Extraction-absorptiometric determination of titanium with N-benzoylphenylhydroxylamine

Abstract

Absorptiometric determination of minute amounts of titanium with N-benzoylphenylhydroxylamine (BPA), based on the extraction of the complex from higher concentrations of hydrochloric acid into chloroform has been investigated.
An absorption maximum of the extract lies at 371 mμ, while the absorption of the reagent blank is very little at the point. Determination of titanium is as follows. Put the sample solution of above 9.6N of hydrochloric acid containing up to 100 μg of titanium into a separating funnel, extract with 10 m/ of 0.1% BPA-chloroform for 12 minutes and measure the absorbancy at 371 mμ or preferably at 380 mμ by reason of the lower absorbancy of the reagent blank as a reference.
The color is stable. Calibration curve obeys Beer's law. The molar absorption coefficient of titanium is 6, 600. Errors coming from variabilities of hydrochloric acid concentration and the ratio V_aq./ V_org. are negligible. A little vanadium, molybdenum and large amounts of iron do not interfere in their lower valent state. Only niobium gives a yellow color to the organic phase.
Good results were obtained by the proposed method for more than 0.001% of titanium in several metal samples.