Electrochemiluminescence determination of pipemidic acid using sulfite as energy transfer mediator

An electrochemiluminescence (ECL) based on energy transfer from electro-generated triplet sulfur dioxide to pipemidic acid (PPA) was studied. A weak ECL from triplet sulfur dioxide 3SO2* was observed when sulfite was electrochemically oxidized in sulfuric acid solution on a Pt electrode. When PPA was present, the weak ECL was enhanced. The enhanced ECL was attributed to energy transfer from to PPA. Based on the enhanced ECL, a flow-injection (FIA) ECL method for the determination of PPA was proposed. The proposed method allowed the measurement of PPA over the range of 1.0 × 10−7 to 2.0 × 10−5 mol l−1. The detection limit was 3.9 × 10−8 mol l−1, and the relative standard deviation for 1.0 × 10−6 mol l−1 PPA (n = 9) was 1.3%. This method was evaluated by the analysis of PPA in pharmaceutical preparations and urine samples.