Voltammetric Determination of Isopropylmethylphenols in Herbal Spices

Thymol and carvacrol-the components of herbal spices-are known for their broad biological activity as antimicrobials and antioxidants. For this reason, it is important to develop new methods for their determination in plant material. A simple, rapid, and sensitive method for determination of total content of these analytes in herbal spices using differential pulse voltammetry (DPV) has been developed. The basis of the research is the oxidation process of isopropylmethylphenols on a platinum microelectrode in glacial acetic acid containing acetonitrile (20%, v/v) and 0.1 mol L-1 sodium perchlorate as the supporting electrolyte. Linear voltammetric responses for thymol and carvacrol were obtained in a wide concentration range from 0.39-1105 and 0.47-640 mu g mL(-1), with a low detection limit of 0.04 and 0.05 .g mL(-1), respectively. The analysis was performed using the multiple standard addition method. The results of the voltammetric determination are in good agreement with the data of the standard chromatographic method. To the best of our knowledge, this is the first presentation of an electrochemical procedure to determine these compounds in these environmental and electrode materials.

Automated summary

A simple, rapid, and sensitive method using differential pulse voltammetry (DPV) has been developed to determine the total content of thymol and carvacrol in herbal spices. The method showed a wide linear response range and low detection limits, with results in good agreement with standard chromatographic methods. This electrochemical procedure is the first of its kind for these compounds in these environmental and electrode materials.