Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India.
Colloids Surf B Biointerfaces. 2010 Jun 1;77(2):200-5. doi: 10.1016/j.colsurfb.2010.01.024. Epub 2010 Feb 4.
A sensitive voltammetric method has been described for the determination of betamethasone sodium phosphate (BSP) using edge plane pyrolytic graphite electrode (EPPGE) modified with single walled carbon nanotubes-cetyltrimethyl ammonium bromide nanocomposite film. The reduction of BSP occurred in a well-defined peak having E(p) -1062 mV in phosphate buffer solution (PBS) of pH 7.2. The voltammetric response of betamethasone sodium phosphate enhanced effectively using cationic surfactant cetyltrimethyl ammonium bromide (CTAB) as electrode surface modifier. The nanotubes-surfactant modified edge plane pyrolytic graphite electrode shows great improvement in peak current and shift of the reduction potential towards less negative potential. The role of cetyltrimethylammonium bromide on electrocatalytic property is discussed. The limit of detection (3sigma/slope) was found to be 0.25 x 10(-9)M and limit of quantification was 0.86 x 10(-9)M. The analytical utility of the proposed method is demonstrated by the direct assay of betamethasone in urine samples of pregnant women.
本文描述了一种使用单壁碳纳米管-十六烷基三甲基溴化铵纳米复合材料修饰的边缘平面热解石墨电极（EPPGE）测定倍他米松磷酸钠（BSP）的灵敏伏安法。在 pH 7.2 的磷酸盐缓冲溶液（PBS）中，BSP 的还原在具有 E（p）-1062 mV 的明确定义的峰中发生。使用阳离子表面活性剂十六烷基三甲基溴化铵（CTAB）作为电极表面修饰剂，可有效增强倍他米松磷酸钠的伏安响应。纳米管-表面活性剂修饰的边缘平面热解石墨电极在峰电流和还原电位向更负的方向移动方面显示出了很大的改善。讨论了十六烷基三甲基溴化铵对电催化性能的作用。检测限（3sigma/斜率）为 0.25 x 10(-9)M，定量限为 0.86 x 10(-9)M。该方法通过直接测定孕妇尿液中的倍他米松，证明了该方法的分析实用性。
