钠等金属离子掩蔽剂作用条件下,刚果红溶液的质量浓度在0.2~26 mg/L之间内与吸光度呈良好线性关系,其线性回归方程为y=0.01415+0.04366x,相关系数R2=0.9998,检出限为0.2 mg/L。在试验条件下,平均回收率为100.4%,RSD≤1.1%,该方法对溶液中刚果红的检查准确度和精密度较高,建立了一种对水样中刚果红快速、准确检测的方法。

In order to quickly and accurately determine the content of congo red in water samples,the determination conditions of congo red in aqueous solution are studied by visible spectrophotometry method. The effects of p H value,water bath temperature,anhydrous ethanol,constant temperature time,Ca（2＋）,Mg（2＋）and Al（3＋）on the determination are comprehensively investigated. And the effects of different p H values,Ca（2＋）,Mg（2＋）and Al（3＋）on the spectroscopic properties of congo red solution are studied by UV absorption spectroscopy. The absorption wavelength is 500 nm,and the p H value of the solution is adjusted between 6 and 11 by 5 m L ammonium chloride-ammonia backwash solution. The constant temperature of water bath is set as 303 K,the volume of anhydrous ethanol is 15 m L and the constant temperature time is 10 min. Under the condition of metal ion masking agent such as EDTA and trisodium citrate,the concentration of congo red solution show a good linear relationship with the absorbance in the range of 0. 2 to 26 mg/L. The linear regression equation is y = 0. 01415 ＋0. 04366 x. The correlation coefficient R2 is 0. 9998. The detection limit is 0. 2 mg/L. Under the experimental conditions,the average recovery is 100. 4% and RSD is no more than 1. 1%. The method has high accuracy and precision in the determination of congo red in solution. In this work,a rapid and accurate method was established for the determination of congo red in water samples.