Abstract: In this paper, a PVCmembrane electrode is prepared for sulbenicillin, 3,3-dimethyl-7-oxo-6-(2-phenyl-2-sulfoacetamido)-4-thia-1-azabicyclo [3, 2, 0] heptane-2-carboxylic acid, based on its ion pair complexes with hexadecyltrioctylammonium iodide (HTOA).Membrane composition of the electrode was optimized by using the sequential level elimination method for orthogonal experimental design.The electrode has a Nernst response range from 6.03×10^-6-1.0× 10^-1 mol/Lwith an average slope of 28.0 mV/pC.The limit of detection is 1.66×10^-6.The electrode responses were not affected by pHin the range 6.3-7.0.The electrode was used for determining sulbenicillin in raw material of drug preparation with satisfactory results.

Key words: Sulbeniciliin, Drug electrode, Sequential level elimination method, Chemometrics