Department of Analytical Chemistry, Faculty of Pharmacy, University of Istanbul, Istanbul, Turkey.
Talanta. 1986 Apr;33(4):366-9.
The application of 5,5'-dithiobis(2-nitrobenzoic acid) (Ellman's reagent) for the determination of microgram quantities of various selected cephalosporins in aqueous solution is described. Cephalosporin derivatives (cephalothin sodium, cephacetrile sodium, cefamandole lithium and nafate, cefoperazone sodium and ceftizoxime sodium) have to be treated with 0.5N sodium hydroxide before determination with Ellman's reagent, which reacts with free thiol groups. An aliquot of the solution is reacted with Ellman's reagent in pH 7.2 phosphate buffer and the absorbance of the resulting yellow solution is measured at 410 nm. The method, which is simple and precise, has been applied to determination of those cephalosporins in formulations, the results being compared with those obtained by the Ni-hydroxylamine method.
5,5'-二硫代双(2-硝基苯甲酸)（Ellman 试剂）在水溶液中用于测定各种选定头孢菌素的微克量的应用。头孢菌素衍生物（头孢噻吩钠、头孢替唑钠、头孢孟多酯钠和头孢替唑钠、头孢哌酮钠和头孢唑肟钠）在与 Ellman 试剂反应之前必须用 0.5N 氢氧化钠处理，Ellman 试剂与游离巯基反应。溶液的一部分与 Ellman 试剂在 pH7.2 的磷酸盐缓冲液中反应，所得黄色溶液的吸光度在 410nm 处测量。该方法简单精确，已应用于制剂中这些头孢菌素的测定，结果与镍羟胺法的结果进行了比较。
