Simultaneous Determination of Nickel(II) and Cobalt(II) by Second-Derivative Spectrophotometry

4-(2-Pyridylazo) resorcinol, PAR, is shown to be useful for simultaneous determination of cobalt(II) and nickel(II) using second-derivative spectrophotometric method with controlled experimental parameters. This method allows the determination of 0.20-1.25 ppm of nickel(II) and 0.25-1.50 ppm of cobalt(II) in mixtures with good precision and accuracy. This method has advantages of simplicity, speed and requires no prior separations.     

Spectrophotometric Determination of Nitrite Ion or Chloramine T with Gallein-Molybdenum Complex and Cobalt (II) with Gallin and Hydrogen Peroxide in a Micellar Media

Abstract

A simple and sensitive spectrophotometric method for the determination of nitrite ion or chloramine T is proposed utilizing a gallein-molybdenum complex in the presence of N-hexadecyltrimethylammonium chloride in acidic media. Also, a sensitive catalytic spectrophotometric procedure for determi     

Spectrophotometric Determination of Metoclopramide and Oxybuprocaine Through Ion Pair Formation with Thiocyanate and Molybdenum(V) or Cobalt(II)

Abstract

Two spectrophotometric methods involve the formation of two different ion pairs between the drug and inorganic complexes, Mo(V) and Co(II) thiocyanates followed by their extraction with dichlor?methane and o-nitrotoluene, respectively. The optimum conditions for the ion pair formation are established. The methods permit the determination of metoclopramide and oxybuprocaine hydrochlorides over a concentration range of 1-20 μg ml^?1 and 20–240 μg ml^?1 using Mo(V) and Co(II) thiocyanates, respectively. Molar ratio of drug to Mo(V) or Co(II) indicates a 2:1 ratio for the two drugs studied in the presence of excess thiocyanate concentration. Results of the analysis of drug substances and their dosage forms by the proposed methods are in good agreement with those obtained by the official methods.     

Selective Extractive Spectrophotometric Determination of Palladium (II) with Di-2-Pyridyl Ketone 2-Pyridyl-Hydrazone (DPPH)

Abstract

Palladium (II) reacts with DPPH in slightly acid medium to form a red colored complex stable in presence of EDTA and extractable into chloroform.

These properties of the Pd(II)-DPPH complex were used for the selective extractive spectrophotometric determination of palladium(II) in presence of several tested cations.     

以Cu(II)为光谱探针离子分光光度法测定异烟肼的新方法

以Cu(II)为光谱探针建立了一种高选择性、高灵敏度测定异烟肼的新方法。试验表明：在pH 6.0时，Cu(II)可被异烟肼还原生成Cu(I)，反应生成的Cu(I) 与SCN-反应生成CuSCN白色乳状沉淀，在硝酸钠的存在下该沉淀可被浮选至水相表面。通过测定水相中剩余Cu(II)的量，可以间接测定异烟肼的含量。已反应Cu(II) 的量与异烟肼的浓度呈良好的线性关系，线性范围为0.050-4.50 µg mL-1，检出限为0.048 µg mL-1。该法已经成功的用于药物样品和病人尿液样品中异烟肼含量的测定。     

Synthesis,Crystal Structure and Characterization of Polynuclear Potassium(I), Copper(II) and Cobalt(II) Complex with Acetylacetonethylenediamine

The title complex [K{Cu(acen)}₃]₂[Co(NCS)₄]·1/4CH₃OH (acen = acetylacetonethylenediamine anion) has been prepared and characterized. Single-crystal x-ray analysis reveals that the complex crystallizes in space group P I with a = 11.442(2), b = 15.098(3), c = 28.500(4) Å, α = 82.77(1), β = 83.58(1), γ = 85.07(1)°. The crystal consists of the complex [K{Cu(acen)}₃]⁺ cations, [Co(NCS)₄]^2? anions and methanol molecules. Three [Cu(acen)] molecules function as bridging ligands through phenolic O atoms to one K⁺ to give the tetranuclear [K{Cu(acen)}₃]⁺ cation. Each copper(II) atom in the cation is in a square-planar geometry, being coordinated by two oxygen atoms and two nitrogen atoms from a quadridentate acen ligand. The cobalt(II) atom is coordinated by four nitrogen atoms of thiocyanate ligands, forming a deformed tetrahedral environment. The IR and UV-Vis spectra have also been investigated.     

Spectrophotometric study of coproporphyrin-I complexes of copper(II) and cobalt(II)

The reagent 3,8,13,18-tetramethyl-21H,23H-porphine-2,7,12,17-tetrapropionic acid or coproporphyrin-I (CPI) was used for the spectrophotometric determination of copper(II) and cobalt(II) in the presence of pyridine and imidazole catalysts. Optimum conditions were investigated and the methods were applied to the determination of parts per billion levels of copper(II) and cobalt(II). The Sandell sensitivities of the recommended procedures were 0.568 μm cm⁻² and 0.464 μg cm⁻² (for A = 0.001) for copper and cobalt, respectively. The relative standard deviations were 2.0% for copper and 1.0% for cobalt. The kinetics of the reaction of CPI with copper(II) and cobalt(II) in the presence of the catalysts and the influence of the temperature were studied, and their kinetic constants determined.The influence of light on the photodecomposition of CPI was also studied.     

Spectrophotometric determination of 1-naphthylamine in urine with pentacyanonitrosylmanganate (II)

A new Spectrophotometric method is proposed for the determination of 1-naphthylamine (R), based on its reaction with Mn(CN)₅NO^2– to form Mn(CN)₅NH₂R^3– and measurement of the absorbance at 472 nm. In aqueous medium the molar absorptivity of the manganese complex is maximum ( = 8.0 × 10³1 · mole^–1 ·cm^–1) in the pH range 5.0–10.0, the colour develops more rapidly at pH 10.0. The absorptivity is increased by a factor of 3.5 if the complex is extracted as an ion-associate into chloroform. The extraction efficiency is 99.2% for a single-step extraction, and a concentration factor of 5 can also be achieved. Linearity of response extends over the range 0.04–1.4 gmg/ml 1-naphthylamine, the coefficient of variation being 1.4% at the 0.29 g/ml level (n = 6). The detection and determination limits are 0.005 and 0.018 g/ml, respectively. The method is selective enough to allow the determination of 1-naphthylamine in the presence of considerable amounts of other amines, such as aminophenols and phenylenediamines. Results obtained in the determination of 1-naphthylamine in human urine were very satisfactory.     

Spectrophotometric Determination of Cobalt in Vitamin Preparations,Steel and Iron Using 2-Hydroxy- 1-Naphthaldehyde Guanylhydrazone

Abstract

A new spectrophotometric determination of cobalt with 2-hydroxy-1-naphthaldehyde guanylhydrazone in acid medium is described. The method is developed on the basis of a yellow cobalt (III) complex (molar absorptivity 1.32×10^?4 L.mol^?1.cm^?1 at 416 nm, stoichiometry 2:1). The method was applied to the determination of cobalt in vitamin preparations, steel and high-purity iron.     

Spectrophotometric Determination of Sparfloxacin in Pharmaceutical Preparations by Ternary Complex Formation with Pd(II) and Eosin

Abstract

A simple, sensitive, and direct spectrophotometric method has been developed for the assay of sparfloxacin in bulk and pharmaceutical preparations. The proposed method is based on the formation of ternary complex between an investigated drug, palladium(II) ion and eosin in the presence of methylcellulose as surfactant and acetate buffer of pH 4.2. Spectrophotometrically, under the optimum conditions, the ternary complex showed absorption maximum at 550 nm, with apparent molar absorptivity of 2.69×10⁴ l mol^?1 cm^?1, Sandell's sensitivity of 0.01458 µg ml^?1 and linearity in the concentration range 1.6–16 µg ml^?1. The composition of the ternary complex was studied by Job's method of continuous variation and the result indicated that the molar ratio of SPFX: Pd: eosin is 1∶1∶1. The optimum reaction conditions and other analytical parameters are evaluated. The proposed method was successfully applied for the determination of SPFX in its pharmaceutical product with mean percentage recoveries of 99.71%. The observed data has been subjected to statistical analysis, which revealed high accuracy and precision.     

Spectrophotometric Determination of Lead by Extraction of the Mixed-Metal Complex Pb(II)-Ca-Purpurin (1,2,4-Trihydroxyanthraquinone)

Abstract

Mixtures of Lead(II) and Ca(II) form with purpurin (P; 1,2,4-Trihydroxyanthraquinone) the mixed-metal-complex PbCaP₃, which is extracted with isobutyl methyl ketone (IBMK) at pH 7.8. The molar absorptivity of the complex is 2.8 × 10⁴ l.mol^?1.cm^?1 at 575 nm and its conditional extraction constant 2.5 × 10¹⁷ 1⁴.mole^?4. The use of this complex for the spectrophotometric determination of lead up to 40 μg has been investigated. The proposed procedure has been successfully applied to the analysis of this metal in different samples.     

Simple,Selective, and Sensitive Spectrophotometric Method for Determination of Trace Amounts of Nickel（Ⅱ）, Copper （Ⅱ）, Cobalt （Ⅱ）, and Iron （Ⅲ） with a Novel Reagent 2-Pyridine Carboxaldehyde Isonicotinyl Hydrazone

A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At a pH value of 7.0, 9,0, 9.0, and 8.0, respectively, which greatly increased the selectivity; nickel, copper, cobalt, and iron reacted with 2-PYAINH to form a 1：2 yellow-orange, 1：2 yellow-green, 1：2 yellow and 1：1 yellow complexes, with absorption peaks at 363, 352, 346, and 359 nm, respectively. Under the optimal conditions, Beer＇s law was obeyed over the ranges of 0.01-1.4, 0.01-1.5, 0.01-2.7, and 0.01-5.4 mg/L respectively. The apparent molar absorptivity and Sandell＇s sensitivities were 8.4×10^4, 5.2×10^4, 7.1×10^4, and 3.9×10^4 L·mol^-l·cm^-1, respectively, and 0.00069, 0.0012, 0.00078, and 0.0014 μg·cm2, respectively. The detection limits were found to be 0.001, 0.002, 0.003, and 0.01 mg/L, respectively. The detailed study of various interfering ions to make the method more sensitive was carried out and selective and several real samples were analyzed with satisfactory results.     

Synthesis of New Reagent Benzyloxybenzaldehydethiosemicarbazone (BBTSC): Selective,Sensitive and Extractive Spectrophotometric Determination of Pd(II) in Water Samples and Synthetic Mixtures

A new reagent, benzyloxybenzaldehydethiosemicarbazone (BBTSC) was synthesized and a new method was developed for the simple, highly selective and extractive spectrophotometric determination of palladium(II) with BBTSC at wave length 365 nm. The metal ion formed a yellow colored complex with BBTSC in acetate buffer of pH 5.0, which was easily extractable into cyclohexanol with 1:1 (Metal: Ligand) composition. The method obeys Beer's law in the range of 5–60 ppm. The molar absorptivity and Sandell's sensitivity were found to be 0.4 × 10⁴ Lt. mol^?1 cm^?1 and 0.02661 μg cm^?2, respectively. The correlation co‐efficient of the Pd(II)‐BBTSC complex was 0.9657, which indicated an excellent linearity between the two variables. The repeatability of the method was checked by finding the relative standard deviation (RSD) (n = 10), which was 0.321% and its detection limit 0.016875 μg.mL^?1. The instability constant of the method was calculated by Asmus' method as 3.5714 × 10^?4. The interfering effect of various cations and anions were also studied. The proposed method was successfully applied for the determination of palladium(II) in synthetic and water samples. The results were compared with those obtained using an atomic absorption spectrophotometer, testing the validity of the method.     

Extractive Spectrophotometric Determination of Fluconazole by Ion-pair Complex Formation with Bromocresol Green

An extraction-spectrophotometric method for the determination of trace amounts of fluconazole was described. Fluconazole was effectively extracted as a 1 ： 1 ion-pair complex with bromocresole green （BCG） at pH 3.0 into chloroform, followed by spectrophotometric determination at 420 nm. Beer＇s law was obeyed over the range of 4-50 μg.mL^-1 of fluconazole with a detection limit of 3.7 μg.mL^-1 . The method is simple, rapid and sensitive. The procedure was applied to the determination of fluconazole in pharmaceutical preparations as well as its recovery from a blood serum sample.     

Cloud Point Extraction Simultaneous Spectrophotometric Determination of Zn(II), Co(II) and Ni(II) in Water and Urine Samples by 1-(2-Pyridylazo)2-Naphthol Using Partial Least Squares Regression

A cloud-point extraction (CPE) process using the nonionic surfactant Triton X-114 to simultaneous extraction and spectrophotometric determination of Zn(II), Co(II) and Ni(II) from aqueous solution using partial least squares (PLS) regression is investigated. The method is based on the color reaction of these cations with 1-(2-pyridylazo)2-naphthol and subsequent micelle-mediated extraction of products. The optimum extraction and reaction conditions such as pH, reagents concentration and effect of time have been studied. Linearity was obeyed in the range 2–150, 5–250 and 2–150 ng mL⁻¹ of Zn(II), Co(II) and Ni(II) respectively. The relative standard error (RSE) for the simultaneous determination of 15 test samples of different concentrations of Zn(II), Co(II) and Ni(II) was 4.38%;, 1.18% and 2.42%, respectively. The total relative standard error (RSE_t) for applying the PLS method to 15 synthetic samples in the linear ranges of these metals was 2.36%. The interference effect of some anions and cations was also tested. The method was applied to the simultaneous determination of Zn(II), Co(II) and Ni(II) in water and human urine samples.     

Cobalt(II) and nickel(II) chelates of some 5-pyrazolone-based,Schiff-base ligands

The cobalt(II) and nickel(II) chelates of Schiff bases, derived by condensing 4-butyryl-3-methyl-1-phenyl-2-pyrazolin-5-one (BMPP) with o-, m-, p-phenylenediamine, benzidine, and ethylenediamine have been synthesized and characterized by elemental analyses, thermogravimetric analyses (TGA), conductance data, magnetic measurements, IR, ¹H NMR, ¹³C NMR, mass, and electronic spectroscopies. Each of the Schiff bases was an ONNO donor to metal forming chelates formulated as [M(L)(H₂O)₂] _n with M = Ni(II) and Co(II) and L is the di-anion of the Schiff base. The monomeric (n = 1) and dimeric (n = 2) species of these metal chelates, based on available evidence, are suggested.     

Application of Multivariate Calibration Methods for the Simultaneous Multiwavelength Spectrophotometric Determination of Fe(II), Cu(II), Zn(II), and Mn(II) in Mixtures

Abstract

A sensitive method for the simultaneous spectrophotometric determination of Fe(II), Cu(II), Zn(II), and Mn(II) in mixtures has been developed with the aid of multivariate calibration methods, such as classical least squares (CLS), principal component regression (PCR) and partial least squares (PLS). The method is based on the spectral differences of the analytes in their complexation reaction with 4‐(2‐pyridylazo)‐resorcinol (PAR) and the use of full spectra with wavelengths in the range of 300–600 nm. It was found that both the spectral positive and negative bands obtained against the PAR blank, are proportional to the concentration for each metal complex. The obtained linear calibration concentration ranges are 0.025–0.6, 0.05–0.8, 0.025–0.8, and 0.05–0.8 µg ml^?1 for Fe(II), Cu(II), Zn(II), and Mn(II), respectively, and the LODs for the four metal ions were found to be approximately 1–3×10^?2 µg ml^?1. The proposed method was applied to a verification set of synthetic mixtures of these four metal ions, with models built in three different wavelength ranges, i.e., 300–450, 450–600, and 300–600 nm, corresponding to the positive, negative bands and their combinations, respectively. It was shown that the PLS model for the 300–600 nm range gave the best results (RPE_T=6.9% and average recovery ～100%; cf. PCR: RPE_T=9.5% and average Recovery ～110%). This method was also successfully applied for the determination of the four metal ions in pharmaceutical preparations, chicken feedstuff, and water samples.     

Analytical Separation of Copper(II), Cobalt(II) and Nickel(II) Using Polymer Bound Anthrantic Acid

Abstract

The preferential complexing tendency of different nietal ions towards chelating agents anchored on a polymer has been used for separation of transition metals. the anthranilic acid group was anchored on the polymeric cellulose back-bone by successive coupling with trifunctional reagent cyanuric chloride, in diozane medium, at pH 7 and 9–10, respectively. This polymer bound chelating agent was used to separate copper(II), nickel(II) and cobalt(II) in the concentration range 1.0–0.1 mmol/L. the separation of a mixture of two components was quantitative using column chromatography.     

过氧化氢氧化桑色素动力学荧光法测定痕量钴(Ⅱ)

建立了以Co(Ⅱ)为催化剂,催化过氧化氢氧化桑色素,使其荧光减弱的催化动力学荧光法。在pH 10.70的Na2B4O7?10H2O - NaOH缓冲溶液中,痕量钴(Ⅱ)离子对0.24%的H2O2溶液氧化 4.0×10-7 mol/L的桑色素溶液有明显的催化作用。在最大波长处( λex/λem = 416.5 nm / 556.4 nm),体系的荧光强度在一定的浓度范围内与Co(Ⅱ)的浓度呈线性相关,线性范围为0.8～8.0 μg/L,检出限为0.14 μg/L。优化了体系的最佳条件,考察了体系的离子干扰情况,对灰钙土和分子筛样品进行了分析检测,回收率分别为95.0～110.0%和98.9%～101.9%。     

Development and Validation of Catalytic Kinetic Spectrophotometric Method for Determination of Copper(II)

A catalytic kinetic spectrophotometric method is developed for the determination of trace amounts of Cu(II). It is based on the catalytic effect of Cu(II) on the oxidation of cysteine (RSH) by hexacyanoferrate(III) in acidic medium. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of hexacyanoferrate(III) at 420nm. The optimum operating conditions regarding concentration of reagents, pH and temperature were established. The working curve is linear in the concentration range of 0–6.35ng·mL^–1. The maximum percentage error and standard deviation for determination of Cu(II) in the range of 1.27–6.35ng·mL^–1 have been calculated to be 3.9 and 0.4 respectively. The detection limit calculated was 0.15ng·mL^–1. The interference effect of several species was also investigated, and it was found that the most common cations and anions do not interfere with the determination. The developed procedure was successfully applied to the determination of Cu(II) in various synthetic and real samples. The typical feature of this procedure is that determination can be carried out at 25°C and/or in the absence of any precision thermostatic bath in the very short analysis time of one minute. The newly developed method was found to have fairly good selectivity, sensitivity, simplicity and rapidity compared to other kinetic methods.Received October 8, 2002; accepted April 7, 2003 Published online July 16, 2003