N,N′-oxalylbis(salicylaldehyde hydrazone) as an analytical spectrophotometric and fluorimetric reagent. Part I. Study of the metal reactivity and application to the determination of aluminium

Abstract

The synthesis, characteristics and analytical applications of N,N,′-oxalylbis(salicylaldehyde hydrazone)(OBSH) are described. The reaction between aluminium and OBSH was studied both spectrophotometrically and spectrofluorimetrically, and methods for the determination of the ion are proposed on the basis of the yellow chelate formed. The spectrophotometric procedure is sensitive (ε₃₉₀= 14.5 × 10³ l mol^–1 cm^–1) and the colour is developed at pH 4.7 in a solution containing 60%V/V of dimethylformamide. The fluorimetric method permits the determination of 0–200 p.p.b. of aluminium in chloroacetic-chloroacetate medium (λ_ex.= 390 nm, λ_em.= 475 nm). Interferences were evaluated for both procedures and indicated that perturbation from transition metal ions such as Pd(II), Ga(III), In(III), Zr(IV), V(V) and Fe(III) may occur although some of them can be eliminated with masking agents or an ion-exchange resin. The methods have been applied to the determination of aluminium in different real samples.