Reagent For Determination Of Copper Research Articles

Physico-analytical studies on some heterocyclic azo dyes and their metal complexes with some transition metals

In this investigation, the azo dyes; 2-(3′-phenyl-5′-pyrazolyl azo) schaffer acid (la) and 2-(3′-phenyl-5′-pyrazolyl azo) resorcinol (Ib); were prepared through diazotizing 3-phenyl-5-aminopyrazole (PAP) and coupling the resulting diazonium salt with Schäffer acid and resorcinol respectively. The prepared azo dyes are characterized using both IR spectra and the elemental analysis (C, H, N and S). The prepared azo dyes are used as chromogenic reagents for the spectrophotometric determination of copper (II), nickel (II), cobalt (II) and zinc (II) ions. The conditional acid dissociation constants of these azo dyes (la and Ib) and the stability constants of its metal ion complexes have been determined by spectro-analytical methods. The effect of pH, time, organic solvent and the foreign ions on the spectrophotometric determination of these ions and their complexes with the azo dyes under study were studied. The stoichiometric ratio (M:L) of the formed complexes was also determined. The molar absorptivity, the Sandell's sensitivity values, the obeyance of Beers law and the stability constants of the formed complexes have been also determined and discussed.

2-chlorobenzaldehyde thiocarbohydrazone: a novel reagent for liquid-liquid extractive spectrophotometric determination of copper(II) from environmental and real samples

ABSTRACT 2-Chlorobenzaldehyde thiocarbohydrazone (2-CBTCH) is proved as a novel analytical chelating reagent to developa simple, fast and selective liquid–liquid extractive spectrophotometric method for trace level determination of copper(II). The method was based upon the complexation reaction of copper(II) with 2-CBTCH in ethanol. It instantly forms orange coloured [Cu(II)-2 CBTCH] complex at room temperature, which was quantitatively extracted in 1-butanol and shows maximum absorption at 470 nm. The values of molar absorptivity and Sandell’s sensitivity of [Cu(II)-2CBTCH] complex are found to be 0.3429 × 104 Lmol−1 cm−1 and 0.01851 µgcm−2, respectively. The system follows Beer’s law up to 17.5 µgmL−1. The stoichiometry of the [Cu(II)-2CBTCH] complex in 1-butanol is determined by Job’s method, mole ratio method is 1:2 and was confirmed by log-log plot method. To intuit the peak extraction conditions several experimental factors such as pH, reagent concentration, selection of solvent, shaking time, interference of cations and anions has been studiedwell. The usage of masking agent lifts the selectivity of the present method. The method has been effectively used for the determination of copper(II) in alloy samples, pharmaceutical samples, fertiliser samples and environmental samples such as leafy vegetables and water samples.

Synthesis of the New 2-[6-Nitro 2-Benzothiazolylazo]-4-Hydroxy Benzoic Acid Organic Reagent for Spectrophotometric Determination of Copper(II)

A new 2-[6-Nitro-2-benzothiazolylazo]-4-hydroxy benzoic acid (NO2BTAHB) organic reagent was synthesized. A sensitive and selective spectrophotometric method was proposed for the rapid determination of Cu(II) using (NO2BTAHB) reagent. The reaction between Cu(II) and (NO2BTAHB) reagent is instantaneous at pH=6.0 and the absorbance remains stable for over 24 hrs. The Method allows for the determination of Cu(II) over the range (0.1-6.0) μg.ml-1, with molar absorptivity of (7.45 × 10+3)l.mol-1.cm-1 and a detection limit of 0.0245 μg.ml-1. Recovery and relative error values of precision and accuracy of method were found to be R.S.D=1.7%, Re=98.6%, and Erel=-1.4%. The properties of complex was studied and show; (M:R) ratio was 1:2 at pH=6.0, and the stability constant of 7.796 × 10+9 L2.mol-2. The interferences of ions (Ni2+, CrO2-, Ca2+, pb2+, Cu+2, WO4 -2, MO4 -2, Co2+, Mg2+, Cd2+, Ba2+, Bi3+) and masking agents effect on absorbance were studied.

Ion Pairs of 5,5-dimethyl-2-(2-hydroxy-3,5-disulfophenylhydrazo)cyclohexane-1,3-dione with Cationic Surface-Active Substances as Analytical Reagent for Determination of Copper(II)

A new organic reagent, 5,5-dimethyl-2-(2-hydroxy-3,5-disulfophenylhydrazo)сyclo-hexane-1,3-dione (H2L), was synthesized by azo coupling of diazonium salts of 2-hydroxy-3,5-disulfoaniline with dimedone. The dissociation constants of H2L were determined by potentiometric titration, being pK 1 = 5.90 ± 0.03 and pK 2 = 9.67 ± 0.04. The interaction in systems of H2L and cationic surface-active substances (CSAS), cetylpyridinium chloride (CPCl), cetylpyridinium bromide (CPBr), or cetyltrimethylammonium bromide (CTABr) was studied in the presence and absence of Cu(II). It was found that the detection limit of Cu(II) using H2L–CSAS pairs decreases in accord with the stability of associates H2L(CPCl)2 > H2L(CPBr)2 > H2L(CTABr)2 and their copper(II) complexes Cu[(HL)(CPCl)2]2 > Cu[(HL)(CPBr)2]2 > Cu[(HL)(CTABr)2]2. The effects of foreign ions and masking substances on the complexation were studied and showed that the reaction of Cu(II) with H2L in the presence of CSAS is more selective. Based on these observations, a procedure for the spectrophotometric determination of copper(II) in soils polluted by oil, seawater, igneous rock, and nickel-based alloys was developed.

Trace Determination of Copper in Foodstuffs and Biological Samples

A new heterocyclic bis-azo dye, 2,6-bis(4-sulfo-1-hydroxy-2-naphthylazo)pyridine, sodium salt (PBS), has been prepared and developed as a sensitive and highly selective chromogenic reagent for spectrophotometric determination of copper. The reagent is found to give a 1:2 (M/L) complex at pH 6.0. Beer's law is followed up to 1.8 ppm with an optimal concentration range between 0.2 and 1.4 ppm. Sandell's sensitivity of the color reaction was calculated to be 0.0013 µg cm−2 with molar absorptivity of 4.9 × 104 l·mol−1 cm−1 at 572 nm. The interfering effects of various cations and anions were also studied. The proposed method was successfully applied to the determination of copper(II) in milk, tea samples, cereals, and legume grains consumed by the Indian vegetarians and in some biological samples. Comparison of the results with those obtained using an atomic absorption spectrophotometer tested the validity of the method.

Spectrophotometric Determination of Copper (II) with 5-Hydroxy-6-Mercapto-Benzo [a] Phenazine

5-Hydroxy-6-mercapto-benzo [a] phenazine (HMBP) is proposed as a sensitive and selective analytical reagent for the extractive spectrophotometric determination of copper (II). Copper reacts with HMBP to give a dark red complex which is soluble in chloroform. The composition of the CuII � HMBP complex is established as 1:2 by Job�s continuous variation method and molar ratio method. The instability constant of the complex calculated by Job�s relation for nonisomolar series is 4.65 . 10-9, at room temperature. The CuII-HMBP complex in chlorophorm shows a maximum absorbance at 495 nm, with molar absorptivity and Sandell�s sensitivity values of 7.39 . 103dm3 mol-1 cm-1 and 0.012 mg cm-2, respectively. Beer�s law is obeyed in the concentration range 0.67 - 26.90 mg mL-1 and the detection limit is 0.59 mg mL-1. A repetition of the method is checked by finding the relative standard deviation (RSD) at 1.00 mg mL-1 CuII of 0.6%. The method is successfully employed for the determination of copper (II) in environmental samples. The reliability of the method is assured by analysing the standard alloys and by inter-comparison of experimental values, using an atomic absorption spectrometer.

Azo derivative of 2-thenoyltrifluoroacetone as a reagent for the photometric determination of copper(II)

Azo derivative of 2-thenoyltrifluoroacetone as a reagent for the photometric determination of copper(II)

Azo derivative of 2-thenoyltrifluoroacetone as a reagent for the photometric determination of copper(II)

1-(2-Thenoyl)-4-trifluoro-2-[2-hydroxy-3-sulfo-5-nitrophenylazo]butadione-1,3 (H2L) was synthesized from 2-thenoyltrifluoroacetone. The formation of a copper(II) complex of the synthesized reagent was studied in the presence and absence of 8-hydroxyquinoline (HR). Monoligand [Cu(HL)2] and mixed-ligand [Cu(HL)2HR] compounds were obtained at pH 4 and 3, respectively. The ratio of components in the monoligand and mixed-ligand compounds were 1 : 2 and 1 : 2 : 1, respectively. Beer’s law was obeyed in the ranges of copper concentrations from 0.20 to 2.56 and from 0.25 to 2.56 µg/mL, respectively. The dissociation constants of the reagent were .K1 = 4.25µ0.01 and .K2 = 8.20µ0.01 . The stability constants of [Cu(HL)2] and [Cu(HL)2HR] complexes were K1 = 4.96µ0.03 and 4.92µ0.01, respectively. A procedure was developed for the photometric determination of copper(II) in rocks.

5(4-dimethylaminobenzylidene) rhodanine as a reagent for the spectrophotometric determination of copper and manganese

The synthesis and spectral characteristics of 5(4-dimethylaminobenzylidene) rhodanine have been investigated. The extraction-spectrophotometric method for the determination of copper and manganese based on their extraction into ethanol with 5(4-dimethylaminobenzylidene) rhodanine (DMABR) from a weakly acidic medium have been developed. The maximum absorbance of the extracted species for Cu and Mn compounds occurs at 480nm.Copper and manganese compounds react with the reagent in the molar ratio 1:1; 1:2;and 1:3 (metal:ligand) at pH 1.09 to 11 in a solution containing 20 % (v/v) of ethanol..A concentration of DMABR three times greater than the metal concentration was necessary for complete complexation; to give molar extinction coefficient (3.8 x 10 3 at pH 2 and 7.6 x 10 3 at pH 8) for Cu-DMABR.and (2.76 x10 3 at pH 2 and 1.5 x 10 3 at pH 8) for Mn-DMABR respectively. The interferences with some metal ions have been studied. The optimum experimental conditions were suggested for the determination of these metal ions. KEY WORDS: 5(4-dimethylaminobenzylidene)rhodanine; copper, manganese ; spectrophotometric method Global Jnl of Pure and Applied Sciences Vol.10(4) 2004: 577-583

2-[2?-(6?-Methyl-benzothiazolyl)azo]-5-dimethylaminobenzoic acid as a new reagent for rapid spectrophotometric determination of copper

2-[2′-(6-methyl-benzothiazolyl)azo]-5-dimethylaminobenzoic acid (MBTAMB) has been synthesized and employed as a new reagent for the spectrophotometric determination of copper(II). A blue complex is formed from MBTAMB and Cu(II) in the range of pH 2.0–5.0 in aqueous ethanol. The composition of the complex is Cu(II) ∶ MBTAMB=1 ∶ 1. The maximum absorption of the complex is at 660 nm, its apparent molar absorptivity is 7.0 × 104 1· mole–1 · cm–1. Beer's law is obeyed for copper in the range of 0–0.72 μg/ml. The method has been used for the determination of micro amounts of copper in aluminium alloy. The proposed method is simple, rapid and accurate.

6-Phenyl -2,3-Dihydro-asym-trirzine-3-thione as a Selectiue Reagent for the Spectrophotometric Determination of Copper

Abstract A sensitive and highly selective spectrophotometric method is described for the determination of 12-120 μg of copper using 6-phenyl-2,3-dihydro-asym-triazine-3-thione (PDTT) as a complexing agent. The red 1:4 water soluble complex was measured at 540nm, e=1.26×104 1. mol−1cm−1. The method was applled for the determination of copper in standard steels (B.C.S.) and estimation of the solubility product of copper (I) iodide. Comperison was also made with the 2-2 biquinoline method.

Hydrazinium thiocyanate as a reagent for determination of copper

Hydrazinium thiocyanate, N 2H 5SCN, has been used for the determination of copper in copper salts. The reagent reduces the copper ions to the cuprous state and precipitates cuprous thiocyanate Cu 2(SCN) 2, quantitatively.

2-Hydroxy-1-acetonaphthoneoxime as analytical reagent

2-Hydroxy-1-acetonaphthoneoxime has now been proposed as a new reagent for the gravimetric determination of copper. Copper in the range 4·0 to 40·0 mg can be accurately determined by this procedure. The interference of the elements usually associated in its alloys and ores is also studied. The method is applied in the analysis of brass and chalcopyrite.

N-Acetylacetone-anthranilic acid as a gravimetric reagent for copper(II)

N-Acetylacetone-anthranilic acid has been employed as a reagent for the gravimetric determination of copper(II). The solid copper(II) chelate formed possesses 1:1 metal-ligand stoichiometry and is found to exist as an unsolvated dimer. The complex has a magnetic moment of 1.88 B.M. at 298 K. A non-planar dimeric structure is suggested to explain the observed facts.

Gallacetophenone oxime as a reagent for gravimetric determination of copper and its separation from other elements

Gallacetophenone oxime is a more useful analytical reagent for the determination of copper in presence of nickel, cadmium, zinc, manganese, selenium and iron than either salicylaldioxime or resacetophenone oxime. It is more soluble in water and its gravimetric factor (0.1486) is more favourable than with either salicylaldioxime (0.1895) or resacetophenone oxime (0.1607).

Solvent extraction of copper(II) by schiff's bases

The solvent extraction of copper(II) by a number of quadridentate Schiff's bases has been investigated. All but one of the reagents are capable of extracting copper(II) quantitatively from aqueous solution and the possibility of using these reagents for determination of copper(II) by absorption spectrophotometry and by atomic absorption spectrophotometry is described. Spectrophotometric determinations are not sensitive but the atomic absorption method allows determinations in the p.p.b. range, similar to ammonium pyrrolidinedithiocarbamate.