The construction and electrochemical response characteristics of poly(vinyl chloride) (PVC) membrane sensors for the determination of
cetirizine drug were described. These sensors were based on the use of the ion-association complexes of the cetirizinium cation (Cet+
) with
phosphomolybdic acid [H3Mo12O40] (PMA) (sensor I), tetraphenylborate (TPB) (sensor II) and ammonium reineckate
(NH4)2[Cr(NCS)4(NH3)2](sensor III) counter anions as ion-exchange sites in a PVC matrix plasticized with dioctylphthalate (DOP). The
sensors revealed fast, stable and Nernstian response between 9.0x10-7
- 1.0x10-3 mol L-1
and 5.2x10-6
- 1.0x10-3 mol L-1 with slope of
59.3±0.2, 60.6±0.3 and 61.5±0.2 mV and dection limits 5.3x10-7
, 3.8x10-6 and 5.2x10-6 mol L-1 for sensor I, II and III respectively. The
intrinsic characteristics of the detectors in a low dispersion manifold under hydrodynamic mode of operation are determined and compared
with data obtained under batch mode of operation. Validation of the method reveals good performance characteristics including long life
span, good selectivity for Cet+ over a wide variety of other organic compounds, long term stability, high reproducibility, fast response, low
detection limit, wide measurement range, acceptable accuracy and precision. Applications of the sensors for the determination of Cet+
in
pharmaceutical samples were also reported. The sensors offered several advantages over many of those previously described and were
amenable for quality control/quality assurance assessment of the homogeneity, stability and purity of ephedrine drug tablets.
Key words: Cetirizine; Potentiometric sensors; Flow injection; Pharmaceutical analysis
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