Determination of Tiopronin in Pharmatceutical Preparations by Time Resolved Chemiluminescence Using the Stopped-Flow Technique

Abstract

An analytical method for the determination of tiopronin in pharmaceuticals was developed. The method is based on measurements of the chemiluminescence (CL) produced by tiopronin upon reaction with sulfuric acid and potassium permanganate as the oxidant in the presence of formaldehyde as emission enhancer. This allows entire chemiluminescence intensity vs. time profiles to be recorded by using the stopped-flow technique in a continuous-flow system, which, in turn, enables the use of a new parameter (the rate of the light decay reaction) in addition to the maximum emission intensity and total emission area, which are proportional to the analyte concentration. The influence of chemical variables such as the type of acid used and its concentration, emission enhancer, and oxidant concentration on the chemiluminescence signal was examined. The calibration graph was linear from 0.05 to 3.00 mg L⁻¹. The limit of detection as determined according to Clayton ranged from 0.12 to 0.17 mg L⁻¹ and the relative standard deviation (RSD) for the analysis of 10 samples containing an analyte concentration of 1.50 mg L⁻¹ was 1.87%.

Keywords:

• Chemiluminescence
• Time-resolved
• Tiopronin
• Stopped-flow

Acknowledgments

This article is part of a Special Issue on Automated Flow Injection Techniques organized by Dr. Paraskevas Tzanavaras of Aristotelian University of Thessaloniki, Greece.

Notes

^a Acadione is the trade mark of tiopronin manufactured by Aventis Laboratory (Paris, France).

^a Applying the IUPAC criterion.