水杨酸在改性钠基蒙脱土修饰电极上的电化学行为及测定

用十六烷基三甲基溴化铵(CTAB)对钠基蒙脱土进行改性,并用红外光谱、X衍射对CTAB-NaMMT进行表征,制备了改性钠基蒙脱土修饰电极(CTAB-NaMMT-CMC/GCE),研究了水杨酸在该修饰电极上的循环伏安行为.结果表明,在pH 0.8的H_2SO_4-Na_2SO_4电解质溶液中,SA在1.19 V出现一明显的氧化峰,在40 ～400 mV/s范围内,其氧化峰电流与扫描速率的平方根(v~(1/2))呈良好线性关系,表明电极过程为受扩散控制不可逆过程.测得SA在该修饰电极上的反应电子数、质子数、传递系数及扩散系数分别为2、2、0.389、1.275×10~(-6) cm~2/s.方波溶出伏安法的氧化峰电流(I_(pa))与SA浓度在8.0×10~(-7) ～1.25×10~(-4) mol/L范围内呈良好的线性关系(r=-0.999 6),检出限为2.27×10~(-7) mol/L,加标回收率为96% ～101%.

Electrochemical Behavior and Determination of Salicylic Acid on Sodium Based Montmorillonite Modified Glassy Carbon Electrode

The montmorillonite was reformed by hexadecyltrimethylammonium bromide(CTAB).The modified clay(CTAB-MMT) was characterized by infrared(IR) spectrometry and X diffraction(XRD) spectrometry.A novel CTAB-MMT clay-modified glassy carbon electrode(CTAB-NaMMT- CMC/GCE)was prepared and the effective area of CTAB-NaMMT-CMC/GCE was calculated to be 0.105 4 cm~2.The electrochemical behavior of salicylic acid(SA) on modified electrode was studied by cyclic voltammetry(CV).The results indicated that in pH 0.8 H_2SO_4-Na_2SO_4 buffer,an obvious oxidation peak of SA appeared at 1.19 V on the modified electrode.The oxidation peak current was linear over the square root of the scanning rate in the range of 40-400 mV/s,indicating the electrode process of SA was irreversible and controlled by diffusion.Reaction electronic numbers(n),proton numbers(m),transfer coefficient(β) and diffusion coefficient of SA were obtained to be 2,2,0.389 and 1.275×10~(-6) cm~2/s,respectively.Experimental parameters were optimized and the correlation between peak current(I_(pa)) and concentration was studied by square-wave stripping voltammetry(SWSV).Under the optimal conditions,the calibration curve showed a good linearity between the oxidation peak current(I_(pa)) and SA concentration in the range of 8.0×10~(-7)-1.25×10~(-4) mol/L(r=-0.999 6) with a detection limit of 2.27×10~(-7) mol/L.The spiked recoveries were in the range of 96%-101%.