Acetylsalicylic Acid Determination in Remidies Using a Gas-Diffusion Flow Injection Analysis- II+

Original Paper

Abstract

In this work is proposed a very simple flow injection method for the analysis of acetylsalicylic acid (asa) in pharmaceutical preparations. The method is based on the asa alkaline hydrolysis forming a solution containing acetate and salicylate. This solution is mixed with a sulfuric acid solution. The acetic acid formed permeates through a PTFE membrane to a deionized water stream presenting less than 20 micro Siemens of conductance. The change in conductance was registered in a chart recorder. Six pharmaceutical preparations purchased in the local market were analyzed. The obtained results were compared with those obtained with the Pharmacopoeia titrimetric method. The statistical t-Student test was applied to compare the results obtained with the two independent methods. In all cases complete agreement was observed, in a confidence level of 95% (α=0.05). Considering six samples analyzed using the proposed method and three determinations for each sample, the observed mean RSD, is 1.1 %. The limit of detection is about 2×10^-4 mol l^-1 (3×SD) and the analytical frequency is 60 determinations per hour.