Spectrophotometric determination of titanium (IV) by solvent extraction of titanium(IV)-indoferron chelate

A new method is proposed for the spectrophotometric determination of titanium (IV), which is based on the extraction of titanium (IV) -indoferron chelate into n-butanol in the presence of 1, 3-diphenylguanidinium cation (DPG). The extracted species shows an absorption maximum at about 600mμ, having a reasonable composition of [TiO (H3R2)·DPG]. The maximum absorbance is obtained when the pH of the aqueous phase is adjusted to 2.5. Under the optimum condition, a good linear relationship between absorbance of organic phase and titanium (IV) content of aqueous phase is obtained in the range 623μg Ti (IV) per 20.0ml. The molar extinction coefficient is about 18000 at 600mμ, and the sensitivity of the reaction is 0.0029μg/cm2 (for log I0/I=0.001). The effect of cations and anions on the determination of titanium (IV) was also examined.