9 research outputs found
Desenvolvimento de método rápido para análise simultânea de metil, etil, propil e butilparabeno em amostras cosméticas e farmacêuticas e estudos de interação com macromoléculas biológicas utilizando eletroforese capilar
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Programa de Pós-Graduação em QuímicaOs p-hidroxibenzoatos de alquila, ou parabenos, fazem parte de uma classe de compostos com atividade antimicrobiana mais utilizada em todo o mundo. Desde os anos 20 eles são adicionados às formulações. Entretanto, o avanço científico e tecnológico levantou a hipótese destes apresentarem atividade cancerígena, entre outros malefícios. Por isto este trabalho propõe tanto o controle da concentração destes compostos em produtos comerciais (capítulo 1), quanto um maior entendimento da sua ação biológica (capítulo 2). O primeiro capítulo aborda o desenvolvimento de um método simples e rápido por eletroforese capilar para análises de rotina de metil, etil, propil e butilparabeno em produtos comerciais, com preparo simples de amostra. O pH e os constituintes do eletrólito foram selecionados usando curvas de mobilidade efetiva versus pH e simulações com o software Peakmaster®. Ácido cinâmico foi usado como padrão interno. O eletrólito foi composto por 20 mmol L-1 de ácido 2-hidroxiisobutírico (HIBA), 30 mmol L-1 de trietilamina (TEA) e 0,3 mmol L-1 de brometo de hexano-1,6-bis(trimetilamônio) (HMB), pH = 10,6. Os experimentos foram realizados em um equipamento de eletroforese capilar modelo HP 7100 CE equipado com detector UV em 297 nm.. As separações eletroforéticas foram conduzidas em um capilar com 32 cm de comprimento total, 8,5 cm de tamanho efetivo e 50 m de diâmetro interno (d.i.). O tempo de corrida foi cerca de 1 minuto. O método apresenta R2 > 0,99 num intervalo entre ~ 0,5 e 30 mg L-1, limite de detecção de 0,1 mg L-1 e de quantificação 0,3-0,4 mg L-1, exatidão avaliada pela adição interna de padrão e pela técnica de HPLC/MS/MS com aplicação em amostras cosméticas e farmacêuticas diversas. O segundo capítulo desta dissertação é o estudo in vitro da interação dos parabenos com albumina do soro bovino (BSA) e o ácido desoxirribonucléico (DNA), utilizando para ambos a técnica de eletroforese capilar. Foram aplicados dois métodos para os estudos de interação com BSA e cálculos das constantes de associação (Kass): eletroforese capilar de afinidade (ACE), e o método baseado no preenchimento parcial do capilar (PF-ACE). Os experimentos foram realizados em um equipamento de eletroforese capilar modelo HP3D CE com detector UV a 270 nm. As separações foram conduzidas em um capilar de sílica fundida com 32 cm de comprimento total, 8,5cm de tamanho efetivo e 50 m de d.i. As condições eletroforéticas foram escolhidas com base nas condições biológicas: o eletrólito de corrida foi composto por 30 mmol L-1 de fosfato e 50 mmol L-1 de Na+, pH = 7,3, 70 mmol L-1 de força iônica e temperatura do capilar mantida em 36,5ºC. Os resultados qualitativos convergiram em ambos os métodos. Quando estudados simultaneamente, as interações paralelas não apresentaram interferência em cada interação específica. As constantes de associação foram calculadas pelo modelo não-linear e pelo modelo linear do duplo-recíproco, e comparadas. O modelo não-linear demonstrou maior confiabilidade apresentando resultados na ordem de 103 e 104, crescentes com o crescimento da hidrofobicidade dos compostos. O estudo de interação com o DNA, por sua vez, foi realizado apenas para o composto propilparabeno, utilizando-se também dois métodos: PF-ACE e outro, offline, por ultrafiltração. Não foi possível observar interação em nenhum dos métodos empregados.The alkyl p-hydroxybenzoates or parabens, belong to a class of compounds with antimicrobial activity most used around the world. They have been added to several formulas since 1920. However, the scientific and technological progress opened the possibility of cancer activity and other evils. Therefore, this paper proposes both the control of the concentration of these compounds in commercial products (Chapter 1), and a greater understanding of its biological action (Chapter 2). The first chapter discusses the development of a simple and rapid method by capillary electrophoresis for routine analysis of methyl, ethyl, propyl and butylparaben in commercial products with simple sample preparation. The pH and the background electrolyte (BGE) constituents were selected using effective mobility-versus-pH curves and simulations using PeakmasterR software. Cinnamic acid was used as internal standard. The BGE was composed of 2-hidroxiisobutirico acid 20 mmol L-1, triethylamine 30 mmol L-1 and methyl hexane-1,6-bis(trimethylammonium) 0.3 mmol L-1, pH = 10.6. The experiments were performed on a capillary electrophoresis device model HP 7100 with UV detector at 297 nm. CE separations conducted in a 32 cm long capillary with 8.5 cm effective length and 50 um internal diameter (i.d.). The run time was about 1 minute. The method developed had R2> 0.99 in a range between ~ 0.5 and 30 mg L-1, detection limit of 0.117-0.127 mg L-1 and quantification limit of 0.3- 0.4 mg L-1, accurately assessed by internal standard addition and by LC-MS/MS technique, and application in several cosmetic and pharmaceutical samples. The second chapter of this dissertation is in vitro interaction of parabens study with bovine serum albumin (BSA) and deoxyribonucleic acid (DNA), using both the capillary electrophoresis technique. Were applied two methods for BSA interaction studies and association constants calculation (Kass): affinity capillary electrophoresis (ACE), and the method based on capillary partial filling (PF-ACE). The experiments were performed on a capillary electrophoresis device model HP3D CE with UV detector at 270 nm. The separations were conducted in a 32 cm long fused silica capillary with 8.5 cm effective length and 50 um internal diameter (i.d.) The electrophoretic conditions were chosen based on biological conditions. The BGE composed of phosphate 30 mmol L-1, pH 7.3, ionic strength 70 mmol L-1 and capillary temperature maintained at 36.5 C. The qualitative results in both methods converged. When studied simultaneously, parallel interactions showed no interference in each specific interaction. The association constants were calculated by nonlinear model and by the linear model of the double-reciprocal, and compared. The non-linear model showed a higher reliability results presented in the order of 103 and 104, increasing with the growth of the compounds hydrophobicity. The DNA- interaction study, in turn, was made only for propylparaben, also using two methods: PF-ACE and the other, offline, by ultrafiltration. Interaction was not observed in any methods employed
Novos complexos mononucleares de Ga III e In III com ligantes não-simétricos: potenciais agentes quimioterápicos e radiafármacos
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Química, Florianópolis, 2012O crescente número de indivíduos que desenvolverão algum tipo câncer exige que sejam desenvolvidos radiofármacos e quimioterápicos seletivos, pois o diagnóstico preciso e um tratamento específico são fundamentais para a possibilidade de cura e da elevação da taxa de sobrevida. Motivados a tentar atender essas necessidades, neste trabalho tivemos como objetivo sintetizar e caracterizar novos complexos mononucleares de GaIII e InIII com ligantes não-simétricos, NO-doadores, hexadentados inéditos, sendo os complexos potenciais radiofármacos e/ou quimioterápicos. Foram obtidos 8 complexos mononucleares de GaIII e de InIII. Os complexos foram caracterizados utilizando-se as técnicas de análise elementar, espectroscopia de infravermelho, ressonância magnética nuclear de 1H, espectrometria de massas, condutivimetria e utilizou-se para os complexos GaL1, InL1, GaL2 e InL5 a difração de raios x para determinar a estrutura cristalina. Todos os complexos de Ga e In obtidos, tiveram sua estabilidade em solução avaliada a partir de coletas de espectros de RMN 1H, em DMSO-d6, nas temperaturas de 22, 36 e 55°C; sendo observado que os complexos são estáveis em solução. A citotoxicidade dos ligantes e complexos foi avaliada frente a células leucêmicas e os resultados revelaram que os complexo são ativos em concentrações a partir de 2,5 ?M, e os ligantes testados também apresentaram citoxicidade a partir de 5,0 ?M. Além disso, todos os compostos induziram a morte celular por apoptose. O fato de as concentrações necessárias para atingir o IC50 serem superiores às utilizadas em radiofarmácia indica que todos os complexos são potenciais radiofármacos.Abstract : The growing number of individuals who will develop some type of cancer require selective radiopharmaceutical and chemotherapeutic agents for accurate diagnosis associated with a specific treatment. The combination of these factors is fundamental for the possibility of cure and raising the survival rate. In and Ga elements stand out in their use as radionuclides (67Ga, 111In, and 68Ga) to obtain radiopharmaceutical used in imaging techniques such as PET and SPECT. Promising results from studies of complex GaIII have boosted interest in this metal-based chemotherapy. InIII have already been described as a potential agent against bacteria and cancer. Motivated by the need to obtain more effective and selective radiopharmaceuticals and chemotherapy, in this work we describe the synthesis and characterization (by infrared spectroscopy, and nuclear magnetic resonance 1H and 13C) of 5 novel ligands mononucleates hexadentate unsymmetrical suitable for obtaining complexes with the cations and GaIII InIII stable under physiological conditions. GaIII and InIII were obtained as complexs with the ligands HL1, H2L2, H3L3 and HL5, and HL1 was also obtained as a complex with Fe. The complexes were characterized by elementar analysis, infrared spectroscopy, nuclear magnetic resonance 1H, mass spectrometry, conductivity measurement and for GaL1, InL1, GaL2 and InL5 complexes x-ray diffraction was also used to determine the crystalline structures. For all complexes obtained, except FeHL1, stability was evaluated in solution from collections of 1H NMR spectra at temperatures of 22, 36 and 55°C; it was observed that the complexes are stable in solution. The cytoxic activity was evaluated for all complexes and ligands in leukemic cells and the results showed that only FeL1 complex is inactive, and the others are active at concentrations from of 5 ìM. Furthermore, all compounds induced cell death by apoptosis. The fact that the concentrations needed to achieve the IC50 are greater than that used in radiopharmacy indicates that all complexes are potential radiopharmaceuticals
ИССЛЕДОВАНИЕ АНАЛЬГЕТИЧЕСКОЙ ЭФФЕКТИВНОСТИ И БЕЗОПАСНОСТИ БЛОКАДЫ НЕРВОВ В ПОПЕРЕЧНОМ ПРОСТРАНСТВЕ ЖИВОТА У ПАЦИЕНТОК, ПЕРЕНЁСШИХ ЭКСТИРПАЦИЮ МАТКИ
No full textHysterectomy is an extensive surgical intervention, which is accompanied by heavy post surgical pain syndrome. Despite mainstreaming of the combined anaesthesis concept, which implies the simultaneous prescription of several analgesics with different mechanisms of action, frequently the quality of postoperative anesthesia continues to be unacceptable. Another option of the problem solution is to introduce the additional regional anesthesia practices, in particular the nerve block anesthesia in the transversus abdominis plane. This study allowed concluding that the block anesthesia of transversus abdominis plane block before hysterectomy does not result in significant reduction of postsurgical pain syndrome and morphine consumption during the first day after surgery, while significantly increases time of the first demand for morphine and helps reducing the dermic hyperalgesia area postoperatively. Экстирпация матки - большое по объёму оперативное вмешательство, которое сопровождается интенсивным послеоперационным болевым синдромом. Несмотря на широкое внедрение в практику концепции мультимодального обезболивания, которая предполагает одновременное назначение нескольких анальгетиков с разными механизмами действия, качество послеоперационного обезболивания зачастую продолжает оставаться неудовлетворительным. Одним из возможных способов решения данной проблемы является внедрение дополнительных регионарных методов обезболивания, в частности блокады нервов в поперечном пространстве живота. В результате исследования сделан вывод, что выполнение блокады поперечного пространства живота латеральным доступом перед операцией экстирпации матки не приводит к статистически значимому уменьшению интенсивности послеоперационного болевого синдрома, расхода морфина в первые сутки после операции, но статистически значимо увеличивает время первого требования морфина и способствует уменьшению площади кожной гиперальгезии после операции
Studies of protein post-translational modifications using high resolution tandem mass spectrometry
No full textElectron capture dissociation (ECD) is a powerful and superior
tandem mass spectrometry (MS) fragmentation technique in the study of
protein post-translational modifications (PTMs) due to its unique features
of preserving labile modifications and providing more detailed sequence
information, which has been used to study protein platination and
disulfide linked proteins. Cisplatin was found cross-linking multiple
methionine (Met) pairs on calmodulin (CaM). The cross–linking of
cisplatin to apo–CaM or Ca–CaM can inhibit the ability of CaM to
recognize its target proteins as proved by a melittin binding assay. To
further establish MS strategies to quickly assign the platinum-modification
sites, a series of peptides with potential cisplatin binding sites were
reacted with cisplatin and then analyzed by ECD. Radical-mediated side
chain losses from the charge-reduced M+Pt species (such as CH3S• or
CH3SH from Met, SH• from Cys, CO2 from Glu or Asp, and NH2• from
amine groups) were found to be characteristic indicators for rapid and
unambiguous localization of the Pt-modification sites on certain amino
acid residues. Furthermore, the potential of cisplatin as a protein crosslinking
reagent was further explored and demonstrated on other peptides
and proteins. Many of the inherent features of cisplatin make it an
interesting cross-linking reagent, such as targeting new protein functional
groups (thioether and imidazole groups), its unique isotopic pattern, its
inherent positive charges, its potential of binding to different functional
groups, etc. However, it was found that the distance constraints obtained from NMR structures of CaM are inconsistent with the measured distance
constraints by cross–linking. Therefore, a newly developed flexibility
simulation method was applied to explore whether the flexibility motions
of CaM might contribute to the observed Pt-crosslinking on CaM. The
flexibility analysis showed that the structural flexibility of CaM is key to
cisplatin crosslinking CaM. ECD mechanism of disulfide bonds is still
under debate. To further explore the ECD mechanism of sulfur–
containing species, a series of disulfide (S–S), sulfur–selenium (S–Se),
and diselenide (Se–Se) bond–containing peptides was studied by ECD.
The results demonstrate that the radical has higher tendency to stay at
selenium rather than sulfur after cleavage of Se–S bonds by ECD and
suggest that direct electron capture at Se–Se and C–Se bonds is the
main process during ECD of inter–chain diselenide peptides. Last but not
least, a new active ion ECD (AI-ECD) method, named Shots-ECD, was
developed and applied to improve Top-down ECD backbone
fragmentation efficiency of disulfide-rich proteins. The results show that
the Shots–ECD approach can not only cleave multiple disulfide bonds but
also significantly improve the backbone cleavage efficiency. This strategy
is fast, efficient, and with no need of chemical reduction of samples and
instrument modification, and therefore can be a powerful approach to
improve top-down ECD efficiency of not only disulfide bonded proteins
but all proteins by Fourier transform ion cyclotron mass spectrometry
(FTICR MS)
Бифункциональные хелаторы к катиону галлия
No full textObjectives. The chemistry of 67Ga and 68Ga radionuclides plays a key role in nuclear medicine for applications in radiopharmaceuticals, in particular, in noninvasive in vivo molecular imaging techniques. The use of radiometals for labeling biomolecules typically requires the use of bifunctional chelators, which contain a functional group for covalent bonding with the targeting vector in addition to the polydentate fragment coordinating the metal. The aim of the present review article is to analyze the currently accumulated experimental material on the development and application of bifunctional chelators of gallium cations in medical research, as well as to identify the main requirements for the structure of the chelator and its complexes with 68Ga, which are used to create effective Gabased pharmaceutical preparations.Results. The review analyzed macrocyclic bifunctional chelators forming stable in vivo complexes with 68Ga and acyclic chelators, whose main advantage is faster complexation kinetics due to the short half-life of 68Ga. The advantages and disadvantages of both types of ligands were evaluated. In addition, a critical analysis of the binding constants and the conditions for the formation of complexes was presented. Examples of the influence of the geometry, lipophilicity, and total charge of the metal complex on the biodistribution of target radiopharmaceuticals were also given.Conclusions. Despite the progress made in the considered areas of bifunctional chelators, the problem of correlating the chemical structure of a metal-based radiopharmaceutical with its behavior in vivo remains important. Comparative studies of drugs having an identical targeting vector but containing different bifunctional chelating agents could help further elucidate the effectof metal chelate moiety on pharmacokinetics. In order to create effective bifunctional chelating agents, it is necessary to take into account such factors as the stability and inertness of the chelator and its complexes under physiological conditions, lipophilicity, complexation kinetics, chelation selectivity, combinatoriality of the basic structure, along with economic aspects, e.g., the availability of raw materials and the complexity of the synthesis scheme.Цели. Химия радионуклидов 67Ga и 68Ga играет одну из ключевых ролей в ядерной медицине для применения в радиофармпрепаратах, в частности, в неинвазивных методах молекулярной визуализации in vivo. Использование радиометаллов для мечения биомолекул обычно требует использования бифункциональных хелаторов, которые, кроме полидентатного фрагмента, координирующего металл, содержат функциональную группу для ковалентного связывания с вектором-мишенью. Цели данного обзора – проанализировать накопленный к настоящему времени экспериментальный материал, касающийся разработки и применения в медицинских исследованиях бифункциональных хелаторов к катиону галлия, а также выявить и проанализировать основные требования, предъявляемые к структуре хелатора и его комплексов с 68Ga, необходимые для создания эффективных фармакологических препаратов на его основе.Результаты. Рассмотрены макроциклические бифункциональные хелаторы, образующие стабильные in vivo комплексы с 68Ga, а также ациклические хелаторы, преимущество которых заключается в более быстрой кинетике комплексообразования, что является ключевым фактором, учитывающим короткий период полураспада 68Ga. Проведена оценка достоинств и недостатков обоих типов лигандов. Кроме того, осуществлен критический анализ констант связывания и условий образования комплексов. Рассмотрены примеры влияния природы металлического комплекса (геометрия, липофильность, общий заряд) на биораспределение целевых радиофармацевтических препаратов.Выводы. Несмотря на достигнутые успехи в рассмотренных направлениях создания бифунциональных хелаторов, по-прежнему важной остается проблема корреляции химической структуры радиофармпрепаратов на основе металлов с их поведением in vivo. В этом отношении сравнительные исследования препаратов, имеющих идентичный вектор нацеливания, но включающих разные бифункциональные хелатируюшие агенты, могут помочь в дальнейшем выявлении влияния металл-хелатного фрагмента на фармакокинетику. В целом можно отметить, что для создания эффективного бифункционального хелатирующего агента нужно принимать во внимание целую совокупность факторов, включающую стабильность и инертность хелатора и его комплексов в физиологических условиях, липофильность, кинетику комплексообразования, селективность хеланирования, комбинаторность базовой структуры, а также экономические аспекты: доступность сырья, сложность схемы синтеза
СОВМЕСТНОЕ ОПРЕДЕЛЕНИЕ ИОНОВ ТЯЖЕЛЫХ МЕТАЛЛОВ МЕТОДОМ КАПИЛЛЯРНОГО ЗОННОГО ЭЛЕКТРОФОРЕЗА С ИСПОЛЬЗОВАНИЕМ КОМПЛЕКС-СЕЛЕКТОРА Людмила Константиновна Неудачина, Елена Леонидовна Лебедева
No full textThe usage of diglycylglycine (GGG) was proposed to improve the separation of the complexes of heavy metal ions with EDTA by capillary zone electrophoresis. The tripeptide can interact with the complexes in capillary and thereby acts as a complex selector.The influence of GGG on the electrophoretic behavior of ten metal complexes (Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II) and Bi(III)) was studied in an acidic media using a negative polarity voltage supply. Three modes were proposed for the implementation of the in-capillary complexation. An addition of the reagent to the phosphate buffer solution changes the migration order of the complexes thus enabling separation of Cr(III) from Zn(II) and Ni(II) and Co(II) from Cd(II) and Mn(II). It is possible to determine Fe(III) and Bi(III) complexes selectively in presence of the other heavy metal ions.An injection of separate zones of EDTA, metal ions and GGG doesn’t provide good separation. A consecutive injection of Me-EDTA and GGG zones leads to Cu(II) and Pb(II) separation. So, it is possible to determine four metal ions (Cu(II), Pb(II), Fe(III) and Bi(III)) simultaneously at 260 nm.Calibration graphs plotted in optimal conditions show linearity within the concentration range from 5·10-6 to 5·10‑3 mol/dm3. Limits of detection were calculated to be from 0.05 mg/dm3 for Pb(II) ions to 0.72 mg/dm3 for Bi(III). The proposed technique was applied for the determination of copper, lead, iron and bismuth in some natural and industrial samples.Keywords: capillary zone electrophoresis, copper, lead, iron, bismuth, EDTA, diglycylglycine. (Russian)DOI: http://dx.doi.org/10.15826/analitika.2014.18.4.013L.K. Neudachina, E.L. Lebedeva Federal State Autonomous Educational Institution of Higher Professional Education «Ural Federal University named after the first President of Russia B.N.Yeltsin» (UrFU), Ekaterinburg, Russian FederationReferences1. Vogt C., Klunder G.L. Separation of metal ions by capillary electrophoresis–diversity, advantages, and drawbacks of detection methods. Fresen. J. Anal. Chem, 2001, vol. 370, no. 4, pp. 316-331. doi:10.1007/s002160100830.2. Timerbaev A.R. Strategies for selectivity control in capillary electrophoresis of metal species. J. Chrom. A, 1997, vol. 792, no. 1-2, pp. 495-518. doi: 10.1016/S0021-9673(97)00618-3.3. Chiari M. Enhancement of selectivity in capillary electrophoretic separations of metals and ligands through complex formation. J. Chrom. A, 1998, vol. 805, no. 1-2, pp. 1-15. doi: 10.1016/S0021-9673(98)00012-0.4. Fukushi K., Hiiro K. Determination of magnesium and calcium ions in seawater by capillary zone electrophoresis. Fresen. J. Anal. Chem., 1996, vol. 356, no. 2, pp. 150154. doi:10.1007/s0021663560150.5. Malik A.K., Seidel B.S., Faubel W. Capillary electrophoretic determination of ferric dimethyldithiocarbamate as iron(III) chelate of EDTA. J. Chrom. A, 1999, vol. 857, no. 1-2, pp. 365-368. doi:10.1016/S0021-9673(99)00789-X.6. Kubán P., Kubán P., Kubán V. Simultaneous capillary electrophoretic separation of small anions and cations after complexation with ethylenediaminetetraacetic acid. J. Chrom. A, 1999, vol. 836, no. 1, pp. 75-80. doi:10.1016/S0021-9673(98)00980-7.7. Chen Z., Naidu R. On-column complexation and simultaneous separation of vanadium(IV) and vanadium(V) by capillary electrophoresis with direct UV detection. Anal. Bioanal. Chem., 2002, vol. 374, no. 3, pp. 520-525. doi: 10.1007/s00216-002-1456-y.8. Baraj B., Martínez M., Sastre A., Aguilar M. Simultaneous determination of Cr(III), Fe(III), Cu(II) and Pb(II) as UV-absorbing EDTA complexes by capillary zone electrophoresis. J. Chrom. A, 1995, vol. 695, no. 1, pp. 103-111. doi: 10.1016/0021-9673(94)01078-S.9. Pozdniakova S., Padarauskas A. Speciation of metals in different oxidation states by capillary electrophoresis using pre-capillary complexation with complexones. Analyst, 1998, vol. 123, no. 7, pp. 1497-1500. doi: 10.1039/A800892B.10. Neudachina L.K., Lakiza N.V., Lebedeva E.L. [Electrophoretic determination of copper(II) ions content in waters after complexation with ethylenediaminetetraacetic acid]. Zavodskaia laboratoriia [Industrial Laboratory], 2011, vol. 77, no. 1, pp. 813(in Russian).11. Lebedeva E.L., Neudachina L.K. [Simultaneous determination of heavy metal ions by capillary zone electrophoresis]. Materialy II Vserossiiskoi konferentsii «Analiticheskaia khromatografiia i kapilliarnyi elektroforez» [Proc. II All-Russ. Conf. “Analytical chromatography and capillary electrophoresis”].Krasnodar, 2013, p. 58 (in Russian).12. Conradi S., Vogt C., Wittrisch H., Knobloch G., Werner G. Capillary electrophoretic separation of metal ions using complex forming equilibria of different stabilities. J. Chrom. A, 1996, vol. 745, no. 1–2, pp. 103–109. doi:10.1016/0021-9673(96)00268-3.13. HaumannI., Bächmann K. On-column chelation of metal ions in capillary zone electrophoresis. J. Chrom. A, 1995, vol. 717, no. 1-2, pp. 385-391. doi:10.1021/ac00002a017.14. Tsioupi D.A., Stefan-vanStaden R.-I., Kapnissi-Christodoulou C.P. Chiral selectors in CE: Recent developments and applications // Electrophoresis. 2013, vol. 34, no. 1, pp. 178-204. doi: 10.1002/elps.201370013.15. Kartsova L.A., Komarova N.V. [Influence of α- and β-cyclodextrins on the separation of positional isomers of benzoic acid nitro, amino, chloro, and hydroxy derivatives by capillary electrophoresis]. Zhurnal analiticheskoi khimii [Journal of Analytical chemistry]. 2003, vol. 58, no. 10, pp. 1085-1092 (in Russian).16. Shpigun O.A., Anan'eva I.A., Budanova N.Iu., Shapovalova E.N. [Use of cyclodextrins for separation of enantiomers]. Uspekhi khimii [Russian Chemical Reviews], 2003, vol. 72, no. 12, pp. 1167-1189 (in Russian).17. Cucinotta V., Contino A., Giuffrida A., Maccarrone G., MessinaM. Application of charged single isomer derivatives of cyclodextrins in capillary electrophoresis for chiral analysis. J. Chrom. A, 2010, vol. 1217, no. 7, pp. 953-967. doi:10.1016/j.chroma.2009.11.094.18. Kuhn R., Stoecklin F., Erni F. Chiral separations by host-guest complexation with cyclodextrin and crown ether in capillary zone electrophoresis. Chromatographia, 1992, vol. 33, no. 1-2, pp. 32-36. doi:10.1007/BF02276847.19. Kuwahara Y., Nagata H., Nishi H., Tanaka Y., Kakehi K. Detection and separation of free amino acid enantiomers by capillary electrophoresis with a chiral crown ether and indirect photometric detection. Chromatographia, 2005, vol. 62, no. 9-10, pp. 505510. doi 10.1365/s10337-005-0658-9.20. Threeprom J., Som-aum W., Lin J. Capillary electrophoresis for the simultaneous determination of metals by using ethylenediamine tetraacetic acid as complexing agent and vancomycin as complex selector. Chinese J. Chem, 2006, vol. 24, no. 12, pp. 1747-1753. doi: 10.1002/cjoc.20069032721. Threeprom J., Som-Aum W., Lin J.-M. Determination of Pb(II), Cu(II) and Fe(III) with capillary electrophoresis using ethylenediaminetetraacetic acid as a complexing agent and vancomycin as a complex selector. Anal. Sci., 2006, vol. 22, no. 9, pp. 1179-1184. doi:10.2116/analsci.22.1179.22. Świątek M., Valensin D., Migliorini C., Gaggelli E., Valensin G., Jeżowska-Bojczuk M. Unusual binding ability of vancomycin towards Cu2+ ions. Dalton T., 2005. no. 23, pp. 3808-3813. doi: 10.1039/b508662k.23. Kucharczyk M., Brzezowska M., Maciag A., Lis T., Jezowska-Bojczuk M. Structural features of the Cu(2+)-vancomycin complex. J. Inorg. Biochem., 2008, vol. 102, no. 4, pp. 936-942. doi:10.1016/j.jinorgbio.2007.12.014.24. Carnegie P.R., Synge R.L.M. Filter-Paper ionophoresis of cupric complexes of neutral amino acids and oligopeptides. Biochem. J., 1961, vol. 78, no. 4, pp. 692-696.25. Talukdar H., Rudra S., Kundu K.K. Thermodynamics of transfer of glycine, diglycine, and triglycine from water to aqueous solutions of urea, glycerol, and sodium nitrate. Can. J. Chem., 1988, vol. 66, no. 3, pp. 461-468. doi:10.1139/v88-080.26. Stiasny E., Scotti H. Das Säure- und Alkali-Bindungsvermögen von Peptiden // Ber. Dtsch. Chem. Ges. 1930, vol. 63, no. 11, pp. 2977-2983. doi: 10.1002/cber.19300631110.27. Toroz D., van Mourik T. Structure of the gas-phase glycine tripeptide. Phys. Chem. Chem. Phys., 2010, vol. 12, no. 14, pp. 3463–3473. doi:10.1039/b921897a.28. Dobbie H., Kermack W.O. Complex-formation between polypeptides and metals. 3. The reaction between cupric ions and diglycylglycine. Biochem. J., 1955, vol. 59, no. 2, pp. 257-264.29. Murphy C.B., Martell A.E. Metal chelates of glycine and glycine peptides. J. Biol. Chem., 1957, vol. 226, no. 1, pp. 037-050.30. Várnagy K., Szabó J., Sóvágó I., Malandrinos G., Hadjiliadis N., Sanna D., Micera G. Equilibrium and structural studies on copper(II) complexes of tetra-, penta- and hexa-peptides containing histidyl residues at the C-termini. J. Chem. Soc. Dalton., 2000. no. 4, pp. 467-472. doi: 10.1039/A907342F.31. The IUPAC Stability Constants Database, SC-Database and Mini-SCDatabase. Available at: http://www.acadsoft.co.uk/scdbase/scdbase.htm (accessed 17 June 2014).32. HySS2009. Hyperquad Simulation and Speciation. Available at: http://www.hyperquad.co.uk/hyss.htm (accessed 17 June 2014).33. Neudachina L.K., Lebedeva E.L., Kuznetsov A.O. [Application of capillary zone electrophoresis to the determination of copper in tea]. Khimiia rastitel'nogo syr'ia [Chemistry of plant raw material]. 2011, no 4, pp. 161-167 (in Russian).На основании анализа литературных данных выбрано соединение (диглицилглицин – ГГГ), способное повысить селективность разделения этилендиаминтетраацетатных комплексов ионов тяжелых металлов методом капиллярного зонного электрофореза (КЗЭ). Показано, что трипептид глицина, взаимодействуя с комплексами Ме-ЭДТА в капилляре, может выступать в роли комплекс-селектора.Влияние ГГГ на электрофоретическое разделение комплексов десяти металлов (Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II) и Bi(III)) исследовано в кислой среде, при отрицательной полярности источника напряжения, с использованием трех вариантов осуществления внутрикапиллярного комплексообразования. Добавление реагента в состав фосфатного ведущего электролита приводит к изменению собственных подвижностей комплексов Ме‑ЭДТА и позволяет отделить комплексы Cr(III) от Zn(II), а Ni(II) и Co(II) – от Cd(II) и Mn(II). Возможно селективное определение комплексов Fe(III) и Bi(III) в присутствии других переходных металлов.Разделение ионов тяжелых металлов при вводе отдельных зон комплексообразующих реагентов и пробы оказывается недостаточно селективным. При вводе отдельных зон ГГГ и комплексов Ме-ЭДТА достигается разделение комплексов Cu(II) и Pb(II). Таким образом, становится возможным одновременное определение ионов четырех металлов (Cu(II), Pb(II), Fe(III) и Bi(III)) при 260 нм.В оптимальных условиях анализа градуировочные графики линейны в диапазоне 5·10-6 ÷ 5·10‑3 моль/дм3, величины пределов обнаружения составляют от 0.05 мг/дм3 для Pb(II) до 0.72 мг/дм3 для Bi(III). Разработанный способ применен для анализа образцов отходов металлургического производства, печного шлака, сложного оксида, а также зеленого чая. Результаты анализа хорошо соотносятся с результатами, полученными методами атомно-абсорбционной и атомно-эмиссионной спектроскопии.Ключевые слова: капиллярный зонный электрофорез, медь, свинец, железо, висмут, ЭДТА, диглицилглицинDOI: http://dx.doi.org/10.15826/analitika.2014.18.4.013 ЛИТЕРАТУРА1. Vogt C., Klunder G.L. Separation of metal ions by capillary electrophoresis–diversity, advantages, and drawbacks of detection methods // Fresen. J. Anal. Chem. 2001. V. 370, № 4. P. 316-331.2. Timerbaev A.R. Strategies for selectivity control in capillary electrophoresis of metal species // J. Chrom. A. 1997. V. 792, № 12. P. 495-518.3. Chiari M. Enhancement of selectivity in capillary electrophoretic separations of metals and ligands through complex formation // J. Chrom. A. 1998. V. 805, № 1-2. P. 1-15.4. Fukushi K., Hiiro K. Determination of magnesium and calcium ions in seawater by capillary zone electrophoresis // Fresen. J. Anal. Chem. 1996. V. 356, № 2. P. 150-154.5. Malik A.K., Seidel B.S., Faubel W. Capillary electrophoretic determination of ferric dimethyldithiocarbamate as iron(III) chelate of EDTA // J. Chrom. A. 1999. V. 857, № 1-2. P. 365-368.6. Kubán P., Kubán P., Kubán V. Simultaneous capillary electrophoretic separation of small anions and cations after complexation with ethylenediaminetetraacetic acid // J. Chrom. A. 1999. V. 836, № 1. P. 75-80.7. Chen Z., Naidu R. On-column complexation and simultaneous separation of vanadium(IV) and vanadium(V) by capillary electrophoresis with direct UV detection // Anal. Bioanal. Chem. 2002. V. 374, № 3. P. 520-525.8. Simultaneous determination of Cr(III), Fe(III), Cu(II) and Pb(II) as UV-absorbing EDTA complexes by capillary zone electrophoresis / B. Baraj [et al.] // J. Chrom. A. 1995. V. 695, № 1. P. 103-111.9. Pozdniakova S., Padarauskas A. Speciation of metals in different oxidation states by capillary electrophoresis using pre-capillary complexation with complexones // Analyst. 1998. V. 123, № 7. P. 1497-1500.10. Неудачина Л.К., Лакиза Н.В., Лебедева Е.Л. Электрофоретическое определение содержания ионов меди(II) в водах после комплексообразования с этилендиаминтетрауксусной кислотой // Зав. лаб. 2011. Т. 77, № 1. С. 8-13.11. Лебедева Е.Л., Неудачина Л.К. Совместное определение ионов тяжёлых металлов методом капиллярного зонного электрофореза // Мат. II Всерос. конф. «Аналитическая хроматография и капиллярный электрофорез». Краснодар, 2013. С. 58.12. Capillary electrophoretic separation of metal ions using complex forming equilibria of different stabilities /S. Conradi[et al.] // J. Chrom. A. 1996. V. 745, № 1-2. P. 103-109.13.HaumannI., Bächmann K. On-column chelation of metal ions in capillary zone electrophoresis // J. Chrom. A. 1995. V. 717, № 1-2. P. 385-391.14. Tsioupi D.A., Stefan-vanStaden R.-I., Kapnissi-Christodoulou C.P. Chiral selectors in CE: Recent developments and applications // Electrophoresis. 2013. V. 34, № 1. P. 178-204.15. Карцова Л.А., Комарова Н.В. Влияние α- и β-циклодекстринов на разделение позиционных изомеров нитро-, амино-, хлор-, гидроксипроизводных бензойной кислоты с использованием капиллярного электрофореза // Журн. аналит. химии. 2003. V. 58, № 10. P. 1085-1092.16. Использование циклодекстринов для разделения энантиомеров / О.A. Шпигун [и др.] // Успехи химии. 2003. V. 72, № 12. P. 1167-1189.17. Application of charged single isomer derivatives of cyclodextrins in capillary electrophoresis for chiral analysis / V. Cucinotta [et al.] // J. Chrom. A. 2010. V. 1217, № 7. P. 953-967.18. Kuhn R., Stoecklin F., Erni F. Chiral separations by host-guest complexation with cyclodextrin and crown ether in capillary zone electrophoresis // Chromatographia. 1992. V. 33, № 1-2. P. 32-36.19. Detection and separation of free amino acid enantiomers by capillary electrophoresis with a chiral crown ether and indirect photometric detection / Y. Kuwahara [et al.] // Chromatographia. 2005. V. 62, № 9-10. P. 505-510.20. Threeprom J., Som-aum W., Lin J. Capillary electrophoresis for the simultaneous determination of metals by using ethylenediamine tetraacetic acid as complexing agent and vancomycin as complex selector // Chinese J. Chem. 2006. V. 24, № 12. P. 1747-1753.21. Threeprom J., Som-Aum W., Lin J.-M. Determination of Pb(II), Cu(II) and Fe(III) with capillary electrophoresis using ethylenediaminetetraacetic acid as a complexing agent and vancomycin as a complex selector // Anal. Sci. 2006. V. 22, № 9. P. 1179-1184.22. Unusual binding ability of vancomycin towards Cu2+ ions / M. Świątek [et al.] //DaltonT. 2005. № 23. P. 3808-3813.23. Structural features of the Cu(2+)-vancomycin complex / M. Kucharczyk [et al.] // J. Inorg. Biochem. 2008. V. 102, № 4. P. 936-942.24. Carnegie P.R., Synge R.L.M. Filter-Paper ionophoresis of cupric complexes of neutral amino acids and oligopeptides // Biochem. J. 1961. V. 78, № 4. P. 692-696.25. Talukdar H., Rudra S., Kundu K.K. Thermodynamics of transfer of glycine, diglycine, and triglycine from water to aqueous solutions of urea, glycerol, and sodium nitrate // Can. J. Chem. 1988. V. 66, № 3. P. 461-468.26. Stiasny E., Scotti H. Das Säure- und Alkali-Bindungsvermögen von Peptiden // Ber. Dtsch. Chem. Ges. 1930. V. 63, № 11. P. 2977-2983.27. Toroz D., van Mourik T. Structure of the gas-phase glycine tripeptide // Phys. Chem. Chem. Phys. 2010. V. 12, № 14. P. 3463-3473.28. Dobbie H., Kermack W.O. Complex-formation between polypeptides and metals. 3. The reaction between cupric ions and diglycylglycine // Biochem. J. 1955. V. 59, № 2. P. 257-264.29. Murphy C.B., Martell A.E. Metal chelates of glycine and glycine peptides // J. Biol. Chem. 1957. V. 226, № 1. P. 037-050.30. Equilibrium and structural studies on copper(II) complexes of tetra-, penta- and hexa-peptides containing histidyl residues at the C-termini / K. Várnagy [et al.] // J. Chem. Soc. Dalton. 2000. № 4. P. 467-472.31. The IUPAC Stability Constants Database, SC-Database and Mini-SCDatabase // Academic Software. [Электронный ресурс]: http://www.acadsoft.co.uk/scdbase/scdbase.htm (дата обращения: 17.06.2014)32. HySS2009. Hyperquad Simulation and Speciation // Protonic Software. [Электронный ресурс]: http://www.hyperquad.co.uk/hyss.htm (дата обращения: 17.06.2014)33. Неудачина Л.К., Лебедева Е.Л., Кузнецов А.О. Применение капиллярного зонного электрофореза для определения содержания меди в чае // Химия раст. сырья. 2011. № 4. С. 161-167.
Estudio y separación de diferentes mezclas enantioméricas mediante electroforesis capilar (CE) utilizando ciclodextrinas como selectores quirales
No full textLa separación de enantiómeros ha sido un constante problema para la química analítica debido a la similitud de los analitos, no obstante, son numerosos los ejemplos que establecen la importancia de lograr dicha resolución. Ante esto, el presente trabajo llevó a cabo la resolución de los enantiómeros del triptófano y de la duloxetina mediante electroforesis capilar utilizando como selectores quirales los oligosacáridos cíclicos conocidos como ciclodextrinas (α, β, γ). Partiendo de un buffer de H3PO4/NaH2PO4 0.1M a un pH 2.5, la optimización del método se realizó ajustando parámetros como el voltaje, la temperatura, el método de inyección y los parámetros de detección. Se establece que las condiciones óptimas para los enantiómeros L/D del triptófano son 9kv de corrida, 30°C, inyección electrocinética (7kv) y una detección a 220 nm. Utilizando la α-CD a una concentración de 4% se logra una máxima resolución de 3.64, obteniendo el enantiómero L con un menor tiempo de migración. Por otro lado, el método para la duloxetina solo cambia la inyección por hidrodinámica (50mmbar). La resolución del analito fue posible utilizando la HP-β-CD (7%), la cual fue previamente funcionalizada desde β-CD mediante una reacción de eterificación con oxido de propileno para aumentar su solubilidad. El estudio permitió una resolución suficiente de ambos analitos (>1.5) en tiempos cortos de análisis y se pudo corroborar la relevancia que tiene que el tamaño del analito y el selector escogido sean similares para que se propicien las interacciones necesarias para la separación.The separation of enantiomers has been a persistent problem for analytical chemistry due to the similarity of the analytes; however, numerous examples highlight the importance of achieving such resolution. Considering this, the present study carried out the resolution of the enantiomers of tryptophan and duloxetine through capillary electrophoresis, using cyclodextrins (α, β, γ) as chiral selectors. With a 0.1M NaH2PO4 buffer adjusted to pH 2.5 with 0.1M H3PO4, the optimization of the method was performed by adjusting parameters such as voltage, temperature, injection, and detection parameters. The optimal conditions for the L/D enantiomers of tryptophan were established to be a running voltage of 9 kV, temperature of 30°C, electrokinetic injection (7 kV), and detection at 220 nm. Using α-CD at a concentration of 4%, a maximum resolution of 3.64 was achieved, with the L-enantiomer exhibiting a shorter migration time. On the other hand, the method for duloxetine only changed the injection to hydrodynamic (50 mbar), and to achieve analyte separation, it was necessary to functionalize β-CD into HP-β-CD through an etherification reaction with propylene oxide to increase its solubility. With the mentioned conditions and the modified selector, a maximum resolution of 1.63 was obtained with 7% HP-β-CD. The study allowed for sufficient resolution of both analytes (>1.5) in short time and stated the relevance of the size of the analyte and the chosen selector that must be somewhat similar to promote the necessary interactions for separation.PregradoLaboratorio de técnicas analíticas avanzadas en productos naturales (LATNAP
Diplomacy of Discontent. Arms Control in Islamic Irans Foreign Policy.
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
