Study of Spectrophotometric Determination of Amoxicillin Using Sodium l,2-Naphthoquinone-4-Sulfonate as the Chemical Derivative Chromogenic Reagent

摘要

A simple and sensitive spectrophotometric method is described for determi-nation of amoxicillin.The method is based on a nucleophilic substitution reaction to measure the pink compound produced by the reaction of amoxicillin with sodium l,2-naphthoquinone-4-sulfonate in pH 9.00 buffer solution.The stoichiometric ratio of the compound is 1:1,and its maximum absorption wavelength is at 468nm,epsilon = 3.91 x 10~3L centre dot mol~(-1)centre dot cm~(-1).The Beer's law is obeyed in the range of 0.8-120 mu g centre dot mL~(-1)of amoxicillin.The linear regression equation is A = 0.041239 + 0.22128 C,with 0.9994 of a linear regression correlation coefficient.The detection limit is 2.0mu g centre dot mL~(-1),and average recovery is over 98.5%.This paper further optimizes the determination of amoxcillin compared to the previous methods,and the kinetic property and reaction mechanism are studied intensively.This proposed method has been successfully applied to the determination of amoxicillin in tablets and capsules.The results obtained by this method agreed well with those by the official method high pressure liquid chromatography(HPLC).