Optical and chromaticity characteristics of copper(II) complex with 1-nitroso-2-naphthol-3,6-disulfonic acid

Optimal conditions of complexation copper(II) with 1-nitroso-2-naphtol-3,6-disulfonic acid were found by the spectrophotometric method. The optimum pH interval for the formation of a complex is 6.5–7.9. A tenfold surplus of the reagent suffices for the quantitative formation of a complex. The chemical and analytical characteristics of a complex in an interval concentration of copper (1.26–6.39) × 10⁻⁵ M are determined. The molar coefficient of absorption of a complex is (1.21 ± 0.01) × 10⁴ (n = 5, P = 0.95). The function and molar coefficient of chromaticity are determined. The most sensitive functions are Z [(2.58 ± 0.04) × 10⁵] and G [(3.88 ± 0.06) × 10⁵] (n = 5, P = 0.95).     

Optical and chromaticity characteristics of palladium(II) complex with 1-nitroso-2-naphthol-3,6-disulfonic acid

Optimal conditions of complexation palladium(II) with 1-nitroso-naphthol-3,6-disulfonic acid were found by the spectrophotometric method (an optimum interval pH 1.2–3.8, a five-multiple surplus reagent). The analytical characteristics of a complex in an interval concentration of palladium(II) (0.94–8.59) × 10⁻⁵ M are determined, ɛ = (9.80 ± 0.02) × 10³ (n = 9, P = 0.95). The function and molar coefficient of chromaticity are determined. The most sensitive functions are G [(7.6 ± 0.1) × 10⁵] and Z [(5.6 ± 0.2) × 10⁵] (n = 5, P = 0.95).     

Optical and chromaticity characteristics of cobalt 1-nitroso-2-naphthol-3,6-disulfonates

The optimum conditions of the complexation of cobalt with nitroso-R salt in the presence of and without ascorbic acid were found. Molar coefficients of chromaticity functions of the complexes were calculated, and it was demonstrated that cobalt(II) and cobalt(III) complexes can be distinguished only with the use of chromaticity functions, whereas their optical characteristics are nearly the same. For practical purposes, it is better to introduce ascorbic acid and to obtain the kinetically inert complex of cobalt(III) with nitroso-R salt.     

Chromaticity characteristics of iron (II, III) complexes with 1-nitroso-2-naphthol-3,6-disulfonic acid

Optimal conditions for the complexation of iron(II, III) with 1-nitroso-2-naphthol-3,6-disulfonic acid in two buffer solutions and the reduction of iron(III) with ascorbic acid or hydroxylamine were found by spectrophotometry and chromaticity measurements. Chemical analytical and chromaticity characteristics of complexes in solutions were determined. It was shown that two complexes formed depending on the oxidation state of iron. Molar coefficients of the chromaticity functions were 20 to 30 times higher than molar absorption coefficients. The complexes exhibited abnormal light absorption maxima (710–720 nm) among the known 1-nitroso-2-naphthol-3,6-disulfonates and were chemically inert, which offers promise for analytical purposes.     

Optical and colorimetric characteristics of a nickel(II) complex with 1-nitroso-2-naphthol-3,6-disulfonic acid

Optimal conditions for the complexation of nickel(II) with 1-nitroso-2-naphthol-3,6-disulfonic acid were found using the spectrophotometric method. The optimal pH interval for complexation was 7.2–8.8 with a fivefold excess of the reagent. The stoichiometric Me: R composition was 1: 2. The molar absorption coefficient and colorimetric characteristics of the complex were determined in the nickel(II) concentration range of (4.09–16.35) × 10⁻⁵ M. The molar absorption coefficient was (7.52 ± 0.05) × 10³ (n = 10, P = 0.95). The most sensitive chromaticity functions were B [(1.83 ± 0.04) × 10⁵] and G [(1.76 ± 0.05) × 10⁵] (n = 9, P = 0.95).     

Determination of trace cadmium in waters by flame atomic absorption spectrophotometry after preconcentration with 1-nitroso-2-naphthol-3,6-disulfonic acid on Ambersorb 572

A procedure for the determination of trace amount of cadmium after adsorption of its 1-nitroso-2-naphthol-3,6-disulfonic acid chelate on Ambersorb 572 has been proposed. This chelate is adsorbed on the adsorbent in the pH range 3-8 from large volumes of aqueous solution of water samples with a preconcentration factor of 200. After being sorbed, cadmium was eluted by 5 mL of 2.0 mol L(-1) nitric acid solution and determined directly by flame atomic absorption spectrophotometery (FAAS). The detection limit (3sigma) of cadmium was 0.32 microg L(-1). The precision of the proposed procedure, calculated as the relative standard deviation of recovery in sample solution (100 mL) containing 5 microg of cadmium was satisfactory (1.9%). The adsorption of cadmium onto adsorbent can formally be described by a Langmuir equation with a maximum adsorption capacity of 19.6 mg g(-1) and a binding constant of 6.5 x 10(-3) L mg(-1). Various parameters, such as the effect of pH and the interference of a number of metal ions on the determination of cadmium, have been studied in detail to optimize the conditions for the preconcentration and determination of cadmium in water samples. This procedure was applied to the determination of cadmium in tap and river water samples.     

A selective and sensitive film for electrocatalysis of ascorbic acid based on polypyrrole doped with nitroso-R(1-nitroso-2-naphthol-3,6-disulfonic acid disodium)

An electrocatalytic detection of ascorbic acid on a nitroso-R modified polypyrrole electrode has been studied. This functionalized polypyrrole film was electropolymerized by constant potential method on a platinum electrode from solution including pyrrole as monomer and nitroso-R as anionic dopant. Electrocatalytic currents of ascorbic acid were linearly dependent on its concentration in the range of 0.12–18.54 mM, with detection limit and relative standard deviation of 0.02 mM and 1.32%, respectively. This modified electrode can be used for determination of ascorbic acid in various pharmaceutical samples. Also, electrochemical behavior of this system was studied by various methods (RDE voltammetry, chronoamperometry, hydrodynamic amperometry and cyclic voltammetry).     

Separation and determination of metals as complexes of 1-nitroso-2-naphthol-6-sulphonic and 2-nitroso-1-naphthol-6-sulphonic acids

A sensitive ion-pair liquid-liquid extraction-spectrophotometric method has been developed for the determination of copper, palladium, iron and cobalt, based on the formation of metal complexes with 1-nitroso-2-naphthol-6-sulphonic acid or 2-nitroso-1-naphthol-6-sulphonic acid as primary ligand, and zephiramine as counter-ion. The coloured metal complexes obtained over different pH ranges are easily and quantitatively extracted into dichloromethane. The method has been tested with samples containing known amounts of copper, palladium, iron and cobalt in ultrapure water. The reagents provide a sensitive spectrophotometric method for determining these metals.     

Atomic absorption spectrophotometric determination of trace copper in waters, aluminium foil and tea samples after preconcentration with 1-nitroso-2-naphthol-3,6-disulfonic acid on Ambersorb 572

An atomic absorption spectrophotometric method for the determination of trace copper after adsorption of its 1-nitroso-2-naphthol-3,6-disulfonic acid chelate on Ambersorb 572 has been developed. This chelate is adsorbed on the adsorbent in the pH range 1–8. The copper chelate is eluted with 5 ml of 0.1 mol l⁻¹ potassium cyanide and determined by flame atomic absorption spectrometry (FAAS). The selectivity of the proposed procedure was also evaluated. Results show that iron(III), zinc(II), manganese(II) and cobalt(II) at the 50 μg l⁻¹ level and sodium(I), potassium(I), magnesium(II), calcium(II) and aluminium(III) at the 1000 μg l⁻¹ level did not interfere. A high enrichment factor, 200, was obtained. The detection limit (3σ) of copper was 0.34 μg l⁻¹. The precision of the method, evaluated by seven replicate analyses of solutions containing 5 μg of copper was satisfactory and the relative standard deviation was 1.7%. The adsorption of copper onto Ambersorb 572 can formally be described by a Langmuir equation with a maximum adsorption capacity of 14.3 mg g⁻¹ and a binding constant of 0.00444 l mg⁻¹. The accuracy of the method is confirmed by analysing tomatoes leaves (NIST 1573a) and lead base alloy (NBS 53e). The results demonstrated good agreement with the certified values. This procedure was applied to the determination of copper in waters (tap, river and thermal waters), aluminium foil and tea samples.     

Photometric determination of aqueous cobalt (II), nickel (II), copper (II) and iron (III) with 1-nitroso-2-naphthol-3,6-disulfonic acid disodium salt in gelatin films

Photometric determination of aqueous Co(II), Cu(II), Ni(II) and Fe(III) was performed using indicator films prepared by immobilization of 1-nitroso-2-naphthol-3,6-disulfonic acid disodium salt (NRS) into hardened photographic film. Immobilization was based on electrostatic interaction of reagent and metal complexes with the gelatin. The isoelectric point pH of hardened gelatin (4.46±0.04) was evaluated by viscometry. Co(II), Fe(III), Ni(II) form 1:3 complexes with NRS in gelatin at pH 2 and Cu(II) forms 1:2 complexes. Their log β′ values were: Co-6.7, Fe-8.6, Cu-8.0, and Ni-6.4. The absorption maxima were: 370nm for NRS, and 430nm, 470nm, 495nm and 720nm for complexes of Co(II), Ni(II), Cu(II) and Fe(III). An algorithm for their simultaneous determination using the indicator films was developed. The detection limits were: c_lim(Co²⁺) = 0.45×10⁻⁵ M, c_lim(Fe³⁺) = 0.50×10⁻⁵ M, c_lim(Cu²⁺) = 0.67×10⁻⁵ M, c_lim(Ni²⁺) = 0.75×10⁻⁵ M,; and their sum c_lim(ΣMn⁺) = 0.82×10⁻⁵ M.      

Synthesis and characterization of a new resin functionalized with 2-naphthol-3,6-disulfonic acid and its application for the speciation of chromium in natural water

A polystyrene divinyl benzene (8%) copolymer has been functionalized by coupling it through NN group with 2-naphthol-3,6-disulfonic acid (NDSA). The resulting resin has been characterized by elemental analysis, thermogravimetric analysis and infrared spectra. The hydrogen ion, water regain and metal ion capacities of the resin have been determined. Two forms of chromium show different exchange capacities at different pH values, viz. Cr(III) selectively retained at pH 6.5 whereas Cr(VI) retained at pH 1.5. Hence complete separation of the two forms of chromium is possible. The kinetic studies show that the exchange of Cr(III) and Cr(VI) follows second-order kinetics. The metal ion concentration was measured by flame atomic absorption spectrometry. The method has been successfully applied for the speciation of chromium in natural water samples.     

Separation and determination of metals as complexes of 1-nitroso-2-naphthol-6-suiphonic and 2-nitroso-1-naphthol-6-sulphonic acids. II. Liquid chromatography on c18 bonded and copolymer stationary phases

An ion-pair Chromatographic system for the separation of copper(II), palladium(II), iron(III) and cobalt(III) as ion-associates of their l-nitroso-2-naphthol-6-sulphonate and 2-nitroso-l-naphthol-6-sulphonate anionic complexes with organic ammonium compounds and inorganic cations has been studied. Isocratic and gradient elution methods were used, and the effects of column material, organic and aqueous modifiers, and pH of the eluent on the retention were examined. The elution time for the metal complex anions depends on the eluent, the proportion of organic solvent in the mobile phase, the pH of the eluent and the extraction coefficient of the compounds. The compounds were identified photometrically with a diode-array detector at wavelengths of 229, 254, 260, 298, 320 and 400 nm. The detection limits for the metals are at the ng/ml level.     

痕量铁催化对氨基二甲替苯胺-H酸显色反应

研究了在pH =5 .7混合酸 氢氧化钠缓冲介质中 ,铁 催化过氧化氢氧化对 氨基二甲替苯胺盐酸盐和H酸 钠盐的氧化偶联反应 ,考察了反应的最佳条件 ,建立了催化动力学光度法测定痕量铁 的新方法。该方法线性范围为 0 .0 0～ 0 .0 2mg L ;检出限为 2 .1× 1 0 - 7g L。直接用于自来水及湖水中铁 的测定 ,结果满意     

The stability sequence of the trivalent rare earth chelates of 2-nitroso-1-naphthol-8-sulphonic acid in aqueous solution

A method is described for estimating the concentration of di(n-octyltin) bis-maleate in five food-simulating solvents recommended by the United States Food and Drug Administration for migration studies on food containers. Atomic absorption spectrometry with electrothermal atomization provides a detection limit of 0.01 ppm tin stabilizer in the food simulators. Both calibration curve and standard addition methods were employed to check for possible matrix effects. Analysis time was less than 90 s per sample. Ethanol solutions were difficult to analyze because of residual inorganic tin blanks, presumably arising from the ethanol container. Water, acetic acid and heptane were free of residual tin blanks. Amounts of tin stabilizer extracted from several different resins ranged from 0.01 to 0.18 ppm.     

Sectrophotometric determination of vanadium(V) with 7-amino-1-naphthol-3,6-disulphonic acid

Summary Vanadium(V) reacts with 7-amino-1-naphthol-3,6-disulphonic acid (2 R-acid) in the ratio 21, forming a red coloured chelate having maximum absorbance at 470 nm. The composition of the chelate has been found by the continuous variations and the mole ratio methods. The system obeys Beer's law between a range of 1.72 to 30.9 p. p. m. of vanadium and the sensitivity is 0.17g/cm² at pH 2.0, The reagent is found to be fairly selective for vanadium.

---

Zusammenfassung Vanadin(V) reagiert mit 7-Amino-l-naphthol-3,6-disulfonsäure im Ver-hältnis 21 und bildet ein rotes Chelat mit dem Absorptionsmaximum bei 470 nm, dessen Zusammensetzung nachJob bestimmt wurde. Zwischen 1,72 und 30,9 ppm V ist das Beersche Gesetz erfüllt. Die Empfindlichkeit beträgt 0,17g/cm² (Sandell) bei pH 2,0. Das Reagens ist für Vanadin ziemlich selektiv.

     

A highly sensitive and rapid assay for protein determination in human urine and penicillin using a Rayleigh light-scattering technique with benzeneazo-8-acetylamino-1-naphthol-3,6-disulfonic acid sodium salt.

A simple and sensitive method was conducted for the determination of trace amounts of proteins with benzeneazo-8-acetylamino-1-naphthol-3,6-disulfonic acid sodium salt (azophloxine, AP) using a Rayleigh light-scattering (RLS) technique. At pH 2.60 and in the presence of an emulsifier OP microemulsion, the RLS of AP can be greatly enhanced by proteins, owing to the interaction between AP and protein. The enhanced intensity is proportional to the concentration of proteins. Four proteins, including bovine serum albumin (BSA), human serum albumin (HSA), lysozyme (Lys) and gamma globulin (gamma-G) have been tested. For example, the linear range of BSA was 0 - 0.06 microg mL(-1) with detection limits of 2.38 ng mL(-1). The method was applied to the analysis of protein in human urine and penicillin samples with satisfactory results. The relative standard deviation was in all instances less than 4.0%, and the recovery was in the range of 97.5 - 104%.     

Column chromatographic pre-concentration of iron(III) in alloys and biological samples with 1-nitroso-2-naphthol-3,6-disulphonate and benzyldimethyltetradecylammonium-perchlorate adsorbent supported on naphthalene using atomic absorption spectrometry

The solid ion-pair material produced from the reaction between benzyldimethyltetradecylammonium chloride (BDTA) and sodium perchlorate on naphthalene provides the basis for a simple, rapid and selective technique for pre-concentrating iron from up to 500 ml of aqueous solution. Iron reacts with disodium 1-nitroso-2-naphthol-3,6-disulphonate (Nitroso-R salt) to form a water-soluble coloured chelate anion. The iron chelate anion forms a water-insoluble, stable iron-Nitroso-R-BDTA complex on naphthalene packed in a column. Trace amounts of iron are quantitatively retained on naphthalene in the pH range 3.5-7.5 and at a flow-rate of 1-2 ml min-1. The solid mass is dissolved out from the column with 5 ml of N,N-dimethylformamide and iron is determined by means of an atomic absorption spectrometer at 248 nm. The calibration graph is linear for concentrations of iron over the range of 0.5-20 micrograms in 5 ml of final solution. The standard deviation and relative standard deviation were calculated. The detection limit of the method was 0.0196 micrograms ml-1 of iron. The sensitivity for 1% absorption was 0.072 microgram ml-1 (0.165 microgram ml-1 by direct atomic absorption spectrometry of aqueous solution). The proposed method was applied to the determination of iron in standard alloys and biological samples.     

Mixed ligand complexes of coumarilic acid/nicotinamide with transition metal complexes

Coumarilate–nicotinamide complexes of Co^II and Zn^II were synthesized and investigated by elemental analysis, magnetic susceptibility, solid state UV–Vis, direct injection probe mass spectra, FTIR spectra, thermoanalytic TG-DTG/DTA, and crystal X-ray diffraction methods. It was obtained that both complex structures contain 2 mol aqua ligands, 2 mol coumarilate (CCA^?) and 2 mol nicotinamide (NA) ligands per formula unit. The CCA^? and NA ligands were bonded to metal cations as monodentate through acidic oxygen and nitrogen of pyridine ring, respectively. Thermal decomposition of each complex starts with dehydration and continue removing of 1 mol NA ligand. The thermal dehydration of the complexes takes place in one or two steps. The decomposition mechanism and thermal stability of the investigated complexes are interpreted in terms of their structures. The final decomposition products are found to be metal oxides.