Extraction by reversed micelles of triton N-42 for the spectrophotometric determination of cetyltrimethylammonium bromide

Micellar preconcentration of 1 : 2 associates of Bromophenol Blue with cetyltrimethylammonium bromide is proposed to improve the procedure for the spectrophotometric determination of cationic surfactants. The preconcentration procedure involves quantitative extraction by reversed micelles of Triton N-42 in decane followed by the decomposition of the micellar solution with chloroform. The loss of 10^–7–10^–5 M cetyltrimethylammonium bromide in 5–100-fold preconcentration was not supported by the added-found method (RSD = 3–5%). The determination limit for cetyltrimethylammonium bromide is 2 × 10^–7 M.Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 1, 2005, pp. 17–21.Original Russian Text Copyright © 2005 by Demidova, Bulavchenko.     

Spectrophotometric Determination of Metoclopramide in Pharmaceutical Preparations

A simple and rapid spectrophotometric method for the determination of metoclopramide is described. The method is based upon simple diazotization reactions with nitrite and aniline as the coupling reagent. The absorbance was measured at 410 nm. The method was optimized for acidity, the amount of reagents required, and the amount of sodium hydroxide. The range of linearity was 0.5–12.0 µg/mL. The method was successfully applied to the determination of metoclopramide in pharmaceutical preparations without any interference from common excipients.__________From Zhurnal Analiticheskoi Khimii, Vol. 60, No. 7, 2005, pp. 711–714.Original English Text Copyright © 2005 by Shah, Rasul Jan, Azam Khan, Amin.The text was submitted by the authors in English.     

Phosphorimetric Determination of Active Components in Medicinal Preparations

The use of room-temperature phosphorescence was proposed for the determination of active components containing naphthalene rings in their structures in medicinal preparations. It was demonstrated that this method can be used for the determination of active components in combined preparations.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 5, 2005, pp. 479–484.Original Russian Text Copyright © 2005 by Rekharskaya, Polenova, Borzenko.     

Xanthones from <Emphasis Type="Italic">Halenia corniculata</Emphasis>. 2. Quantitative Determination of Total γ-Pyrone Content in the Aerial Part

A method for quantitative determination of total γ-pyrone content in the aerial part of Halenia corniculata was developed. Their total content in various samples of the aerial part was investigated.__________Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 245–247, May–June, 2005.     

A new procedure for the spectrophotometric determination of nitrogen(II) oxide in solutions

A new simple and reliable procedure was developed for the spectrophotometric determination of nitrogen(II) oxide. The procedure is based on the determination of excess oxygen after its reaction with NO. Alkaline solutions of thiourea dioxide were used for the determination of oxygen. It was found that the decomposition of an alkaline solution of thiourea dioxide under aerobic conditions is accompanied by the formation of dithionite, and its concentration is proportional to the concentration of oxygen in the solution. The absorbance of the resulting dithionite was measured at 315 nm. The solutions obeyed Beers law at oxygen concentrations of 1 × 10^–5–1.5 × 10^–3 M. The analytical range for NO was 1 × 10^–5–1.5 × 10^–3 M. The proposed procedure was also used for the determination of nitrogen(II) oxide in aqueous-ethanolic solutions.Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 1, 2005, pp. 27–29.Original Russian Text Copyright © 2005 by Pukhovskaya, Guseva, Makarov, Naidenko.     

Arrays of Nonselective Nonionic-Surfactant Sensors for the Separate Determination of the Homologues of Polyoxyethylated Nonylphenols

It was demonstrated that multisensor systems of the electronic tongue type based on nonselective solid-contact potentiometric sensors can be used for the separate determination of the homologues of nonionic surfactants— polyoxyethylated nonylphenols with different numbers of oxyethyl groups. The cross-sensitivity parameters were calculated for modified and unmodified sensors for nonionic surfactants. The artificial neural network method was used for processing analytical signals.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 6, 2005, pp. 646–653.Original Russian Text Copyright © 2005 by Mikhaleva, Kulapina.Presented at the VI All-Russian Conference (with International Participation) on Electrochemical Methods of Analysis (EMA-2004, Ufa, May 23–27, 2004).     

Solubility of Adipic Acid in Organic Solvents and Water

The solubility of adipic acid in methanol, ethanol, propanol, isopropanol, n-butanol, tert-butanol, acetone, 1,4-dioxane, acetic acid, and water was measured within the 0–60°C temperature range. A sampler for determination of the temperature dependence of the solubility of solids in liquids by the isothermal method was suggested. The thermodynamic parameters of solution of adipic acid in the above solvents were calculated. The dependence of the solubility on the solvent and temperature was considered.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 3, 2005, pp. 403–407.Original Russian Text Copyright © 2005 by Gaivoronskii, Granzhan.     

A test method for determining palladium in chloride solutions on the solid phase of a fibrous anion exchanger

The sorption of palladium(II) from chloride solutions on polyacrylonitrile fiber filled with the AV-17 anion exchanger (PANF-AV-17) and its subsequent determination with p-nitrosodiethylaniline on the solid phase were studied. The results of determining palladium with this reagent on the solid phase of polyacrylonitrile fiber filled with the KU-2 cation exchanger and the AV-17 anion exchanger were compared. A test method was developed for determining palladium on the PANF-AV-17 solid phase. Sorption was performed in the batch mode; the analytical signal was estimated by measuring the diffuse reflection coefficient or visually using a color scale. The detection limit was 0.005 µg/mL; the range of the calibration scale was 0–0.2 µg/mL at the volume of the test solution 10–20 mL. The accuracy of the procedure was verified by the added-found method in the analysis of tap water and a standard reference sample of natural sodium chloride water. The relative standard deviation was no more than 25%; the time of the analysis of 5 or 6 samples was 25–30 min.Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 1, 2005, pp. 85–90.Original Russian Text Copyright © 2005 by Dedkova, Shvoeva, Savvin.     

An Easy Spectrophotometric Method for the Determination of Hypochlorite Using Thionin

A simple, rapid, and sensitive spectrophotometric method has been developed for the determination of hypochlorite using thionin. The method is based on the reaction of hypochlorite with potassium iodide in acidic medium to liberate iodine. The liberated iodine bleaches the violet color of thionin, which is measured at 600 nm. The decrease in absorbance is directly proportional to the concentration of hypochlorite. Beer’s law is obeyed in the range 0.2– 1.2 µg/mL of hypochlorite. The molar absorptivity, Sandell’s sensitivity, detection limit, and quantitation limit are found to be 1.489 × 10⁴ L/(mol cm), 3.25 × 10⁻³ µg cm⁻², 0.1026 µg/mL, and 0.3112 µg/mL, respectively. The method has been successfully applied to the determination of hypochlorite in various samples of natural water, tap water, milk, etc.__________From Zhurnal Analiticheskoi Khimii, Vol. 60, No. 8, 2005, pp. 798–801.Original English Text Copyright © 2005 by Narayana, Mathew, Vipin, Sreekumar, Cherian.The text was submitted by the authors in English.     

Rheological Equations for Concentrated Suspensions

The dependence of viscosity on stress in stable concentrated suspension is studied, the physical meaning of rheological constants in the rheological equation for these suspensions is revealed, and a method for experimental determination of these constants is described.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 2, 2005, pp. 219–223.Original Russian Text Copyright © 2005 by Bibik.     

Determination of Benzylpenicillin,Ampicillin, and Carbenicillin by Paper Chromatography

A mobile phase was developed for selective determination of benzylpenicillin, carbenicillin, and ampicillin in drugs by paper chromatography.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005, pp. 613–615.Original Russian Text Copyright © 2005 by Alekseev, Nersesova, Khalyapina.     

Determination of total thallium in soils by atomic emission spectrography using a two-jet arc plasmatron

A procedure is proposed for the direct determination of total thallium in solid soil samples by atomic emission spectrography with spectral excitation in an two-jet argon-arc plasmatron. The conditions for spectrum excitation and registration have been optimized. The analytical possibilities of the two zones in the plasma jet, before and after the jet confluence, were compared using the determination of thallium in soils as an example. Reference samples were artificial mixtures prepared on the basis of real soils. The accuracy of the results was estimated using the t-test in the analysis of samples with the known analyte concentrations. The experimentally found detection limit is 0.3–0.5 mg/kg. The relative standard deviation at an insignificant systematic error is 12–15% (n = 20; P = 0.95).Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 2, 2005, pp. 165–170.Original Russian Text Copyright © 2005 by Cherevko, Polyakova.This revised version was published online in April 2005 with corrections to the author names and book review format.     

Spectrophotometric determination of cationic and anionic surfactants with anionic dyes in the presence of nonionic surfactants,part II: Development of batch and flow injection methods

On the basis of the changes in absorption spectra of azo dyes on the addition of an organic onium ion, spectrophotometric methods for the determination of organic onium salts and anionic surfactants were developed, and applied to flow injection method. Propyl orange (PO^–) was used for the determination of organic onium ions. Pairs of PO^– and Zeph⁺ (tetradecyldimethyl-benzylammonium ion) or PO^– and nC₁₈TMA⁺ (n-octadecyltrimethylammonium ion) were used for the determination of anionic surfactants. The determination range of organic onium ions were (0–3) × 10^–5 M by a batch method and were (0–2) × 10^–5 M by a flow injection method. The determination ranges of anionic surfactants were (0–2) × 10^–5 M by the batch method, and were (0–5) × 10^–5 M by the flow injection method, and the detection limit corresponding toS/N = 3 was 3 × 10^–7 M by the flow injection method. By the proposed flow injection method, anionic surfactants in water samples were determined.     

Extraction-Coulometric Determination of Copper as Copper(II) 8-Hydroxyquinolinate

Conditions were selected for the coulometric determination of copper(II) by titrating copper(II) 8-hydroxyquinolinate extracted to chloroform with electrochemically generated bromine. The procedure was tested on model solutions and samples of surface waters. The detection limit is 5 × 10^–7 M at a generation current and time of 1 × 10^–3 A and 10 s, respectively.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 5, 2005, pp. 504–506.Original Russian Text Copyright © 2005 by Shlyamina, Morozova, Anisimova, Budnikov.     

Kinetic Determination of Mercury(II) at Trace Level from Its Catalytic Effect on a Ligand Substitution Process

A catalytic kinetic method (CKM) is presented for the determination of mercury(II) based on its catalytic effect on the rate of substitution of N-methylpyrazinium ion (Mpz⁺) onto hexacyanoferrate(II). The progress of the reaction was monitored spectrophotometrically at 655 nm by registering the increase in absorbance of the product [Fe(CN)₅(Mpz]²⁻ under the reaction conditions: 5 × 10⁻³ mol L⁻¹ [Fe(CN)₆]⁴⁻), 5 × 10⁻⁵ mol L⁻¹ [Mpz⁺], T = 25.0 ± 0.1°C, pH 5.00 ± 0.02 and ionic strength, I = 0.1 mol L⁻¹ (KNO₃). Quantitative rate data at specified experimental conditions showed a linear dependence of the absorbance after fixed time A _t on the concentration of mercury(II) catalyst in the range 20.06–702.1 ng mL⁻¹. The maximum relative standard deviations and percentage errors for the determination of mercury(II) in the range of 20.06–200.6 ng mL⁻¹ were calculated to be 1.7 and 2.7% respectively. The detection limit was found to be 7.2 ng mL⁻¹ of mercury(II). Accuracy (expressed in terms of recoveries) was in the range of 98–103%. Figures of merit and interference due to many cations and anions was investigated and discussed. The applicability of the method was demonstrated by determining the mercury(II) in different synthetic samples and confirming the results using atomic absorption spectrophotometry. The proposed method allowed determination of mercury(II) in the range 20.06–702.1 ng mL⁻¹ with very good selectivity and an output of 30 samples h⁻¹.__________From Zhurnal Analiticheskoi Khimii, Vol. 60, No. 6, 2005, pp. 654–661.Original English Text Copyright © 2005 by Surendra Prasad.This article was submitted by the author in English.     

Optimized and Validated Spectrophotometric Methods for the Determination of Roxatidine Acetate Hydrochloride in Drug Formulations Using 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone and <Emphasis Type="Italic">p</Emphasis>-Chloranilic Acid

Two simple and sensitive spectrophotometric procedures are proposed for the determination of roxatidine in pure form and in tablets. Both methods are based on the charge transfer complexation reaction of the drug with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or p-chloranilic acid resulting in colored products. In both cases, the absorbance measurement was made at 530 nm. Beer’s law was obeyed in the concentration ranges 5–65 and 10–260 µg mL⁻¹ with DDQ and p-chloranilic acid, respectively. A series of variables were studied to optimize the reaction conditions. No interference was observed from the common excipients present in the formulations. The described methods were applied successfully for the analysis of roxatidine in pharmaceutical preparations. Statistical comparison of the results with those from our UV reference method shows excellent agreement. Both methods are validated statistically and do differ significantly in accuracy.__________From Zhurnal Analiticheskoi Khimii, Vol. 60, No. 7, 2005, pp. 715–722.Original English Text Copyright © 2005 by Nafisur Rahman, Mohammad Kashif.The text was submitted by the authors in English.     

Solid Phase Extraction and Spectrophotometric Determination of Silver with 2-(2-Quinolylazo)-5-Dimethylaminophenol

A new chromogenic reagent, 2-(2-quinolylazo)-5-Dimethylaminophenol (QADMAP) was synthesized, and a sensitive, selective, and rapid method was developed for the determination of the μg/L level of silver ions. The method is based on the rapid reaction of silver(I) with QADMAP and the solid phase extraction of the colored chelate using a C₁₈ cartridge. The QADMAP reacts with Ag(I) in the presence of a citric acid-sodium hydroxide buffer solution (pH 5.0) and a sodium dodecyl sulfonate (SDS) medium to form a violet chelate of molar ratio 1 : 2 (silver to QADMAP). This chelate was enriched by solid phase extraction with C₁₈ cartridge, and the retained chelate was eluted from the cartridge using ethanol (with 1% acetic acid). In the ethanol medium (with 1% acetic acid), the molar absorptivity of the chelate was 1.25 × 10⁵ L mol⁻¹ cm⁻¹ at 584 nm. Beer’s law was obeyed in the range 0.01–0.6 μg/mL. The relative standard deviation for eleven replicate samples of 0.01 μg/mL was 1.86%. The detection limit is 0.02 μg/L in the original samples. The method was applied to the determination of μg/L levels of silver ions in water with good results.__________From Zhurnal Analiticheskoi Khimii, Vol. 60, No. 6, 2005, pp. 566–570.Original English Text Copyright © 2005 by Huang, Yang, Hu, Yin.This article was submitted by the authors in English.     

Simultaneous determination of plutonium and americium in biological and environmental samples

A radiochemical method is given to determine the specific activity of²³⁸Pu, and²⁴¹Am from the global fallout in environmental and biological samples. The radiochemical recovery was for human livers Pu: 60–70%, Am: 40–60%; Bran: Pu: 50–70%, Am: 30–40%; Soil: Pu: 50–80%, Am: 30–50%. The resolution of the alpha-spectrum was for soils 30–40 keV and for livers and brans 40–60 KeV. To facilitate the wet ashing of large amounts of bran (15 kg), which are necessary to determine the presently very small activity concentrations of the transuranic elements in these types of samples, a fermentation process was employed. The procedure was tested by using NBS standard reference material and subsequently applied for the determination of Pu and Am from the global fallout in livers, plant tissues (bran), and soils.     

Determination of the herbicide acetochlor by fluorescence polarization immunoassay

A fluorescence polarization immunoassay procedure was developed for determining the herbicide acetochlor from the group of chloroacetanilides. Conjugates of fluorescent labeled acetochlor derivatives (tracers) with glycylaminofluorescein and ethylenediaminofluorescein were synthesized. The effect of the tracer structure on the analytical characteristics of the determination and on antigen-antibody binding constants was studied. The developed immunoassay procedures are characterized by a detection limit of 10 ng/mL and an analytical range of 0.01–10 µg/mL. The procedure is highly specific; other pesticides caused no interference with the determination of acetochlor, and the percent cross-reactivities for related chloroacetanilide herbicides were no higher than 2.4% for metolachlor and lower than 0.1% for alachlor.Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 1, 2005, pp. 91–96.Original Russian Text Copyright © 2005 by Deryabina, Yakovleva, Popova, Eremin.     

X-ray Fluorescence Determination of Carbon,Nitrogen, and Oxygen in Fish and Plant Samples

The potentials of X-ray fluorescence analysis in the determination of carbon, nitrogen, and oxygen in materials of plant and animal origin were studied. The contribution of photoelectron excitation to the analytical signal and the effect of uncertainties in the attenuation coefficient on the calculation of element concentrations by the absorption correction method were estimated. Methods for calculating analyte concentrations using simple linear regression with absorption correction and multiple regression were compared. The results were also compared with those of pyrolysis-gas-chromatography. The error of the method was 1–2% for element concentrations between 10 and 50% and 25% in the range of nitrogen concentration 1–2%.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 5, 2005, pp. 485–489.Original Russian Text Copyright © 2005 by Farkov, Ilicheva, Finkelshtein.