Journal of Analytical Methods in Chemistry http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Quantitative Determination of Lercanidipine Enantiomers in Commercial Formulations by Capillary Electrophoresis Mon, 02 Mar 2015 13:59:05 +0000 http://www.hindawi.com/journals/jamc/2015/294270/ An enantioselective method based on capillary electrophoresis (CE) using cyclodextrin (CD) as chiral selector was developed and validated for determination of lercanidipine (LER) enantiomers, a drug calcium channel blocker which exerts antihypertensive effects of long duration, in a pharmaceutical formulation. Optimum separation of LER enantiomers was obtained on a 50 cm × 50 μm id capillary using a sodium acetate buffer solution 200 mmol/L pH 4.0 containing 10 mmol/L of 2,3,6-o-methyl-β-cyclodextrin (TM-β-CD) as background electrolyte. The capillary temperature and voltage were 15°C and 25 kV, respectively, hydrodynamic injection and detection at 237 nm. Linearity was obtained in the range 12.5–100 μg/mL for both enantiomers (). The RSD (%) and relative errors (, %) obtained in precision and accuracy studies (intraday and interday) were lower than 5%. After validation, the method was applied to quantify the enantiomers of LER in commercial tablets and the results were satisfactory in terms of accuracy and precision, both less than 5%. Therefore, this method was found to be appropriate for enantioselective quality control of LER enantiomers in pharmaceutical formulations. Luciana Pereira Lourenço, Fernando Armani Aguiar, Anderson Rodrigo Moraes de Oliveira, and Cristiane Masetto de Gaitani Copyright © 2015 Luciana Pereira Lourenço et al. All rights reserved. Robust PLS Prediction Model for Saikosaponin A in Bupleurum chinense DC. Coupled with Granularity-Hybrid Calibration Set Mon, 02 Mar 2015 11:48:05 +0000 http://www.hindawi.com/journals/jamc/2015/583841/ This study demonstrated particle size effect on the measurement of saikosaponin A in Bupleurum chinense DC. by near infrared reflectance (NIR) spectroscopy. Four types of granularity were prepared including powder samples passed through 40-mesh, 65-mesh, 80-mesh, and 100-mesh sieve. Effects of granularity on NIR spectra were investigated, which showed to be wavelength dependent. NIR intensity was proportional to particle size in the first combination-overtone and combination region. Local partial least squares model was constructed separately for every kind of samples, and data-preprocessing techniques were performed to optimize calibration model. The 65-mesh model exhibited the best prediction ability with root mean of square error of prediction (RMSEP) = 0.492 mg·g−1, correlation coefficient , and relative predictive determinant (RPD) = 2.58. Furthermore, a granularity-hybrid calibration model was developed by incorporating granularity variation. Granularity-hybrid model showed better performance than local model. The model performance with 65-mesh samples was still the most accurate with RMSEP = 0.481 mg·g−1, , and RPD = 2.64. All the results presented the guidance for construction of a robust model coupled with granularity-hybrid calibration set. Zhisheng Wu, Min Du, Xinyuan Shi, Bing Xu, and Yanjiang Qiao Copyright © 2015 Zhisheng Wu et al. All rights reserved. Discrimination and Content Analysis of Fritillaria Using Near Infrared Spectroscopy Wed, 18 Feb 2015 06:42:28 +0000 http://www.hindawi.com/journals/jamc/2015/752162/ Fritillaria is a traditional Chinese herbal medicine which can be used to moisten the lungs. The objective of this study is to develop simple, accurate, and solvent-free methods to discriminate and quantify Fritillaria herbs from seven different origins. Near infrared spectroscopy (NIRS) methods are established for the rapid discrimination of seven different Fritillaria samples and quantitative analysis of their total alkaloids. The scaling to first range method and the partial least square (PLS) method are used for the establishment of qualitative and quantitative analysis models. As a result of evaluation for the qualitative NIR model, the selectivity values between groups are always above 2, and the mistaken judgment rate of fifteen samples in prediction sets was zero. This means that the NIR model can be used to distinguish different species of Fritillaria herbs. The established quantitative NIR model can accurately predict the content of total alkaloids from Fritillaria samples. Yu Meng, Shisheng Wang, Rui Cai, Bohai Jiang, and Weijie Zhao Copyright © 2015 Yu Meng et al. All rights reserved. Phytochemical Analysis and Anti-Inflammatory Activity of the Extracts of the African Medicinal Plant Ximenia caffra Tue, 17 Feb 2015 14:25:02 +0000 http://www.hindawi.com/journals/jamc/2015/948262/ A method was developed for identification and quantification of polyphenols in the leaves of Ximenia caffra using HPLC/UV/MS. Based on analyzing the MS and UV data and in comparison to the authentic standards, a total of 10 polyphenols were identified and quantified, including gallic acid, catechin, quercetin, kaempferol, and their derivatives. The total content of these compounds was found to be approximately 19.45 mg/g in the leaf and the most abundant is quercetin-rutinoside (9.08 mg/g). The total phenolic content as measured by Folin-Ciocalteu assay was 261.87 ± 7.11 mg GAE/g and the total antioxidant capacity as measured in vitro was 1.46 ± 0.01 mmol Trolox/g. The antiproliferative effect of the leaf extract was measured by MTS assay with IC50 value of 239.0 ± 44.5 μg/mL. Cell-based assays show that the leaf extract inhibits the mRNA expression of proinflammatory genes (IL-6, iNOS, and TNF-α) by using RT-qPCR, implying its anti-inflammatory effects. It was further demonstrated that the underlying therapeutic mechanism involves the suppression of NF-κB, a shared pathway between cell death and inflammation. Jing Zhen, Yue Guo, Tom Villani, Steve Carr, Thomas Brendler, Davis R. Mumbengegwi, Ah-Ng Tony Kong, James E. Simon, and Qingli Wu Copyright © 2015 Jing Zhen et al. All rights reserved. Electrochemical Studies for Cation Recognition with Diazo-Coupled Calix[4]arenes Tue, 17 Feb 2015 11:19:42 +0000 http://www.hindawi.com/journals/jamc/2015/579463/ The electrochemical properties of diazophenylcalix[4]arenes bearing ortho-carboxyl group (o-CAC) and ortho-ester group (o-EAC), respectively, in the presence of various metal ions were investigated by voltammetry in CH3CN. o-CAC and o-EAC showed voltammetric changes toward divalent metal ions and no significant changes with monovalent alkali metal ions. However, o-CAC preferentially binds with alkaline earth and transition metal ions, whereas no significant changes in voltammetric signals are observed in o-EAC with alkaline earth metal ions. o-EAC only binds with other transition metal ions. This can be explained on metal ion complexation-induced release of proton from the azophenol to the quinone-hydrazone tautomer followed by internal complexation of the metal ion with aid of nitrogen atoms and ortho-carbonyl groups in the diazophenylazocalix[4]arenes. Bongsu Kim and Tae Hyun Kim Copyright © 2015 Bongsu Kim and Tae Hyun Kim. All rights reserved. Fast HPLC-MS/MS Method for Determining Penicillin Antibiotics in Infant Formulas Using Molecularly Imprinted Solid-Phase Extraction Mon, 16 Feb 2015 11:36:47 +0000 http://www.hindawi.com/journals/jamc/2015/959675/ The dairy cattle may suffer from different infections relatively often, but the inflammation of the mammary gland is very important to the farmer. These infections are frequently treated with penicillin antimicrobial drugs. However, their use may result in the presence of residues in animal products, such as milk powder and/or infant formulas, and it represents a potential risk for consumers. To monitor this, the EU has defined safe maximum residue limits (MRLs) through Commission Regulation (EU) number 37/2010. Although LC-MS is a trustful option for confirmation and quantification of antibiotics, the analysis of real samples with complex matrices frequently implies previous clean-up steps. In this work, precipitation polymerization has been used and different molecularly imprinted polymer (MIP) sorbents were tested and optimized for the fast and simultaneous solid-phase extraction (MISPE) of eight common penicillins (ampicillin, amoxicillin, oxacillin, penicillin G, penicillin V, cloxacillin, dicloxacillin, and nafcillin). The extracts were analyzed using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) and the applicability of these polymers as sorbents for the extraction of penicillins at MRL levels in milk powder (infant formulas) was proved. The limits of detection and quantification were below the legal tolerances, except for LOQ for oxacillin and cloxacillin. Mónica Díaz-Bao, Rocío Barreiro, José Manuel Miranda, Alberto Cepeda, and Patricia Regal Copyright © 2015 Mónica Díaz-Bao et al. All rights reserved. Determination of Matrine in Rat Plasma after Oral Administration of Novel Korean Herbal Medicine KIOM-MA128 and Application of PK Mon, 16 Feb 2015 10:00:41 +0000 http://www.hindawi.com/journals/jamc/2015/431632/ KIOM-MA128 is a novel Korean herbal medicine with antiatopic, anti-inflammatory, and antiasthmatic effects. Matrine is thought to be a potential chemical marker of KIOM-MA128, but pharmacokinetic studies on KIOM-MA128 had not been performed. This study describes a simple and rapid method using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to determine the concentration of matrine in rats plasma after administration of KIOM-MA128. The isocratic mobile phase consisted of methanol and distilled water, and the flow rate was 0.15 mL/min. The accuracy and precision of the assay, as well as stability tests, were performed in accordance with FDA regulations for the validation of bioanalytical methods. The half-life and of matrine after administration of KIOM-MA128 were 4.29 ± 2.20 h and 1.8 ± 1.23 h, respectively. and of matrine after administration of KIOM-MA128 at 4 g/kg and 8 g/kg were 595.10 ± 182.91 ng/mL, 5336.77 ± 1503.84 ng/mL·h and 850.46 ± 120 ng/mL, 9583.10 ± 888.92 ng/mL·h, respectively. The validated method was successfully applied to a pharmacokinetic study in rats after oral administration of KIOM-MA128. Hyun-moon Back, Byungjeong Song, Jung-woo Chae, Hwi-yeol Yun, Jin Yeul Ma, and Kwang-il Kwon Copyright © 2015 Hyun-moon Back et al. All rights reserved. Chemical Composition and Seasonality of Aromatic Mediterranean Plant Species by NMR-Based Metabolomics Mon, 16 Feb 2015 09:26:51 +0000 http://www.hindawi.com/journals/jamc/2015/258570/ An NMR-based metabolomic approach has been applied to analyse seven aromatic Mediterranean plant species used in traditional cuisine. Based on the ethnobotanical use of these plants, the approach has been employed in order to study the metabolic changes during different seasons. Primary and secondary metabolites have been detected and quantified. Flavonoids (apigenin, quercetin, and kaempferol derivatives) and phenylpropanoid derivatives (e.g., chlorogenic and rosmarinic acid) are the main identified polyphenols. The richness in these metabolites could explain the biological properties ascribed to these plant species. Monica Scognamiglio, Brigida D’Abrosca, Assunta Esposito, and Antonio Fiorentino Copyright © 2015 Monica Scognamiglio et al. All rights reserved. Statistical Methods for the Investigation of Solvolysis Mechanisms Illustrated by the Chlorides of the Carbomethoxy Protecting Groups NVOC and FMOC Thu, 12 Feb 2015 05:58:49 +0000 http://www.hindawi.com/journals/jamc/2015/941638/ The solvolysis of 4,5-dimethoxy-2-nitrobenzyl chloroformate (NVOC-Cl, 1) is followed at 25.0°C in twenty hydroxylic solvents. A comparison with previously published rates for benzyl chloroformate and p-nitrobenzyl chloroformate indicates that the inductive effect of the nitro and the two methoxy groups strongly influences the rate of reaction. For 1, the specific rates of solvolysis are correlated using an extended Grunwald-Winstein (G-W) treatment. A direct comparison with the data for phenyl chloroformate (PhOCOCl) in identical solvents strongly suggests that the addition step within an addition-elimination mechanism is rate-determining for both substrates. A reevaluation of the kinetic data for 9-fluorenylmethyl chloroformate (FMOC-Cl, 2) involves a correlation of versus . In this plot, deviations were observed in solvents rich in a hydrogen-bonding fluoroalcohol component. Omitting the aqueous fluoroalcohol rate measurements for 2 in an analysis using the extended G-W equation suggested the occurrence of dual pathways differing in the dependences upon the ionizing power and nucleophilicity of the solvent. In addition, the fluorenyl ring is rotated out of the plane containing the ether oxygen and, as a result, PhOCOCl is found to solvolyze 20 times faster than 2 in ethanol and methanol. Malcolm J. D’Souza, Jasbir K. Deol, Maryeah T. Pavey, and Dennis N. Kevill Copyright © 2015 Malcolm J. D’Souza et al. All rights reserved. Voltammetric Determination of Codeine on Glassy Carbon Electrode Modified with Nafion/MWCNTs Mon, 09 Feb 2015 08:19:50 +0000 http://www.hindawi.com/journals/jamc/2015/626458/ A glassy carbon electrode modified with a Nafion/MWCNTs composite is shown to enable the determination of codeine using differential pulse voltammetry in phosphate buffer of pH 3.0. At a preconcentration time of 15 s, the calibration graph is linear in the 0.5 µM (0.15 mg·L−1) to 15 µM (4.5 mg·L−1) concentration range with a correlation coefficient of 0.998. The detection limit at a preconcentration time of 120 s is as low as 4.5 μg·L−1. The repeatability of the method at a 0.6 μg·L−1 concentration level, expressed as the RSD, is 3.7% (for ). The method was successfully applied and validated by analyzing codeine in drug, human plasma, and urine samples. Robert Piech, Martyna Rumin, and Beata Paczosa-Bator Copyright © 2015 Robert Piech et al. All rights reserved. Systematic HPLC/ESI-High Resolution-qTOF-MS Methodology for Metabolomic Studies in Nonfluorescent Chlorophyll Catabolites Pathway Mon, 09 Feb 2015 06:11:41 +0000 http://www.hindawi.com/journals/jamc/2015/490627/ Characterization of nonfluorescent chlorophyll catabolites (NCCs) and dioxobilane-type nonfluorescent chlorophyll catabolite (DNCC) in peel extracts of ripened lemon fruits (Citrus limon L.) was performed by HPLC/ESI-high resolution-qTOF-MS method. Compounds were identified in samples on the basis of measured accurate mass, isotopic pattern, and characteristic fragmentation profile with an implemented software postprocessing routine. Three NCC structures already identified in other vegetal tissues were present in the lemon fruit peels (Cl-NCC1; Cl-NCC2; Cl-NCC4) while a new structure not defined so far was characterized (Cl-NCC3). This catabolite exhibits an exceptional arrangement of the peripheral substituents, allowing concluding that the preferences for the NCC modifications could be a species-related matter. José Julián Ríos, María Roca, and Antonio Pérez-Gálvez Copyright © 2015 José Julián Ríos et al. All rights reserved. Determination of Sinomenine in Cubosome Nanoparticles by HPLC Technique Thu, 05 Feb 2015 09:11:17 +0000 http://www.hindawi.com/journals/jamc/2015/931687/ We applied HPLC technique to quantitatively analyze sinomenine in cubosome nanoparticles. The chromatographic method was performed by using an isocratic system. The mobile phase was composed of methanol-PBS(pH6.8)-triethylamine (50 : 50 : 0.1%) with a flow rate of 1 mL/min; the detection wavelength was at 265 nm. Sinomenine can be successfully separated with good linearity (the regression equation is ; ) and perfect recovery (102.2%). The chromatograph technique was proper for quality control of sinomenine in cubosome nanoparticles. Yanfang Zhou, Chunlian Guo, Hongying Chen, Yudai Zhang, Xinsheng Peng, and Ping Zhu Copyright © 2015 Yanfang Zhou et al. All rights reserved. A Structural Study of Escherichia coli Cells Using an In Situ Liquid Chamber TEM Technology Thu, 05 Feb 2015 06:21:24 +0000 http://www.hindawi.com/journals/jamc/2015/829302/ Studying cell microstructures and their behaviors under living conditions has been a challenging subject in microbiology. In this work, in situ liquid chamber TEM was used to study structures of Escherichia coli cells in aqueous solutions at a nanometer-scale resolution. Most of the cells remained intact under electron beam irradiation, and nanoscale structures were observed during the TEM imaging. The analysis revealed structures of pili surrounding the E. coli cells; the movements of the pili in the liquid were also observed during the in situ tests. This technology also allowed the observation of features of the nucleoid in the E. coli cells. Overall, in situ TEM can be applied as a valuable tool to study real-time microscopic structures and processes in microbial cells residing in native aqueous solutions. Yibing Wang, Xin Chen, Hongliang Cao, Chao Deng, Xiaodan Cao, and Ping Wang Copyright © 2015 Yibing Wang et al. All rights reserved. Quantification of Sunscreen Benzophenone-4 in Hair Shampoos by Hydrophilic Interactions Thin-Layer Chromatography/Densitometry or Derivative UV Spectrophotometry Wed, 04 Feb 2015 06:41:06 +0000 http://www.hindawi.com/journals/jamc/2015/695658/ Benzophenone-4 (BZ4) was separated from surfactants, dyes, preservatives, and other components of hair shampoos by thin-layer chromatography on silica gel 60 stationary phase, with ethyl acetate-ethanol-water-pH 6 phosphate buffer (15 : 7 : 5 : 1 v/v/v/v) as mobile phase. Densitometry scanning of chromatograms was performed at 285 nm. The densitometric calibration curve for BZ4 was nonlinear (second-degree polynomial), with . The limits of detection and quantification were ca. 0.03 and ca. 0.1 μg spot−1, respectively. The results obtained by HPTLC-densitometry were compared to those obtained by zero and 2nd derivative UV spectrophotometry. In the case of spectrophotometric methods, calibration curves were linear with . The chromatographic method was fully validated. Anna W. Sobańska, Katarzyna Kałębasiak, Jarosław Pyzowski, and Elżbieta Brzezińska Copyright © 2015 Anna W. Sobańska et al. All rights reserved. Study of Grape Polyphenols by Liquid Chromatography-High-Resolution Mass Spectrometry (UHPLC/QTOF) and Suspect Screening Analysis Wed, 04 Feb 2015 06:34:11 +0000 http://www.hindawi.com/journals/jamc/2015/350259/ Suspect screening analysis is a targeted metabolomics method in which the identification of compounds relies on specific available information, such as their molecular formula and isotopic pattern. This method, coupled to liquid chromatography-high-resolution mass spectrometry, is effective in the study of grape metabolomics, in particular for characterization of flavonols, stilbene derivatives, and anthocyanins. For identification of compounds expected in the samples, a new database of putative compounds was expressly constructed by using the molecular information on potential metabolites of grape and wine from the literature and other electronic databases. Currently, this database contains around 1,100 compounds. The method allows identification of several hundred grape metabolites with two analyses (positive and negative ionization modes), and performing of data reprocessing using “untargeted” algorithms also provided the identification of some flavonols and resveratrol trimers and tetramers in grape for the first time. This approach can be potentially used in the study of metabolomics of varieties of other plant species. Riccardo Flamini, Mirko De Rosso, and Luigi Bavaresco Copyright © 2015 Riccardo Flamini et al. All rights reserved. Stability-Indicating RP-HPLC Method for Simultaneous Estimation of Enrofloxacin and Its Degradation Products in Tablet Dosage Forms Thu, 29 Jan 2015 15:36:11 +0000 http://www.hindawi.com/journals/jamc/2015/735145/ The present work was the development of a simple, efficient, and reproducible stability-indicating reverse-phase high performance liquid chromatographic (RP-HPLC) method for simultaneous determination enrofloxacin (EFX) and its degradation products including ethylenediamine impurity, desfluoro impurity, ciprofloxacin impurity, chloro impurity, fluoroquinolonic acid impurity, and decarboxylated impurity in tablet dosage forms. The separation of EFX and its degradation products in tablets was carried out on Kromasil C-18  mm, 5 m) column using 0.1% (v/v) TEA in 10 mM KH2PO4 (pH 2.5) buffer and methanol by linear gradient program. Flow rate was 1.0 mL min−1 with a column temperature of 35°C and detection wavelength was carried out at 278 nm and 254 nm. The forced degradation studies were performed on EFX tablets under acidic, basic, oxidation, thermal, humidity, and photolytic conditions. The degraded products were well resolved from the main active drug and also from known impurities within 65 minutes. The method was validated in terms of specificity, linearity, LOD, LOQ, accuracy, precision, and robustness as per ICH guidelines. The results obtained from the validation experiments prove that the developed method is a stability-indicating method and suitable for routine analysis. V. Ashok Chakravarthy, B. B. V. Sailaja, and Avvaru Praveen Kumar Copyright © 2015 V. Ashok Chakravarthy et al. All rights reserved. A Fluorescence-Based Method for Rapid and Direct Determination of Polybrominated Diphenyl Ethers in Water Thu, 29 Jan 2015 15:35:05 +0000 http://www.hindawi.com/journals/jamc/2015/853085/ A new method was developed for rapid and direct measurement of polybrominated diphenyl ethers (PBDEs) in aqueous samples using fluorescence spectroscopy. The fluorescence spectra of tri- to deca-BDE (BDE 28, 47, 99, 153, 190, and 209) commonly found in environment were measured at variable emission and excitation wavelengths. The results revealed that the PBDEs have distinct fluorescence spectral profiles and peak positions that can be exploited to identify these species and determine their concentrations in aqueous solutions. The detection limits as determined in deionized water spiked with PBDEs are 1.71–5.82 ng/L for BDE 28, BDE 47, BDE 190, and BDE 209 and 45.55–69.95 ng/L for BDE 99 and BDE 153. The effects of environmental variables including pH, humic substance, and groundwater chemical composition on PBDEs measurements were also investigated. These environmental variables affected fluorescence intensity, but their effect can be corrected through linear additivity and separation of spectral signal contribution. Compared with conventional GC-based analytical methods, the fluorescence spectroscopy method is more efficient as it only uses a small amount of samples (2–4 mL), avoids lengthy complicated concentration and extraction steps, and has a low detection limit of a few ng/L. Huimei Shan, Chongxuan Liu, Zheming Wang, Teng Ma, Jianying Shang, and Duoqiang Pan Copyright © 2015 Huimei Shan et al. All rights reserved. Applied Circular Dichroism: A Facile Spectroscopic Tool for Configurational Assignment and Determination of Enantiopurity Thu, 29 Jan 2015 08:36:27 +0000 http://www.hindawi.com/journals/jamc/2015/865605/ In order to determine if electronic circular dichroism (ECD) is a good tool for the qualitative evaluation of absolute configuration and enantiopurity in the absence of chiral high performance liquid chromatography (HPLC), ECD studies were performed on several prescriptions and over-the-counter drugs. Cotton effects (CE) were observed for both S and R isomers between 200 and 300 nm. For the drugs examined in this study, the S isomers showed a negative CE, while the R isomers displayed a positive CE. The ECD spectra of both enantiomers were nearly mirror images, with the amplitude proportional to the enantiopurity. Plotting the differential extinction coefficient () versus enantiopurity at the wavelength of maximum amplitude yielded linear standard curves with coefficients of determination () greater than 97% for both isomers in all cases. As expected, Equate, Advil, and Motrin, each containing a racemic mixture of ibuprofen, yielded no chiroptical signal. ECD spectra of Suphedrine and Sudafed revealed that each of them is rich in 1S,2S-pseudoephedrine, while the analysis of Equate vapor inhaler is rich in R-methamphetamine. Macduff O. Okuom, Raychelle Burks, Crysta Naylor, and Andrea E. Holmes Copyright © 2015 Macduff O. Okuom et al. All rights reserved. Solid-Phase Extraction Strategies to Surmount Body Fluid Sample Complexity in High-Throughput Mass Spectrometry-Based Proteomics Tue, 27 Jan 2015 09:51:03 +0000 http://www.hindawi.com/journals/jamc/2015/250131/ For large-scale and standardized applications in mass spectrometry- (MS-) based proteomics automation of each step is essential. Here we present high-throughput sample preparation solutions for balancing the speed of current MS-acquisitions and the time needed for analytical workup of body fluids. The discussed workflows reduce body fluid sample complexity and apply for both bottom-up proteomics experiments and top-down protein characterization approaches. Various sample preparation methods that involve solid-phase extraction (SPE) including affinity enrichment strategies have been automated. Obtained peptide and protein fractions can be mass analyzed by direct infusion into an electrospray ionization (ESI) source or by means of matrix-assisted laser desorption ionization (MALDI) without further need of time-consuming liquid chromatography (LC) separations. Marco R. Bladergroen and Yuri E. M. van der Burgt Copyright © 2015 Marco R. Bladergroen and Yuri E. M. van der Burgt. All rights reserved. Regularities of Anthocyanins Retention in RP HPLC for “Water–Acetonitrile–Phosphoric Acid” Mobile Phases Mon, 26 Jan 2015 11:59:08 +0000 http://www.hindawi.com/journals/jamc/2015/732918/ The influence of exchange of HCOOH (System 2) by phosphoric acid (System 1) for acidification of the “acetonitrile–water” mobile phases for reversed-phase HPLC of anthocyanins was investigated in the framework of relative retention analysis. The differences and similarities of anthocyanins separation were revealed. It has been shown that some common features of the quantitative relationships may be used for preliminary anthocyanins structure differentiation, according to the number of OH-groups in anthocyanidin backbone as well as to a number of saccharide molecules in glycoside radicals in position 3 of the anthocyanin without MS detection. V. I. Deineka, L. A. Deineka, and I. I. Saenko Copyright © 2015 V. I. Deineka et al. All rights reserved. General Analytical Procedure for Determination of Acidity Parameters of Weak Acids and Bases Mon, 26 Jan 2015 09:54:03 +0000 http://www.hindawi.com/journals/jamc/2015/530731/ The paper presents a new convenient, inexpensive, and reagent-saving general methodology for the determination of values for components of the mixture of diverse chemical classes weak organic acids and bases in water solution, without the need to separate individual analytes. The data obtained from simple pH-metric microtitrations are numerically processed into reliable values for each component of the mixture. Excellent agreement has been obtained between the determined values and the reference literature data for compounds studied. Bogusław Pilarski, Roman Kaliszan, Dariusz Wyrzykowski, Janusz Młodzianowski, and Agata Balińska Copyright © 2015 Bogusław Pilarski et al. All rights reserved. Chitosan Hydrogels for Chondroitin Sulphate Controlled Release: An Analytical Characterization Wed, 31 Dec 2014 13:23:25 +0000 http://www.hindawi.com/journals/jamc/2014/808703/ This paper provides an analytical characterization of chitosan scaffolds obtained by freeze-gelation toward the uptake and the controlled release of chondroitin sulphate (CS), as cartilage repair agent, under different pH conditions. Scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and liquid chromatography-UV spectrophotometry (LC-UV) techniques were exploited to obtain qualitative and quantitative descriptions of polymer and drug behaviour in the biomaterial. As for morphology, SEM analysis allowed the evaluation of scaffold porosity in terms of pore size and distribution both at the surface (Feret diameter  μm) and on the cross section (Feret diameter  μm). LC and ATR-FTIR evidenced a pH-dependent CS loading and release behaviour, strongly highlighting the role of electrostatic forces on chitosan/chondroitin sulphate interactions. Annalisa Bianchera, Enrico Salomi, Matteo Pezzanera, Elisabeth Ruwet, Ruggero Bettini, and Lisa Elviri Copyright © 2014 Annalisa Bianchera et al. All rights reserved. Determination of β-Cyano-L-alanine, γ-Glutamyl-β-cyano-L-alanine, and Common Free Amino Acids in Vicia sativa (Fabaceae) Seeds by Reversed-Phase High-Performance Liquid Chromatography Mon, 22 Dec 2014 06:20:34 +0000 http://www.hindawi.com/journals/jamc/2014/409089/ A method for determination of β-cyano-L-alanine, γ-glutamyl-β-cyano-L-alanine and other free amino acids in Vicia sativa is presented. Seed extracts were derivatized by reaction with diethyl ethoxymethylenemalonate and analyzed by reverse-phase high-performance liquid chromatography. Calibration curves showed very good linearity of the response. The limit of detection and quantification was 0.15 and 0.50 μM, respectively. The method has high intra- (RSD = 0.28–0.31%) and interrepeatability (RSD = 2.76–3.08%) and remarkable accuracy with a 99% recovery in spiked samples. The method is very easy to carry out and allows for ready analysis of large number of samples using very basic HPLC equipment because the derivatized samples are very stable and have very good chromatographic properties. The method has been applied to the determination of γ-glutamyl-β-cyano-L-alanine, β-cyano-L-alanine, and common free amino acids in eight wild populations of V. sativa from southwestern Spain. Cristina Megías, Isabel Cortés-Giraldo, Julio Girón-Calle, Javier Vioque, and Manuel Alaiz Copyright © 2014 Cristina Megías et al. All rights reserved. Quantification of Caffeoylquinic Acids in Coffee Brews by HPLC-DAD Sun, 21 Dec 2014 00:10:19 +0000 http://www.hindawi.com/journals/jamc/2014/965353/ The influence of different brewing conditions on the concentration of the main caffeoylquinic acids (3-caffeoylquinic acid (3-CQA), 4-caffeoylquinic acid (4-CQA), and 5-caffeoylquinic acid (5-CQA)) was investigated. For this purpose, twenty-four coffee brews were extracted and analyzed using HPLC-DAD at 325 nm. Our findings demonstrate the great impact of brewing techniques on the caffeoylquinic acids (CQAs) content. The major isomer was 3-CQA, accounting for about 50% of the total CQAs, followed by 5-CQA and 4-CQA, accounting for about 24–36% for each one. The total content of CQAs was in the range of 45.79 to 1662.01 mg/L, found in iced cappuccino and pod espresso, respectively. In conclusion, this study demonstrates that coffee brews, in particular those prepared using pressurized methods, can be considered as the potential sources of antioxidants such as CQAs. Marzieh Moeenfard, Lígia Rocha, and Arminda Alves Copyright © 2014 Marzieh Moeenfard et al. All rights reserved. Research of Recognition Method of Discrete Wavelet Feature Extraction and PNN Classification of Rats FT-IR Pancreatic Cancer Data Thu, 04 Dec 2014 09:37:41 +0000 http://www.hindawi.com/journals/jamc/2014/564801/ Sprague-Dawley (SD) rats’ normal and abnormal pancreatic tissues are determined directly by attenuated total reflectance Fourier transform infrared (ATR-FT-IR) spectroscopy method. In order to diagnose earlier stage of SD rats pancreatic cancer rate with FT-IR, a novel method of extraction of FT-IR feature using discrete wavelet transformation (DWT) analysis and classification with the probability neural network (PNN) was developed. The differences between normal pancreatic and abnormal samples were identified by PNN based on the indices of 4 feature variants. When error goal was 0.01, the total correct rates of pancreatic early carcinoma and advanced carcinoma were 98% and 100%, respectively. It was practical to apply PNN on the basis of ATR-FT-IR to identify abnormal tissues. The research result shows the feasibility of establishing the models with FT-IR-DWT-PNN method to identify normal pancreatic tissues, early carcinoma tissues, and advanced carcinoma tissues. Chayan Wan, Wenqing Cao, and Cungui Cheng Copyright © 2014 Chayan Wan et al. All rights reserved. Characteristic Fingerprint Based on Low Polar Constituents for Discrimination of Wolfiporia extensa according to Geographical Origin Using UV Spectroscopy and Chemometrics Methods Tue, 02 Dec 2014 13:01:19 +0000 http://www.hindawi.com/journals/jamc/2014/519424/ The fungus species Wolfiporia extensa has a long history of medicinal usage and has also been commercially used to formulate nutraceuticals and functional foods in certain Asian countries. In the present study, a practical and promising method has been developed to discriminate the dried sclerotium of W. extensa collected from different geographical sites based on UV spectroscopy together with chemometrics methods. Characteristic fingerprint of low polar constituents of sample extracts that originated from chloroform has been obtained in the interval 250–400 nm. Chemometric pattern recognition methods such as partial least squares discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA) were applied to enhance the authenticity of discrimination of the specimens. The results showed that W. extensa samples were well classified according to their geographical origins. The proposed method can fully utilize diversified fingerprint characteristics of sclerotium of W. extensa and requires low-cost equipment and short-time analysis in comparison with other techniques. Meanwhile, this simple and efficient method may serve as a basis for the authentication of other medicinal fungi. Yan Li, Ji Zhang, Yanli Zhao, Zhimin Li, Tao Li, and Yuanzhong Wang Copyright © 2014 Yan Li et al. All rights reserved. Optimization of Ultrasonic Extraction of Phenolic Compounds from Epimedium brevicornum Maxim Using Response Surface Methodology and Evaluation of Its Antioxidant Activities In Vitro Wed, 12 Nov 2014 08:12:29 +0000 http://www.hindawi.com/journals/jamc/2014/864654/ The ultrasound-assisted extraction of phenolic compounds from Epimedium brevicornu Maxim was modeled using response surface methodology. A Central Composite Design (CCD) was employed to optimize three extraction variables, including ethanol concentration (X1), extraction time (X2), and ratio of aqueous ethanol to raw material (X3), for the achievement of high extraction yield of the phenolic compounds. The optimized conditions are X1 of 50% (v/v), X2 of 27.5 min, and X3 of 250 mL/g. Under these conditions, the experimental yield is 4.29 ± 0.033% . The antioxidant activity was evaluated using the DPPH assay and ferric-reducing antioxidant power (FRAP). And it indicates that the phenolic compounds from Epimedium brevicornu Maxim possess significant antioxidant activity. HPLC analysis reveals that the main phenolic compound in the extract product was identified as gallic acid, catechin (Cianidanol), p-hydroxybenzoic acid, vanillic acid, caffeic acid, ferulaic acid, rutin, benzoic acid, and quercetin. Yan Zhao, Yingying Hou, Guosheng Tang, Enbo Cai, Shuangli Liu, He Yang, Lianxue Zhang, and Shijie Wang Copyright © 2014 Yan Zhao et al. All rights reserved. Simultaneous Determination of Uric Acid and Xanthine Using a Poly(Methylene Blue) and Electrochemically Reduced Graphene Oxide Composite Film Modified Electrode Tue, 11 Nov 2014 13:21:50 +0000 http://www.hindawi.com/journals/jamc/2014/984314/ Poly(methylene blue) and electrochemically reduced graphene oxide composite film modified electrode (PMB-ERGO/GCE) was successfully fabricated by electropolymerization and was used for simultaneous determination of uric acid (UA) and xanthine (Xa). Based on the excellent electrocatalytic activity of PMB-ERGO/GCE, the electrochemical behaviors of UA and Xa were studied by cyclic voltammetry (CV) and square wave voltammetry (SWV). Two anodic sensitive peaks at 0.630 V (versus Ag/AgCl) for UA and 1.006 V (versus Ag/AgCl) for Xa were given by CV in pH 3.0 phosphate buffer. The calibration curves for UA and Xa were obtained in the range of 8.00 × 10−8~4.00 × 10−4 M and 1.00 × 10−7~4.00 × 10−4 M, respectively, by SWV. The detection limits for UA and Xa were  M and  M, respectively. Finally, the proposed method was applied to simultaneously determine UA and Xa in human urine with good selectivity and high sensitivity. Gen Liu, Wei Ma, Yan Luo, Deng-ming Sun, and Shuang Shao Copyright © 2014 Gen Liu et al. All rights reserved. A Modified o-Phthalaldehyde Fluorometric Analytical Method for Ultratrace Ammonium in Natural Waters Using EDTA-NaOH as Buffer Tue, 11 Nov 2014 12:48:36 +0000 http://www.hindawi.com/journals/jamc/2014/728068/ In the existence of appropriate amount of disodium ethylenediaminetetraacetate (EDTA), precipitation would not occur in seawater and other natural waters even if the sample solution was adjusted to strong basicity, and the NH3-OPA-sulfite reaction at the optimal pH range could be used to determine ammonium in natural waters. Based on this, a modified o-phthalaldehyde fluorometric analytical method has been established to determine ultratrace ammonium in natural waters. Experimental parameters, including reagent concentration, pH, reaction time, and effect of EDTA, were optimized throughout the experiments based on univariate experimental design. The results showed that the optimal pH range was between 10.80 and 11.70. EDTA did not obviously affect the fluorometric intensity. The linearity range of the proposed method was 0.032–0.500 µmol/L, 0.250–3.00 µmol/L, and 1.00–20.0 µmol/L at the excitation/emission slit of 3 nm/5 nm, 3 nm/3 nm, and 1.5 nm/1.5 nm, respectively. The method detection limit was 0.0099 µmol/L. Compared to the classical OPA method, the proposed method had the advantage of being more sensitive and could quantify ultratrace ammonium without enrichment. Hongzhi Hu, Ying Liang, Shuo Li, Qing Guo, and Chancui Wu Copyright © 2014 Hongzhi Hu et al. All rights reserved. Determination of Sunset Yellow and Tartrazine in Food Samples by Combining Ionic Liquid-Based Aqueous Two-Phase System with High Performance Liquid Chromatography Wed, 05 Nov 2014 06:23:28 +0000 http://www.hindawi.com/journals/jamc/2014/964273/ We proposed a simple and effective method, by coupling ionic liquid-based aqueous two-phase systems (IL-ATPSs) with high performance liquid chromatography (HPLC), for the analysis of determining tartrazine and sunset yellow in food samples. Under the optimized conditions, IL-ATPSs generated an extraction efficiency of 99% for both analytes, which could then be directly analyzed by HPLC without further treatment. Calibration plots were linear in the range of 0.01–50.0 μg/mL for both Ta and SY. The limits of detection were 5.2 ng/mL for Ta and 6.9 ng/mL for SY. This method proves successful for the separation/analysis of tartrazine and sunset yellow in soft drink sample, candy sample, and instant powder drink and leads to consistent results as obtained from the Chinese national standard method. Ou Sha, Xiashi Zhu, Yanli Feng, and Weixing Ma Copyright © 2014 Ou Sha et al. All rights reserved.