表面活性效应下强力霉素伏安行为及其检测

Voltammetric Behaviour of Doxycycline in the Presence of Surfactant and Its Determination

研究了表面活性效应对强力霉素(DOC)伏安行为的影响及表面活性剂存在下该分子的伏安检测方法。以B-R缓冲溶液(p H=2.0)为支持电解质,2.0×10-4 mol/L十二烷基苯磺酸钠(SDBS)的存在将明显有助于DOC的富集。在该实验条件下,DOC在导电碳黑糊电极上发生1质子、2电子转移的不可逆氧化,过程受扩散控制。对表面活性剂种类及其浓度、缓冲液种类及p H值、富集电位及时间等影响伏安分析的因素进行了研究。优化条件下,DOC的氧化峰电流与其浓度在1.0×10-7-2.3×10-5 mol/L范围内呈良好的线性关系,检测限为4.5×10-8 mol/L(S/N=3)。将该电化学方法应用于淡水渔业水样中痕量DOC的检测,得到了较满意的结果(平均回收率为97.44%-105.28%)。

The effects of surfactant on the voltammetric behavior of doxycycline （DOC） were investigated using conductive carbon black paste electrode （CCBPE） as working electrode. A new electrochemical method for determining DOC in aqueous solution was developed with the help of surfactant. The electrostatic interaction between the DOC molecules and the sodium dodecyl benzene sulfonate （SDBS） by self-assembled on the surface of CCBPE promoted the accumulation of the analyte. In B-R buffer solution of pH 2.0, the presence of 2.0×10–4 mol/L SDBS significantly improved the sensitivity of detection of DOC. In the presence of SDBS, the voltammetric behavior of DOC was investigated by cyclic voltammetry. An irreversible and adsorption-controlled electrode reaction occurs with 1 proton and 2 electrons participation. Under the optimum conditions, the anodic peak current of DOC is proportional to its concentration in the range of 1.0×10–7-2.3×10–5 mol/L with a detection limit of 4.5×10–8 mol/L （S/N=3）. Inorganic ions do not have negative effects on the determination, while organic molecules have positive effects probably due to the competitive adsorption function. The average recoveries in the range of 97.44%-105.28% were obtained. Thus, the developed method for the determination of DOC possesses advantages such as simple operation, fast response, low detection limitation, good recovery, and repeatability.