Spectrophotometric Determination Of Metal Ions Research Articles

Direct Spectrophotometric Determination of Lead (II) in Industrial Samples using 1, 3-Benzenediamine, N, N'-bis(2-furanylmethylene) in Presence of Surfactant

Schiff's base are one of the excellent chelating agents that used for the spectrophotometric determination of metal ions. It was observed that 1, 3-Benzenediamine, N,N'-bis(2-furanylmethylene) (BDFM) formed a brown colored complex with lead (II) at 620 nm. Lead (II) was chelated with the Schiff's base (BDFM) in acidic medium at pH = 3.5 using acetate buffer in presence of sodium laureth sulfate (SLS) as a surfactant. The effect of time, temperature and foreign ions were studied. The stoichiometric composition of the formed complex was found to be 1:2 (metal: ligand) by Job's method of continuous variation. Beer's law was obeyed in the range of 10-110 μg mL-1 with molar absorptivity 10.16×103 L mol-1cm-1. The proposed method was applied for the determination of lead in gasoline, solders, gutters and wastewater.

A spectrophotometric method for the determination of zinc, copper, and cobalt ions in metalloproteins using Zincon

Zincon (2-carboxy-2′-hydroxy-5′-sulfoformazylbenzene) has long been known as an excellent colorimetric reagent for the detection of zinc and copper ions in aqueous solution. To extend the chelator’s versatility to the quantification of metal ions in metalloproteins, the spectral properties of Zincon and its complexes with Zn2+, Cu2+, and Co2+ were investigated in the presence of guanidine hydrochloride and urea, two common denaturants used to labilize metal ions in proteins. These studies revealed the detection of metals to be generally more sensitive with urea. In addition, pH profiles recorded for these metals indicated the optimal pH for complex formation and stability to be 9.0. As a consequence, an optimized method that allows the facile determination of Zn2+, Cu2+, and Co2+ with detection limits in the high nanomolar range is presented. Furthermore, a simple two-step procedure for the quantification of both Zn2+ and Cu2+ within the same sample is described. Using the prototypical Cu2+/Zn2+–protein superoxide dismutase as an example, the effectiveness of this method of dual metal quantification in metalloproteins is demonstrated. Thus, the spectrophotometric determination of metal ions with Zincon can be exploited as a rapid and inexpensive means of assessing the metal contents of zinc-, copper-, cobalt-, and zinc/copper-containing proteins.

Quercetin- and morinsulfonates as analytical reagents

Sulfonate derivatives of quercetin and morin, quercetin-5"-sulfonic acid (QSA) and sodium morin-5"-sulfonate (NaMSA), form complexes with p-, d-, and f-electron metal ions in solution and a solid state similarly to quercetin and morin. QSA and NaMSA are well-soluble in water, contrary to quercetin and morin. Metal ion complexes of QSA and MSA have high absorption coefficients of 104 L3 mol–1 cm–1. Therefore, those complexes can be conveniently used for the spectrophotometric determination of metal ions. Moreover, some of complexes reveal strong luminescence and can be applied to spectrofluorimetric analysis.

Spectrophotometric determination of metal ions in electroplating solutions in the presence of EDTA with the aid of multivariate calibration and artificial neural networks

Metal ions such as Co(II), Ni(II), Cu(II), Fe(III) and Cr(III), which are commonly present in electroplating baths at high concentrations, were analysed simultaneously by a spectrophotometric method modified by the inclusion of the ethylenediaminetetraacetate (EDTA) solution as a chromogenic reagent. The prediction of the metal ion concentrations was facilitated by the use of an orthogonal array design to build a calibration data set consisting of absorption spectra collected in the 370–760 nm range from solution mixtures containing the five metal ions earlier. With the aid of this data set, calibration models were built based on 10 different chemometrics methods such as classical least squares (CLS), principal component regression (PCR), partial least squares (PLS), artificial neural networks (ANN) and others. These were tested with the use of a validation data set constructed from synthetic solutions of the five metal ions. The analytical performance of these chemometrics methods were characterized by relative prediction errors and recoveries (%). On the basis of these results, the computational methods were ranked according to their performances using the multi-criteria decision making procedures preference ranking organization method for enrichment evaluation (PROMETHEE) and geometrical analysis for interactive aid (GAIA). PLS and PCR models applied to the spectral data matrix that used the first derivative pre-treatment were the preferred methods. They together with ANN-radial basis function (RBF) and PLS were applied for analysis of results from some typical industrial samples analysed by the EDTA-spectrophotometric method described. DPLS, DPCR and the ANN-RBF chemometrics methods performed particularly well especially when compared with some target values provided by industry.

Visible spectrophotometric determination of metal ions: the influence of structure on molar absorptivity value of copper(II) complexes in aqueous solution

In this study, the structure–absorptivity relationship problem is dealt with, on the basis of a considerable mass of data (117 complexes) concerning equatorial complexes of copper(II) in aqueous solution. Some spectrophotometric measurements have been carried out and as well as some molar absorptivity calculations on copper(II)–ammonia ( ε 640=77 M −1 cm −1 for the Cu(NH 3) 4 2+ species) and copper(II)–biuret ( ε 505=46 M −1 cm −1 for the Cu(C 2H 3N 3O 2) 2 2− species) systems have been made, in order to complete the quantitative information necessary for the discussion. It was found that the qualitative relationship between ε max and λ max, for the complexes in question is traceable back to a hyperbolic type of path; the dispersion of the data in the cartesian plane ( ε max, λ max) is analyzed and discussed. It has been found that the dissociated peptide nitrogen is, amongst those under study (namely: amino nitrogen; peptide nitrogen; imidazole nitrogen; carboxylate oxygen; alcoholate oxygen; hydroxide oxygen; water oxygen), that which corresponds to the major increase of ε max for copper(II). On the contrary, the one which corresponds to the minor increase is the imidazole donor (that is pyridine nitrogen of imidazole residue), which manifests the ability to lower the ε max values of the equatorial complexes of copper(II). Moreover, contrary to what has been previously demonstrated for λ max, for ε max it does not appear to be correct to schematize the ligand with its donor groups in order to assess spectrum–structure correlations. Consequently, this study contains a type of methodological proposal, even beyond the metal ion specifically in question, for the analyses of the selection criteria of the molecular characteristics that a ligand must possess in order to form a co-ordination compound of analytical interest with a determined metal ion.

Circular Dichroism Spectrophotometric Determination of Metal Ions by Using Optically Resolved Sparingly Soluble fac(S)-[Rh(aet)3](aet = 2-Aminoethanethiolate)

Abstract Sparingly soluble neutral fac(S)-[Rh(aet)3] (aet = 2-aminoethanethiolate) was optically resolved completely. The S-bridged complex formation of the optically active isomer of fac(S)-[Rh(aet)3] was utilized for the selective determination of metal ions by using circular dichroism spectra.

Spectrophotometric determination of trace amounts of cobalt with 2-hydroxybenzaldehyde-5-nitro-pyridylhydrazone in presence of surfactant after separation with Amberlite IRC-718 resin

2-Hydroxybenzaldehyde-5-nitro-pyridylhydrazone (2HB-5NPH) was synthesized and its application in the spectrophotometric determination of metal ions was studied in the presence of surfactants. A separation procedure, using a short column filled with Amberlite IRC 718, is proposed for the spectrophotometric determination of traces of cobalt. The influence of several ions, as interference, was discussed. The procedure was applied to determination of cobalt in mixture sample with satisfactory results (≥recovery 96%; relative error ≤2%; relative standard deviation ≤1.2% in the concentration range of 0.02–2.0 mg l−1; detection limit, 0.01 mg l−1 in solution). Control of the pH during the column operation is essential because the adsorption capacities are very sensitive to change in pH. Their separation was carried out in 0.005 M Malic acid, 1.5 M HCl, 2.0 M HNO3 media.

Synthesis of N-Hydroxy-N-(o-chlorophenyl)-N′-(p-methoxyphenyl)benzamidine Hydrochloride and Its Reactions with Various Metal Ions

Abstract A new reagent N-hydroxy-N-(o-chlorophenyl)-N′-(p-methoxyphenyl)benzamidine hydrochloride, has been synthesized and is characterized on the basis of mp, elemental analysis, IR and UV spectra. The reactions of the reagent with metal ions suggest that new methods can be developed for gravimetric and extraction spectrophotometric determination of metal ions. The reagent has been successfully used for the extraction-spectrophotometric determination of vanadium(V) in presence of phenol. Many common ions including Co2+, Zn2+, Ag+, Mn2+, etc. do not interfere in the determination. The method has been applied for the determination of vanadium in steel samples.

Formation Constants of Ternary Complexes of Some Heavy Metal Ions with N-(2-Acetamido)iminodiacetic Acid and Aliphatic or Aromatic Acids

N-(2-Acetamido)iminodiacetic acid (H[sub 2]ADA) is considered as one of the biologically important ligands. It is used as a complexing agent in the field of metal ion buffers working at the physiological pH range. Furthermore, it is widely used as an analytical chelating agent for the spectrophotometric determination of metal ions. Solution equilibria of the ternary systems involving La(III), Y(III), Ce(III), and UO[sub 2][sup 2+], N-(2-acetamido)iminodiacetic acid, and some aliphatic or aromatic acids have been investigated potentiometrically. The formation of 1:1:1 mixed ligand complexes is inferred from the potentiometric titration curves. Formation constants of the different binary and ternary complexes formed in such systems were determined at 25 [+-] 0.1 C and [mu] = 0.1 mol dm[sup [minus]3] (KNO[sub 3]). It is deduced that the mixed ligand complexes are more stable than the corresponding binary complexes containing the aliphatic or aromatic acidate moiety. The order of stability of the binary and ternary complexes is investigated and discussed in terms of the nature of both the metal ion and the secondary ligand (aliphatic or aromatic acid).

Masking agents in the spectrophotometric determination of metal ions with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol and non-ionic surfactant

Efficient masking methods were found for the selective spectrophotometric determination of metal ions with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in a micellar solution of a non-ionic surfactant. N-(Dithiocarboxy)sarcosine (DTCS) and nitrilotriacetic acid were good choices for the determination of iron(II). Triethylenetetraamine and DTCS (or dimercaptosuccinic acid and diethylenetriamine) were an excellent combination for the specific determination of manganese(II). A combination of pyrophosphate and ethylene glycol bis(2-aminoethyl ether)-N,N,N′,N′-tetraacetic acid was useful for the determination of cobalt(II). Hence, iron, manganese and cobalt were determined with high selectivity in various samples such as natural waters, metal samples and soil.

Pyridylazo Compounds As Analytical Reagents: A Review

A large number of 2-pyridylazo compounds have been proposed as reagents for the spectrophotometric determination of several metal ions. The application of 2-pyridylazo compounds for the determination of many metal ions is listed and several procedures are described to illustrate the fundamental conditions for the spectrophotometric determination of these metal ions.

Analytical reactions of 5-amino-orotic acid

The potential of 5-amino-orotic acid (AOA) for spectrophotometric determination of metal ions is explored. Only the reactions with copper(II), cobalt(II) and osmium(VIII) are sensitive and suitable for this purpose. Ternary complexes of copper(II) formed with AOA and ammonia or pyridine can also be used for photometric determination of the metal and given better sensitivity and selectivity than the binary complex. Optimum conditions for determination of all the three metal ions have been established.

Spectrophotometric determination of vanadium and niobium: Xylenol orange as a chromogenic reagent

The formation of red coloured chelates of vanadium(V) and niobium(V) with xylenol orange (DCAC) having λmax at 490 nm (at pH 5.0) and 530 nm (at pH 5.5) have been reported. The colour formation has been applied to the spectrophotometric determination of metal ions. The colour has been found to be stable between pH 3.5–6.5 and 2.0–7.0 respectively. The sensitivity of the reagent is 0.051μg/cm2 of vanadium and 0.093μg/cm2 of niobium. Maximum colour intensity has been found for Nb-DCAC chelate at pH 5.5 whereas no appreciable change has been found for V-DCAC chelate between pH 4.5 and 6.5.

Synthesis of heterocyclic azo compounds for spectrophotometric determination of metal ions

Synthesis of heterocyclic azo compounds for spectrophotometric determination of metal ions