Modified analcime loaded with zincon as a useful material for the separation and preconcentration of trace palladium and its determination by third-derivative spectrophotometry

This work assesses the potential of natural analcime zeolite as a sorbent for the preconcentration of palladium. Palladium is quantitatively retained on modified analcime zeolite loaded with zincon using the column method in the pH range from 2.5 to 3.5 at a flow rate of 1 mL/min. The palladium complex was removed from the column with 5.0 mL of dimethylsulfoxide (DMSO) and determined by third-derivative spectrophotometry. The detection limit is 0.03 μg/mL (signal-to-noise ratio = 3) in the final solution. Since it is possible to retain 0.15 μg of palladium from 600 mL of solution passing through the column, elution with 5.0 mL of DMSO gives a detection limit of 0.25 ng/mL for palladium in the initial aqueous solution. The calibration curve is linear over the range 0.1 to 5.0 μg/mL of palladium(II) in the final solution with a correlation coefficient of 0.9996. Seven replicated determinations of 5.0 μg of palladium in 5.0 mL dimethylsulfoxide gave a mean d ³ A/dλ³ (peak-to-peak signal between λ₂ = 625 and λ₁ = 654 nm) of 0.64 with a relative standard deviation of 1.2%. The sensitivity of the method (d ³ A/dλ³) is 0.5843 mL/μg of palladium(II) from the slope of the calibration curve. The interference of a large number of anions and cations has been studied and the optimized conditions developed were utilized for the determination of trace palladium in various synthetic and water samples. The text was submitted by the authors in English.     

Spectrophotometric determination of palladium(II) based on its catalytic effect on the reduction of azure I by sodium hypophosphite

A catalytic-spectrophotometric method for the determination of traces of palladium(II) is proposed. The reaction is based on the catalytic action of palladium(II) on the reduction of azure I (λ_max = 647 nm) by sodium hypophosphite. The various variables affecting the sensitivity were studied, and a study of interfering ions was also carried out. The reaction gave a detection limit of 4.3 ng/mL palladium(II) and good reproducibility with a relative standard deviation of 1.53–1.98% in the palladium(II) concentration range 40–200 ng/mL. The method yielded another linear range (5–40 ng/mL) when using slightly different conditions. In this case, the detection limit was 0.78 ng/mL palladium(II), and the relative standard deviation for ten replicate analyses of 20 ng/mL palladium(II) was 2.05%. The method was applied to the determination of palladium in a sample of activated charcoal. The text was submitted by the authors in English.     

Flame atomic absorption spectrometric determination of trace amounts of palladium,gold and nickel after cloud point extraction

In this article, a sensitive cloud point extraction procedure for the preconcentration of trace amounts of palladium, gold and nickel prior to their determination by flame atomic absorption spectrometry has been developed. The cloud point extraction method is based on the complexation of Pd(II), Au(II), and Ni(II) ions with 1-(2-pyridylazo)-2-naphthol and entrapping in non-ionic surfactant Triton X-114. The main factors affecting cloud point extraction efficiency, such as pH of sample solution, concentration of 1-(2-pyridylazo)-2-naphthol and Triton X-114, equilibration temperature and time, were investigated in detail. Under the optimized conditions, calibration curves were constructed for the determination of palladium, gold and nickel according to the general procedure. Linearity was maintained from 0.01 to 1.0 μg/mL for palladium, 10.0 μg/mL to 1.5 μg/mL for gold, and 10.0 μg/mL to 0.5 μg/mL for nickel. Detection limits based on three times the standard deviation of the blank divided by the slope of analytical curve (3Sb/m) for Pd(II), Au(III), and Ni(11) ions were 3.4, 3.9, and 2.4 μg/mL, respectively. Seven replicate determination of a mixture of 0.5 μg/mL palladium and gold and 0.2 μg/mL nickel gave a mean absorbance of 0.174, 0.150, and 0.201 with relative standard deviation ±1.5, ±1.3, and ±1.8%, respectively. The high efficiency of cloud point extraction to carry out the determination of analytes in complex matrices was demonstrated. The proposed method has been applied for determination of trace amount of palladium, gold and nickel in certified reference material and water samples with satisfactory results.     

Preconcentration and separation of trace amounts of palladium using dithiooxamide functionalized chelating resin followed by its determination using radiotracer technique

The work describes a procedure of preconcentration and separation of trace amounts of Pd(II) by solid phase extraction of the metal ion by dithiooxamide groups incorporated into a matrix of polystyrene-divinylbenzene whereas the determination of palladium has been carried out by radiotracer technique using ¹⁰⁹Pd (T _1/2 = 13.43 hr, E _γ = 311, 647 keV). The experiments were carried out using both batch method and column operation. Parameters such as the amount of resin, effect of pH, equilibration rate, sorption and desorption of metal ions have been studied. The maximum sorption capacity for palladium was found to be 0.10 mmol·g⁻¹ at pH 6.0. The method is rapid, has a good accuracy and can be used routinely.     

Spectrophotometric determination of manganese(VII) using benzyltriphenylphosphoniumchloride as a new reagent and application of artificial neural network to extending the dynamic range of determination

A simple and selective spectrophotometric method is proposed for the determination of trace amounts of manganese. The method is based on the extraction of manganese as a MnO₂-benzyltriphenylphosphoniumchloride ion pair with chloroform. An artificial neural network (ANN) has been applied to the handling of the spectrophotometric data of this complex in the organic phase to extend the dynamic range of manganese determination (0.020–6.0 μg/mL). A three-layer back-propagation network (50:75:1) was used with root-mean-square error (rmse) 0.001 and momentum (m) 0.8 overall. The application of BP-ANN makes it possible to extend the dynamic range of the determination of manganese from its narrow linear range of 0.020–2.5 μg/mL to the dynamic range 0.020–6.0 μg/mL. The text was submitted by the author in English.     

Cloud point extraction and spectrophotometric determination of Cu(II) in saturated saline solutions using 4-ethyl-1-(pyridin-2-yl)thiosemicarbazide

4-Ethyl-1-(pyridin-2-yl)thiosemicarbazide (HEPTS) has been used as a new complexing agent in cloud point extraction (CPE) for preconcentration and determination of trace amounts of copper in saturated saline medium. The chemical variables affecting the separation and determination processes were optimized. Copper(II) is preconcentrated using 0.05% (w/v) Triton X-114 and 10⁻⁴ M HEPTS at pH 6. The surfactant rich phase containing the complex was dissolved in 2 mL MeOH and determined spectrophotometrically. The calibration curve is linear in the 0.1–25 ng/mL copper range. The proposed method was applied successfully in the determination of copper in water and saturated saline samples. The reaction between CuSO₄ and HEPTS yields a deep-blue solid complex which is characterized by analytical and spectroscopic analyses.     

Spectrophotometric determination of nickel in biological samples using 1-azobenzene-3-(3-hydroxyl-2-pyridyl)-triazene

A new sensitive and selective chromogenic reagent, 1-azobenzene-3-(3-hydroxyl-2-pyridyl)-triazene (ABHPT), was synthesized. It has been found that ABHPT reacts with nickel(II) in a borax buffer solution (pH 10.0) to form 2: 1 red complexes with the maximum absorption at 530 nm. The apparent molar absorptivity of the complex is 2.6 × 10⁵ L/(mol cm). Most metal ions can be tolerated in considerable amounts, whereby only zinc and mercury may interfere with the determination of nickel(II). Nevertheless, this can be easily eliminated by prior separation with sulfhydryl dextran gel. A new method for the spectrophotometric determination of trace nickel(II) was developed. Beer’s law is obeyed for 0–15 μg of nickel(II) in 25 mL of solution. The limit of quantification, limit of detection, and relative standard deviation are 0.74 ng/mL, 0.25 ng/mL, and 1.0%, respectively. The method has been applied to the determination of trace nickel(II) in biological samples with satisfactory results. The text was submitted by the authors in English.     

Analytical study of the phenyl-2-pyridyl ketone azine-palladium system. Photometric determination of palladium

Phenyl-2-pyridyl ketone azine reacts with palladium(II) to produce a yellow 1:1 complex (λ_max = 425 nm, ? = 10.4 × 10³M^?1 cm^?1 in aqueous ethanolic solution) and a red-violet 3:1 complex (λ_max = 530?540 and 380?390 nm). The yellow complex in aqueous ethanolic solution has been used for the spectrophotometric determination of trace amounts of palladium. The method has been applied to the determination of palladium in some catalysts and one mineral.     

Kinetic spectrophotometric determination of trace manganese (II) with dahlia violet in nonionic microemulsion medium

A new catalytic kinetic spectrophotometric method has been developed for the determination of trace amount of manganese (II) in nonionic microemulsion medium. The method is based on the catalytic effect of manganese (II) on the oxidation of dahlia violet by potassium periodate with nitrilotriacetic acid as an activitor in the presence of nonionic microemulsion. Under the optimum conditions, the calibration graph is linear in the range of 0.0004-0.0056 μg ml⁻¹ of manganese (II) at 580 nm. The detection limit achieved is 3.75×10⁻⁵ μg ml⁻¹. Manganese (II) in foodstuff samples was determined with satisfactory results.     

Spectrophotometric determination of trace cadmium in vegetables with 3,5-bis(4-phenylazophenylaminodiazo)benzoic acid

A new highly sensitive and selective chromogenic reagent, 3,5-bis(4-phenylazophenylaminodiazo)benzoic acid (BPPABA) has been synthesized and applied to the determination of trace cadmium(II) in vegetables. The method is based on the color reaction between BPPABA and cadmium (II). In the presence of Triton X-100, cadmium(II) reacts with BPPABA in Na₂B₄O₇-NaOH buffer solution (pH 10.5), forming red complex with maximum absorption at 530 nm. Under the optimal conditions, Beer’s law is obeyed within 0–12 μg of cadmium within 25 mL of solution, and the apparent molar absorptive coefficient of the complex is 2.8 × 10⁵ L/mol cm. The detection limit and the relative standard deviation were found to be 0.92 μg/L and 1.0%, respectively. Interference of foreign ions was also investigated. Most of the metal ions are tolerated in considerable amounts except for Hg(II), Cu(II) and Ni(II). To eliminate the interference of foreign ions, metal ion imprinted polymer technique was utilized.     

A simple and selective flow-injection spectrophotometric determination of copper(II) by using acetylsalicylhydroxamic acid

A new simple, and rapid flow-injection spectrophotometric method is developed for the determination of trace amounts of Cu(II) by using a new chromogenic reagent acetylsalicylhydroxamic acid (AcSHA). The method is based on the formation of colored Cu(II)-(AcSHA)₂ complex. The optimum conditions for the chromogenic reaction of Cu(II) with AcSHA is studied and the colored (green) complex is selectively monitored at λ_max 700 nm. With the reagent carrier solvent (dimethylsulfoxide (DMSO) and acetate buffer, pH 4.2) flow-rate of 1 ml min⁻¹, a detection limit (2S) of 1 μg l⁻¹ Cu(II) was obtained at a sampling rate of 80 sample h⁻¹. The calibration graph was linear in the Cu(II) concentration range 5-120 μg l⁻¹. The relative standard deviation (n=10) was 0.64% for a sample containing 60 μg l⁻¹ Cu(II). The detailed study of various interferences confirmed the high selectivity of the developed method. The method was successfully applied to determine trace amounts of copper(II) in river and seawater samples. The accuracy of the method was demonstrated by the analysis of standard reference materials C12X3500 and C14XHS 50.     

Indirect Determination of Sulfide by Extraction Flotation Spectrophotometry of Copper(II) with Ammonium Sulfate‐Ethanol‐Water System

A new extraction flotation spectrum method for indirect determination of trace amounts of sulfide by ammonium sulfate‐ethanol‐water system was developed. It showed that Cu(II) could combine with S^2? into precipitate (CuS) which was floated in the surface of ethanol and water in the presence of ammonium sulfate. The sulfide can be indirectly determined by determining the flotation yield of Cu(II). The linear range from 2.4 × 10^?8to 3.2 × 10^?6g/mL and the detect limit of 2.0 × 10^?8g/mL was achieved. The results showed the determination of S^2? was not affected by Pb(II), Zn(II), Cd(II), Fe(II), Co(II),Ni(II), Mn(II) and Cl^?, Br^?, I^?, etc. In the paper, the method was successfully applied to the determination of a trace amount of sulfide in polluted water samples with the advantages of simplicity of equipment, rapidity, low cost, etc.     

Simultaneous First Derivative Spectrophotometric Determination of Palladium and Nickel Using 2-(2-Thiazolylazo)-5-Dimethylaminobenzoic Acid as an Analytical Reagent

 A simple, rapid, selective, sensitive and economical method has been developed for the simultaneous determination of trace amounts of palladium and nickel in aqueous methanolic medium using 2-(2-thiazolylazo)-5-dimethylam inobenzoic acid as an analytical reagent by first derivative spectrophotometr y. Palladium is determined by measuring base to peak distance at λ=695.0 nm while nickel is estimated by zero crossing method in the mixture. The linearity is maintained between 0.12–1.75 μg mL⁻¹ for palladium and 0.07–1.60 μg mL⁻¹ for nickel in the pH range 2.8–7.2 and 3.4–8.8 respectively. Seven replicate determinations of 1.0 μ g mL⁻¹ of palladium and 0.8 μg mL⁻¹ of nickel in a mixture give a mean signal height of 0.391 for Pd and 0.541 for Ni with relative standard deviations of 0.9% and 1.2%, respectively. The sensitivity of the proposed method is 0.391 (dA/dλ)/(μg mL⁻¹) for palladium and 0.685 (dA/dλ)/(μg mL⁻¹) for nickel. Various parameters have been optimised for the simultaneous determination of palladium and nickel in various complex samples. Received March 30, 1999. Revision November 25, 1999.     

Kinetic Analysis of Cobalt in Veterinary Products

A novel kinetic method for the determination of trace amounts of Co(II) has been developed. The proposed method based on the catalytic effect of Co(II) on the oxidation of xylenol orange tetra sodium salt by H₂O₂ in the presence of cationic surfactant (N‐dodecylpyridinium chloride). Co(II) at μg.mL^?1 was determined spectrophotometrically by measuring the decrease in the absorbance of xylenol orange at 577 nm by the differential method. The method is precise, selective, and sensitive. The detection limit of the procedure was 0.058 μg.mL^?1. The relative standard deviation for the replicate determination (n = 6) of 0.7 μg.mL^?1 was 1.285%. The results compared satisfactorily with those of atomic absorption spectrometry. The method was successful for the analysis of Co(II) in veterinary and synthetic samples.     

Catalytic spectrophotometric determination of molybdenum (VI) with the hydrazine-metanil yellow system

A new catalytic Spectrophotometric method for the determination of trace amounts of molybdenum (VI) has been proposed. The method is based on the catalytic effect of Mo(VI) on the reduction of metanil yellow by hydrazine dihydrochloride. Under experiment condition, the linear range of determination is 20–160 ng/mL for molybdenum and the detection limit is 11.2ng/mL. The method has been used to determine trace molybdenum in bean samples with the recovery of 96.0–99.0%, with relative standard deviations of 1.50–2.53%.     

Resonance Rayleigh scattering for the determination of cationic surfactants with Eosin Y

Resonance Rayleigh scattering (RRS) of cationic surfactants–Eosin Y systems and their analytical application have been studied. In aqueous solution at pH 2∼3, Eosin Y reacts with a monomer of cationic surfactants (CS), such as Zephiramine (Zeph), tetradecylpyridinium bromide (TPB), cetylpyridinium bromide (CPB), cetylpyridinium chloride (CPC) and cetyltrimethylammonium bromide (CTMAB), to form an ion associate and a new RRS spectrum appears. The spectral characteristics of the five ion associates are similar and their maximum scattering wavelengths (λ_max) are all at 313 nm. The intensity of RRS at λ_max of the ion associate is directly proportional to the concentration of CS in the range of 0∼3.0 μg/25 mL. The technique has high sensitivity for the determination of CS; their detection limit is between 5.57 ng/mL and 7.60 ng/mL depending on the CS. In this case, most metal and non-metal ions, NH₄ ⁺ and some anionic surfactants do not interfere, so that the method has a good selectivity. It can be applied to the determination of trace amounts of cationic surfactants in water samples. Received: 9 September 1998 / Revised: 17 November 1998 / Accepted: 18 November 1998     

一种催化固体基质室温磷光法测定奋乃静

建立了罗丹明6G(Rhodamene.6G,Rhod 6G+)电子效应催化固体基质室温磷光法(SS-RTP)测定痕量奋乃静(Perphenazine,PPH)的新方法.方法的线性范围为0.080~28×10-9g/L,线性相关系数为0.999 l,相对标准偏差为1.5%~3.1%,检出限为4.8×10-14g/L.方法应用于血样、脉样中残留奋乃静含量的测定,结果令人满意.     

Determination of ultramicroquantities of Au(III) by its catalytic effect on 4-hydroxyl coumarone oxidation with potassium permanganate

A simple and fast kinetic method is based on the oxidation of 4-OH coumarone using KMnO₄ and the determination of ultramicroamounts of Au(III) by its catalytic effect on this reaction. The sensitivity of the method is 25 ng/mL. The relative error ranges between 9.20–3.90% for the concentration interval 5 × 10⁻⁸–2 × 10⁻⁷ g/mL. The selectivity of the method is very good, and the effect of foreign ions is investigated. The proposed approach has been applied to the determination of traces of Au(III) in copper ore. The text was submitted by the authors in English.     

FI spectrophotometric determination of Pd with DBOK-chlorophosphonazo

A flow injection method was developed for the determination of palladium, based on the reaction of palladium with DBOK-chlorophosphonazo with a detection limit of 0.07 μg/mL and a linear calibration range from 0.1 to 3.2 μg/mL of palladium. The reaction product has a maximum absorption at 630 nm. The method was applied to determine Pd²⁺ in catalysts and in anode mud samples. The relative error is less than 3% and the recovery of palladium is in the range 95% to 105% Received: 27 April 1998 / Revised: 24 August 1998 / Accepted: 26 August 1998     

FI spectrophotometric determination of Pd with DBOK-chlorophosphonazo

A flow injection method was developed for the determination of palladium, based on the reaction of palladium with DBOK-chlorophosphonazo with a detection limit of 0.07 μg/mL and a linear calibration range from 0.1 to 3.2 μg/mL of palladium. The reaction product has a maximum absorption at 630 nm. The method was applied to determine Pd²⁺ in catalysts and in anode mud samples. The relative error is less than 3% and the recovery of palladium is in the range 95% to 105% Received: 27 April 1998 / Revised: 24 August 1998 / Accepted: 26 August 1998