A poly(vinyl chloride) membrane electrode for the determination of the diuretic furosemide

New polymeric electrode responding to furosemide was constructed by incorporating the furosemide-aliquat ion pair complex into a poly(vinyl chloride) (PVC) membrane. The electrode exhibited a linear response over the concentration range 1.59 x 10(-4)-1.00 X 10(-2) mol L-1, a detection limit Of,. 19 X 10(-4) mol L-1 with E = - 245.6 - 58.9log[Fur]. The pH did not affect the response of the electrode within the range 7.0-10.0. Direct potentiometry was used to assay furosemide in pharmaceutical preparations. The results were compared with those obtained with spectrophotometric and chromatographic reference methods.