Characterization of complexes involved in the spectrophotometric determination of cobalt with 4-(2-pyridylazo)resorcinol

Široki, M.; Marić, Lj.; Štefanac, Z.; Herak, Mirta

doi:10.1016/s0003-2670(01)81957-7

Cited by 44 publications

(15 citation statements)

References 17 publications

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“…The results showed that the ternary complex has a composition of 1 : 2 : 1 (Co : PAR : Nt). Having in mind the obtained molar ratios and several reports, which convincingly demonstrate that the labile Co(II)-PAR complex can be easily oxidized to an inert Co(III)-PAR complex, [Co 3+ (PAR) 2 ] − , by the atmospheric oxygen [13,26,29,32,33,36,45], we suggest the following formula of the extracted ternary species: (NtH)…”

Section: Composition Of the Complex And Suggested Formulasupporting

confidence: 63%

“…A maximum is recorded at 520 nm, where the blank absorbs insignificantly. It is shifted to 10 nm as compared to the maximum of the binary Co-PAR chelate existing in aqueous medium (in the pH interval from 3.5 to 10): 510 nm [9,27,29,31,39]. The observed bathochromic effect is small and gives us grounds to suggest the formation of a ternary compound of the ion-association type.…”

Section: Resultsmentioning

confidence: 94%

“…− , which can readily react with bulky organic compounds [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] to give ternary complexes with good extraction behavior and analytical potential. In the present paper, we investigated the complex formation in a liquidliquid extraction system containing Co(II), PAR, and Nitron (Nt).…”

Section: Introductionmentioning

confidence: 99%

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Complex Formation in a Liquid-Liquid Extraction System Containing Cobalt(II), 4-(2-Pyridylazo)resorcinol, and Nitron

Racheva

Gavazov

Lekova

et al. 2013

Journal of Materials

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Complex formation and liquid-liquid extraction were studied in a system containing cobalt(II), 4-(2-pyridylazo)resorcinol (PAR), 1,4-diphenyl-3-(phenylamino)-1H-1,2,4-triazole (Nitron, Nt), water, and chloroform. The effect of some experimental parameters (pH, shaking time, concentration of PAR, and concentration of Nt) was systematically investigated, and the optimum conditions for cobalt extraction as an ion-association complex, (NtH + )[Co 3+ (PAR) 2 ], were found. The following key equilibrium constants were calculated: constant of association (Log = 4.77 ± 0.06), constant of distribution (Log D = 1.34 ± 0.01), and constant of extraction (Log ex = 6.11 ± 0.07). Beer's law was obeyed for Co concentrations up to 1.7 g mL −1 with a molar absorptivity of 6.0 × 10 4 L mol −1 cm −1 at max = 520 nm. Some additional characteristics, such as limit of detection, limit of quantification, and Sandell's sensitivity, were estimated as well.

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Section: Composition Of the Complex And Suggested Formulasupporting

confidence: 63%

Section: Resultsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Complex Formation in a Liquid-Liquid Extraction System Containing Cobalt(II), 4-(2-Pyridylazo)resorcinol, and Nitron

Racheva

Gavazov

Lekova

et al. 2013

Journal of Materials

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“…[21][22][23][24][25][26][27][28][29][30][31][32] Tetrazolium cations (TZ n+ ) form analytically important ion-association complexes with Co(SCN) 4 2-, 33,34 and M-PAR anionic chelates, where M is V(V), V(IV), In(III) and Ga(III). 4-(2-Pyridylazo)resorcinol (PAR) was one of the first azo reagents used for the spectrophotometric determination of cobalt due to its high sensitivity as a chromogenic reagent.…”

Section: Introductionmentioning

confidence: 99%

Liquid-liquid extraction of ion-association complexes of cobalt(II)-4-(2-pyridylazo)resorcinol with ditetrazolium salts

Divarova

Stojnova

Racheva

et al. 2015

JSCS

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The formation and liquid-liquid extraction of ion-association complexes between Co(II)-4-(2-pyridylazo)resorcinol (Co(II)-PAR) anionic chelates and cations of three ditetrazolium chlorides (DTC), i.e., blue tetrazolium chloride (BTC), neotetrazolium chloride (NTC) and nitro blue tetrazolium chloride (NBTC), were studied. The optimum conditions for the formation and solvent extraction of the ion-association complex chelates were determined. It has been found that in the Co(II)-PAR-DTC systems, the reactants are present in the mole ratio 1:2:1 and the general formula of complexes was suggested. The extraction equilibria were investigated and quantitatively characterized by the equilibrium constants and the recovery factors. The analytical characteristics of the complexes were calculated.

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“…For this reason, a wide variety of spectrophotometric methods for the determination of cobalt have been developed. The main chromogenic reagents are pyridylazo reagents, thiazolylazo reagents, benzothiazolylazo reagents, 8-aminoquinoline derivatives, porphyrins, nitroso dyes and the similar [8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24]. Each chromogenic system has its advantages and disadvantages with respect to sensitivity, selectivity and rapidity.…”

Section: Introductionmentioning

confidence: 99%

Study of 2-(2-quinolinylazo)-5-dimethylaminobenzoic acid as a new chromogenic reagent for the spectrophotometric determination of cobalt

Zhong¹,

Yang²,

Wang³

et al. 2002

Anal Bioanal Chem

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2-(2-Quinolinylazo)-5-dimethylaminobenzoic acid (QADMAB) is proposed as a new sensitive and selective chromogenic reagent for spectrophotometric determination of cobalt. The QADMAB reacts with cobalt in the presence of cetyl trimethylammonium bromide (CTMAB) medium to form a violet complex of molar ratio 1:2 (cobalt to QADMAB) in the pH range 3.2-5.2. The molar absorptivity of the complex is 1.28x10(5) L mol(-1) cm(-1) at 625 nm. Beer's law is obeyed in range 0.01-0.32 micro g mL(-1). The relative standard deviation for eleven replicate samples of 0.2 micro g mL(-1) is 0.76%. This method was applied to the determination of cobalt in biological samples, Vitamin B(12), alloys and water with good results.

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Characterization of complexes involved in the spectrophotometric determination of cobalt with 4-(2-pyridylazo)resorcinol

Cited by 44 publications

References 17 publications

Complex Formation in a Liquid-Liquid Extraction System Containing Cobalt(II), 4-(2-Pyridylazo)resorcinol, and Nitron

Complex Formation in a Liquid-Liquid Extraction System Containing Cobalt(II), 4-(2-Pyridylazo)resorcinol, and Nitron

Liquid-liquid extraction of ion-association complexes of cobalt(II)-4-(2-pyridylazo)resorcinol with ditetrazolium salts

Study of 2-(2-quinolinylazo)-5-dimethylaminobenzoic acid as a new chromogenic reagent for the spectrophotometric determination of cobalt

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