N-Phenyl-N'-acetylthiourea-a specific reagent for photometric determination of ruthenium.

N-Phenyl-N'-acetylthiourea is recommended as a specific chelating agent for the spectrophotometric determination of ruthenium. The blue complex formed in 5-8M hydrochloroic acid is not extractable into common organic solvents but is soluble in 30% ethanol solution. The colour is stable for up to 48 hr and Beer's law is obeyed at 650 nm over the metal concentration range 2-18 mug/ml. The molar absorptivity is 4.7 x 10(3) l.mole(-1). cm(-1).

Extraction and spectrophotometric determination of ruthenium and osmium with thiobenzhydrazide.

Ruthenium forms a pink complex with thiobenzhydrazide in hot 1.0-4.5M hydrochloric acid medium, which can be extracted with chloroform, and the extract shows maximal absorbance at 520 nm. The chloroform-extractable osmium-thiobenzhydrazide complex formed at pH 2.3-4.8 shows maximal absorption at 385 nm as well as at 480-490 nm. The colour of the extracts of both the complexes is stable for more than 24 hr and can be employed for the spectrophotometry of ruthenium and osmium in the presence of a considerable excess of diverse ions commonly associated with them. Ruthenium and osmium can be quantitatively separated from one another with thiobenzhydrazide.

Use of 3-hydroxy-1,3-diphenyltriazine in the spectrophotometric determination of copper, palladium, iron, cobalt, nickel, and molybdenum.

3-Hydroxy-1,3-diphenyltriazine (HDPTA) forms brightly coloured complexes with copper, palladium, iron, cobalt and nickel ions, which are readily extractable in benzene. The deep yellow molybdenum complex is completely soluble in 60% ethanol. All the chelates have a definite absorption maximum between 398 and 422 nm, the reagent absorption being negligible above 415 nm. The molar composition of the chelates is ML(2), except for iron and cobalt which form ML(3) complexes. Microquantities of these metals can be determined spectrophotometrically with HDPTA.