A SIMPLE SPECTROPHOTOMETRIC DETERMINATION OF LEAD IN MEDICINAL LEAF AND ENVIRONMENTAL SAMPLES USING SCHIFF BASE LIGAND

K. Deepa and N. V. V. Jyothi*

ABSTRACT

A simple, rapid and sensitive spectrophotometric method is developed for the determination of Pb (II) using 2, 4– Dihydroxy benzophenone-2-Amino thiophenol (BPBT) as an analytical reagent. The reagent has been synthesized and characterized using IR, 1H NMR and Mass spectral data. The metal ion in aqueous medium, forms light yellow colored complex with BPBT at pH = 9.0 (ammonium chloride – ammonium hydroxide) performance utmost absorbance at 347 nm. Thus, analytical studies are more carried out at 347 nm. The reagent BPBT reacts with lead (II) metal ion in acidic medium to provide light yellow colored 1:1 (M:L) metal ligand complex. The color metal ligand complex reactions were instantaneous and absorbance values remain constant for 24 hours. The stoichiometric composition of the metal ligand complex is studied with the Job’s continuous variation and molar ratio methods. The Beer’s law is obeyed in the range of 0.27-2.4 μg ml−1of metal ion. The molar absorptivity and sandell’s sensitivity of the metal complex are found to be 5.59 x 10 4 Lmol-1cm-1 and 0.00178 μg/ cm-2 respectively. Since BPBT ligand method is more sensitive, it is applied for the determination of lead in medicinal leaf and environmental samples.

Keywords: Spectrophotometry, Lead (II) determination, 2,4–Dihydroxy benzophenone-2-Amino thiophenol (BPBT), Medicinal leaf and Environmental samples.