Selective Electrochemical Detection of Catechin Compounds in Herbal Medicines

Most electrochemical sensors reported for catechin determination in herbal medicines actually involve the detection of not only catechins but also other flavonoids. This work proposes a strategy to selectively detect and quantify flavan-3-ol, known as catechins, in the presence of other flavonoids by complexation with AlCl3. Flavonoids (e.g., rutin, quercetin) form stable complex with AlCl3 which affect the electrooxidation of these molecules. Hence, the electrochemical oxidation of catechin is free from the interference of other flavonoids as shown by differential-pulse voltammetry using glassy-carbon electrode. The approach was applied to herbal medicines and mass-spectrometry confirmed the presence of catechins in such samples.