苯酚及3种苯二酚异构体在多壁碳纳米管修饰玻碳电极上的电化学行为研究及循环伏安法测定水样中总酚含量

Study on the Electrochemical Behaviors of Phenol and Three Isomers of Dihydroxybenzene at the MWCNTs Modified GCE and CV Determination of Total Phenols in Water Samples

移取1.00×10-3 mol·L-1的苯酚、对苯二酚、邻苯二酚和间苯二酚标准溶液各5.00mL,分别置于4支比色管中,各加pH 5.0的柠檬酸-柠檬酸钠缓冲溶液3.00mL,用水定容至10mL,采用多壁碳纳米管修饰的玻碳电极为工作电极,以0.25V·s-1速率扫描获得循环伏安曲线。结果发现:0.225,0.333,0.727V处的氧化峰电流的加和与总酚浓度在0.5~2 000μmol·L-1内呈线性关系,检出限(3S/N)为0.15μmol·L-1。方法用于测定环境水样中总酚含量,加标回收率在95.0%~105%之间,测定值的相对标准偏差(n=6)小于6.0%。

Aliquots of 5.00 mL of standard solution of 1.00×10-3 mol·L-1 phenol,hydroquinone,catechol and resorcinol were taken and placed separately in 4 colorimetric tubes.Portions of 3.00 mL of citric acid-sodium citrate buffer solution（pH 5.0）were added to each of the tubes and the volume of the mixture were made up to10 mL with water.Cyclic voltammetry curves of the 4 solutions were taken at a scanning rate of 0.25 V·s-1,using a multi-walled carbon nanotube modified glassy carbon electrode as working electrode.It was shown that linear relationship was kept between the sum of oxidation peak currents,at 0.225,0.333,and 0.727 V,and the concentration of total phenols in the range of 0.5-2 000μmol·L-1,with detection limit（3 S/N）of 0.15μmol·L-1.The method was used to determine total phenols in environmental water samples,and recovery was tested by standard addition method,giving values of recovery in the range of 95.0%-105%,and RSDs（n=6）less than6.0%.