Graphite Electrode Potentiometric Sensor Modified by Surface Imprinted Silica Gel to Measure Valproic Acid

The aim of the study was to produce a Polyvinyl chloride-based membrane containing a polymer imprinted with a valproic acid molecule which was directly coated on a graphite electrode to determine the amount of valproic acid in aqueous samples. With the dispersion of molecularly imprinted polymer particles in dioctyl phthalate plasticizer as a solvent mediator, this potentiometric sensor was designed and after that it was embedded in a polyvinyl chloride matrix. The designed electrode showed a near-Nernstian slope of 54.1 ± 1 mV decade-1 in the concentration range of 10-6-10-2 M and a detection limit of 10-6 M with a response time of about 40 seconds for valproic acid and can be used for 2 months without divergence changing the potential. The fabricated electrode, in the pH range among 3.5-8.5, indicates the good sensitivity to valproic acid relative to the other ions. Finally, this electrode can be used as an indicator electrode in determining the concentration of valproic acid in valproic acid tablets.