差分脉冲伏安法测定化妆品中氧氟沙星

Determination of ofloxacin in cosmetics by differential pulse voltammetry

研究氧氟沙星在羧基化多壁碳纳米管修饰玻碳电极(COOH–MWCNTs/GCE)上的电化学行为,建立利用该电极上以差分脉冲伏安法(DPV)测定化妆品中氧氟沙星的方法。在pH 4.00的混合磷酸盐缓冲溶液中,以经过0.1 mg/mL羧基化多壁碳纳米管修饰的玻碳电极为工作电极,采用DPV法测量样品溶液,记录扫描图谱的峰电位和峰电流。氧氟沙星在约1.02 V处有明显的氧化峰,其浓度在4.0×10^(–5)~5.0×10^(–4)mol/L范围内与峰电流具有良好的线性关系,线性相关系数为0.995,氧氟沙星的检出限为2.087×10^(–7)mol/L。实际样品加标回收率为99.8%~100.4%,测定结果的相对标准偏差为1.53%~2.88%(n=5)。氧氟沙星在COOH-MWCNTs/GCE上有良好的响应,电极灵敏度较高,该方法简便、经济,可应用于化妆品、药品中氧氟沙星的测定。

The electrochemical behavior of ofloxacin on a multi-wall carbon nanotubes modified carbon paste electrode was studied,and the method was established for the determination of ofloxacin in cosmetics by differential pulse voltammetry.In a mixed phosphate(PBS)buffer solution with pH 4.00,a glassy carbon electrode modified with 0.1 mg/mL multi-walled carbon nanotubes was used as a working electrode.The sample solution was determined by differential pulse voltammetry method,and the peak potential and peak current were recorded.Ofloxacin had a significant oxidation peak at about 1.02 V and its peak current showed a good linear relationship with the ofloxacin concentration in the range of 4.0×10^(–5)–5.0×10^(–4) mol/L with the correlation coefficient of 0.995,the detection limit was 2.087×10^(–7) mol/L.For the real sample determination,the recoveries of actual samples were 99.8%–100.4%with RSD of 1.53%–2.88%(n=5).Ofloxacin had a good electrochemical response on this modified electrode with high sensitivity.This method is simple and economical which can be used for the detection of ofloxacin in cosmetics and pharmaceuticals.