Cyclohexane-1, 3-Dione bis (4-Methylthiosemicarbazone) as a Spectrophotometric Reagent for the Determination of Zn (II)

Abstract

The spectrophotometric study of reddish cyclohexane-1, 3-dione bis (4-methylthiosemicarbazone)-Zn(II) was made in dimethylformamide-water solution (λ_max= 475 nm, ∑ = 3.3×10⁴ 1.mole⁻¹. cm⁻¹. Sandell sensitivity = 2×10⁻² μg Zn(II).cm⁻², stoichiometry 1:1, and apparent stability constant 6.1×10⁴). A new method for the spectrophotometric determination of Zn(II) is proposed for concentrations between 0.1 and 2.5 ppm. The relative error (95% confidence level) is 0.7% for 1.0 pprn of Zn(II).

The extraction with ethylacetate of the reddish complex was also studied spectrophotometrically (λ_max = 493 nm, ∑ in organic phase = 4.8×10⁴ 1.mole⁻¹.cm. Sandell sensitivity = 3.4×10⁻⁴ μg Zn(II).cm⁻², stoichiometry 1:1, apparent extraction constant 1.4×10⁴). A new method for the extraction-spectrophotometric determination of Zn(II) is proposed for concentrations, in aqueous phase, between 0.02 and 0.30 ppm. The relative error (95% confidence level) is 1.0% for 0.15 pprn of Zn(II).

Key Words:

• CYCLOHEXANE-1
• 3-DIONE BIS (4-METHYLTHIOSEMICARBAZONE)
• ZINC
• SPECTROPHOTOMETRIC