Extractive Spectrophotometric Determination of Trace Hg (II) in Eye Drops and Ayurvedic Medicines Using Pyridine 2-Carboxaldehyde 2-Hydroxybenzoylhydrazone

Abstract

A rapid, simple and selective spectrophotometric method was developed for the determination of mercury (II) by using reagent, Pyridine-2-carboxaldehyde 2-hydroxybenzoylhydrazone (PAHB). The reagent is highly selective and sensitive and it forms yellow coloured complex with mercury (II) having composition 1:2 (M:L) in alkaline pH range. Absorption of coloured complex in toluene is measured with reagent as blank at ƛmax 385 nm. The beers law is obeyed in concentration range from 0.5-5.8 ppm for mercury (II)Pyridine-2-carboxaldehyde 2-hydroxybenzoylhydrazone complex and it was evaluated from Ringboms plot. Molar absorptivity and Sandells sensitivity value for mercury (II)Pyridine-2-carboxaldehyde 2-hydroxybenzoylhydrazone complex are 5.87 ng cm -2 and 3.14 x 104 l mol -1 cm -1 , respectively. The sensitivity of the developed method was checked in presence of various foreign ions. The method is successfully applied for mercury (II) determination in binary, synthetic mixtures and real pharmaceutical samples. The accuracy and reliability of method was verified by AAS.