New potentiometric sensor for total phenolic assay of plant extracts

Abstract In this study, a sensitive, fast, and inexpensive new potentiometric determination method based on the Folin–Ciocalteu reagent (FCR) is proposed to determine the total phenolic content in plant extracts. For this purpose, a potentiometric-based all-solid-state-contact polyvinyl chloride membrane sensor was developed. Gallic acid compound was used as the active component (ionophore) in the developed sensor and the potentiometric behavior of the sensor was characterized. The detection limit of the selective sensor to the FCR was determined as 0.022 mol L−1 and showed a linear potential change in the concentration range of 0.0039 to 0.5 mol L−1 and a fast response time of 40 to 45 s. The developed sensor was also applied to the plant extracts and the obtained measurement results were found to be in agreement with the spectrometer results in the literature.