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

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Petya Vassileva Racheva ◽  
Kiril Blazhev Gavazov ◽  
Vanya Dimitrova Lekova ◽  
Atanas Nikolov Dimitrov
Keyword(s):  
Complex Formation ◽  
Limit Of Detection ◽  
Equilibrium Constants ◽  
Ion Association ◽  
Molar Absorptivity ◽  
Liquid Extraction ◽  
Optimum Conditions ◽  
Limit Of Quantification ◽  
Liquid Liquid Extraction ◽  
Experimental Parameters

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+)[Co3+(PAR)2], were found. The following key equilibrium constants were calculated: constant of association (Log β=4.77±0.06), constant of distribution (LogKD=1.34±0.01), and constant of extraction (LogKex=6.11±0.07). Beer’s law was obeyed for Co concentrations up to 1.7 μg mL−1 with a molar absorptivity of 6.0×104 L mol−1 cm−1 at λmax=520 nm. Some additional characteristics, such as limit of detection, limit of quantification, and Sandell’s sensitivity, were estimated as well.

scholarly journals Phenylmethoxybis(tetrazolium) ion-association complexes with an anionic indium(III) — 4-(2-pyridylazo)resorcinol chelate

2013 ◽  
Vol 11 (2) ◽  
pp. 280-289 ◽  
Author(s):  
Teodora Stefanova ◽  
Kiril Gavazov
Keyword(s):  
Limit Of Detection ◽  
Ion Association ◽  
Molar Absorptivity ◽  
Tetrazolium Salt ◽  
Limit Of Quantification ◽  
Tetrazolium Chloride ◽  
Liquid Liquid Extraction ◽  
Blue Tetrazolium ◽  
Blue Tetrazolium Chloride ◽  
Molar Absorptivity Coefficient

AbstractComplex formation and liquid-liquid extraction were studied in systems containing indium(III), 4-(2-pyridylazo)resorcinol (PAR), phenylmethoxybis(tetrazolium) salt (MBT), water and chloroform. The following MBTs, which differ only by the number of -NO2 groups in their cationic parts, were used: 3,3′-(3,3′-dimetoxy-4,4′-biphenylene)bis(2,5-diphenyl-2H-tetrazolium chloride) (Blue Tetrazolium chloride, BT), 3,3′-(3,3′-dimetoxy-4,4′-biphenylene)bis[2-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride] (Nitro Blue Tetrazolium chloride, NBT) and 3,3′-(3,3′-dimetoxy-4,4′-biphenylene)bis[2,5-di(4-nitrophenyl)-2H-tetrazolium chloride] (Tetranitro Blue Tetrazolium chloride, TNBT). The composition of the formed ternary complexes was determined, In:PAR:MBT=1:2:2, and the optimum conditions for their extraction found: pH, shaking time, concentration of the reagents and the sequence of their addition. Some key constants were estimated: constants of extraction (Kex), constants of association (β) and constants of distribution (KD). BT appears to be the best MBT for extraction of the In(III)-PAR species, [In3+(OH)3(PAR)2]4−, (Log Kex=10.9, Log β=9.8, Log KD=1.12, R%=92.7%). Several additional characteristics concerning its application as extraction-spectrophotometric reagent were calculated: limit of detection (LOD = 0.12 µg cm−3), limit of quantification (LOD = 0.40 µg cm−3) and Sandell’s sensitivity (SS =1.58 ng cm−2); Beer’s law is obeyed for In(III) concentrations up to 3.2 µg mL−1 with a molar absorptivity coefficient of 7.3×104 L mol−1 cm−1 at λmax=515 nm.

scholarly journals Ternary ion-association complexes between the indium(III) - 4-(2-pyridylazo)resorcinol anionic chelate and some tetrazolium cations

2011 ◽  
Vol 9 (6) ◽  
pp. 1143-1149 ◽  
Author(s):  
Galya Toncheva ◽  
Kiril Gavazov ◽  
Vanya Lekova ◽  
Kirila Stojnova ◽  
Atanas Dimitrov
Keyword(s):  
Complex Formation ◽  
Ternary Complex ◽  
Ion Association ◽  
Liquid Extraction ◽  
Extraction Time ◽  
Tetrazolium Salt ◽  
Optimum Conditions ◽  
Tetrazolium Chloride ◽  
Tetrazolium Bromide ◽  
Liquid Liquid Extraction

AbstractComplex formation and liquid-liquid extraction were studied in systems containing indium(III), 4-(2-pyridylazo)resorcinol (PAR), tetrazolium salt (TZS), water and chloroform. Two different TZS were used: 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT). The optimum conditions for extraction of In(III) as a ternary complex, (TT+)[In(PAR)2] or (MTT+)[In(PAR)2], were found: pH, extraction time, concentration of PAR and concentration of TZS. The constants of extraction (Kex), constants of association (β), constants of distribution (KD) and recovery factors (R%) were determined. The apparent molar absorptivities in chloroform were calculated to be ɛ′520=6.6×104 L mol−1 cm−1 and ɛ′515=7.1×104 L mol−1 cm−1 for the systems with TTC (I) and MTT (II), respectively. Beer’s law was obeyed for In(III) concentrations up to 3.4 µg mL−1 in both the cases. The limits of detection (LOD=0.07 µg mL−1I and LOD=0.12 µg mL−1II), limits of quantification (LOQ=0.24 µg mL−1I and LOQ=0.41 µg mL−1II) and Sandell’s sensitivities (SS) were estimated as well.

scholarly journals Extraction-spectrophotometric investigations on two ternary ion-association complexes of gallium(III)

2012 ◽  
Vol 10 (4) ◽  
pp. 1262-1270 ◽  
Author(s):  
Kirila Stojnova ◽  
Kiril Gavazov ◽  
Galya Toncheva ◽  
Vanya Lekova ◽  
Atanas Dimitrov
Keyword(s):  
Complex Formation ◽  
Ion Association ◽  
Chloroform Extract ◽  
Liquid Extraction ◽  
Optimum Conditions ◽  
Triphenyltetrazolium Chloride ◽  
Liquid Liquid Extraction ◽  
Ion Associate ◽  
Optimum Extraction ◽  
Principal Species

AbstractComplex formation and liquid-liquid extraction were studied in systems containing Ga(III), azoderivative of resorcinol {4-(2-pyridylazo)resorcinol (PAR) or 4-(2-thiazolylazo)resorcinol (TAR)}, 2,3,5-triphenyltetrazolium chloride (TTC), water and chloroform. The optimum conditions w.r.t. pH, extraction time, concentration of ADR and concentration of TTC for the extraction of Ga(III) as an ion-associate complex were found.. The composition of the extracted complexes, (TT+)[Ga(PAR)2] (I), (TT+)[Ga(TAR)2] (II) or (TT+)2[Ga(OH)(TAR)2] (III), and the constants of association (β) between 2,3,5-triphenyltetrazolium cation (TT+) with corresponding anionic chelates were established by several methods. The constants of distribution (KD) and extraction (Kex) of the principal species I and III were determined as well. The apparent molar absorptivities of the chloroform extract at the optimum extraction-spectrophotometric conditions were ɛ′510=9.5×104 L mol−1 cm−1 (I) and ɛ′530=4.6×104 L mol−1 cm−1 (III). The validity of Beer’s law was checked and analytical characteristics that were calculated are reported herein.

Spectrophotometeric Determination of Trifluoperazine HCL in Pure Forms and Pharmaceutical Preperations

2017 ◽  
Vol 9 (5) ◽  
Author(s):  
Mohammad Hamzah Hamzah ◽  
Rawa M M Taqi ◽  
Muna M. Hasan ◽  
Raid J. M. Al-Timimi
Keyword(s):  
Standard Method ◽  
Limit Of Detection ◽  
Molar Absorptivity ◽  
Dosage Forms ◽  
Oxidizing Agent ◽  
Optimum Conditions ◽  
Limit Of Quantification ◽  
Cerium Ion ◽  
Blank Solution

A simple and accurate spectrophotometric method for the determination of Trifluoperazine HCl in pure and dosage forms was developed. The method is based on the reaction between Trifluoperazine HCl and p-chloroaniline in the presence of cerium ion as oxidizing agent which lead to the formation of violate color product that absorbed at a maximum wavelength 570nm while the blank solution was pink. Under the optimum conditions a linear relationship between the intensity and concentration of TRF in the range 4-50μg/ml was obtained . The molar absorptivity 3.74×103 L.mol-1.cm-1 , Limit of detection (2.21μg/ml), while limit of quantification was 7.39μg/ml. The proposed analytical method was compared with standard method using t-test and F-test , the obtained results shows there is no significant differences between proposed method and standard method. Based on that the proposed method can be used as an alternative method for the determination of TRF in pure and dosage forms.

scholarly journals Extraction-Chromogenic System for Cobalt Based on 5-Methyl-4-(2-thiazolylazo) Resorcinol and Benzalkonium Chloride

2021 ◽  
Vol 68 (1) ◽  
pp. 37-43
Author(s):  
Danail G. Georgiev Hristov ◽  
Petya Vassileva Racheva ◽  
Galya Konstantinova Toncheva ◽  
Kiril Blazhev Gavazov
Keyword(s):  
Benzalkonium Chloride ◽  
Limit Of Detection ◽  
Ion Association ◽  
Molar Absorptivity ◽  
Sensitivity Limit ◽  
Deprotonated Form ◽  
Limit Of Quantification ◽  
Optimum Ph ◽  
Ion Associate ◽  
Ph Range

The interaction between CoII and 5-methyl-4-(2-thiazolylazo)-resorcinol (MTAR) was studied in a water-chloroform system, in the presence or absence of benzalkonium chloride (BZC) as a cationic ion-association reagent. The optimum pH, concentration of the reagents and extraction time for the extraction of Co were found. In the presence of BZC, the extracted ion-associate could be represented by the formula (BZ+)[CoIII(MTAR2–)2], where MTAR is in its deprotonated form. The following extraction-spectrophotometric characteristics were determined: absorption maximum, molar absorptivity, Sandell’s sensitivity, limit of detection, limit of quantification, constant of extraction, distribution ratio and fraction extracted. In the absence of BZC, the extraction is incomplete and occurs in a narrow pH range. The extracted chelate contains one deprotonated and one monoprotonated ligand: [CoIII(MTAR2–)(HMTAR–)].

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

2015 ◽  
Vol 80 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Vidka Divarova ◽  
Kirila Stojnova ◽  
Petya Racheva ◽  
Vanya Lekova ◽  
Atanas Dimitrov
Keyword(s):  
Equilibrium Constants ◽  
Ion Association ◽  
Liquid Extraction ◽  
Tetrazolium Chloride ◽  
Molar Ratios ◽  
Liquid Liquid Extraction ◽  
Blue Tetrazolium ◽  
Blue Tetrazolium Chloride ◽  
Extraction Equilibria ◽  
Ditetrazolium Salts

The formation and liquid-liquid extraction of ion-association complexes between Co(II)-4-(2-Pyridylazo)resorcinol (PAR) anionic chelates and cations of three ditetrazolium chlorides were studied: Blue Tetrazolium chloride (BTC), Neotetrazolium chloride (NTC) and Nitro Blue Tetrazolium chloride (NBT). The optimum conditions for the formation and solvent extraction of the ion-association comlpex chelates were determined. It has been found that in the systems of Co(II)-PAR-DTS, the reactants are reacted in molar ratios 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.

Application of a ternary complex of tungsten(VI) with 4-nitrocatechol and thiazolyl blue for extraction-spectrophotometric determination of tungsten

2006 ◽  
Vol 60 (4) ◽  
Author(s):  
V. Lekova ◽  
K. Gavazov ◽  
A. Dimitrov
Keyword(s):  
Limit Of Detection ◽  
Ion Association ◽  
Extraction Process ◽  
Chloroform Extract ◽  
Molar Absorptivity ◽  
Limit Of Quantification ◽  
Diphenyltetrazolium Bromide ◽  
Optimum Ph ◽  
Association Complex

AbstractA new ternary ion-association complex of tungsten(VI), 4-nitrocatechol (NC), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (Thiazolyl Blue, MTT) was obtained and studied using an extraction-spectrophotometric method. The optimum pH, reagent concentrations, and extraction time were determined. The composition of the complex was found to be W(VI): NC: MTT = 1: 2: 2. The extraction process was investigated quantitatively and the key constants were calculated. The molar absorptivity of the chloroform extract at λmax = 415 nm was 2.8 × 104 dm3 mol−1 cm−1, and the Beer’s law was obeyed up to 8.8 μg cm−3 tungsten(IV). The limit of detection and limit of quantification were calculated to be 0.27 μg cm−3 and 0.92 μg cm−3, respectively. The effect of foreign ions and reagents was studied and a competitive method for determination of tungsten in products from ferrous metallurgy was developed. The residual standard deviation and the relative error were 0.53 % and 0.2 %, respectively.

scholarly journals Optimization and validation of the salting-out assisted liquid-liquid extraction method and analysis by gas chromatography to determine pesticides in water

2018 ◽  
Vol 43 (1SI) ◽  
pp. 11
Author(s):  
Alessandra Aparecida Zinato Rodrigues ◽  
Antônio Augusto Neves ◽  
Maria Eliana Lopes Ribeiro De Queiroz ◽  
André Fernando De Oliveira ◽  
Lucas Henrique Figueiredo Prates ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Single Phase ◽  
Limit Of Detection ◽  
Liquid Extraction ◽  
Solvent Ratio ◽  
Limit Of Quantification ◽  
Salting Out ◽  
Extraction Solvent ◽  
Liquid Liquid Extraction ◽  
Pesticides In Water

The salting-out assisted liquid-liquid extraction (SALLE) was developed for the analysis of four pesticides (cypermethrin, chlorpyrifos, deltamethrin, and thiamethoxam) in water samples. For its optimization, a 2³ factorial design was used to evaluate the simultaneous behavior of three factors: sample and extraction solvent ratio, saline concentration, and stirring mode. A 1.0 mL saline solution (NaCl) was added to the single-phase mixture of water and extraction solvent to separate the phases. The mixture was stirred, allowed to stand and the top organic phase containing the pesticides of interest was analyzed by gas chromatography coupled with electron capture detector (GC/ECD). The optimized method was validated for some merit figures. The limit of detection of the method ranged from 0.15 to 5.5 µg L-1 and the limit of quantification from 5.5 to 18.2 µg L-1. The method showed satisfactory results for the linearity (R2 ≥ 0,990), precision (CV < 9 %) and accuracy (72 % ≤ recovery ≤ 90 %) for all the assessed analytes. The method showed to be simple, efficient and inexpensive for the extraction of pesticide residues. The validated method was applied to ten samples of water collected in the Zona da Mata region of the state of Minas Gerais, Brazil.

Liquid–liquid extraction and cloud point extraction for spectrophotometric determination of vanadium using 4-(2-pyridylazo)resorcinol

2015 ◽  
Vol 69 (4) ◽  
Author(s):  
Teodora S. Stefanova ◽  
Kiril K. Simitchiev ◽  
Kiril B. Gavazov
Keyword(s):  
Cloud Point ◽  
Spectrophotometric Determination ◽  
Cloud Point Extraction ◽  
Limit Of Detection ◽  
Molar Absorptivity ◽  
Liquid Extraction ◽  
Optimal Conditions ◽  
Liquid Liquid Extraction ◽  
Relative Standard

AbstractLiquid-liquid extraction (LLE) and cloud point extraction (CPE) of vanadium(V) ternary complexes with 4-(2-pyridylazo)resorcinol (PAR) and 2,3,5-triphenyl-2H-tetrazolum chloride (TTC) were investigated. The optimal conditions for vanadium extraction and spectrophotometric determination were identified. The composition (V : PAR : TTC) of the extracted species was 1 : 2 : 3 (optimal conditions; LLE), 2 : 2 : 2 (low reagents concentrations; LLE), 1 : 1 : 1 (short heating time; CPE), and 1 : 1 : 1 + 1 : 1 : 0 (optimal extraction conditions; CPE). LLE, performed in the presence of 1,2-diaminocyclohexane-N,N,N’,N’-tetraacetic acid and NH4F as masking agents, afforded the sensitive, selective, precise, and inexpensive spectrophotometric determination of vanadium. The absorption maximum, molar absorptivity, limit of detection, and linear working range were 559 nm, 1.95 × 105 dm3 mol−1 cm−1, 0.7 ng cm−3, and 2.2-510 ng cm−3, respectively. The procedure thus developed was applied to the analysis of drinking waters and steels. The relative standard deviations for V(V) determination were below 9.4 % (4-6 × 10−7 mass %; water samples) and 2.12 % (1-3 mass %; steel samples).

scholarly journals Ternary complexes of vanadium(IV) with 4-(2-pyridylazo)-resorcinol (PAR) and ditetrazolium chlorides (DTC)

2010 ◽  
Vol 8 (2) ◽  
pp. 461-467 ◽  
Author(s):  
Fatma Genç ◽  
Kiril Gavazov ◽  
Murat Türkyilmaz
Keyword(s):  
Limit Of Detection ◽  
Molar Absorptivity ◽  
Extraction Constant ◽  
Ternary Complexes ◽  
Limit Of Quantification ◽  
Tetrazolium Chloride ◽  
Liquid Liquid Extraction ◽  
Blue Tetrazolium ◽  
Blue Tetrazolium Chloride ◽  
Molar Absorptivity Coefficient

AbstractComplex formation and liquid-liquid extraction have been studied for ternary complexes of vanadium(IV) with 4-(2-pyridylazo)-resorcinol (PAR) and ditetrazolium chlorides (DTC) in a water-chloroform medium. The specific ditetrazolium compounds investigated were i) 3,3′-(4,4′-biphenylene)-bis(2,5-diphenyl-2H-tetrazolium) chloride (Neotetrazolium chloride, NTC); ii) 3,3′-(3,3′-dimetoxy-4,4′-biphenylene)-bis(2,5-diphenyl-2H-tetrazolium) chloride (Blue Tetrazolium chloride, BTC); and iii) 3,3′-(3,3′-dimetoxy-4,4′-biphenylene)-bis[2-(4-nitrophenyl)-5-phenyl-2H-tetrazolium] chloride (Nitro Blue Tetrazolium chloride, NBT). Molar absorptivity coefficients and the composition of the complexes have been calculated. Association constants (β) have also been obtained for the interactions between the vanadium(IV) — PAR anionic chelates [VO(PAR)2]2− (I) and [VO(OH)2(PAR)2]4− (II), and ditetrazolium cations (DT2+). Some special features of NBT as an extraction-spectrophotometric reagent for vanadium(IV) have been discussed. Unlike NTC and BTC which form complexes with both I and II, NBT associates only with II. The pH interval for complete extraction of (NBT2+)2[VO(OH)2(PAR)2] is broader and allows work at lower pH values the other ion-associates of V(IV,V)-PAR that were studied. NBT is -therefore the appropriate reagent both for direct V(IV) determination and for V(IV)/V(V) separation. Some additional characteristics for the V(IV)-PAR-NBT-water-chloroform system have been determined: extraction constant, distribution constant, recovery factor, limit of detection and limit of quantification. Beer’s law is valid up to 1.4 μg mL−1 vanadium(IV) with molar absorptivity coefficient of 3.55×104 L mol−1 cm−1 at λmax=559 nm.

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