Electrochemical performance of a new imidazolium ionic liquid crystal and carbon paste composite electrode for the sensitive detection of paracetamol

Abstract A new ionic liquid crystal (ILC) bearing a biphenyl core and a terminal imidazolium moiety was synthesized which exhibited two enantiotropic smectic A mesophases having a wide phase range. Interestingly one of these mesophases exhibited the features of a biaxial phase. A composite electrode containing the synthesized ILC and carbon paste (CP) was fabricated and employed for the successful electrochemical detection of a clinically important analgesic drug, paracetamol. The ILC-CP composite electrode displayed an enhanced current response due to a versatile combination of properties namely, good ionic conductivity, increased edge-site defects and excellent electrocatalytic activity. The composite electrode responded quickly upon addition of paracetamol and the peak current of anodic oxidation enhanced at lower over potential compared to the carbon paste electrode (CPE). Differential pulse voltammetric (DPV) experiments for the detection of paracetamol yielded acceptable linear range from 0 to 120 μM with a good detection limit of 2.8 μM. Interference test results showed anti-interfering ability in presence of a mixture of interferents. The electrode stability was evaluated from DPV current response and 92.6% current was retained after one month which revealed the excellent stability. The electrode was successfully applied for the direct determination of paracetamol in pharmaceutical formulations.