壳聚糖/乙炔黑修饰电极上萘酚异构体的电化学行为及同时测定

Electrochemical Behavior and Simultaneous Determination of Naphthol Isomers on Glassy Carbon Electrode Modified with Acetylene Black and Chitosan

制备了壳聚糖/乙炔黑复合修饰电极（CS-AB/GCE）,采用SEM和交流阻抗法对其进行表征。并利用循环伏安法（CV）研究了萘酚异构体（α-N和β-N）在该修饰电极上的电化学行为,对实验条件进行了优化。结果表明,在p H 7.0的PBS缓冲液中,α-N和β-N在该修饰电极上均出现一不可逆氧化峰,且在20-200m V/s范围内,其峰电流与扫速呈线性关系,表明电极过程是受吸附控制的不可逆过程。计算了电极过程的部分动力学参数,优化了差分脉冲伏安法（DPV）的实验参数,并对α-N和β-N进行同时测定,发现二者的微分氧化峰电流值与其浓度在2.5×10-6-1.0×10-4mol/L范围内呈良好的线性关系（rα-N=0.996;rβ-N=0.998）。α-N和β-N的检出限（S/N=3）分别为3.4×10-7mol/L和2.4×10-7mol/L。采用该法对实际水样进行检测,得到α-N和β-N的加标回收率分别为96.7%-105.1%和98.8%-103.9%。

A new modified electrode（ CS -AB/GCE）prepared with acetylene black and chitosan was used to determine naphthol isomers. The properties of electrode surface were characterized by SEM and Nyquist plots. The electrochemical behaviors of α-N and β-N on CS - AB/GCE was studied by cyclic voltammetry（CV）. Inβuences of type of buffer solution, ratio of CS to AB, amounts of CS and AB, pH value, concentration of naphtho/isomers and scan rate were discussed. The results indica- ted that there were two oxidation peaks respectively belonged to α-N and β-N in pH 7.0 PBS buffer. The oxidation peak currents of both α-N and β-N were linear with scan rate（v） in the range of 20 - 200 mV/s, which showed that the electrode processes of α-N and β-N were controlled by adsorption. Some important parameters for these electrochemical processes were also determined. The effect area （A） , electron number （n） and proton number （m） of the modified electrode were obtained to be 0. 390 2 cm2, 1 and 1, respectively. The adsorption capacity were 2. 788 × 10-9 mol/cm2 for a-N, and 5. 603 × 10 -9 mol/cm2 for β-N. Under the optimal conditions, the differential pulse vohammetry （DPV） with derviative technique was used to determine naphthol isomers quantitatively. Good linear relationships between peak currents and concentrations of α-N and β-N were observed in the range of 2. 5 × 10-6 - 1.0 × 10-4 mol/L, and the detection limits（S/N =3） were 3.4 × 10-7 mol/L for α-N and 2. 4 × 10-7 mol/L for β-N. The proposed method was applied in the determination of α-N and/3-N in water samples with spiked recoveries of 96. 7% - 105. 1% and 98. 8% - 103.9% , respectively.