A new simple and sensitive extractive potentiometric method for the determination of mercury (II) with isonicotinic acid hydrazide (INH) has been developed. INH has been synthesized and characterized by elemental analysis. Mercury was complexed with INH to form reddish yellow color Hg-INH complex. Hg-INH complex extracts quantitatively (99.45%) into methanol (MeoH) from an aqueous solution of PH The complex has maximum absorbance at 420nm (λmax). The molar absorbitivity and sandell’s sensitivity of the complex was 2.609x10^(-3)lit.mole-1.cm-1 and 1.673x10^(-2)μg/cm2 respectively. The developed method obeys Beer’s law in the concentration range of 1.0 to 20 ppm. The composition of the complex (metal: was applied for the determination of mercury in sewage waste and spiked water samples.
