New Potentiometric Screen-printed Sensors for Determination of Trimebutine Drug in Tablets, Serum and Urine Samples

A new sensitive and selective modified screen printed electrodes (MSPEs) and carbon paste electrodes (MCPEs) were studied in order to determine trimbutine maleate (TM) in pure, tablets, urine, and serum samples. These sensors were embodied with multiwalled carbon nanotubes (MWCNTs) since it improved the quality of the sensors in presence of potassium tetrakis (p-chlorophenyl) borate (KTpClPB) ionophore. A good Nernstian response for the constructed sensors, at optimum paste composition, was exhibited for determination of TM in concentration range of 1.5 × 10-7 - 1.0 × 10-2 and 1.0 × 10-7- 1.0 × 10-2 mol L-1 at 25 °C with detection limit of 1.5 × 10-7 and 1.0 × 10-7 mol L-1 for MCPE and MSPE, respectively. It seemed that the potential of the electrodes was independent on pH in the range of 2.0-8.0, 2.0-8.5, 2.0-8.5, and 2.0-9.0 giving slope as 56.77 ± 1.11, 57.82 ± 0.54, 57.95 ± 0.37, and 58.99 ± 0.28 mV decade-1 for electrodes I, II, III, and IV, respectively. MCPEs and MSPEs gave response time about 8 and 6 s with long lifetime (more than 3 and 5 months), respectively. A high selectivity of sensors was observed for TM regarding to a large number of interfering species. The constructed sensors were successfully applied for determination of TM in pure form, its pharmaceutical preparations and biological fluids using standard addition, calibration, and potentiometric titration methods with high precision and accuracy. The results showed a good agreement between the proposed method and the HPLC official method.