Highly reproducible, simple and selective analytical method for extractive UV-visible spectrophotometric determination of ruthenium(III): Analysis of catalyst, fissium alloy and sequential separation.

ABSTRACT

An easy and selective method has been developed for the extractive spectrophotometric determination of ruthenium(III) with 4-(4'-flurobenzylideneimino)-3-methyl-5-mercapto-1,2,4-triazole (FBIMMT) as a chelating reagent. The basis of the method is the formation of stable complex of 'soft base' FBIMMT with 'soft acid' ruthenium(III). The reagent FBIMMT in n-butanol easily forms extractable yellow coloured complex with ruthenium(III) in acetate buffer of pH 4.8. The absorbance of [Ru(III)-FBIMMT] complex is measured at 394 nm against the reagent blank. Good linearity range of concentration up to 27.0 µg mL-1 of ruthenium(III) is attained with correlation coefficient R2 = 0.998. The optimum concentration range is 6 to 27.0 µg mL-1 which is deduced by Ringbom's plot. The apparent molar absorptivity found to be 2.75 × 103 L mol-1 cm-1. Some additional characteristics such as limit of detection (LOD = 0.48 µg mL-1), limit of quantification (LOQ = 1.19 µg mL-1), and Sandell's sensitivity (SS = of 0.0367 µg cm-2) are also estimated. The composition of [Ru(III)-FBIMMT] complex has been established from Job's continuous variation method, mole ratio method, and log-log plot method. The specificity towards ruthenium(III) is well studied and appropriate masking agents are applied wherever required to boost it. The intra-day and inter-day precision values are found to be brilliant with % relative standard deviation of 0.52 and 0.68 respectively with % accuracy within the range of 99.00-100. The method is effectively used for determination of ruthenium(III) from water samples, binary and ternary synthetic mixtures, fissium alloy samples and catalyst materials. A scheme for sequential group separation of ruthenium(III), palladium(II) and osmium(VIII) has also been developed. The reproducible results of the present method confirm that the method has a good potential for quantitative determination of ruthenium(III) from various matrices.