научный журнал по химии Журнал аналитической химии ISSN: 0044-4502

БАЛДИН М.Н., ГРУЗНОВ В.М., ЕФИМЕНКО А.П., МАКСИМОВ Е.М., НАУМЕНКО И.И., ПРОНИН В.Г. — 2015 г.

Приведены результаты исследования условий обнаружения следов маркирующих веществ, добавляемых в состав промышленных пластических взрывчатых веществ, в воздухе путем концентрирования и последующего анализа на модернизированном газовом хроматографе ЭХО-В-ИДПС с поликапиллярной колонкой, ионизационным детектором перестраиваемой селективности (ИДПС) с использованием атмосферного воздуха в качестве газа-носителя. Показано значительное влияние влажности воздуха на предел обнаружения 4-нитротолуола и 2,3-диметил-2,3-динитробутана, наибольшая чувствительность ИДПС наблюдается при влажности газа-носителя менее 8.5 мг/м3. Для концентрирования маркирующих веществ наиболее подходят концентраторы на основе сорбента Tenax либо выполненные в виде металлических сеток, покрытых стационарной неподвижной фазой. Пределы обнаружения паров маркирующих веществ при отборе 1 л воздуха в концентратор 22 пг/см3 для 4-нитротолуола и 0.1 пг/см3 для 2,3-диметил-2,3-динитробутана.

БЫЧКОВА О.А., ЗАВОДОВА М.Н., НИКИТИНА Т.Г., НИКОНОРОВ В.В. — 2015 г.

Методика экстракционно-фотометрического определения ванадия с N-бензоил-N-фенилгидроксиламином (N-БФГА) усовершенствована применительно к анализу природных вод. Зависимость оптической плотности экстрактов от концентрации ванадия(V) в водном растворе линейна в диапазоне 0–1500 мкг/л и описывается уравнением A = (10.70 ± 0.02) ? 10-4cv (мкг/л). Молярный коэффициент поглощения комплекса в хлороформе составляет 5450 ± 10, а коэффициент его распределения между фазами равен 26.1 ± 0.5. Показано, что ванадий в природных водах существует как в свободной, так и в связанной формах. Преобладающие анионные формы ванадия(V), по-видимому, свободны, а катионные формы ванадия(IV) связаны с органическими компонентами природных вод. Для разрушения последних рекомендовано окислительное вскрытие проб кипячением с 1 мл конц. HClO4 до появления паров.

АРТЮХ Е.В., ЗАНОЗИНА И.И., КИСЕЛЕВА Н.В., КОЛЫЧЕВ И.А., ТЕМЕРДАШЕВ З.А. — 2015 г.

Рассмотрены состояние и проблемы определения дитиофосфатов цинка в моторных маслах, используемых в качестве многофункциональной присадки и определяющих их антиокислительные, противоизносные и антифрикционные свойства. Изучены факторы, мешающие определению присадок в анализируемых объектах, и способы их устранения. Оценены методы анализа, применяемые для скрининга и определения дитиофосфатов цинка в моторных маслах. С учетом сложного состава масляной матрицы при определении дитиофосфатов цинка наиболее предпочтительна схема анализа, включающая предварительное их выделение с использованием твердофазной экстракции на гидроксилированном силикагеле, отделение компонентов базовой масляной основы и ряда присадок с использованием двухстадийной экстракции с последующим детектированием аналита методом ВЭЖХ. Предложенная схема определения дитиофосфатов цинка в моторных маслах апробирована на ряде коммерческих образцов, получены удовлетворительные результаты.

ГРУЗИНА Т.Г., ИМИНОВА Ю.В., МАЛЫШЕВА М.Л., РЕЗНИЧЕНКО Л.С., РОЖАНЧУК Т.С., ТАНАНАЙКО О.Ю., УЛЬБЕРГ З.Р. — 2015 г.

Выполнено модифицирование угольного и золотого электродов биокомпозитной пленкой на основе оксида кремния, гемоглобина (hemoglobin, Hb) и глюкозооксидазы (glucose oxidase, GOx) методом осаждения с использованием электрогенерированного катализатора. Иммобилизированные в пленке белки сохраняют каталитическую активность в течение трех недель. Стабильность аналитического сигнала модифицированного электрода значительно увеличивается при введении в золь наночастиц Au диаметром 20 нм и бромида цетилтриметиламмония (20 ККМ). Золотой электрод, модифицированный биокомпозитной пленкой SiO2 Hb GOx Au, использован для вольтамперометрического определения глюкозы в модельных растворах и сыворотке свиной крови. Градуировочный график линеен в интервале 0.015–0.20 мМ, предел обнаружения – 0.008 мМ глюкозы. Разработанный способ модифицирования перспективен для получения чувствительных элементов биферментных амперометрических сенсоров.

ЕВТЮГИН Г.А., СТОЙКОВА Е.Е. — 2015 г.

Рассмотрены основные закономерности функционирования электрохимических биосенсоров, включающих в состав биочувствительного слоя дендримеры различного состава. Определены роль и значение дендримеров как матрицы для иммобилизации биологических компонентов биосенсоров, увеличения плотности рецепторов и медиаторов электронного переноса. Приведены примеры реализации различных типов биосенсоров на основе ферментов, иммунохимических реагентов и нуклеиновых кислот.

2015

АНТОНОВИЧ В.П., ВЕРШИНИН В.И. — 2015 г.

Сопоставлены цели и реальные итоги развития некоторых научных направлений, важных в истории аналитической химии (создание специфических органических реагентов и др.). Многолетние исследования аналитиков в этих направлениях привели к выявлению новых закономерностей и практически полезным результатам. Однако в ряде случаев намеченные революционные цели достигнуты не были, преувеличенные ожидания не оправдались. Соответствующие уроки истории могут быть полезны при рассмотрении перспектив популярных сегодня научных направлений, в частности, наноаналитики.

МАШЬЯНОВ Н.Р., ТАЦИЙ Ю.Г. — 2014 г.

DILEK KLCAN, HAYATI FILIK — 2014 г.

This work describes a new, simple, and sensitive colorimetric determination method for indoxyl sulfate (indican) by fiber optic UV-Vis spectrophotometry coupled to cloud point extraction as the separation-preconcentration method. This method is based on the diazotization of sulphanilic acid in acidic medium followed by its coupling with indoxyl sulfate (indican), which gives an azo product and extraction of the colored product using the cloud point extraction (CPE) technique. The optimal extraction and reaction conditions (e.g., acid and reagent concentrations, effect of time) were studied, and the analytical characteristics of the method (e.g., limit of detection, linear range, preconcentration factor) were obtained. Linear response was achieved within 0.9 44 and the detection limit was estimated as . The inter-day and intra-day relative standard deviations were in the ranges 1.2–1.3% and 1.6–1.8% for indican. The method was applied to the determination of indican in human spiked urine samples; Recoveries within 96–99% were obtained.

ALI REZA ZAREI, REIHANEH HAJIAGHABOZORGY, SHAHRAM GHANBARI PAKDEHI — 2014 г.

A simple and highly sensitive method developed for preconcentration and spectrophotometric determination of ultra trace amounts of azide ion (N ) in water and biological samples using dispersive liquid–liquid microextraction (DLLME) technique. The method is based on ion association formation of azide ion with malachite green and extraction of the ion pairing product using DLLME technique. Some important parameters, such as reaction conditions and the kind and volume of extraction solvent and disperser solvent were studied and optimized. The calibration curve was linear in the range of 0.5 50 g/L of azide ion. Also, the enrichment factor and extraction recovery obtained were 24.7 and 98.7%, respectively. The method was applied to the determination of azide ion in water and biological samples.

CAL?SKAN A.C., SENDIL O., SOMER G. — 2014 г.

A new indirect differential pulse polarographic (DPP) method is established for the trace determination of mercury(II). Because of its toxic effects on human health, trace determination of mercury is very important. An indirect method had to be used since no polarographic peak is observed in its direct determination. According to the standard potentials, the reaction between Sn(II) and Hg(II) was found suitable. The peak of Sn(II) at about –0.40 V is sharp, high and very reproducible, which enables the determination of low concentrations of Hg(II). For this purpose, to a known amount of Sn(II) present in the polarographic cell (acetic acid, HAc, pH 1–2), the unknown Hg(II) sample is added and the quantitative reaction takes place directly in the cell. The Hg(II) concentration is calculated simply from the decrease of the Sn(II) peak. The limit of detection (LOD) was found as 2 ? 10-7 M for S/N = 3. Interferences of some common cations, such as Fe, Cd, Cu, Zn and Pb and anions have been investigated. Only Pb had an overlapping peak with Sn(II). This peak overlap was eliminated simply by working at pH 2 (HAc electrolyte), because of the shift of the Pb peak in the Ac complex to –0.7 V. This method was successfully applied to synthetic samples and raw salt sample taken from a salt lake in Turkey.

ENSAFI ALI A., MASOUD FOULADGAR — 2014 г.

A color changeable optode for thallium(III) ions in aqueous solutions was prepared by physical inclusion of a of 4-(2-pyridylazo)-resorcinol into a plasticized PVC film. The increasing in the absorbance of the optode at 524 nm is proportional to thallium(III) concentration. Different parameters effecting on the sensitivity such as sample parameters and composition of the membrane were optimized. The response times of the prepared test-system are found to be 230, 210, and 180 s for 4.8 ? 10-6, 4.8 ? 10-5, and 4.8 ? 10-4 M Tl(III), respectively. The analytical performance of the optode was evaluated, obtaining a linear concentration range of two decades of concentration, 3.1 ? 10-6 – 4.7 ? 10-4 M Tl(III), with a limit of detection of 1.8 ? 10-6 M Tl(III). Selectivity of the optode is also studied. Application of the optode to the determination of Tl(III) in some aqueous samples yields good results.

ALEKSANDRA GUZ, BARBARA SZPIKOWSKA-SROKA, JUSTYNA POLEDNIOK — 2014 г.

A simple and accurate spectrophotometric method for determination of sodium 2-sulfanylethanesulfonate (MESNa) with leuco xylene cyanol FF (LXCFF) has been developed. The proposed method is based on the reaction of MESNa with potassium iodate(V) in acidic medium, to liberate iodine, which oxidized leuco xylene cyanol FF to its blue form xylene cyanol FF. The xylene cyanol FF dye formed shows maximum and stable absorbance at pH 4.1–4.2. Absorbance of the obtained colored products was measured at 613 nm. The molar absorptivity, limit of detection and limit of determination of the method were found to be 3.64 ? 104 L/mol cm, 0.29 and 0.33 , respectively. The colour system obeys Beers laws in the range of MESNa. All the variables were studied in order to optimize the reaction conditions. The procedure was used for determination of MESNa in pharmaceutical preparations. Reliability of determination was confirmed applying standard iodometric method, recommended by European and Polish Pharmacopoeia.

BIAN W.W., JIANG C.Q., WANG L., ZHANG N. — 2014 г.

A new spectrofluorimetric method is described for the determination of uric acid (UA), that can remarkably reduce the fluorescence intensity of the enoxacin (ENX)–terbium ion (Tb3+) complex at 545 nm. The reduced fluorescence intensity of Tb3+ ion at pH 5.7 is proportional to the concentration of UA. Optimum conditions for the determination of UA have been investigated. The linear range and detection limit for the determination of UA are 6.0 ?10-7 3.0 ? 10-5 M and 1 ? 10-7 M, respectively. The relative standard deviation (RSD) was 0.4% for 6 ? 10-6 M UA (n = 11). The method is simple, practical and relatively free of interferences. It has been successfully applied to assess UA in serum at the level of 3 ? 10-4 M with an RSD of 5–7% (n = 3). The results were evaluated by comparison with a common clinical spectrophotometric method using phosphotungstic acid as developer.

DEILAMY-RAD G., KHALAFI-NEZHAD A., PARHAMI A., TAVALLALI H. — 2014 г.

We report here a selective, efficient and very simple receptor which can easily detect F- in the presence of a wide range of other anions [Cl-, Br-, I-, HSO , NO , Acetate (AcO-) and Benzoate (BzO-)] by use of colorimetric or fluorometric detection. 4-Chloro-2,6-bis(hydroxymethyl) phenol (CBHMP) is a simple and available phenolic receptor having no special chromophoric function. In this colorimetric method, naked-eye detection of F- with CBHMP is described. Interestingly, fluorometric detection of F- is also possible by highly selective fluorescent quenching response CBHMP in dimethyl sulfoxide (DMSO) media.

HWANG H.S., KANG C.N., KANG J.S., KIM H.J., KIM S.H., PARK H.K., PARK Y.S. — 2014 г.

A simple and rapid liquid chromatography-tandem mass spectrometry method for Enalapril in human plasma was developed and applied to pharmacokinetic and bioequivalence test for 2 formulations of Enalapril (10 mg) capsules in healthy korean volunteers under fasting state. The analytes were extracted from plasma by simple protein precipitation by acetonitrile, separated on YMC C8 column using methanol–10 mM ammonium formate (80 : 20, v/v) as the mobile phase, and detected by tandem mass spectrometry with Turbo IonSpray interface operating in the positive ion mode for Enalapril and Glibenclamide (IS) in MRM mode. The ionization was optimized using electro-spray ionization (ESI) (+) and selectivity was achieved by MS/MS analysis, m/z 376.447 234.1 for Enalapril and m/z 494.1 369.1 for IS. The assay exhibited good linearity in the concentration ranges of 1.0 300 ng/mL for Enalapril in human plasma with lower limit of quantification (LLOQ) of 1.0 ng/mL. The chromatographic run time was approximately 2.0 min. No endogenous compounds were found to interfere with the analysis. The accuracy and precision were acceptable for concentrations over the standard ranges. The method was successfully applied to pharmacokinetic (PK) and bioequivalence (BE) studies by determination of Enalapril in the blood sample taken up to 12 h after oral administration of two Enalapril (10 mg) formulations and results from PK analysis suggested that the 2 types of 10 mg Enalapril tablets should be considered to be bioequivalent for both the extent and rate of absorption in normal volunteers.

ADEM ASAN, BEDIHA AKMESE, NURULLAH SANLI, SENEM SANLI — 2014 г.

Simple, accurate, precise and fully validated analytical methods for the simultaneous determination of salmeterol xinafoate and fluticasone propionate in combined dosage forms have been developed. These drugs were exposed to thermal, photolytic, hydrolytic and oxidative stress conditions, and the stressed samples were detected by the proposed method. Additionally, pKa values of three ionizable drugs (salmeterol xinafoate, fluticasone propionate and thioridazine) were determined using by the dependence of the retention factor on pH of the mobile phase. The effect of the mobile phase composition on the ionization constant was studied by measuring the pKa in different acetonitrile–water mixtures, ranging between 50 and 65% (v/v) using LC–UV method.

DEIA ABD EL-HADY, YOUSSEF AHMED K. — 2014 г.

A new simple, sensitive and reliable adsorptive and affinity linear sweep voltammetric method at in situ mercury film electrode for the determination of singulair in tablets and its interaction with human serum albumin (HSA) was investigated. The solubility of singulair in aqueous media was enhanced by inclusion with hydroxypropyl-?-cyclodextrin (HP CD). The nature of the electrochemical process of singulair was studied by affinity cyclic voltammetry (ACV). Reproducibility of the proposed method was checked giving interday precision of 0.073 standard deviation. The limit of detection and limit of quantification were 0.05 and 0.16 fg/L, respectively. In the present work, singulair was interacted with HSA by 1 : 1 stoichiometry to form electroinactive supramolecular complex. The binding constant was precisely estimated by coupling affinity linear sweep voltammetry (ALSV) and ACV with non-linear regression analysis based on the shifting of analyte peak potentials. The proposed experiments and data analysis could be used to investigate the binding constant of drug with protein within one hour.

CORREIA ADRIANA N., DJENAINE DE SOUZA, HELENA BECKER, MELO LUISA C., OLIVEIRA SAMEQUE DO N., PEDRO DE LIMA-NETO, RIBEIRO FRANCISCO W. P., SOARES JANETE E., SOARES THISIANIA R. V. — 2014 г.

The electrochemical behaviour and analytical detection procedure for nimesulide (NIM) and ofloxacin (OFX) and their assay in commercial formulations were evaluated using square-wave voltammetry (SWV) combined with a hanging mercury drop electrode (HMDE). All experimental and voltammetric conditions were previously optimized to obtain the best analytical signal in terms of intensities and profile of the reduction peaks. For NIM, the peak currents were related to the one-electron reduction of a nitro group to a stable radical anion, which is followed by a one-electron transfer and a protonation step with a consequent formation of a nitrosoanion. The voltammetric results indicated that the mechanism of OFX involved the transfer of two electrons and two protons in a totally irreversible reduction related to the conversion of a ketone group to an alcohol group. Analytical parameters such as linearity range, equations of the analytical curves, correlation coefficients, detection and quantification limits, recovery efficiency, and relative standard deviation for repeatability and reproducibility experiments were compared to similar results obtained by the use of UV-Vis spectrophotometry, and the results showed that the voltammetric procedure using HMDE is suitable to determine pharmaceutical compounds in complex samples. The applicability of the proposed procedure was tested on pharmaceutical formulations of NIM and OFX by observing the stability, specificity, recovery and precision of the procedure in tablets, oral solution and ophthalmic solution.

KOSTI D.A., MICI R.J., MITI M.N., MITI S.S., PAVLOVI A.N. — 2014 г.

An efficient, highly sensitive, fast and selective kinetic method for determination of traces of Cu(II) was developed and applied for its quantification in different real samples. The method was based on the catalytic effect of Cu(II) traces on the redox reaction of artificial azo-dye tartrazine (tri-sodium-5-hydroxy-1-(4-sulfophenyl)-4-[(4-sulfophenyl)azo]pyrazole-3-carboxylate) with H2O2. The optimum operating conditions regarding reagent concentration were examined and established. Linearity of the method was obtained in the concentration range from 13 to 318 ng/mL of Cu(II), with a detection limit (LOD) (3sb/m ) of 2 ng/mL, and limit of quantification (LOQ) (10sb/m) of 7 ng/mL. Obtained results for Cu(II) determination in analyzed samples, as well as the development and validation of the proposed analytical procedure have given and discussed.