Determination of diclofenac in pharmaceuticals and urine samples using a membrane sensor based on the ion associate of diclofenac with Rhodamine B

摘要

The potentiometric response characteristics of a diclofenac selective electrode,based on ion association in di?erent plasticizers,were compared.The sensitivity,working range,detection limit and selectivity of membrane sensors demonstrated significant dependence on the type of plasticizers.The potentiometric unit presented a linear response toward diclofenac concentrations between 1×10~(-5)-5×10~(-2) mol L~(-1),with slopes of approximately 60 mV dec~(-1),and exhibited a response time of 3 s. The potentiometric analysis of sodium diclofenac in pharmaceutical formulations was perfomed by the membrane electrode proposed and compared with the results of potentiometric titration given by the Pharmacopoeia of Ukraine.