硫茚酸的吸附伏安特性及其应用

Adsorptive voltammetric behavior of Sulindac and its application

目的为了研究硫茚酸(Sulindac)的吸附伏安特性。方法在KHP(pH 4.20)底液中,硫茚酸在汞电极上有一线性扫描还原峰,峰电位Epc=-1.21 V(vs.Ag/AgCl),该峰具有明显的吸附性。结果吸附粒子为硫茚酸中性分子,测得硫茚酸在汞电极上的饱和吸附量为1.16×10-10mol/cm2,每个硫茚酸分子所占电极面积为1.43 cm2,硫茚酸在悬汞电极上的吸附符合Frumkin等温式。测得吸附系数β=1.22×106,吸引因素γ=1.02,电子转移数n为2,不可逆吸附的电子转移系数α为0.86,表面电极反应速度常数ks=0.32/s。结论建立了吸附伏安法测定硫茚酸的最佳条件,检出限为1.0×10-9mol/L,该方法可用于硫茚酸片剂中硫茚酸含量的测定。

Aim To study on the adsorptive voltammetric behavior of Sulindac {（Z）-5-fluoro-2- methyl-1-（（4-（methylsulfinyl）phenyl）methylene） 1H-indene-3-acetic acid}. Methods In a supporting electrolyte containing KHP（pH 4.20）, a reduction peak of Sulindac was observed by linear-sweep voltammetry at Hg electrode. The peak showed a potential of -1.21 V（vs. Ag/AgCl） and adsorptive characteristics. Results The adsorbed species were the neutral molecules of Sulindac. The saturated adsorption amount of Sulindac at Hg eletrode was 1.16 × 10^-10 mol/cm^2 , and each Sulindac molecule occupied 1.43 cm^2. On the Sulindac of HMDE（Hanging Mercury Drop Electrode） surface, the adsorption of Sulindac obeyed Frumkin adsorption isotherm relationship. The adsorption coefficient （ β ） was 1.22 × 10^6. The attractive factor （ γ ） was 1.02. The number of electrons transferred per Sulindac molecule （ n ） was 2. The transfer coefficient （ α ） of the irreversible adsorptive of Sulindac was 0.86. The rate constant of surface Sulindac electrode reaction ks was 0.32 s^- 1. Conclusion The mechanism of electrochemical reduction of Sulindac at Hg electrode was explored. The detection limit of the adsorptive stripping voltammetry of Sulindac was 1.0 × 10^-9 mol/L under optimized condition. The method can be used for measuring Sulindac in the troche containing Sulindac.