Journal of Analytical Methods in Chemistry https://www.hindawi.com The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. Acupuncture Injection Combined with Electrokinetic Injection for Polydimethylsiloxane Microfluidic Devices Thu, 23 Feb 2017 12:34:03 +0000 http://www.hindawi.com/journals/jamc/2017/7495348/ We recently reported acupuncture sample injection that leads to reproducible injection of nL-scale sample segments into a polydimethylsiloxane (PDMS) microchannel for microchip capillary electrophoresis. The advantages of the acupuncture injection in microchip capillary electrophoresis include capability of minimizing sample loss and voltage control hardware and capability of introducing sample plugs into any desired position of a microchannel. However, the challenge in the previous study was to achieve reproducible, pL-scale sample injections into PDMS microchannels. In the present study, we introduce an acupuncture injection technique combined with electrokinetic injection (AICEI) technique to inject pL-scale sample segments for microchip capillary electrophoresis. We carried out the capillary zone electrophoresis (CZE) separation of FITC and fluorescein, and the mixture of 10 μM FITC and 10 μM fluorescein was separated completely by using the AICEI method. Ji Won Ha Copyright © 2017 Ji Won Ha. All rights reserved. Stability Study of Algerian Nigella sativa Seeds Stored under Different Conditions Wed, 01 Feb 2017 00:00:00 +0000 http://www.hindawi.com/journals/jamc/2017/7891434/ In a study to determine the stability of the main volatile constituents of Nigella sativa seeds stored under several conditions, eight storage conditions were established, based on the ecological abiotic effects of air, heat, and light. Six replicates each were prepared and analyzed with Headspace-Gas Chromatography-Mass Spectrometry (HS-GC-MS) for three time points at the initial (1st day (0)), 14th (1), and 28th (2) day of storage. A targeted multivariate analysis of Principal Component Analysis revealed that the stability of the main volatile constituents of the whole seeds was better than that of the ground seeds. Exposed seeds, whole or ground, were observed to experience higher decrement of the volatile composition. These ecofactors of air, heat, and light are suggested to be directly responsible for the loss of volatiles in N. sativa seeds, particularly of the ground seeds. Muhammad Safwan Ahamad Bustamam, Kamarul Arifin Hadithon, Ahmed Mediani, Faridah Abas, Yaya Rukayadi, Nordin Lajis, Khozirah Shaari, and Intan Safinar Ismail Copyright © 2017 Muhammad Safwan Ahamad Bustamam et al. All rights reserved. Pencil Graphite Electrodes: A Versatile Tool in Electroanalysis Tue, 31 Jan 2017 00:00:00 +0000 http://www.hindawi.com/journals/jamc/2017/1905968/ Due to their electrochemical and economical characteristics, pencil graphite electrodes (PGEs) gained in recent years a large applicability to the analysis of various types of inorganic and organic compounds from very different matrices. The electrode material of this type of working electrodes is constituted by the well-known and easy commercially available graphite pencil leads. Thus, PGEs are cheap and user-friendly and can be employed as disposable electrodes avoiding the time-consuming step of solid electrodes surface cleaning between measurements. When compared to other working electrodes PGEs present lower background currents, higher sensitivity, good reproducibility, and an adjustable electroactive surface area, permitting the analysis of low concentrations and small sample volumes without any deposition/preconcentration step. Therefore, this paper presents a detailed overview of the PGEs characteristics, designs and applications of bare, and electrochemically pretreated and chemically modified PGEs along with the corresponding performance characteristics like linear range and detection limit. Techniques used for bare or modified PGEs surface characterization are also reviewed. Iulia Gabriela David, Dana-Elena Popa, and Mihaela Buleandra Copyright © 2017 Iulia Gabriela David et al. All rights reserved. Chemical Composition, Physicochemical Characteristics, and Nutritional Value of Lannea kerstingii Seeds and Seed Oil Tue, 31 Jan 2017 00:00:00 +0000 http://www.hindawi.com/journals/jamc/2017/2840718/ The chemical composition, main physicochemical properties, and nutritional value of seed flour and seed oil of Lannea kerstingii were studied. The results indicated that seeds contained 3.61% moisture, 57.85% fat, 26.39% protein, 10.07% carbohydrates, and 2.08% ash. Potassium was the predominant mineral, followed by magnesium and calcium. The essential amino acids were at higher levels than the estimated amino acid requirements of FAO/WHO/UNU except for lysine. Fatty acid composition showed that oleic acid was the major fatty acid, followed by palmitic, linoleic, and stearic acids. Physicochemical properties of the seed oil were melting point, 19.67°C; refractive index (25°C), 1.47; iodine value, 60.72/100 g of oil; peroxide value, 0.99 meq. O2/kg of oil; -anisidine value, 0.08; total oxidation (TOTOX) value, 2.06; oxidative stability index (120°C), 52.53 h; free fatty acids, 0.39%; acid value, 0.64 mg of KOH/g of oil; saponification value, 189.73. Total amount of tocopherols, carotenoids, and sterols was 578.60, 4.60, and 929.50 mg/kg of oil, respectively. γ-Tocopherol (82%), lutein (80%), and β-sitosterol (93%) were the most abundant forms of tocopherols, carotenoids, and sterols, respectively. Seeds of L. kerstingii constitute an alternative source of stable vegetable oil and protein for nutritional and industrial applications. Judicaël Thomas Ouilly, Patrice Bazongo, Adjima Bougma, Nèbpawindé Kaboré, Anne Mette Lykke, Amadé Ouédraogo, and Imaël Henri Nestor Bassolé Copyright © 2017 Judicaël Thomas Ouilly et al. All rights reserved. Transfer Assessment of Carbendazim Residues from Rape Flowers to Apicultural Products Thu, 26 Jan 2017 09:58:05 +0000 http://www.hindawi.com/journals/jamc/2017/6075405/ Carbendazim is usually used to control the Sclerotinia sclerotiorum of rapes during the flowering period. This paper presents a study on transfer assessment of carbendazim residues from rape flowers to apicultural products. In the field trials, the rapes were sprayed with carbendazim on standard dosage. Bees produced apicultural products (bee pollen, honey, and royal jelly) from sprayed rapes. Apicultural products were collected on a regular basis. Carbendazim residues were extracted from bee pollen, honey, and royal jelly, respectively. HPLC/ESI-MS/MS method was developed and partially validated to identify and quantify carbendazim residues. The limits of quantification in pollen, honey, and royal jelly were 0.01 mg/kg. Mathematical curve fitting was carried out on the basis of transfer assessment of carbendazim residues from rape flowers to apicultural products. The respective carbendazim residues were  mg/kg in pollen on 18th day,  mg/kg in honey on 24th day, and  mg/kg in royal jelly on 22nd day. Transfer assessment and mathematical curve fitting of carbendazim residues from rape flowers to apicultural products show carbendazim diminished over spraying time. The gap of carbendazim residues between pollen and honey is decreased with time. The carbendazim residues in pollen are 10 times higher than that of honey and jelly. Ying-Hong Li, Bei-Lei Zhou, Ming-Rong Qian, Qiang Wang, and Hu Zhang Copyright © 2017 Ying-Hong Li et al. All rights reserved. Structural and Quantitative Analysis of Three C-Glycosylflavones by Variable Temperature Proton Quantitative Nuclear Magnetic Resonance Mon, 23 Jan 2017 00:00:00 +0000 http://www.hindawi.com/journals/jamc/2017/4934309/ Quantitative nuclear magnetic resonance is a powerful tool in drug analysis because of its speed, precision, and efficiency. In present study, the application of variable temperature proton quantitative nuclear magnetic resonance (VT-1H-qNMR) for the calibration of three C-glycosylflavones including orientin, isoorientin, and schaftoside as reference substances was reported. Since there was conformational equilibrium due to the restricted rotation around the C(sp3)-C(sp2) bond in C-glycosylflavones, the conformational behaviors were investigated by VT-NMR and verified by molecular mechanics (MM) calculation. The VT-1H-qNMR method was validated including the linearity, limit of quantification, precision, and stability. The results were consistent with those obtained from mass balance approach. VT-1H-qNMR can be deployed as an effective tool in analyzing C-glycosylflavones. Jing Liu, Yang Liu, Zhong Dai, Lan He, and Shuangcheng Ma Copyright © 2017 Jing Liu et al. All rights reserved. The Application of FT-IR Spectroscopy for Quality Control of Flours Obtained from Polish Producers Sun, 22 Jan 2017 00:00:00 +0000 http://www.hindawi.com/journals/jamc/2017/4315678/ Samples of wheat, spelt, rye, and triticale flours produced by different Polish mills were studied by both classic chemical methods and FT-IR MIR spectroscopy. An attempt was made to statistically correlate FT-IR spectral data with reference data with regard to content of various components, for example, proteins, fats, ash, and fatty acids as well as properties such as moisture, falling number, and energetic value. This correlation resulted in calibrated and validated statistical models for versatile evaluation of unknown flour samples. The calibration data set was used to construct calibration models with use of the CSR and the PLS with the leave one-out, cross-validation techniques. The calibrated models were validated with a validation data set. The results obtained confirmed that application of statistical models based on MIR spectral data is a robust, accurate, precise, rapid, inexpensive, and convenient methodology for determination of flour characteristics, as well as for detection of content of selected flour ingredients. The obtained models’ characteristics were as follows: , PRESS = 2.14; , PRESS = 0.69; , PRESS = 1.27; , PRESS = 0.76, for content of proteins, lipids, ash, and moisture level, respectively. Best results of CSR models were obtained for protein, ash, and crude fat (; 0.82; and 0.78, resp.). Katarzyna Sujka, Piotr Koczoń, Alicja Ceglińska, Magdalena Reder, and Hanna Ciemniewska-Żytkiewicz Copyright © 2017 Katarzyna Sujka et al. All rights reserved. Development of a Novel, Sensitive, Selective, and Fast Methodology to Determine Malondialdehyde in Leaves of Melon Plants by Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry Thu, 19 Jan 2017 12:22:11 +0000 http://www.hindawi.com/journals/jamc/2017/4327954/ Early production of melon plant (Cucumis melo) is carried out using tunnels structures, where extreme temperatures lead to high reactive oxygen species production and, hence, oxidative stress. Malondialdehyde (MDA) is a recognized biomarker of the advanced oxidative status in a biological system. Thus a reliable, sensitive, simple, selective, and rapid separative strategy based on ultra-high-performance liquid chromatography coupled to positive electrospray-tandem mass spectrometry (UPLC-(+)ESI-MS/MS) was developed for the first time to measure MDA, without derivatization, in leaves of melon plants exposed to stress conditions. The detection and quantitation limits were 0.02 μg·L−1 and 0.08 μg·L−1, respectively, which was demonstrated to be better than the methodologies currently reported in the literature. The accuracy values were between 96% and 104%. The precision intraday and interday values were 2.7% and 3.8%, respectively. The optimized methodology was applied to monitoring of changes in MDA levels between control and exposed to thermal stress conditions melon leaves samples. Important preliminary conclusions were obtained. Besides, a comparison between MDA levels in melon leaves quantified by the proposed method and the traditional thiobarbituric acid reactive species (TBARS) approach was undertaken. The MDA determination by TBARS could lead to unrealistic conclusions regarding the oxidative stress status in plants. Melisa E. Yonny, Ariel Rodríguez Torressi, Mónica A. Nazareno, and Soledad Cerutti Copyright © 2017 Melisa E. Yonny et al. All rights reserved. Preparation of TiO2 Nanotubes Loaded on Polyurethane Membrane and Research on Their Photocatalytic Properties Tue, 17 Jan 2017 09:31:52 +0000 http://www.hindawi.com/journals/jamc/2017/9629532/ To solve the problem of separation and recovery of photocatalyst in water, the modification of TiO2 was studied as well as its immobilization and photocatalytic properties. To improve surface properties, TiO2 nanotubes were synthesized by a hydrothermal method and silylated by silane coupling agents to introduce a certain functional group. Supported on polyurethane (PU) membrane, TiO2 nanotubes were prepared to produce immobilized PU/TiO2. Catalysts were characterized and identified by means of Fourier-transform infrared spectroscopy (FTIR), attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), and scanning electron microscopy (SEM). Results showed that silylated TiO2 nanotubes were well grafted on the surface of the activated PU membrane. With a 300 W high pressure mercury lamp as light source, the photocatalytic activity and stability of immobilized PU/TiO2 were investigated with degrading methyl orange. It was showed that the target is degraded by immobilized PU/TiO2 with high activation and the catalytic performance is stable for a long time if catalyst is washed with ethanol. Longli Lin, Qijun Wu, Xun Gong, and Yu Zhang Copyright © 2017 Longli Lin et al. All rights reserved. Simultaneous Determination of 5 Flavonoids and 7 Saponins for Quality Control of Traditional Chinese Medicine Preparation Xinnaoshutong Capsule Using HPLC-VWD-ELSD Mon, 16 Jan 2017 06:43:02 +0000 http://www.hindawi.com/journals/jamc/2017/3190185/ Xinnaoshutong capsule (XC) is a traditional Chinese prescription derived from the ripe fruit of Tribulus terrestris L. (TT). Although XC has long been considered as an important herbal medicine, no analytical method of marker compounds for quality assessment is registered in the Chinese Pharmacopoeia. A simple analytical method of twelve marker components was developed and validated by HPLC-VWD-ELSD method. Chromatographic separation by HPLC was carried out on a Hedera ODS 2 column (4.6 × 250 mm, 5 μm) by gradient elution with acetonitrile-water (0.1% formic acid) as the mobile phase. Various extraction conditions were optimized to achieve twelve marker compounds with faster extraction and higher recovery. The analytical condition was then validated in terms of the linearity, accuracy and precision, repeatability, and stability. The twelve markers were successfully quantified in 30 batches of commercial samples. The developed HPLC-VWD-ELSD could be used as a rapid and reliable way in the assessment and quality control of XC and TT. Jin Li, Yang Bai, Peng Zhang, Jun He, Jun Cao, Mingrui An, Li-min Hu, Xiu-mei Gao, and Yan-xu Chang Copyright © 2017 Jin Li et al. All rights reserved. Semiautomated Alignment of High-Throughput Metabolite Profiles with Chemometric Tools Thu, 12 Jan 2017 07:15:13 +0000 http://www.hindawi.com/journals/jamc/2017/9402045/ The rapid increase in the use of metabolite profiling/fingerprinting techniques to resolve complicated issues in metabolomics has stimulated demand for data processing techniques, such as alignment, to extract detailed information. In this study, a new and automated method was developed to correct the retention time shift of high-dimensional and high-throughput data sets. Information from the target chromatographic profiles was used to determine the standard profile as a reference for alignment. A novel, piecewise data partition strategy was applied for the determination of the target components in the standard profile as markers for alignment. An automated target search (ATS) method was proposed to find the exact retention times of the selected targets in other profiles for alignment. The linear interpolation technique (LIT) was employed to align the profiles prior to pattern recognition, comprehensive comparison analysis, and other data processing steps. In total, 94 metabolite profiles of ginseng were studied, including the most volatile secondary metabolites. The method used in this article could be an essential step in the extraction of information from high-throughput data acquired in the study of systems biology, metabolomics, and biomarker discovery. Ze-ying Wu, Zhong-da Zeng, Zi-dan Xiao, Daniel Kam-Wah Mok, Yi-zeng Liang, Foo-tim Chau, and Hoi-yan Chan Copyright © 2017 Ze-ying Wu et al. All rights reserved. Tetracyclines in Food and Feedingstuffs: From Regulation to Analytical Methods, Bacterial Resistance, and Environmental and Health Implications Thu, 12 Jan 2017 00:00:00 +0000 http://www.hindawi.com/journals/jamc/2017/1315497/ Antibiotics are widely used as growth promoters in animal husbandry; among them, the tetracyclines are a chemical group of relevance, due to their wide use in agriculture, surpassing in quantities applied almost every other antibiotic family. Seeing the considerable amounts of tetracyclines used worldwide, monitoring of these antibiotics is paramount. Advances must be made in the analysis of antibiotics to assess correct usage and dosage of tetracyclines in food and feedstuffs and possible residues in pertinent environmental samples. The tetracyclines are still considered a clinically relevant group of antibiotics, though dissemination of tolerance and resistance determinants have limited their use. This review focuses on four different aspects: (i) tetracyclines, usage, dosages, and regulatory issues that govern their food-related application, with particular attention to the prohibitions and restrictions that several countries have enforced in recent years by agencies from both the United States and the European Union, (ii) analytical methods for tetracyclines, determination, and residues thereof in feedstuffs and related matrices with an emphasis on the most relevant and novel techniques, including both screening and confirmatory methods, (iii) tetracycline resistance and tetracycline-resistant bacteria in feedstuff, and (iv) environmental and health risks accompanying the use of tetracyclines in animal nutrition. In the last two cases, we discuss the more relevant undesirable effects that tetracyclines exert over bacterial communities and nontarget species including unwanted effects in farmers. Fabio Granados-Chinchilla and César Rodríguez Copyright © 2017 Fabio Granados-Chinchilla and César Rodríguez. All rights reserved. Simultaneous Determination of Dexamethasone, Ondansetron, Granisetron, Tropisetron, and Azasetron in Infusion Samples by HPLC with DAD Detection Wed, 11 Jan 2017 00:00:00 +0000 http://www.hindawi.com/journals/jamc/2017/6749087/ A simple and rapid high-performance liquid chromatography with diode array detector (HPLC-DAD) method has been developed and validated for simultaneous quantification of five antiemetic agents in infusion samples: dexamethasone, ondansetron, granisetron, tropisetron, and azasetron. The chromatographic separation was achieved on a Phenomenex C18 column (4.6 mm × 150 mm, 5 μm) using acetonitrile-50 mM KH2PO4 buffer-triethylamine (25 : 74 : 1; v/v; pH 4.0). Flow rate was 1.0 mL/min with a column temperature of 30°C. Validation of the method was made in terms of specificity, linearity, accuracy, and intra- and interday precision, as well as quantification and detection limits. The developed method can be used in the laboratory to routinely quantify dexamethasone, ondansetron, granisetron, tropisetron, and azasetron simultaneously and to evaluate the physicochemical stability of referred drugs in mixtures for endovenous use. Fu-chao Chen, Lin-hai Wang, Jun Guo, Xiao-ya Shi, and Bao-xia Fang Copyright © 2017 Fu-chao Chen et al. All rights reserved. LC-MS-Based Metabolic Fingerprinting of Aqueous Humor Thu, 05 Jan 2017 09:28:04 +0000 http://www.hindawi.com/journals/jamc/2017/6745932/ Aqueous humor (AH) is a transparent fluid which fills the anterior and posterior chambers of the eye. It supplies nutrients and removes metabolic waste from avascular tissues in the eye. Proper homeostasis of AH is required to maintain adequate intraocular pressure as well as optical and refractive properties of the eye. Application of metabolomics to study human AH may improve knowledge about the molecular mechanisms of eye diseases. Until now, global analysis of metabolites in AH has been mainly performed using NMR. Among the analytical platforms used in metabolomics, LC-MS allows for the highest metabolome coverage. The aim of this study was to develop a method for extraction and analysis of AH metabolites by LC-QTOF-MS. Different protocols for AH preparation were tested. The best results were obtained when one volume of AH was mixed with one volume of methanol : ethanol (1 : 1). In the final method, 2 µL of extracted sample was analyzed by LC-QTOF-MS. The method allowed for reproducible measurement of over 1000 metabolic features. Almost 250 metabolites were identified in AH and assigned to 47 metabolic pathways. This method is suitable to study the potential role of amino acids, lipids, oxidative stress, or microbial metabolites in development of ocular diseases. Karolina Pietrowska, Diana Anna Dmuchowska, Paulina Samczuk, Tomasz Kowalczyk, Pawel Krasnicki, Malgorzata Wojnar, Aleksandra Skowronska, Zofia Mariak, Adam Kretowski, and Michal Ciborowski Copyright © 2017 Karolina Pietrowska et al. All rights reserved. Diosgenin: Recent Highlights on Pharmacology and Analytical Methodology Wed, 28 Dec 2016 12:35:57 +0000 http://www.hindawi.com/journals/jamc/2016/4156293/ Diosgenin, a steroidal sapogenin, occurs abundantly in plants such as Dioscorea alata, Smilax China, and Trigonella foenum graecum. This bioactive phytochemical not only is used as an important starting material for the preparation of several steroidal drugs in the pharmaceutical industry, but has revealed also high potential and interest in the treatment of various types of disorders such as cancer, hypercholesterolemia, inflammation, and several types of infections. Due to its pharmacological and industrial importance, several extraction and analytical procedures have been developed and applied over the years to isolate, detect, and quantify diosgenin, not only in its natural sources and pharmaceutical compositions, but also in animal matrices for pharmacodynamic, pharmacokinetic, and toxicological studies. Within these, HPLC technique coupled to different detectors is the most commonly analytical procedure described for this compound. However, other alternative methods were also published. Thus, the present review aims to provide collective information on the most recent pharmacological data on diosgenin and on the most relevant analytical techniques used to isolate, detect, and quantify this compound as well. Mafalda Jesus, Ana P. J. Martins, Eugenia Gallardo, and Samuel Silvestre Copyright © 2016 Mafalda Jesus et al. All rights reserved. Measurement of Total Free Iron in Soils by H2S Chemisorption and Comparison with the Citrate Bicarbonate Dithionite Method Sun, 25 Dec 2016 08:12:42 +0000 http://www.hindawi.com/journals/jamc/2016/7213542/ Free iron is one of the major analytical items for soil basic properties. It is also an important indicator for understanding the genesis of soil, soil classification, and soil distribution behavior. In this study, an alternative analytical method (chemisorption) based on thermodynamic knowledge was proposed for measurement of total free iron oxides in soils. Several representative soil samples belonging to alfisols, ultisols, inceptisols, and entisols were collected from Taiwan and tested by the chemisorption, and the estimated total free iron oxides were compared with those measured from the traditional citrate bicarbonate dithionite (CBD) method. Experimental results showed that the optimal operating temperature was found to be at 773 K and the carbon monoxide (CO) is the best gaseous reagent to promote the formation of FeS. The estimated total free iron oxides for soil samples determined from the chemisorption in the presence of CO were very close to those from the CBD technique. The result of regression indicates that the estimated total free iron is strongly correlated with the CBD-Fe content () in the presence of CO. Shui-Sheng Fan, Feng-Hsiang Chang, Hsin-Ta Hsueh, and Tzu-Hsing Ko Copyright © 2016 Shui-Sheng Fan et al. All rights reserved. Quantitative Analysis in Combination with Fingerprint Technology and Chemometric Analysis Applied for Evaluating Six Species of Wild Paris Using UHPLC-UV-MS Wed, 21 Dec 2016 12:25:53 +0000 http://www.hindawi.com/journals/jamc/2016/3182796/ A fast method was developed by ultra high performance liquid chromatography (UHPLC) for simultaneous determination of polyphyllin I and polyphyllin II. Chemometric analyses including principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) based on UHPLC chromatography were used to evaluate 38 batches from six species of Paris. Variable importance of projection was applied to select important peaks. Meanwhile, similarity analysis of UHPLC fingerprint was used to evaluate the sample of Paris polyphylla yunnanensis (PPY) and P. axialis (PA). The results indicated that the total content of saponins in PPY and PA collected from Baoshan City of Yunnan Province above 8.07 mg/g was stronger than that from other areas of the rest of species. PLS-DA showed better performance than PCA with regard to classifying the samples. Retention time during 20–27 minutes of UHPLC was screened as significant peak for distinguishing Paris of different species and original geography. All of PPY and PA with similarity value were more than 0.80. It indicated that quantitative analysis combined with chemometric and similarity analyses could evaluate the different species of Paris effectively and comprehensively. Yuangui Yang, Ji Zhang, Hang Jin, Jinyu Zhang, and Yuanzhong Wang Copyright © 2016 Yuangui Yang et al. All rights reserved. Catalase-Based Modified Graphite Electrode for Hydrogen Peroxide Detection in Different Beverages Sun, 18 Dec 2016 14:49:05 +0000 http://www.hindawi.com/journals/jamc/2016/8174913/ A catalase-based (NAF/MWCNTs) nanocomposite film modified glassy carbon electrode for hydrogen peroxide (H2O2) detection was developed. The developed biosensor was characterized in terms of its bioelectrochemical properties. Cyclic voltammetry (CV) technique was employed to study the redox features of the enzyme in the absence and in the presence of nanomaterials dispersed in Nafion® polymeric solution. The electron transfer coefficient, α, and the electron transfer rate constant, , were found to be 0.42 and 1.71 s−1, at pH 7.0, respectively. Subsequently, the same modification steps were applied to mesoporous graphite screen-printed electrodes. Also, these electrodes were characterized in terms of their main electrochemical and kinetic parameters. The biosensor performances improved considerably after modification with nanomaterials. Moreover, the association of Nafion with carbon nanotubes retained the biological activity of the redox protein. The enzyme electrode response was linear in the range 2.5–1150 μmol L−1, with LOD of 0.83 μmol L−1. From the experimental data, we can assess the possibility of using the modified biosensor as a useful tool for H2O2 determination in packaged beverages. Giovanni Fusco, Paolo Bollella, Franco Mazzei, Gabriele Favero, Riccarda Antiochia, and Cristina Tortolini Copyright © 2016 Giovanni Fusco et al. All rights reserved. Application of Multivariable Analysis and FTIR-ATR Spectroscopy to the Prediction of Properties in Campeche Honey Wed, 14 Dec 2016 12:59:45 +0000 http://www.hindawi.com/journals/jamc/2016/5427526/ Attenuated total reflectance-Fourier transform infrared spectrometry and chemometrics model was used for determination of physicochemical properties (pH, redox potential, free acidity, electrical conductivity, moisture, total soluble solids (TSS), ash, and HMF) in honey samples. The reference values of 189 honey samples of different botanical origin were determined using Association Official Analytical Chemists, (AOAC), 1990; Codex Alimentarius, 2001, International Honey Commission, 2002, methods. Multivariate calibration models were built using partial least squares (PLS) for the measurands studied. The developed models were validated using cross-validation and external validation; several statistical parameters were obtained to determine the robustness of the calibration models: (PCs) optimum number of components principal, (SECV) standard error of cross-validation, () coefficient of determination of cross-validation, (SEP) standard error of validation, and () coefficient of determination for external validation and coefficient of variation (CV). The prediction accuracy for pH, redox potential, electrical conductivity, moisture, TSS, and ash was good, while for free acidity and HMF it was poor. The results demonstrate that attenuated total reflectance-Fourier transform infrared spectrometry is a valuable, rapid, and nondestructive tool for the quantification of physicochemical properties of honey. Francisco Anguebes, Lucio Pat, Bassam Ali, Armando Guerrero, Atl V. Córdova, Mohamed Abatal, and José P. Garduza Copyright © 2016 Francisco Anguebes et al. All rights reserved. Immobilization of NTPDase-1 from Trypanosoma cruzi and Development of an Online Label-Free Assay Wed, 14 Dec 2016 07:08:31 +0000 http://www.hindawi.com/journals/jamc/2016/9846731/ The use of IMERs (Immobilized Enzyme Reactors) as a stationary phase coupled to high performance chromatographic systems is an interesting approach in the screening of new ligands. In addition, IMERs offer many advantages over techniques that employ enzymes in solution. The enzyme nucleoside triphosphate diphosphohydrolase (NTPDase-1) from Trypanosoma cruzi acts as a pathogen infection facilitator, so it is a good target in the search for inhibitors. In this paper, immobilization of NTPDase-1 afforded ICERs (Immobilized Capillary Enzyme Reactors). A liquid chromatography method was developed and validated to monitor the ICER activity. The conditions for the application of these bioreactors were investigated, and excellent results were obtained. The enzyme was successfully immobilized, as attested by the catalytic activity detected in the TcNTPDase-1-ICER chromatographic system. Kinetic studies on the substrate ATP gave of 0.317 ± 0.044 mmolL−1, which still presented high affinity compared to in solution. Besides that, the ICER was stable for 32 days, enough time to investigate samples of possible inhibitors, including especially the compound Suramin, that inhibited 51% the enzyme activity at 100 µmolL−1, which is in accordance with the data for the enzyme in solution. Felipe Antunes Calil, Juliana Maria Lima, Arthur Henrique Cavalcante de Oliveira, Christiane Mariotini-Moura, Juliana Lopes Rangel Fietto, and Carmen Lucia Cardoso Copyright © 2016 Felipe Antunes Calil et al. All rights reserved. Preparation of a Specific ssDNA Aptamer for Brevetoxin-2 Using SELEX Mon, 12 Dec 2016 09:07:14 +0000 http://www.hindawi.com/journals/jamc/2016/9241860/ The existing assays for detecting brevetoxin (BTX) depend on expensive equipment with a professional operator or on an antibody with limited stability, which requires complex processes, a high cost, and a considerable amount of time. The development of an alternative detection probe is another promising research direction. This paper reports the use of aptamers binding to BTX-2 in an analytical assay using the systematic evolution of ligands by exponential enrichment (SELEX). After 12 rounds of selection, the secondary structures of 25 sequences were predicted. Compared to other aptamers, Bap5 has relatively high affinity with the lowest dissociation constant of 4.83 μM, and IC50 is 73.81 ng mL−1. A good linear regression formula of with a coefficient correlation of = 0.9798 was obtained using a biotin-avidin ELISA. Moreover, there is no cross-reaction with the detected marine toxins, except for BTX-2. Thus, Bap5 has potential to detect BTX-2 in shellfish in the future as a substitute for the recognition probe. Rui-Yun Tian, Chao Lin, Shi-Yu Yu, Sheng Gong, Pan Hu, Yan-Song Li, Zong-Cheng Wu, Yang Gao, Yu Zhou, Zeng-Shan Liu, Hong-Lin Ren, and Shi-Ying Lu Copyright © 2016 Rui-Yun Tian et al. All rights reserved. Intravascular Residence Time Determination for the Cyanide Antidote Dimethyl Trisulfide in Rat by Using Liquid-Liquid Extraction Coupled with High Performance Liquid Chromatography Wed, 07 Dec 2016 13:23:33 +0000 http://www.hindawi.com/journals/jamc/2016/6546475/ These studies represent the first report on the intravascular residence time determinations for the cyanide antidote dimethyl trisulfide (DMTS) in a rat model by using high performance liquid chromatography coupled with ultraviolet absorption spectroscopy (HPLC-UV). The newly developed sample preparation included liquid-liquid extraction by cyclohexanone. The calibration curves showed a linear response for DMTS concentrations between 0.010 and 0.30 mg/mL with = 0.9994. The limit of detection for DMTS via this extraction method was 0.010 mg/mL, and the limit of quantitation was 0.034 mg/mL. Thus this calibration curve provided a tool for determining DMTS in the range between 0.04 and 0.30 mg/mL. Rats were given 20 mg/kg DMTS dose (in 15% Polysorbate 80) intravenously, and blood samples were taken 15, 60, 90, 120, and 240 min after DMTS injections. The data points were plotted as DMTS concentration in RBCs versus time, and the intravascular residence time was determined graphically. The results indicated a half-life of 36 min in a rat model, suggesting that the circulation time is long enough to provide a reasonable time interval for cyanide antagonism. Deepthika De Silva, Steven Lee, Anna Duke, Siva Angalakurthi, Ching-En Chou, Afshin Ebrahimpour, David E. Thompson, and Ilona Petrikovics Copyright © 2016 Deepthika De Silva et al. All rights reserved. Accurate Assessment of the Oxygen Reduction Electrocatalytic Activity of Mn/Polypyrrole Nanocomposites Based on Rotating Disk Electrode Measurements, Complemented with Multitechnique Structural Characterizations Wed, 30 Nov 2016 13:50:19 +0000 http://www.hindawi.com/journals/jamc/2016/2030675/ This paper reports on the quantitative assessment of the oxygen reduction reaction (ORR) electrocatalytic activity of electrodeposited Mn/polypyrrole (PPy) nanocomposites for alkaline aqueous solutions, based on the Rotating Disk Electrode (RDE) method and accompanied by structural characterizations relevant to the establishment of structure-function relationships. The characterization of Mn/PPy films is addressed to the following: (i) morphology, as assessed by Field-Emission Scanning Electron Microscopy (FE-SEM) and Atomic Force Microscope (AFM); (ii) local electrical conductivity, as measured by Scanning Probe Microscopy (SPM); and (iii) molecular structure, accessed by Raman Spectroscopy; these data provide the background against which the electrocatalytic activity can be rationalised. For comparison, the properties of Mn/PPy are gauged against those of graphite, PPy, and polycrystalline-Pt (poly-Pt). Due to the literature lack of accepted protocols for precise catalytic activity measurement at poly-Pt electrode in alkaline solution using the RDE methodology, we have also worked on the obtainment of an intralaboratory benchmark by evidencing some of the time-consuming parameters which drastically affect the reliability and repeatability of the measurement. Patrizia Bocchetta, Carolina Ramírez Sánchez, Antonietta Taurino, and Benedetto Bozzini Copyright © 2016 Patrizia Bocchetta et al. All rights reserved. Influence of Extreme Storage Conditions on Extra Virgin Olive Oil Parameters: Traceability Study Wed, 30 Nov 2016 11:56:33 +0000 http://www.hindawi.com/journals/jamc/2016/7506807/ This study reflects the effect of extreme storage conditions on several extra virgin olive oil (EVOO) varieties (arbequina, hojiblanca, and picual). The conditions were simulated in the laboratory, by means of heating treatments in stove at different temperatures (40 and 60°C) and times (two and three weeks). The aim is the evaluation of the deterioration of the quality parameters and minority components, which are responsible for the nutritional and therapeutic properties (fatty acids, polyphenols, pigments, and tocopherols), and organoleptic qualities. The quality criteria and limits used in this work are according to International Olive Council. The results contribute to the control of the traSceability for the commercialization of the EVOO. Alfredo Escudero, Natividad Ramos, M. Dolores La Rubia, and Rafael Pacheco Copyright © 2016 Alfredo Escudero et al. All rights reserved. Mass Spectrometry of Polymer Electrolyte Membrane Fuel Cells Tue, 29 Nov 2016 14:07:18 +0000 http://www.hindawi.com/journals/jamc/2016/6097285/ The chemical analysis of processes inside fuel cells under operating conditions in either direct or inverted (electrolysis) mode and their correlation with potentiostatic measurements is a crucial part of understanding fuel cell electrochemistry. We present a relatively simple yet powerful experimental setup for online monitoring of the fuel cell exhaust (of either cathode or anode side) downstream by mass spectrometry. The influence of a variety of parameters (composition of the catalyst, fuel type or its concentration, cell temperature, level of humidification, mass flow rate, power load, cell potential, etc.) on the fuel cell operation can be easily investigated separately or in a combined fashion. We demonstrate the application of this technique on a few examples of low-temperature (70°C herein) polymer electrolyte membrane fuel cells (both alcohol- and hydrogen-fed) subjected to a wide range of conditions. Viktor Johánek, Anna Ostroverkh, Roman Fiala, Andrii Rednyk, and Vladimír Matolín Copyright © 2016 Viktor Johánek et al. All rights reserved. Synthesis and Characterization of Molecular Imprinting Polymer Microspheres of Piperine: Extraction of Piperine from Spiked Urine Sun, 27 Nov 2016 10:49:23 +0000 http://www.hindawi.com/journals/jamc/2016/5671507/ Molecularly imprinted polymer (MIP) microspheres for Piperine were synthesized by precipitation polymerization with a noncovalent approach. In this research Piperine was used as a template, acrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, and 2,2′-azobisisobutyronitrile (AIBN) as an initiator and acetonitrile as a solvent. The imprinted and nonimprinted polymer particles were characterized by using Fourier transform infrared spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM). The synthesized polymer particles were further evaluated for their rebinding efficiency by batch binding assay. The highly selected imprinted polymer for Piperine was MIP 3 with a composition (molar ratio) of 0.5 : 3 : 8, template : monomer : cross-linker, respectively. The MIP 3 exhibits highest binding capacity (84.94%) as compared to other imprinted and nonimprinted polymers. The extraction efficiency of highly selected imprinted polymer of Piperine from spiked urine was above 80%. Rachel Marcella Roland and Showkat Ahmad Bhawani Copyright © 2016 Rachel Marcella Roland and Showkat Ahmad Bhawani. All rights reserved. Rapid Quantitative Analysis of Forest Biomass Using Fourier Transform Infrared Spectroscopy and Partial Least Squares Regression Thu, 24 Nov 2016 09:42:05 +0000 http://www.hindawi.com/journals/jamc/2016/1839598/ Fourier transform infrared reflectance (FTIR) spectroscopy has been used to predict properties of forest logging residue, a very heterogeneous feedstock material. Properties studied included the chemical composition, thermal reactivity, and energy content. The ability to rapidly determine these properties is vital in the optimization of conversion technologies for the successful commercialization of biobased products. Partial least squares regression of first derivative treated FTIR spectra had good correlations with the conventionally measured properties. For the chemical composition, constructed models generally did a better job of predicting the extractives and lignin content than the carbohydrates. In predicting the thermochemical properties, models for volatile matter and fixed carbon performed very well (i.e., > 0.80, RPD > 2.0). The effect of reducing the wavenumber range to the fingerprint region for PLS modeling and the relationship between the chemical composition and higher heating value of logging residue were also explored. This study is new and different in that it is the first to use FTIR spectroscopy to quantitatively analyze forest logging residue, an abundant resource that can be used as a feedstock in the emerging low carbon economy. Furthermore, it provides a complete and systematic characterization of this heterogeneous raw material. Gifty E. Acquah, Brian K. Via, Oladiran O. Fasina, and Lori G. Eckhardt Copyright © 2016 Gifty E. Acquah et al. All rights reserved. Study on the Effect of the Three-Dimensional Electrode in Degradation of Methylene Blue by Lithium Modified Rectorite Wed, 16 Nov 2016 10:27:16 +0000 http://www.hindawi.com/journals/jamc/2016/8198235/ This study presents the electrochemical degradation of methylene blue (MB) wastewater in a synthetic solution using three-dimensional particle electrodes. The novel particle electrodes were fabricated in this work using the lithium modified rectorite (Li-REC). The adsorption property of the fabricated particle electrodes was studied in a series of experiments. The optimum electrochemical operating conditions of plate distance, cell voltage, and concentration of electrolyte were 2 cm, 9 V, and 0.06 mol L−1, respectively. It was also found that microwave irradiation can effectively improve the adsorption property and electrical property of the fabricated electrodes. In addition, the scanning electron microscope (SEM) of the fabricated electrodes was investigated. The experimental results revealed the order of adsorption property and electrical property of the fabricated electrodes. So, fabricated electrodes are not only of low cost and mass produced, but also efficient to achieve decolorization of MB solution. Jian Huang, Yin’an Ming, Ying Du, Yingru Wang, and Ci’en Wang Copyright © 2016 Jian Huang et al. All rights reserved. Determination of Metal Impurities in Carbon Nanotubes Sampled Using Surface Wipes Wed, 16 Nov 2016 10:00:57 +0000 http://www.hindawi.com/journals/jamc/2016/3834292/ Residual metal impurities in carbon nanotubes (CNTs) provide a means to distinguish CNT from non-CNT sources of elemental carbon in environmental samples. A practical and cost-effective analytical approach is needed to support routine surface monitoring of CNT metal tracers using wipe sampling. Wipe sampling for CNT metal tracers is considered a qualitative indicator of the presence of CNTs, not a quantitative exposure metric. In this study, two digestion approaches (microwave-assisted nitric acid/H2O2 digestion and ultrasonic nitric/HF acid digestion) in conjunction with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) determination were evaluated for their ability to extract metal impurities from CNT particles captured on wipe substrates. Aliquots of different carbon nanotubes (including NIST 2483 single-wall CNT) with and without GhostWipes™ (ASTM E-1792 compliant) were used to compare the performance of the digestion methods. The microwave digestion method accommodated the bulky wipe sample and also eliminated potential ICP-MS signal interferences related to incomplete digestion. Although quantitative recoveries requiring lengthy multistep digestion protocols may be necessary in other applications, the near-total recoveries achieved in the present study for CNT catalyst elements were adequate for identifying surface contamination of CNTs in the workplace using wipe sampling. Mary-Luyza Avramescu, Pat E. Rasmussen, and Marc Chénier Copyright © 2016 Mary-Luyza Avramescu et al. All rights reserved. Study of the Antioxidant Property Variation of Cornelian Cherry Fruits during Storage Using HPTLC and Spectrophotometric Assays Thu, 10 Nov 2016 14:51:23 +0000 http://www.hindawi.com/journals/jamc/2016/2345375/ Cornus species fruits are well known as a rich source of antioxidant compounds responsible for their diverse health benefits. The present study aims to investigate the variation of the total antioxidant capacity of Cornelian cherry (Cornus mas L.) fruits during storage, using high-performance thin-layer chromatography (HPTLC) and two spectrophotometric assays based on different mechanisms: the 2,2-azinobis(3-ethylbenzothiazolyne-6-sulphonic acid) radical cation () assay and the ferric reducing antioxidant power (FRAP) assay. The fruit extract was stored at room temperature (22°C) for 19 days. No major differences in the total antioxidant capacity were observed during this period, indicating that storage does not have any deleterious effect on the antioxidant properties of the investigated fruits extract. The antioxidant capacity varied between 12.91 and 12.83 µmol Trolox/g fruit as determined by the HPTLC method and from 36.13 to 33.93 µmol Trolox/g fruit as determined by the ABTS assay. Anamaria Hosu, Claudia Cimpoiu, Luminita David, and Bianca Moldovan Copyright © 2016 Anamaria Hosu et al. All rights reserved.