Development of a reliable analytical method for extraction spectrophotometric determination of ruthenium(III) from catalyst and fissium alloy using o-methylphenyl thiourea as a chromogenic chelating ligand.

A simple and selective method is developed for the extraction spectrophotometric determination of ruthenium(III) using o-methylphenyl thiourea (OMPT) as a chromogenic chelating ligand. The basis of the proposed method is ruthenium(III)-OMPT complex formation in aqueous hydrochloric acid media (3.0molL(-1)) after 5.0min heating on a boiling water bath and the complex formed is extracted into chloroform. The absorbance of green colored ruthenium(III)-OMPT complex is measured at 590nm against the reagent blank. Beer's law was obeyed up to 42.5µgmL(-1) of ruthenium(III) and the optimum concentration range is 7.56-39.81µgmL(-1) of ruthenium(III) as evaluated by Ringbom's plot. Molar absorptivity and Sandell's sensitivity of ruthenium(III)-OMPT complex in chloroform are 2.34×10(3)Lmol(-1) cm(-1) and 0.043µgcm(-2) respectively. The composition of ruthenium(III):OMPT complex (1:2) was established from slope ratio method, mole ratio method and Job's continuous variation method. Complex was stable for more than 48h. The interfering effect of various foreign ions was studied and suitable masking agents are used wherever necessary to enhance the selectivity of the method. Proposed method is successfully applied for determination of ruthenium(III) from binary and ternary synthetic mixtures, synthetic mixtures corresponding to fissium alloy and ruthenium catalyst. Repetition of the method was checked by finding relative standard deviation (R.S.D) for 10 determinations which was 0.23%. A scheme for sequential separation of palladium(II), ruthenium(III), rhodium(III) and platinum(IV) has been developed.

Extraction chromatography of aluminium (III) and mutual separation of aluminium (III), gallium (III), indium (III) and thallium (III) with N-n-octylaniline.

A selective method has been developed for the extraction chromatography of aluminium (III) and its separation from several metal ions with a chromatographic column containing N-n-octylaniline (a liquid anion exchanger) coated on silanized silica gel as a stationary phase. The aluminium (III) was quantitatively extracted with the 0.065 mol/L N-n-octylaniline in 0.013 to 0.05 mol/L sodium succinate at a flow rate of 1.0 mL/min. The extracted metal ion has been recovered by eluting with 25.0 mL of 0.05 mol/L hydrochloric acid and estimated spectrophotometrically with aurintricarboxylic acid. The effects of the acid concentration, the reagent concentration, the flow rate and the eluting agents have been investigated. The log-log plots of distribution coefficient (Kd (Al (III))) versus N-n-octylaniline concentration in 0. 005 and 0. 007 mol/L sodium succinate gave the slopes of 0.5 and 0.7 respectively and showed the probable composition of the extracted species was 1:1 (metal to amine ratio) and the nature of extracted species was [RR'NH2(+), Al succinate2(-)]org. The extraction of aluminium(III) was carried out in the presence of various ions to ascertain the tolerance limit of individual ions. Aluminium(III) has been separated from multicomponent mixtures, pharmaceutical samples and synthetic mixtures corresponding to alloys. A scheme for mutual separation of aluminium (III), indium (III), gallium (III) and thallium (III) has been developed by using suitable masking agents. The method is fast, accurate and precise.