A green cloud-point extraction-chromogenic system for vanadium determination

Stefanova-Bahchevanska, Teodora; Milcheva, Nikolina; Zaruba, Serhii; Andruch, Vasiľ; Delchev, Vassil B.; Simitchiev, Kiril; Gavazov, Kiril B.

doi:10.1016/j.molliq.2017.10.046

Cited by 24 publications

(7 citation statements)

References 38 publications

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“…8,10,[14][15][16] Among the most promising and widely used are the azo dyes. 8,[15][16][17][18][19][20][21][22][23][24] Azo derivatives of resorcinol (ADR), such as 4-(2-pyridylazo)resorcinol (PAR), 24,25 4-(2-thiazolylazo)resorcinol (TAR), 26,27 and 5-methyl-4-(2-thiazolylazo)resorcinol (MTAR) 28,29 form ternary complexes it the presence of cationic ion-association reagents (CIAR). Their composition, stability, and extraction-chromogenic characteristics depend on the particular pair of reagents.…”

Section: Introductionmentioning

confidence: 99%

Extraction-Chromogenic Systems for Vanadium(V) Based on Azo Dyes and Xylometazoline Hydrochloride

Hristov¹,

Milcheva²,

Gavazov³

2019

ACSi

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Liquid-liquid extraction-chromogenic systems for vanadium(V) based on xylometazoline hydrochloride (XMZ) and azo derivatives of resorcinol (ADRs) were studied. The following ADRs were used: 4-(2-thiazolylazo)resorcinol (TAR), 5-methyl-4-(2-thiazolylazo)resorcinol (MTAR), and 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR). Concentration of the reagents, pH of the aqueous medium and shaking time were subjects of optimization experiments. The chloroform-extracted ternary complexes were of composition 1:1:1. The molar absorptivity coefficients (ε λ), absorption maxima (λ), constants of extraction (Log K), and fractions extracted (E%) were found to be ε 553 = 2.50 × 10 4 dm 3 mol-1 cm-1 , Log K = 3.5, and E = 96% (ADR = TAR); ε 550 = 1.88 × 10 4 dm 3 mol-1 cm-1 , Log K = 3.4, and E = 98% (ADR = MTAR); and ε 554 = 2.62 × 10 4 dm 3 mol-1 cm-1 , Log K = 5.0, and E = 99.5% (ADR = HTAR). The Sandell's sensitivities and Beer's law limits were determined as well.

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Section: Introductionmentioning

confidence: 99%

Extraction-Chromogenic Systems for Vanadium(V) Based on Azo Dyes and Xylometazoline Hydrochloride

Hristov¹,

Milcheva²,

Gavazov³

2019

ACSi

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“…The proposed HTAR–TTC procedure can be described as simple, cheap, fast, sensitive, and reliable. It does not require any special or expensive equipment and is easier to implement than DLLME-SFOD [ 54 ], UA-CPE [ 17 , 55 ], or MA-CPE [ 53 ]. It is faster than many procedures requiring prolonged extraction (10–20 min) [ 16 , 21 , 56 ], centrifugation + cooling (10 min) [ 54 ], sonification at elevated temperature + centrifugation + cooling (17–28 min) [ 17 , 55 ], incubation at elevated temperature + cooling (55–110 min) [ 53 , 57 ], or two-fold extraction [ 21 ].…”

Section: Resultsmentioning

confidence: 99%

Extractive Spectrophotometric Determination and Theoretical Investigations of Two New Vanadium(V) Complexes

Gavazov,

Racheva,

Saravanska

et al. 2023

Molecules

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Two new vanadium (V) complexes involving 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR) and tetrazolium cation were studied. The following commercially available tetrazolium salts were used as the cation source: tetrazolium red (2,3,5-triphenyltetrazol-2-ium;chloride, TTC) and neotetrazolium chloride (2-[4-[4-(3,5-diphenyltetrazol-2-ium-2-yl)phenyl]phenyl]-3,5-diphenyltetrazol-2-ium;dichloride, NTC). The cations (abbreviated as TT+ and NTC+) impart high hydrophobicity to the ternary complexes, allowing vanadium to be easily extracted and preconcentrated in one step. The complexes have different stoichiometry. The V(V)–HTAR–TTC complex dimerizes in the organic phase (chloroform) and can be represented by the formula [(TT+)[VO2(HTAR)]]2. The other complex is monomeric (NTC+)[VO2(HTAR)]. The cation has a +1 charge because one of the two chloride ions remains undissociated: NTC+ = (NT2+Cl−)+. The ground-state equilibrium geometries of the constituent cations and final complexes were optimized at the B3LYP and HF levels of theory. The dimer [(TT+)[VO2(HTAR)]]2 is more suitable for practical applications due to its better extraction characteristics and wider pH interval of formation and extraction. It was used for cheap and reliable extraction–spectrophotometric determination of V(V) traces in real samples. The absorption maximum, molar absorptivity coefficient, limit of detection, and linear working range were 549 nm, 5.2 × 104 L mol−1 cm−1, 4.6 ng mL−1, and 0.015–2.0 μg mL−1, respectively.

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“…The interfering effect of V(V) and Fe(III) is smaller. If necessary, Fe(III) can be masked with HPO 4 2− [ 66 ] or separated by the fluoride method [ 67 ], as described below.…”

Section: Resultsmentioning

confidence: 99%

Use of a Hydrophobic Azo Dye for the Centrifuge-Less Cloud Point Extraction–Spectrophotometric Determination of Cobalt

et al. 2022

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The hydrophobic azo dye 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR, H2L) was studied as part of a system for the centrifuge-less cloud point extraction (CL-CPE) and spectrophotometric determination of traces of cobalt. The extracted 1:2 (Co:HTAR) complex, [CoIII(HL−)(L2−)]0, shows an absorption maximum at 553 nm and contains HTAR in two different acid–base forms. Optimum conditions for its formation and CL-CPE were found as follows: 1 × 10−5 mol L−1 of HTAR, 1.64% of Triton X-114, pH of 7.8, incubation time of 20 min at ca. 50 °C, and cooling time of 30 min at ca. −20 °C. The linear range, limit of detection, and apparent molar absorptivity coefficient were 5.4–189 ng mL−1, 1.64 ng mL−1, and 2.63 × 105 L mol−1 cm−1, respectively. The developed procedure does not use any organic solvents and can be described as simple, cheap, sensitive, convenient, and environmentally friendly. It was successfully applied to the analysis of artificial mixtures and real samples, such as steel, dental alloy, rainwater, ampoules of vitamin B12, and saline solution for intravenous infusion.

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A green cloud-point extraction-chromogenic system for vanadium determination

Cited by 24 publications

References 38 publications

Extraction-Chromogenic Systems for Vanadium(V) Based on Azo Dyes and Xylometazoline Hydrochloride

Extraction-Chromogenic Systems for Vanadium(V) Based on Azo Dyes and Xylometazoline Hydrochloride

Extractive Spectrophotometric Determination and Theoretical Investigations of Two New Vanadium(V) Complexes

Use of a Hydrophobic Azo Dye for the Centrifuge-Less Cloud Point Extraction–Spectrophotometric Determination of Cobalt

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