Development of a novel isoniazid-membrane-field-effect transistor

The Isoniazid (INH) sensing Membrane-Sensitive Field-Effect Transistor (MEMFET) device was developed. The optimized INH membrane was composed from a complex mixture of 7% (w/w) ion pair [H₃-INH][Co(C₂B₉H₁₁)₂]₃, 30% (w/w) polymer (polyvinyl chloride) (PVC), and 63% (w/w) of plasticizing agent o-nitrophenyloctyl ether (NPOE) which was dissolved in tetrahydrofuran (THF) solution. The potentiometric response was evaluated. The device exhibited excellent selectivity and a linear response over the concentration range from 3×10^-6 M to 1×10^-1 M with a slope of 55 ± 0.2 mV/decade. The INHMEMFETs are suitable for use with aqueous solutions of pH 9.5-5 and were found insensitive to the other antituberculosis (Sulfanilamide, Rifampicin, Ethambutol and pyrazinecarboxamide).