The interaction of Ru(IV) ions with a novel analytical reagent-5-hydroxyimino-4-imino-1,3-thiazolidin-2-one, by spectrophotometric method was investigated. The complex is formed at pH 5.0 in acetate buffer medium after heating in the boiling water bath (~371 K) for 25 min. The complex has maximum absorption at 350 nm and is stable for 24 h. Beer's law is valid over the concentration range of 0.5-6.1 µg mL-1 for Ru(IV). The molar absorptivity at λ = 350 nm is 6.21 × 10 3 L mol-1 cm-1. The limit of detection of this method is 0.2 µg mL-1. The interfering effect of various cations and anions on the spectrophotometric determination of the Ru(IV) were investigated. The proposed method was successfully applied to the determination of Ru(IV) in alloys.

5-Hydroxyimino-4-imino-1,3-thiazolidine-2-one has been suggested as a new organic reagent for the voltammetric determination of platinum. The optimal conditions of Pt(IV) voltammetric determination using 5-hydroxyimino-4- imino-1,3-thiazolidine-2-one on the peak of catalytic hydrogen currents have been determined: the background electrolyte is 0.3 M NaCl, pH of the solution is 2.0, 50-fold concentration excess of organic reagent. The sensitive method of Pt(IV) voltammetric determination was developed (LOD = 4.1·10-9 М). The range of determinable contents covers two concentration orders. The selectivity of the developed methods have been studied towards concomitant metals ions. The accuracy of the developed method has been tested on model solutions using “added-found” method. The method has been approved during the analysis of a real sample, viz. the catalyst for oxidation of exhaust gases of the car “Chevrolet”.

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The simple, rapid spectrophotometric method for palladium(II) ions determination using a new analytical reagent is described. The interaction of Pd(II) ions with a reagent, of the class of azolidones, 4-(N′-(4-imino-2-oxo-thiazolidine-5-ylidene)-hydrazino)-benzoic acid, in water medium results in the formation of a complex. The Pd(II)-p-ITYBA complex shows maximum absorbance at a wavelength of 450 nm. The molar absorptivity is 4.30 × 103 L·mol−1·cm−1. The optimal pH for complex formation is 7.0. The developed method has a wide linearity range of 0.64–10.64 µg·mL−1 for Pd(II). The detection limit is 0.23 µg·mL−1. It was found that Co(II), Ni(II), Zn(II), Fe(III), Cu(II), Al(III), and many anions do not interfere with the Pd(II) determination. The proposed method was tested in the analysis of model solutions and successfully applied for the determination of palladium in catalyst. The obtained results show that this method can be used for serial determinations of palladium in various objects.

Уперше досліджено хіміко-аналітичні характеристики нового реагенту 4-(4-іміно-2-оксо-тіазолідин-5-ілазо)-бензойної кислоти, який є представником класу азолідонів. Досліджено вплив кислотності середовища на вигляд спектрів поглинання розчинів 4-(4-іміно-2-оксо-тіазолідин-5-ілазо)-бензойної кислоти. Розраховано середні значення ефективних молярних коефіцієнтів світлопоглинання цього барвника за довжини хвилі 390 нм, яка лежить у межах від 3,0·10 3 до 2,40·10 4 л·моль -1 ·см -1 залежно від кислотності середовища. Розроблено методику визначення цього реагенту за власним світлопоглинанням. Закон Бера справджується при 390 нм у широкому концентраційному інтервалі від 1,0·10 -6 до 6,0·10 -5 моль/л.Ключові слова: 4-(4-іміно-2-оксо-тіазолідин-5-ілазо)-бензойна кислота, азолідони, спектрофотометрія.