College of Environment & Chemical Engineering, Xi'an Polytechnic University, Xi'an 710048, PR China.
Talanta. 2009 Nov 15;80(1):163-7. doi: 10.1016/j.talanta.2009.06.045. Epub 2009 Jul 1.
A simple yet sensitive method is developed for the determination of sericin using voltammetry based on the interaction between sericin and carmine for the first time. In the absence of sericin, carmine has a pair of well-defined redox peaks in a pH 1.81 Britton-Robinson buffer solution. Although no new redox peaks appear upon the addition of sericin into a carmine solution, the peak currents of the old peaks reduce while the peak potentials shift positively. This observation is attributed to the decrease in the diffusion coefficient and electrode reaction rate constant of carmine in the presence of sericin. A binding mechanism is proposed and discussed, and the binding constant and binding ratio are calculated as 2.32 x 10(6) L mol(-1) and 1:1, respectively. Furthermore, the decrease in the peak currents is found proportional to the sericin concentration in the range of 32.0-800.0 microg mL(-1) with a detection limit of 13.52 microg mL(-1). The method is further applied to the determination of sericin in degumming wastewater with satisfied average recoveries from 96.7 to 103.3%. The results are in good agreement with those obtained by the conventional Coomassie brilliant blue G-250 spectrophotometric method.
一种简单而灵敏的方法是基于丝胶与胭脂红之间的相互作用，首次利用伏安法来测定丝胶。在没有丝胶的情况下，胭脂红在 pH 值为 1.81 的 Britton-Robinson 缓冲溶液中有一对定义良好的氧化还原峰。尽管在向胭脂红溶液中加入丝胶后没有出现新的氧化还原峰，但旧峰的峰电流减小而峰电位正向移动。这一观察结果归因于丝胶存在时胭脂红的扩散系数和电极反应速率常数降低。提出并讨论了一种结合机制，并计算出结合常数和结合比分别为 2.32 x 10(6) L mol(-1)和 1:1。此外，发现峰电流的降低与丝胶浓度在 32.0-800.0 microg mL(-1)范围内呈正比，检测限为 13.52 microg mL(-1)。该方法进一步应用于脱胶废水中丝胶的测定，平均回收率从 96.7%到 103.3%不等。结果与传统考马斯亮蓝 G-250 分光光度法得到的结果吻合良好。
