Rapid, selective, direct and derivative spectrophotometric determination of titanium with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone.

A simple and sensitive spectrophotometric method is developed for the determination of titanium in aqueous medium. The metal ion forms a reddish brown coloured complex with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone (2,4-DHBINH) in the pH range 1-7. The complex shows two absorption maxima, one at 430 nm and the other at 500 nm. The reagent shows appreciable absorbance of 430 nm and negligible absorbance at 500 nm at pH 1.5. Beer's law is obeyed in the range 0.09 to 2.15 mug ml(-1) of titanium(IV). The molar absorptivity and the Sandell's sensitivity of the method are 1.35 x 10(4) 1 mol(-1) cm(-1) and 0.0049 mug cm(-2), respectively. A method for the determination of titanium by first-order derivative spectrophotometry is also proposed. The methods have been employed successfully for the determination of titanium in several alloy and steel samples.

Rapid and selective spectrophotometric determination of manganese in steels and alloys using resacetophenone oxime.

A sensitive spectrophotometric method is developed for the determination of manganese in aqueous medium. The metal ion forms a yellowish brown coloured complex with resacetophenone oxime (RPO) in ammonium chloride and ammonium hydroxide buffer of pH 10.5. The 1:1 complex shows maximum absorbance at 380 nm with a Beer's law range of 0.09-1.7 ppm. The molar absorptivity and the Sandell sensitivity are found as 2.5 x 10(4) l.mole(-1).cm(-1) and 0.002 mug/cm(2), respectively. The stability constant of the complex calculated by Job's method is 7.5 x 10(5). The interfering effects of various cations and anions are studied. The present method is applied to the determination of manganese in some steel and alloy samples.