New potentiometric membrane sensors for determination of alverine citrate in pharmaceutical compounds and biological fluids

The construction and performance characteristics of novel alverine citrate (Alv) plastic membrane electrodes based on incorporation of alverine citrate with the ion exchangers, sodium tetraphenylborate (Alv-TPB), ammonium reineckate (Alv-Rt) and a mixture of both (Alv-TPB/Rt) into plasticized poly(vinyl chloride) membrane are described. The sensors showed a near-Nernstian slope of 57.24, 56.31 and 57.01 mV decade-1 at 25±0.1°C within the concentration range 1.00×10-5–1.00×10-2, 1.99 ×10-5-1.00×10-2 and 3.98×10-5-1.00×10-2 M Alv, with detection limits of 4.07×10-6, 3.98×10-6, 9.33× 10-6 M Alv for Alv-TPB, Alv-Rt, Alv-TPB/Rt electrodes, respectively. The membrane electrodes performed satisfactorily over pH ranges of 1.48–7.56, 1.52–7.97 and 1.56–7.82 for the three electrodes, respectively. The selectivity coefficients of the developed sensors indicated excellent selectivity for Alv. Surface analysis using scanning electron microscopy was used to determine the cause of the limited life span of plastic membrane electrode. The proposed sensors displayed useful analytical characteristics for the determination of Alv in pharmaceutical preparation and biological fluids such as plasma and urine samples.