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The identification of tumor-related microRNAs(miRNAs)exhibits excellent promise for the early diag-nosis of cancer and other bioanalytical applications.Therefore,we developed a sensitive and efficient biosensor using polyadenine(polyA)-mediated fluorescent spherical nucleic acid(FSNA)for miRNA analysis based on strand displacement reactions on gold nanoparticle(AuNP)surfaces and electrokinetic signal amplification(ESA)on a microfluidic chip.In this FSNA,polyA-DNA biosensor was anchored on AuNP surfaces via intrinsic affinity between adenine and Au.The upright conformational polyA-DNA recognition block hybridized with 6-carboxyfluorescein-labeled reporter-DNA,resulting in fluores-cence quenching of FSNA probes induced by AuNP-based resonance energy transfer.Reporter DNA was replaced in the presence of target miRNA,leading to the recovery of reporter-DNA fluorescence.Sub-sequently,reporter-DNAs were accumulated and detected in the front of with Nafion membrane in the microchannel by ESA.Our method showed high selectivity and sensitivity with a limit of detection of 1.3 pM.This method could also be used to detect miRNA-21 in human serum and urine samples,with re-coveries of 104.0％-113.3％and 104.9％-108.0％,respectively.Furthermore,we constructed a chip with three parallel channels for the simultaneous detection of multiple tumor-related miRNAs(miRNA-21,miRNA-141,and miRNA-375),which increased the detection efficiency.Our universal method can be applied to other DNA/RNA analyses by altering recognition sequences.
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@#In this paper, micellar electrokinetic chromatography (MEKC) with glucose-β-cyclodextrin (Glu-β-CD) as chiral selector and ionic liquid surfactant N-butyl-N-methyl pyrrolidine lauryl sulfate ([C4MP] [C12SO4]) micelles formed at low pH as a pseudo stationary phase was applied for the chiral separation of four acidic drugs naproxen,warfarin, ketoprofen and ibuprofen.Under the same conditions,significantly improved separation of tested drug enantiomers was achieved with the MEKC system based on [C4MP][C12SO4] compared with the system based on the conventional surfactant sodium dodecyl sulfate (SDS).Several primary parameters affecting enantioseparation such as type and proportion of organic modifier, concentration and pH of the running buffer, concentration of chiral selector,concentration of ionic liquid surfactant and applied voltage were systematically investigated.
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The present study determined five saponins in Xuesaitong Dropping Pills(XDP) by micellar electrokinetic chromatography(MEKC), and evaluated between-batch consistency by MEKC fingerprints and similarity analysis. A background buffer was composed of 20 mmol·L~(-1) sodium tetraborate-20 mmol·L~(-1) boric acid solution(pH 8.5), 55 mmol·L~(-1) sodium dodecyl sulfate(SDS), 23 mmol·L~(-1) β-cyclodextrin, and 13% isopropyl alcohol. All separations were performed at 25 ℃,20 kV and the detection wavelength was set at 203 nm. The separation channel was a fused silica capillary with a dimension of 75 μm I.D. and a total length of 50.2 cm(effective length of 40.0 cm). The contents of notoginsenoside R_1, and ginsenosides Rg_1, Re, Rb_1, Rd were determined with their quality control ranges set. The fingerprints of XDP were established and the between-batch consistency was evaluated by similarity analysis. The contents of five saponins from the 19 batches of XDP were stable in the fixed ranges. Statistical analysis was carried out on the results of multiple batches of samples, and the specific quality control ranges were recommended as follows: notoginsenoside R_1 21.92-34.16 mg·g~(-1), ginsenosides Rg_1 83.54-131.78 mg·g~(-1), ginsenosides Re 13.58-19.82 mg·g~(-1), ginsenosides Rb_1 89.40-129.90 mg·g~(-1), and ginsenosides Rd 22.34-35.67 mg·g~(-1). Eleven characteristic peaks were identified in the fingerprints. Five peaks, notoginsenoside R_1 and ginsenosides Rg_1, Re, Rb_1, Rd, were identified with reference standards. The similarities of the 19 batches of samples were all above 0.988, indicating good between-batch consistency. This method is green and simple, and can be used for the quantitative determination and quality evaluation of XDP. It can also provide references for the quality control of other Chinese medicinal dripping pills.
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Cromatografía Capilar Electrocinética Micelar , Medicamentos Herbarios Chinos , Micelas , Control de Calidad , SaponinasRESUMEN
OBJECTIVE: To establish a method for analysis of related substances in biapenem with micellar electrokinetic capillary chromatography(MEKC). METHODS: In order to improve the separation selectivity, a zwitterionic surfactant, 3-(N, N-dimethylhexadecylammonium)-propanesulfonate(PAPS) was used. The optimal separation conditions were as follows: the total length of the capillary was 48.5 cm (the effective length was 48 cm), the buffer was 90 mmol•L-1 tris(hydroxymethyl)aminomethane (tris)-phosphate buffer containing 17 mmol•L-1 PAPS and 3 mg•mL-1 polyoxyethylene 23 lauryl ether (Brij 35), the applied voltage was 22 kV, and the capillary temperature was controlled at 30℃. Further more, the specificity, linearity, precision, repeatability, stability and durability were studied. The contents of related substances in biapenem commercial samples were analyzed. RESULTS: The MEKC method, which was a comparable analysis method to HPLC, successfully separated the adjacent impurities of biapenem by using the zwitterionic surfactant PAPS. The specific test showed that this method was especially suitable for the detection of biapenem dimers A, B and open-ring compound. CONCLUSION: In this method, MEKC with zwitterionic surfactant is for the first time applied to the analysis of related substances in biapenem (amphoteric drugs). It provides a feasible analysis method with high sensitivity, good specificity and reproducibility for the quality control of biapenem.
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OBJECTIVE@#To establish a micellar electrokinetic capillary chromatography-based method for identification and quantitative detection of interleukin-12 (IL-12) and analysis of its unfolding process.@*METHODS@#An uncoated fused-silica capillary (inner diameter 50 μm) with a total length of 48.5 cm (40 cm to the detector) was used for the experiment. The factors influencing the separation efficiency of IL-12 were analyzed, and a standard curve of IL-12 concentration was established. The mixture of IL-12 and anti-IL-12 antibody was incubated in a water bath at 38 ℃ for 40 min, and capillary electrophoresis was then performed under the same conditions. The results were compared with those of IL-12 and anti-IL-12 antibody to identify IL-12. IL-12 and dithiothreitol (DTT) were incubated at 60 ℃ in water bath for different lengths of times, and the unfolding process of IL-12 was analyzed based on electrophoresis results of IL-12 in different states.@*RESULTS@#A micellar capillary electrophoresis on-line sweep method was established with 80 mmol/L borate (pH=9.3) containing 30 mmol/L sodium dodecyl sulfate (SDS) as the buffer solution. This system showed a good linear relationship between the peak area and the mass concentration of IL-12 with a linear correlation coefficient of 0.9991 within the linear range of 2 to 120 ng/L. As the incubation time of IL-12 and DTT prolonged, the disulfide bond of IL-12 gradually opened and resulted in distinct changes in the protein peak.@*CONCLUSIONS@#This capillary electrophoresis-based method is simple and sensitive for IL-2 analysis and allows rapid detection of changes in IL-12 content in the setting of tumors and analysis of the possible causes.
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Estudos envolvendo os glicocorticoides merecem destaque devido a serem hormônios responsáveis pela transferência de informações e instruções às células, desta forma regulando o metabolismo, desenvolvimento, crescimento, função imune e também auxiliam no controle das funções tanto reprodutivas quanto tecidual. Estes também são sintetizados e amplamente utilizados com finalidade terapêutica processos alérgicos, tratamento de doenças autoimunes, em transplantes no pré-operatório e/ou pós-operatório-, devido a sua eficiente ação como imunossupressores e anti-inflamatórios. Os dois primeiros capítulos deste trabalho exibem uma revisão da literatura com foco em considerações gerais sobre os glicocorticoides, metodologias empregadas na análise destes hormônios e fundamentos da eletroforese capilar. Na sequência, o quarto capitulo, mostra a otimização da separação de 17 glicocorticoides utilizando cromatografia eletrocinética micelar devido a alto grau hidrofóbico dos analitos. Para tal, a composição do eletrólito consistiu em 20mM de tetraborato de sódio (pH=9.3) e 30 mM de dodecil sulfato de sódio (como surfactante), e a interação soluto-micela e, portanto, retenção do soluto, foi manipulada com a adição (volume/volume) de solventes orgânicos na composição de até 20% acetonitrila (ACN), 20% etanol (EtOH) e 1% tetrahidrofurano (THF), a qual se baseia num modelo de desenho de misturas (totalizando dez diferentes eletrólitos), e através desta abordagem um ótimo de separação foi obtido (13,3% EtOH, 3,3% ACN e 0,17% THF). A melhor condição de separação foi testada qualitativamente numa amostra de urina de um voluntário que faz uso contínuo de prednisona como terapia corticoidal. As misturas de solventes estudadas neste trabalho afetam a solubilidade dos hormônios na fase aquosa e a estrutura micelar também sofre grande impacto,principalmente na camada de solvatação. O quarto capítulo busca racionalizar tais efeitos através da obtenção de descritores, e as informações contidas nos descritores hidrofóbicos e hidrofílicos são sempre relevantes e contribuem nas correlações encontradas. Obteve três grupos de comportamento distinto, onde a capacidade doadora e aceptora de prótons para a realização de ligações de hidrogênios foram as interações consideradas as mais relevantes para o comportamento observado da separação. E o capítulo final, apresenta possibilidades de aproveitamento no controle de qualidade na indústria farmacêutica, métodos baseados na injeção e tensão inversas foram propostos a fim de ganho de tempo de análise (máximo de 5 minutos), estes foram validados seguindo o protocolo preconizado pela ANVISA (Agência Nacional de Vigilância Sanitária) nos parâmetros: precisão, exatidão, seletividade, linearidade, limites de detecção e quantificação e robustez; e aplicados na quantificação de quatro (diferentes formulações comerciais contendo glicocorticoides (prednisona 20 mg, betametasona 4 mg, furoato de mometasona 200 mcg e dipropionato de beclometasona 200 mcg)
Studies involving glucocorticoids deserve to be highlighted because they are hormones responsible for the transfer of information and instructions to cells, thus regulating metabolism, development, growth, immune function and also assist in the control of both reproductive and tissue functions. These are also synthesized and widely used for therapeutic purposes - allergic processes, treatment of autoimmune diseases, in preoperative and/or postoperative transplants - due to their efficient action as immunosuppressants and anti-inflammatories. The first two chapters of this paper present a review of the literature focusing on general considerations about glucocorticoids, methodologies used in the analysis of these hormones and fundamentals of capillary electrophoresis. Subsequently, the fourth chapter shows the optimization of the separation of 17 glucocorticoids using micellar electrokinetic chromatography due to the high hydrophobic degree of the analytes. To this end, the electrolyte composition consisted of 20 mM sodium tetraborate (pH = 9.3) and 30 mM sodium dodecyl sulfate (as a surfactant), and the solute-micelle interaction and therefore solute retention was manipulated with organic solvent in the composition of up to 20% acetonitrile (ACN), 20% ethanol (EtOH) and 1% tetrahydrofuran (THF), which is based on a mixture design model (totaling ten different electrolytes), and through this approach an optimal separation was obtained (13.3% EtOH, 3.3% ACN and 0.17% THF). The best separation condition was qualitatively tested in a urine sample from a volunteer who makes continuous use of prednisone as corticosteroid therapy. The solvent mixtures studied in this work affect the solubility of the hormones in the aqueous phase and the micellar structure also has a great impact, especially on the solvation layer. The fourth chapter seeks to rationalize these effects by obtainingdescriptors, and the information contained in the hydrophobic and hydrophilic descriptors is always relevant and contributes to the correlations found. It obtained three groups of distinct behavior, where the donor and acceptor capacity of protons for the realization of hydrogen bonds were the interactions considered the most relevant for the observed behavior of the separation. And the final chapter presents possibilities of use in quality control in the pharmaceutical industry, methods based on injection and reverse voltage were proposed in order to gain analysis time (maximum of 5 minutes), these were validated following the protocol recommended by ANVISA (Brazilian National Agency of Sanitary Surveillance) in the parameters: precision, accuracy, selectivity, linearity, limits of detection and quantification and robustness; and applied in the quantification of four different commercial formulations containing glucocorticoids (prednisone 20 mg, betamethasone 4 mg, mometasone furoate 200 mcg and beclomethasone dipropionate 200 mcg)
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Electroforesis Capilar , Composición de Medicamentos , Glucocorticoides/análisis , Esteroides , Cromatografía Capilar Electrocinética Micelar/métodosRESUMEN
Some new types of microemulsion using phospholipids as the main surfactant were prepared for electrokinetic chromatography and the quantitative structure-retention relationship of neutral solutes in these microemulsion electrokinetic chromatography (MEEKC) systems was studied by solvation parameters model.By using dynamic coating capillary, and with dimethyl sulfoxide (DMSO) and dodecyl benzene as the marker of electroosmotic flow and microemulsion droplets, a total of 17 kinds of stable microemulsions containing soybean phospholipids or other surfactants were prepared and the linear salvation energy relationship equations were developed for these MEEKC systems with 26 small neutral compounds.The coefficients of linear solvation energy relationship (LSER) equations were used to evaluate the similarity of two MEEKC systems.Results indicated that LSER characteristics of phospholipids-MEEKC systems were similar to those of other microemulsion systems.The volume and hydrogen bond basicity of solutes were mostly contributed to the retention in MEEKC.The different types and concentration of oil phase had no evident influence on the retention.
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Objective To establish a micellar electrokinetic capillary chromatography method for content determination of geniposide in Biyuanshu Oral Liquid. Methods Acetaminophen was used as an internal standard, and the separation was performed on an uncoated fused silica capillary of 52 cm × 50 μm ID (42 cm effective length) with the separation voltage of 25.0 kV. The running buffer contained 50 mmol/L borax, 100 mmol/L sodium dodecyl sulfate and 15％ acetonitrile (pH=10). The sample was injected by pressure (10 s, 0.5 psi) and detected at 238 nm. Results Geniposide was in good linearity range of 15.02–320.48 μg/mL (r=0.9995). The repeatability (low, medium and high concentration of samples) and intermediate precision assays gave satisfactory RSD values of less than 1.77％and 2.01％, respectively. The average recovery of geniposide in Biyuanshu Oral Liquid was 97.50％ and the RSD was 4.43％. The contents of geniposide determined by micellar electrokinetic capillary chromatography were in accordance with the results of HPLC analysis. Conclusion The method is simple, fast, accurate and precise, which can be used for the content determination of geniposide in Biyuanshu Oral Liquid.
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Abstract A rapid and sensitive micellar electrokinetic capillary chromatography method with UV photodiode-array detection was developed for the simultaneous determination of atorvastatin and ezetimibe in fixed dose drug combination. Experimental conditions such as buffer concentration and pH, surfactant concentration, system temperature, applied voltage, injection parameters were optimized in order to improve the efficiency of the separation. The best results were obtained when using fused silica capillary (48 cm length X 50 µm ID) and 25 mM borate buffer electrolyte at pH 9.3 containing 25 mM SDS, + 30 kV applied voltage, 20 ºC system temperature. The separation was achieved in approximately 2 minutes, with a resolution of 7.02, the order of migration being atorvastatin followed by ezetimibe. The analytical performance of the method was verified with regard to linearity, precision, robustness and the limit of detection and quantification were calculated.
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Cromatografía Capilar Electrocinética Micelar/métodos , Ezetimiba/administración & dosificación , Atorvastatina/administración & dosificación , Preparaciones Farmacéuticas/análisis , Fraccionamiento de la Dosis de RadiaciónRESUMEN
Objective: To establish a rapid method for detecting acetylbritannilactone (ABL) by online sweeping-micellar electrokinetic chromatography (MEKC) and to elevate the sensitivity of the detection. Methods: The combination of online sweeping technique with MEKC was used to determine the content of ABL in the extract of Inula britannica in plasma of rats. Results: ABL was completely separated within 15 min in running buffer and sample buffer. The optimal conditions were as follows: on uncoated fused quartz silica capillary, with separation voltage of 23 kV, capillary temperature of 25 °C, and detection wavelength of 195 nm. The regression equations revealed good linear relationships between the peak area and concentration of ABL (r = 0.998), with the detection limits of 0.005-0.15 mg/mL. The relative standard deviations of migration time and peak areas for intra- and inter-batch were < 2.45% and < 2.26%, respectively. The recovery rate of this method was 96.3%-97.2%. Conclusion: This method provides some advantages in separation speed, testing sensitivity, and operating convenience, with low sample and reagent consumption. The online sweeping-MEKC is an effective method for pharmacokinetic study and analysis on tracing biological samples. © 2014 Tianjin Press of Chinese Herbal Medicines.
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Bioanalytical methods are widely used for quantitative estimation of drugs and their metabolites in physiological matrices. These methods could be applied to studies in areas of human clinical pharma-cology and toxicology. The major bioanalytical services are method development, method validation and sample analysis (method application). Various methods such as GC, LC-MS/MS, HPLC, HPTLC, micellar electrokinetic chromatography, and UFLC have been used in laboratories for the qualitative and quan-titative analysis of carbamazepine in biological samples throughout all phases of clinical research and quality control. The article incorporates various reported methods developed to help analysts in choosing crucial parameters for new method development of carbamazepine and its derivatives and also enu-merates metabolites, and impurities reported so far.
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A sensitive analytical method based on reversed microemulsion electrokinetic chromatography ( MEEKC) combined with on_line preconcentration technique was developed for the determination of polycyclic aromatic hydrocarbons ( PAHs ) in cosmetics. For six lipophilic PAHs analytes which are difficult to be separated under conventional conditions, three stacking techniques including large volume sample stacking ( LVSS) , dynamic pH junction and sweeping ( LVSS_DypH_sweep ) were combined to realize the efficient preconcentration and separation. Under the optimum conditions, including the microemulsion buffer with the composition of 2. 4%(w/w)SDS_0. 6% (w/w) octane_6. 6% (w/w)n_butyl alcohol_20 mmol/L NaH2PO4 ( pH 2 . 2 ) , HCB injection time of 20 s ( 16 kPa ) and sample injection time of 80 s ( 16 kPa ) , good enrichment effect was reached with the enrichment factors ranged from 25 to 80 , and the PAHs were analyzed successfully within 27 min. The developed method was used to analyze the PAHs in cosmetics. The recoveries ranged from 90 . 6% to 95 . 9%. The RSD values ( n=5 ) were less than 5 . 1%.
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A rigorous microscale electrokinetic model for hydrogel-colloid composites is adopted to compute macroscale profiles of electrolyte concentration, electrostatic potential, and hydrostatic pressure across membranes that separate electrolytes with different concentrations. The membranes are uncharged polymeric hydrogels in which charged spherical colloidal particles are immobilized and randomly dispersed with a low solid volume fraction. Bulk membrane characteristics and performance are calculated from a continuum microscale electrokinetic model (Hill 2006b, c). The computations undertaken in this paper quantify the streaming and membrane potentials. For the membrane potential, increasing the volume fraction of negatively charged inclusions decreases the differential electrostatic potential across the membrane under conditions where there is zero convective flow and zero electrical current. With low electrolyte concentration and highly charged nanoparticles, the membrane potential is very sensitive to the particle volume fraction. Accordingly, the membrane potential - and changes brought about by the inclusion size, charge and concentration - could be a useful experimental diagnostic to complement more recent applications of the microscale electrokinetic model for electrical microrheology and electroacoustics (Hill and Ostoja-Starzewski 2008, Wang and Hill 2008).
Um modelo eletrocinético rigoroso para compósitos formados por um hidrogel e um colóide é adotado para computar os perfis macroscópicos de concentração eletrolítica, potencial eletrostático e pressão hidrostática através de uma membrana que separa soluções com diferentes concentrações eletrolíticas. A membrana é composta por um hidrogel polimérico sem carga elétrica onde partículas esféricas são imobilizadas e dispersas aleatoriamente com baixa fração de volume do sólido. As características da membrana e a sua performance são calculadas a partir de um modelo eletrocinético de contínuo microscópico (Hill 2006b, c). As computações realizadas neste artigo quantificam os potenciais de corrente e de membrana. Para o potencial de membrana, aumentando a fração de volume das inclusões carregadas negativamente diminui o diferencial do potencial eletrostático através da membrana sob condições de fluxo convectivo e corrente elétrica nulos. Para concentrações eletrolíticas baixas o potencial de membrana torna-se muito sensível à fração de volume das partículas. De maneira similar, o potencial de membrana e as cargas elétricas trazidos pelo tamanho da inclusão, carga e concentração podem prover um diagnóstico experimental útil para complementar aplicações mais recentes do modelo eletrocinético microscópico em eletroacústica e eletro-micro-reologia (Hill and Ostoja-Starzewski 2008, Wang and Hill 2008).
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The porochemoelectroelastic analytical models and solutions have been used to describe the response of chemically active and electrically charged saturated porous media such as clays, shales, and biological tissues. However, these attempts have been restricted to one-dimensional consolidation problems, which are very limited in practice and not general enough to serve as benchmark solutions for numerical validation. This work summarizes the general linear porochemoelectroelastic formulation and presents the solution of an inclined wellbore drilled in a fluid-saturated chemically active and ionized formation, such as shale, and subjected to a three-dimensional in-situ state of stress. The analytical solution to this geometry incorporates the coupled solid deformation and simultaneous fluid/ion flows induced by the combined influences of pore pressure, chemical potential, and electrical potential gradients under isothermal conditions. The formation pore fluid is modeled as an electrolyte solution comprised of a solvent and one type of dissolved cation and anion. The analytical approach also integrates into the solution the quantitative use of the cation exchange capacity (CEC) commonly obtained from laboratory measurements on shale samples. The results for stresses and pore pressure distributions due to the coupled electrochemical effects are illustrated and plotted in the vicinity of the inclined wellbore and compared with the classical porochemoelastic and poroelastic solutions.
Modelos analíticos poroelásticos incluindo acoplamento químico e elétrico e soluções têm sido utilizados paradescrever a resposta de meios porosos saturados ativos química e eletricamente tais como argilas, folhelhos e tecidos biológicos. Entretanto tais tentativas têm sido restritas a problemas de consolidação unidimensional os quais exibem limitações na prática não constituindo exemplos realistas para validação de soluções numéricas. Este trabalho apresenta formulações gerais dos modelos poroelásticos lineares incluindo acoplamento químico e elétrico e apresenta a solução de um problema de estabilidade de um poço perfurado através de uma formação saturada quimicamente ativa e ionizada tal como um folhelho submetido a um estado tridimensional de tensão. A solução analítica para esta geometria incorpora o acoplamento entre a deformação do sólido e o fluxo simultâneo de fluido e íons induzido pelos gradientes de poro pressão, potencial químico e potencial elétrico sob condições isotérmicas. O fluido residente na formação é modelado como uma solução eletrolítica composta de um solvente e cátions e anions dissolvidos. A abordagem analítica integra na solução o uso quantitativo da capacidade de troca catiônica (CTC) comumente obtida por medidas experimentais em amostras de folhelhos. Os resultados obtidos para as distribuições de tensões e poro pressão devido ao acoplamento eletroquímico são ilustrados e plotados na vizinhança do poço inclinado e comparados com as soluções clássicas poroelásticas com acoplamento químico.
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The preparation of electrophoretic microcolumn and its application to the electrophoretic separation of amino acids with a 2-mm I.D. fused-silica microcolumn packed with uniform quartz microncrystal prepared by hydrothermal synthesis are reported. With 1.5 mmol/L disodium phosphate buffer solution (pH 11.5) containing 30% (V/V) methanol, the tryptophan, phenylalanine and tyrosine were separated by the microcolumn electrophoresis and detected by an UV spectrophotometer without derivatization. The limits of detection were 0.038, 0.21 and 0.20 mol/L, respectively. The separation efficiency of tryptophan was 4.4×104 plates/m. The sample capacity of the electrophoretic microcolumn achieved 35 μL. The precisions of the microcolumn electrophoresis were satisfactory. The thermal effects of the electrophoretic microcolumn that without packing, packed with 360 μm quartz sand and with 9 μm length quartz microncrystal were discussed, respectively. It was found that the electrophoretic microcolumn packed with quartz microncrystal was able to inhibit Joule heat, increase sample capacity and enhance detection sensitivity. The microcolumn electrophoresis is one of the high-performance separation techniques for an in-situ, real-time and portable electrokinetic flow analysis system.
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OBJECTIVE:To develop a simple micellar electrokinetic capillary chromatography for determination of theophylline concentration in human plasma. METHODS: The determination of plasma sample(without any pretreatment) was performed on un-coated fused-silica capillaries (at an effective length of 21 cm) in which the cathodic buffer solution (solution A) was 15 mmol?L-1 borax(pH=10) and the running buffer solution(solution B) was sodium dodecyl sufate (SDS)(200 mmol?L-1) -contained solution A. The sample was injected into capillary by pressure with separation voltage of 12 kV;the UV detection wavelength was set at 280 nm;quantitation was performed by external standard peak area method. RESULTS: The average determination time of each sample was 11 min;the linear range of theophylline was 1.25～40 ?g?mL-1 with its lowest detectable limit at 0.5 ?g?mL-1;the average methodological recovery was 90.33%(RSD=2.51%);the intra-day RSD was 2.34%～3.36% and the inter-day RSD was 2.03%～6.51%,respectively. CONCLUSION: The developed method is simple,rapid and sensitive and it is applicable for the therapeutic drug monitoring of theophylline.
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OBJECTIVE: A micellar electrokinetic capillary chromatography(MECC) method was established for determination of benzoic acid and salicylic acid in Zuguang san.METHODS: An uncoated silica capillary(75 ?m?55 cm,effective length 47 cm) was used with 20 mmol?L-1 borate-30 mmol?L-1 SDS-4% methanol(pH 9.8) as the running buffer solution.The internal standard was antiscorbic acid.The detection wavelength was set at 250 nm.RESULTS:The calibration curves were linear in the range of 120～320 ?g?mL-1 for benzoic acid(r=0.999 8) and 80～320 ?g?mL-1(r=0.999 5) for salicylic acid.The average recoveries were 98.37% and 100.69%,respectively and the RSD were 4.47%(n=9) and 1.61%(n=9),respectively.CONCLUSION: MECC method was proved to be simple,sensitive and reproducible with high recovery rate and it is applicable for the determination of the contents of benzoic acid and salicylic acid in Zuguang san.
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Neste trabalho são apresentados os resultados preliminares da avaliação de técnica eletroquímica na remoção de compostos orgânicos em água, em escala laboratorial. Cela eletroquímica simples foi construída para os testes e uma metodologia básica foi empregada. O método consiste em provocar a migração de espécies polares ou ionizadas em direção ao eletrodo de carga oposta. Fenol e o herbicida atrazina foram os contaminantes avaliados. Os ensaios foram realizados em função do tempo de aplicação de carga, acompanhada a evolução do pH entre os eletrodos e as concentrações relativas avaliadas por medidas de absorbância na região do ultra-violeta. Os melhores resultados foram conseguidos para operações acima de 30 minutos, indicando migração proporcional a 62% para o fenol, mas inferior a 30% para a atrazina.
In this work the preliminary results of a lab scale evaluation of electrokinetic technique for the removal of organic contaminants in water are presented. A simple cell was constructed and a basic methodology was followed. The method consists in provoke the migration of ionized or polar specimens solved in aqueous solution in direction of the opposite charged electrode. Phenol (C6H5OH) and herbicide atrazine (6-chlorine-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4 diamine), was chosen as standard contaminants. The testes were performed in function of charge application time, mapping the pH between electrodes and the concentration assessed by absorbance measurements in ultra-violet region. The best results were attained after 30 minutes operation, showing migration proportional to 62% for phenol, but inferior to 30% atrazine.
RESUMEN
Resumen. El envenenamiento por escorpiones es un problema de salud pública en la zona suroccidental de Venezuela. El Tityus zulianus es uno de los escorpiones que causa, especialmente en niños, edema pulmonar e insuficiencia cardíaca que pueden ser fatales y que se han atribuido en parte a una gran descarga simpática. La administración intraperitoneal de (20 µg/g peso) de veneno del T. zulianus a ratones anestesiados durante microdiálisis subcutánea provocó aumento de secreciones, dificultad respiratoria, convulsiones y muerte entre 30 min a 2 h. En los dializados recolectados antes y después de recibir el veneno, se analizaron 7 aminoácidos por electroforesis capilar con detección mediante fluorescencia inducida por láser (EC-DFIL). Se encontró un aumento en arginina (39%), fenilalanina (40%) y glutamato (94%), sin cambios en valina, serina y aspartato, en los animales que recibieron veneno con respecto a sus valores pretratamiento. Estos cambios porcentuales fueron significativos al comparar veneno vs. vehículo después de la inyección; y antes vs. después de recibir el veneno. Para este momento no hay una explicación clara del significado de estos aumentos de aminoácidos específicos. Se requieren nuevos estudios para conocer si estos cambios bioquímicos tienen o no una relación con los mecanismos de acción molecular del veneno o algunos de sus componentes y/o con las manifestaciones clínicas. De acuerdo con la literatura revisada, este es el primer reporte de la combinación de microdiálisis subcutánea y EC-DFIL en el estudio in vivo del emponzoñamiento por escorpiones en ratones.
Abstract. Scorpion human envenoming is a public health hazard in the southwest of Venezuela. Tityus zulianus is one of the scorpion species whose venom causes lung edema and cardiac failure in children. These occasionally deadly manifestations have been attributed to a massive sympathetic discharge. The intraperitoneal administration of T. zulianus venom (20 µg/g mouse) to anesthetized mice during subcutaneous microdialysis caused increased secretions, dyspnea, seizures and death between 30 min to 2 h. Seven amino acids were analyzed by capillary electrophoresis with laser induced fluorescence detection (CE-LIFD) in the collected samples before and after the venom administration. We found an increase of arginine (39%), phenylalanine (40%) and glutamate (94%), with no changes in valine, serine and aspartate, changes were significant when the injection of venom and vehicle were compared and before vs after venom injection. Further investigation is needed to know if the observed changes could be related to the molecular mechanisms of the venom or some of its components and therefore with the envenoming symptoms. To our knowledge, this is the first report with subcutaneous microdialysis and CE-LIFD coupling in scorpion envenomation studies in vivo, in mice.
Asunto(s)
Animales , Masculino , Ratones , Aminoácidos/biosíntesis , Venenos de Escorpión/administración & dosificación , Aminoácidos/análisis , Electroforesis Capilar , Inyecciones Intraperitoneales , Microdiálisis/métodos , PielRESUMEN
This article reviewed the feature and the advances in the application of micellar electrokinetic capillary chromatography(MECC),an important mean of high performance capillary electrophoresis(HPCE),for the analysis of complicated component of medicine,.The analysis of multi-component of routine medicine,chiral drugs,illicit drugs,Chinese medicine,drug and its metabolites were introduced.