Архив научных статейиз журнала «Журнал аналитической химии»
DEVELOPMENT AND VALIDATION OF UHPLC–DAD METHOD FOR THE DETERMINATION OF CHOLESTERYL-HEXAHYDROPHTHALOYL-5-FLUOROURACIL IN LIPID NANOEMULSION
ALANAZI FARS K., ALSARRA IBRAHIM A., FAIYAZ SHAKEEL, NAZRUL HAQ, RADWAN AWWAD A. — 2015 г.
An ultra HPLCdiode array detector (UHPLCDAD) method was developed and validated for rapid determination of cholesteryl-hexahydrophthaloyl-5-fluorouracil (CH5F) conjugate in standard drug, lipid nanoemulsion and dissolution samples. The chromatographic identification of this conjugate was achieved on Hypersil GOLD 50 ? 2.1 mm reversed phase C18 column having a 1.9 m packing as a stationary phase using methanolwater (80 : 20, v/v) as a mobile phase, at a flow rate of 0.4 mL/min with DAD detection at 276 nm. The proposed UHPLCDAD method is linear in the concentration range of 1 50 g/mL with correlation coefficient of 0.998. The proposed method is precise, accurate, robust, sensitive and specific for analysis of the conjugate. High assay value (98.7%) of CH5F conjugate in lipid nanoemulsion was obtained by the proposed method. Forced degradation studies indicated that conjugate was sufficiently stable under oxidative stress conditions degraded under acid, base and thermal stress conditions. The proposed UHPLCDAD method successfully and resolved drug conjugate peak in the presence of its degradation products which established stability and indicating property of the method. Results of the present study indicated that the proposed UHPLCDAD method can be successfully used for routine determination of CH5F conjugate in standard drug and pharmaceutical formulations.
ENANTIOSEPARATION OF TERBUTALINE BY ON-LINE CONCENTRATION CAPILLARY ELECTROPHORESIS COUPLING WITH PARTIAL FILLING TECHNIQUE
JIAQIN LIU, JUAN LI, SHUYA CUI, XIAOLI HU — 2015 г.
A novel, simple and sensitive method for the enantioseparation of terbutaline enantiomers was developed using capillary zone electrophoresis (CZE) in combination with partial filling technique and field-amplified sample concentration. Under optimal conditions, the racemic terbutaline was resolved in less than 21 min by partially filling a fused-silica capillary with 15 mM -cyclodextrin ( -CD, 1.9 psi, 90 s) and carrying out an electrophoresis with 50 mM phosphate buffer (pH 1.8) at 15 kV separation voltage. The sensitivity was further improved by using field-amplified sample injection (0.2 psi, 2.5 s water plug). Compared with conventional CZE, the resolution and sensitivity of two enantiomers were much improved (the detection limit decreased by 1825-fold).
HIGHLY SELECTIVE SOLID PHASE EXTRACTION OF MERCURY ION BASED ON NOVEL ION IMPRINTED POLYMER AND ITS APPLICATION TO WATER AND FISH SAMPLES
MAJID GHAHRAMAN AFSHAR, MAJID SOLEIMANI — 2015 г.
A novel ion imprinted polymer (IIP) material has been synthesized for mercury ion. The IIP material is applied to the solid phase extraction (SPE) of Hg2+ from complex matrixes including water and fish samples. The IIPSPE method is operated prior to cold vapor atomic absorption spectroscopy (CVAAS) to determine mercury ion. In the polymer synthesis, mercury ion, 2-vinylpyridine, ethyleneglycol dimethacrylate and 2,2-azobisisobutyronitrile are used as target, Hg2+ complexing reagent monomer, cross-linker and initiator, respectively. The polymer is characterized on the basis of FT-IR and thermal analysis (thermogravimetric, TGA; differential thermic, DTA; and differential scanning calorimetry, DSC). The obtained polymer block is ground, sieved and Hg2+ ions are removed from polymer particles by leaching with EDTA, which leaves a cavity in the polymer particles. The maximum Hg2+ adsorption capacity of IIP is 24.6 mg/g. Effective parameters on retaining Hg2+ such as pH, flow rate of sample and eluent, nature of the eluent, ionic strength, selectivity coefficient and retention capacity are investigated . The detection limit and the relative standard deviation are 5 ? 10-4 ng/mL and 2.4%, respectively. After 20 adsorption cycles, the recovery of Hg2+ on IIP is only decreased by 3.2%. The column selective adsorption experiments of Na+, Cu2+, Pb2+, Cd2+, Ca2+ and Mg2+ ions with respect to mercury are conducted by using imprinted and non-imprinted polymer. These results showed that the IIP is highly selective for Hg2+ over the other metals.
IV ВСЕРОССИЙСКИЙ СИМПОЗИУМ “РАЗДЕЛЕНИЕ И КОНЦЕНТРИРОВАНИЕ В АНАЛИТИЧЕСКОЙ ХИМИИ И РАДИОХИМИИ”
ТЕМЕРДАШЕВ З.А., ЦИЗИН Г.И. — 2015 г.
IX ВСЕРОССИЙСКАЯ КОНФЕРЕНЦИЯ ПО АНАЛИЗУ ОБЪЕКТОВ ОКРУЖАЮЩЕЙ СРЕДЫ “ЭКОАНАЛИТИКА-2014”
ЗАЛЕТИНА М.М. — 2015 г.
KINETIC-SPECTROPHOTOMETRIC DETERMINATION OF NEOMYCIN
DJORDJEVIC A.S., KOSTIC D.A., MILETIC G.Z., MITIC S.S., RASIC MISIC I.D. — 2015 г.
A new kinetically-based spectrophotometric method for the determination of micro quantities of neomycin is described in this paper. It is an adaptation of the modified Berthelot method which is a widely used colorimetric procedure for urea determination. The method was developed due to neomycin effect on 2,2-dicarboxyindophenol formation. The experimental conditions for successful determination of neomycin were optimized. The relative standard deviation (RSD) for the neomycin concentration interval of 77 154 g/mL, ranges from 0.7 to 1%. The method was directly applied to determining neomycin in ophthalmic drops. The obtained results in analyzed pharmaceutical samples were in accordance with disc-diffusion microbiological method results.
LEAD PRECONCENTRATION AS RAC-(E,E)-N,N-BIS(2-CHLOROBENZYLIDENE)CYCLOHEXANE-1,2-DIAMINE COMPLEXES FROM WATER AND TOBACCO SAMPLES BY DISPERSIVE LIQUID–LIQUID MICROEXTRACTION
ALOTHMAN Z.A., HABILA M.A., SOYLAK M., WARAD I., YILMAZ E. — 2015 г.
A dispersive liquid - liquid microextraction (DLLME) procedure for determination of Pb(II) in water and tobacco samples has been developed using rac-(E,E)-N,N-bis(2-chlorobenzylidene)cyclohexane-1,2-diamine as a chelating agent. Factors influencing the efficiency of DLLME have been optimised, including metal solution pH, type and amount of dispersing solvent, type and amount of extraction solvent, amount of chelating agent and sample volume. The optimized conditions for maximum recovery were as follows: sample pH 6; dispersing solvent, 500 L of ethanol; extraction solvent, 150 L of chloroform; chelating agent, 150 L of 0.01% rac-(E,E)-N,N-bis(2-chlorobenzylidene)cyclohexane-1,2-diamine; and sample volume, 15 mL. The method was validated using the certified reference material SPS-WW2 waste water. The method offered a limit of detection (LOD) of 2.6 g/L, a limit of quantification (LOQ) of 8.5 g/L, and a relative standard deviation (RSD) of 5.2%.
LEAD(II) ION SELECTIVE POLY(ANILINE) SOLID CONTACT ELECTRODE BASED ON 1,2-BIS(N-BENZOYLTHIOUREIDO)ETHANE, -PROPANE AND -BUTANE IONOPHORESK
HAK-JOO LEE, SUNG-MIN AHN, TAE-KEE HONG, WON-SIK HAN, YOUNG-HOON LEE — 2015 г.
The lead ion selective electrodes were manufactured by synthesizing a benzoyl thioureido group ionophores having two sulfur groups on the both ends of ethane, propane and butane molecules. The ionophore containing propane moiety showed the best responsivity to lead ion. With the 1,3-bis(N,N-benzoylthioureido)propane (BTP) ionophore, the best result was found when it included with the o-nitrophenyloctylether (o-NPOE) plasticizer with the highest permittivity and the oleic acid (OA) additive. The ratio of BTP : polyvinyl chloride : o-NPOE : potassium tetrakis(4-chlorophenyl)borate : OA was 2.5 : 16.5 : 30.5 : 1.5 : 0.5, the response range was 1.0 ? 10-6.4 1.0 ? 10-1.0 M, and the response slope was 30.4 mV/decade. Addition of OA led to an excellent result for the responsivity, cation interference effect, correlation coefficient, response time and reproducibility. The electrode represented constant characteristics irrelevant to variation of pH between 27, the stabilization time was 30 s, the response time was about 30 s, and the reproducibility represented ±0.81 and ±1.40 mV for 1.0 ? 10-2.0 and 1.0 ? 10-3.0 M lead, respectively.
LOW DENSITY SOLVENT BASED DISPERSIVE LIQUID–LIQUID MICROEXTRACTION AND PRECONCENTRATION OF MULTIRESIDUE PESTICIDES IN ENVIRONMENTAL WATERS FOR LIQUID CHROMATOGRAPHIC ANALYSIS
ABERA GURE, NEGUSSIE MEGERSA, TESFA BEDASSA — 2015 г.
A simple, efficient and selective sample preparation technique using low density based dispersive liquidliquid microextraction has been developed for the analysis of nine multiresidue pesticides inculding six sulfonylurea and three organophosphorus pesticides in environmental waters by HPLC-diod array detector. Various experimental parameters affecting the extraction efficiency were investigated. Under the optimum experimental conditions, matrixmatched calibration curves were established in groundwater and good linearities were obtained with coefficient of determination (r2) of 0.990 or better. The limits of detection and quantification were in the ranges 0.83.3 and 2.5 11.0 g/L, at a signal-to-noise ratio of 3 and 10, respectively. The relative standard deviations of the precision studies were varied over the range of 0.213%. The proposed method was successfully applied to selective extraction of the target pesticide residues in different environmental waters and acceptable recoveries, in the range 81121%, were obtained.
MAGNETIC MOLECULARLY IMPRINTED POLYMER NANOPARTICLES FOR SELECTIVE EXTRACTION OF COPPER FROM AQUEOUS SOLUTIONS PRIOR TO ITS FLAME ATOMIC ABSORPTION DETERMINATION
MASSOUD KAYKHAII, MOSTAFA KHAJEH, SAYYED HOSSAIN HASHEMI — 2015 г.
This paper describes a pre-concentration procedure using magnetic molecularly imprinted polymer (MMIP) nanoparticles for the extraction of copper(II) from aqueous samples prior to its atomic absorption determination. Cumorin complex was used as template molecule which was chemically bonded to MMIP nanoparticles. MMIP nanoparticles were characterized by scanning electron microscopy as well as Fourier transform infrared spectroscopy. The extraction conditions including pH value, adsorption and desorption time, temperature, amount of ligand and ionic strength of the sample matrix were studied and optimized. The method showed good extraction recoveries (96) with relative standard deviation below 3.4% for real samples. The linear range of calibration curve was between 5 1000 g/L with a correlation coefficient (r 2) of 0.996. The detection limit was 0.5 g/L. The method was suitable for the determination of trace copper in drinking water samples.
MODIFIED UFLC-PDA METHOD FOR DETERMINATION OF NITROSAMINES
JOSHI RAJESH K., PAI SANDEEP R., SUGANDHA SHARMA — 2015 г.
Tobacco-specific nitrosamines, viz. N-nitrosonornicotine (NNN) and 4-methylnitrosamino-1-3-pyridyl-1-butanone (NNK) were determined by using a modified ultra flow liquid chromatography-photo diode array (UFLC-PDA) technique using C18 100A Phenomenex column (Luna, 5 , 4.6 ? 150 mm) with 10% acetonitrile (ACN) in 1 mM ammonium acetate buffer pH 8 by ammonium hydroxide; ACN and water with 0.75% glacial acetic acid (pH 2.82) solvent system. It was feasible to compute accurate calibration curve for both compounds using the solvent system by determining the peak area as a function of the concentration. Limits of detection of 0.12 for NNN and 0.02 for NNK were found. This technique allows a reasonably accurate detection of NNN and NNK with the solvent system developed. The study finds an optimum mobile phase for detecting NNN and NNK with effective resolution.
OILS AND GREASE DETERMINATION BY FT-IR AND N-HEXANE AS EXTRACTION SOLVENT
ANNA MARIA GIRELLI, ANNA MARIA TAROLA, REMO BUCCI, STEFANO TAFANI — 2015 г.
Recently FT-IR spectroscopy has enjoyed renewed interest for detection and quantification of contamination by oils and grease (OG), especially in water samples. This is due to the development of a new approach using less harmful solvents. This paper presents the development of a new FT-IR method that uses n-hexane as a substitute to Freon 113 in the extraction process. This solvent has a high solubility for the desired organic compounds, low miscibility with water and a low boiling point to facilitate its removal from the extracted material. Results regarding the calibration curves, recovery, precision, detection and quantitation limits are presented. Even if the recovery is not too high (45%), the preconcentration factor of 2 ? 103 permits the detection of OG at levels >83 g/L.
OPTIMIZATION OF SOXTEC EXTRACTION PROCEDURE FOR DETERMINATION OF POLYBROMINATED DIPHENYL ETHERS IN BIVALVE MOLLUSC
CARRO N., COBAS J., NEGREIRA N. — 2015 г.
A comprehensive and efficient method is presented for the determination of 9 polybrominated diphenyl ether congeners (PBDEs), 2,4,4-tribromodiphenyl ether (PBDE-28), 2,3,4,4-tetrabromodiphenyl ether (PBDE-47), 2,2,4,4,6-pentabromodiphenyl ether (PBDE-66), 2,2,4,4,5-pentabromodiphenyl ether (PBDE-100), 2,2,3,4,4-pentabromodiphenyl ether (PBDE-99), 2,2,4,4,5,6-hexabromodiphenyl ether (PBDE-85), 2,2,4,4,5,5-hexabromodiphenyl ether (PBDE-154), 2,2,4,4,5,5-hexabromodiphenyl ether (PBDE-153) and 2,2,3,4,4,5,6-heptabromodiphenyl ether (PBDE-183), in mollusc bivalve samples. An experimental design was used to evaluate the influence of several operational parameters on the extraction performance and to obtain the best experimental conditions. Under the final working conditions, freeze-dried mollusc was placed in the Soxtec thimble in order to extract PBDEs with 100 mL of n-hexaneacetone (4 : 1) after 1.5 and 1 h of boiling and rinsing times, respectively. Soxtec extracts were additionally purified on a multilayered column and after injected in the gas chromatography combined with mass spectrometry (GCMS) system. Quantitative recoveries of the analytes at three concentration levels ranged between 80 and 108%, and limits of quantification of the method (LOQs) between 0.5 and 20 ng/g. Analysis of mussel and clam samples showed that PBDE-47 and PBDE-99 were presented in almost all samples with concentrations between 0.6 and 2.6 ng/g dry weight. Moreover, a certified reference material (NIST 2974a) was used. The obtained concentrations were in agreement with the certified values.
POTENTIOMETRIC DETERMINATION OF CADMIUM USING COATED PLATINUM AND PVC MEMBRANE SENSORS BASED ON N,N-BIS(SALICYLALDEHYDE)PHENYLENEDIAMINE (SALOPHEN)
HADI BEHROOJ PILI, MOHAMMAD MIRZAEI — 2015 г.
The construction and performance characteristics of novel PVC membrane (PME) and coated platinum (CPtE) cadmium ion selective electrodes based on N,N-bis(salicylaldehyde)phenylenediamine (salophen) are described. The electrodes exhibit linear responses along with near Nernstian slopes of 28.9 ± 0.4 (PME) and 29.2 ± 0.6 (CPtE) mV/decade of concentration within the Cd2+ ion concentration range of 5.7 ? 10-8 to 3.7 ? 10-3 M for PME and 3.0 ? 10-8 3.0 ? 10-3 M for CPtE. These sensors are applicable in a pH range of 2.57.5. The lower detection limits by PME and CPtE are 3.2 ? 10-8 and 1.6 ? 10-8 M, respectively. They have a response time less than 14 s and can be used practically for a period of at least 2 months without any measurable divergence in results. The electrode can also tolerate partially non-aqueous media (ethanol, methanol and acetone) up to 30%. The electrodes showed excellent selectivity towards Cd2+ ion over a wide range of alkali, alkaline earth, and transition metals ions. They were successfully applied to the direct determination of Cd2+ ions in tap water, aqueduct water, and river water and soil sample. In addition the electrodes were used as an indicator electrode in potentiometric titration of Cd2+ ion with EDTA.
PROFILING OF BACTERIAL CELLULAR FATTY ACIDS BY PYROLYTIC DERIVATIZATION TO 3-PYRIDYLCARBINOL ESTERS
ADAM KURKIEWICZ, SLAWOMIR KURKIEWICZ — 2015 г.
Pyrolytic derivatization to 3-pyridylcarbinol esters coupled with gas chromatographymass spectrometry (GCMS) was applied to determine cellular fatty acid (CFA) profiles of Escherichia coli, Aerobacter aerogenes, Pseudomonas fluorescens, Bacillus subtilis and Clostridium perfringens. The structures of bacterial CFAs were inferred from the interpretation of mass spectra with electron ionization of the corresponding 3-pyridylcarbinol esters. In the method used, the entire bacterial cells are pyrolyzed in the presence of a derivatizing reagent, and CFA isolation prior to the GCMS analysis is not required. The method is argued to be a cheap, fast and accurate alternative to classical esterification to 3-pyridylcarbinol esters, while still providing more detailed results than methods based on esterification to methyl esters. Significat reduction in the required minimum bacterial mass allows for fast identification of the microorganisms, in particular slow growing bacteria species.
QUANTIFICATION OF BIODIESEL IN BIODIESEL DIESEL BLENDS USING SPECTROFLUORIMETRY AND MULTIVARIATE CALIBRATION
BARBEIRA P.J.S., CORGOZINHO C.N.C. — 2015 г.
With the aim to increase the percentage of biofuel in Brazils energy assets, biodiesel has been compulsorily added to regular diesel oil since January 2008, currently at a concentration of 5% (v/v). The method used to quantify the biodiesel in biodieseldiesel blends has limitations with respect to their sensitivity to contaminants containing carbonyl groups. In this context, the objective was to develop a simple analytical and low cost method for the quantification of biodiesel in biodieseldiesel blends combining multivariate calibration to spectrofluorimetry. The proposed method provided the determination of biodiesel in the range of 0.4 to 19.0% (v/v) with prediction errors less than 0.35% (v/v) using synchronized spectrofluorimetry and partial least squares. In the range of 4.5 to 20.0% (v/v) the average relative error was less than 4%. The method is simple, fast, requires no pre-treatment of samples and can be performed on site, featuring low cost and good accuracy.
RAPID MICROWAVE ASSISTED PREPARATION OF FATTY ACID METHYL ESTERS FOR THE ANALYSIS OF FATTY ACID PROFILES IN FOODS
BRUNTON N.P., COLLINS M.J., JR, MASON C. — 2015 г.
A microwave (MW) assisted rapid high through-put method for the preparation of fatty acid methyl esters (FAME) for the analysis of fatty acid profiles in a selection of foods was evaluated by comparing fatty acid profiles with those resulting from conventional FAME preparation. The microwave method gave fatty acid profiles in close agreement with those arising from conventional methods and the protocol gave acceptable recoveries (98102%) and repeatability (RSDs for replicate analyses 0.565.2%). In comparison to conventional methods the MW assisted method was simple, rapid and universally effective across foods ranging from dairy products to ready meals. EU regulation (No. 1169/2011) requiring declaration of the saturated, monounsaturated and polyunsaturated content of foods is placing pressure on processors and contract laboratories to analyse fatty acid profiles using relatively low through-put conventional methods. MW assisted preparation of FAMEs offers analysts a high-through-put, rapid and universal method to help overcome this potentially costly and labour intensive regulatory hurdle.
SENSITIVE SPECTROFLUORIMETRIC DETERMINATION OF ALFUZOSIN IN PHARMACEUTICAL PREPARATIONS AND HUMAN URINE USING DANSYL CHLORIDE
AYCA KARASAKAL, SEVGI TATAR ULU — 2015 г.
A sensitive and selective spectrofluorimetric method was developed for the determination of alfuzosin in pharmaceutical preparations and urine. The method is based on reaction of alfuzosin with 1-dimethylaminonaphthalene-5-sulphonyl (dansyl) chloride in carbonate buffer of pH 9.7 to yield a highly fluorescent derivative that is measured at 516 nm after excitation at 405 nm. The developed method was validated according to the criteria for analytical method, showing good performances in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, recovery and robustness. The fluorescence intensity versus concentration plot was rectilinear over the range of 25 to 500 ng/mL. The LOD and LOQ were found to be 8 and 25 ng/mL, respectively. The method was successfully applied to the determination of alfuzosin in pharmaceutical preparations and urine.
SIMPLE HPLC–FLUORESCENCE DETERMINATION OF EUGENOL IN CLOVE OIL AFTER PRE-COLUMN DERIVATIZATION WITH 4-(N-CHLOROFORMYLMETHYL-N-METHYLAMINO)- 7-NITRO-2,1,3-BENZOXADIAZOLE
YASUHIKO HIGASHI — 2015 г.
Eugenol is a phenolic flavor constituent of various plants, including clove and cinnamon. Eugenol content in clove oil has been analyzed by HPLCUV after pre-column derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F). Here, we present a simple, more sensitive HPLCfluorescence method for determination of eugenol in clove oil by pre-column derivatization with 4-(N-chloroformylmethyl-N-methylamino)-7-nitro-2,1,3-benzoxadiazole (NBD-COCl). The retention time of NBD-CO-eugenol was 14.9 min. A standard curve, obtained after derivatization with NBD-COCl in borate buffer (pH 9.0) at room temperature for 1 min, was linear in the range of 0.025 to 0.4 g/mL with r2 value of 0.9992. The limit of detection was 0.006 g/mL (signal-to-noise ratio of 3 : 1). This is 6.7-fold lower in terms of concentration and about 45-fold lower in terms of absolute amount, compared with the previous method using NBD-F. The coefficients of variation were less than 9.4%. The content of eugenol in clove oil (1.00 g) was 0.73 ± 0.05 g (range 0.65 to 0.79 g). Recovery tests were satisfactory (86 ± 5%; range 80 to 92%).
SIMULTANEOUS DERIVATIZATION/PRE-CONCENTRATION OF 3-PHENOXYBENZALDEHYDE AS TRANSFORMATION PRODUCT OF PERMETHRIN WITH 2,4-DINITROPHENYLHYDRAZINE BY SOLID PHASE EXTRACTION AND SPECTROPHOTOMETRIC DETECTION
FATEMEH SABERMAHANI, MAHBOUBEH SAEIDI, ZEINAB YAZDANI — 2015 г.
A simple, cheap and sensitive solid phase extraction method has been described for simultaneous derivatization and preconcentration of 3-phenoxybenzaldehyde (3-pbAl) in aqueous samples. The method is based on the reaction of 3-pbAl with 2,4-dinitrophenylhydrazine (DNPH) to form 2,4-dinitrophenyhydrazone in a column packed with silica gel. Using 100 mg of the sorbent, this compound was sorbed at pH 3 and recovered with 4 mL acetonitrile prior to its spectrophotometric determination at 407 nm. The effect of DNPH concentration, pH, sample flow rate and volume, elution conditions and foreign ions has been investigated. A preconcentration factor of 25 was achieved by passing 100 mL of sample through the column. The relative standard deviation for 5 replicate analyses at three concentration levels of 3-pbAl was from 0.34 to 1.12%.The calibration curve was linear from 0.01 to 5 of 3-pbAl, and limit of detection(S/N = 3) was 1.4 ng/mL. Molar absorptivity was found to be 4.7 ? 104 L/mol cm.