IJSRP, Volume 2, Issue 12, December 2012 Edition [ISSN 2250-3153]
S.Satyasree, V. Krishna Reddy , P. Raveendra Reddy
Highly sensitive and selective direct and derivative spectrophotometric methods are proposed for the determination of aluminium in various materials. 2-hydroxy-3-methoxybenzaldehyde-p-hydroxybenzoic hydrazone reacts with Al(III) forming yellow coloured soluble complex in aqueous dimethyl formamide which has a λmax at 410 nm in the pH range 4.5 – 5.5. Sensitivity of the method has significantly increased in the presence of 0.02% of cetyl pyridinium chloride miscellar medium. The system obeyed Beer’s law in the range 0.027 – 1.079 μg mL-1 of Al(III). The molar absorptivity (4.19 x 104 L mol-1 cm-1), detection limit (3.8 x 10-3 μg mL-1) and determination limit (1.16 x 10-2 μg mL-1) indicate the sensitivity of the proposed method. The studies on effect of diverse ions showed almost all the anions (except F-) and majority of the cations do not interfere in more than 50 fold excess. The interference from Ni(II), Fe(III), Cu(II) and Ti(IV) was eliminated by using suitable masking agents. The direct method was applied for the determination of aluminium in silicate minerals, industrial sludges and in soils. The sensitivity and selectivity of the proposed method is further enhanced in the first to fourth order derivative spectrophotometric methods developed. Second order derivative method was applied for the determination of Al(III) in plant extracts, hair, tea and water samples.