International Journal of Analytical Chemistry The latest articles from Hindawi © 2018 , Hindawi Limited . All rights reserved. Simultaneous Determination of Nitroimidazoles and Quinolones in Honey by Modified QuEChERS and LC-MS/MS Analysis Mon, 01 Jan 2018 09:20:25 +0000 This study reports an analytical method for the determination of nitroimidazole and quinolones in honey using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A modified QuEChERS methodology was used to extract the analytes and determine veterinary drugs in honey by LC-MS/MS. The linear regression was excellent at the concentration levels of 1–100 ng/mL in the solution standard curve and the matrix standard curve. The recovery rates of nitroimidazole and quinolones were 4.4% to 59.1% and 9.8% to 46.2% with relative standard deviations (RSDs) below 5.2% and the recovery rates of nitroimidazole and quinolones by the matrix standard curve ranged from 82.0% to 117.8% and 79% to 115.9% with relative standard deviations (RSDs) lower than 6.3% in acacia and jujube honey. The acacia and jujube honeys have stronger matrix inhibition effect to nitroimidazole and quinolones residue; the matrix inhibition effect of jujube honey is stronger than acacia honey. The matrix standard curve can calibrate matrix effect effectively. In this study, the detection method of antibiotics in honey can be applied to the actual sample. The results demonstrated that the modified QuEChERS method combined with LC-MS/MS is a rapid, high, sensitive method for the analysis of nitroimidazoles and quinolones residues in honey. Haiyan Lei, Jianbo Guo, Zhuo Lv, Xiaohong Zhu, Xiaofeng Xue, Liming Wu, and Wei Cao Copyright © 2018 Haiyan Lei et al. All rights reserved. Characterization of Fossil and Renewable Fuels Mon, 01 Jan 2018 08:52:28 +0000 Xing Fan, Bo Chen, Xun Hu, Nilusha Sudasinghe, and Ya-He Zhang Copyright © 2018 Xing Fan et al. All rights reserved. A New Method for the Determination of Sucrose Concentration in a Pure and Impure System: Spectrophotometric Method Thu, 28 Dec 2017 00:00:00 +0000 Analytical chemistry is a set of procedures and techniques used to identify and quantify the composition of a sample of material. It is also focused on improvements in experimental design and the creation of new measurement tools. Analytical chemistry has broad applications to forensics, medicine, science, and engineering. The objective of this study is to develop a new method of sucrose dosage using a spectrophotometry method in a pure and impure system (presence of glucose and fructose). The work performed shows the reliability of this method. A model linking sucrose solution absorbance and mass percentage of glucose and fructose has been developed using experimental design. The results obtained show that all the investigated factors (sucrose concentration, mass percentage of glucose, and mass percentage of fructose) have a positive effect on the absorbance. The effect of the interaction between glucose and fructose on the absorbance is very significant. A. Borji, Fz. Borji, and A. Jourani Copyright © 2017 A. Borji et al. All rights reserved. Preparation and Anticorrosion of Octadecyl Trichlorosilane SAMs for Copper Surface Thu, 14 Dec 2017 00:00:00 +0000 The self-assembled monolayer (SAM) was prepared using octadecyl trichlorosilane (OTS) in distilled solution on the copper surface. The effect of inhibitor concentration on the rate of inhibition efficiency and corrosion rate in corrosion medium on copper by using polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM) was studied. The results showed that OTS SAMs exhibit the better corrosion resistance; the corrosion potential of copper OTS SAMs protection increased by about 1.02 V, while the corrosion current density decreased to 0.59 A/cm2. The corrosion rate is minimized and flattened and can reach 9.2% while the inhibition efficiency reached 95.4%, when the corrosion inhibitor has concentration of 40 ppm. Xue Shouqing and Liu Xiaohui Copyright © 2017 Xue Shouqing and Liu Xiaohui. All rights reserved. Analytical Strategies Involved in the Detailed Componential Characterization of Biooil Produced from Lignocellulosic Biomass Wed, 13 Dec 2017 00:00:00 +0000 Elucidation of chemical composition of biooil is essentially important to evaluate the process of lignocellulosic biomass (LCBM) conversion and its upgrading and suggest proper value-added utilization like producing fuel and feedstock for fine chemicals. Although the main components of LCBM are cellulose, hemicelluloses, and lignin, the chemicals derived from LCBM differ significantly due to the various feedstock and methods used for the decomposition. Biooil, produced from pyrolysis of LCBM, contains hundreds of organic chemicals with various classes. This review covers the methodologies used for the componential analysis of biooil, including pretreatments and instrumental analysis techniques. The use of chromatographic and spectrometric methods was highlighted, covering the conventional techniques such as gas chromatography, high performance liquid chromatography, Fourier transform infrared spectroscopy, nuclear magnetic resonance, and mass spectrometry. The combination of preseparation methods and instrumental technologies is a robust pathway for the detailed componential characterization of biooil. The organic species in biooils can be classified into alkanes, alkenes, alkynes, benzene-ring containing hydrocarbons, ethers, alcohols, phenols, aldehydes, ketones, esters, carboxylic acids, and other heteroatomic organic compounds. The recent development of high resolution mass spectrometry and multidimensional hyphenated chromatographic and spectrometric techniques has considerably elucidated the composition of biooils. Yao Lu, Guo-Sheng Li, Yong-Chao Lu, Xing Fan, and Xian-Yong Wei Copyright © 2017 Yao Lu et al. All rights reserved. A Multivariate Methodological Workflow for the Analysis of FTIR Chemical Mapping Applied on Historic Paint Stratigraphies Sun, 03 Dec 2017 00:00:00 +0000 In the field of applied researches in heritage science, the use of multivariate approach is still quite limited and often chemometric results obtained are often underinterpreted. Within this scenario, the present paper is aimed at disseminating the use of suitable multivariate methodologies and proposes a procedural workflow applied on a representative group of case studies, of considerable importance for conservation purposes, as a sort of guideline on the processing and on the interpretation of this FTIR data. Initially, principal component analysis (PCA) is performed and the score values are converted into chemical maps. Successively, the brushing approach is applied, demonstrating its usefulness for a deep understanding of the relationships between the multivariate map and PC score space, as well as for the identification of the spectral bands mainly involved in the definition of each area localised within the score maps. Giorgia Sciutto, Paolo Oliveri, Silvia Prati, Emilio Catelli, Irene Bonacini, and Rocco Mazzeo Copyright © 2017 Giorgia Sciutto et al. All rights reserved. Robustness of Tomato Quality Evaluation Using a Portable Vis-SWNIRS for Dry Matter and Colour Sun, 03 Dec 2017 00:00:00 +0000 The utility of a handheld visible-short wave near infrared spectrophotometer utilising an interactance optical geometry was assessed in context of the noninvasive determination of intact tomato dry matter content, as an index of final ripe soluble solids content, and colouration, as an index of maturation to guide a decision to harvest. Partial least squares regression model robustness was demonstrated through the use of populations of different harvest dates or growing conditions for calibration and prediction. Dry matter predictions of independent populations of fruit achieved ranging from 0.86 to 0.92 and bias from −0.14 to 0.03%. For a CIE colour model, prediction ranged from 0.85 to 0.96 and bias from −1.18 to −0.08. Updating the calibration model with new samples to extend range in the attribute of interest and in sample matrix is key to better prediction performance. The handheld spectrometry system is recommended for practical implementation in tomato cultivation. U. K. Acharya, P. P. Subedi, and K. B. Walsh Copyright © 2017 U. K. Acharya et al. All rights reserved. Alkaloids Profiling of Fumaria capreolata by Analytical Platforms Based on the Hyphenation of Gas Chromatography and Liquid Chromatography with Quadrupole-Time-of-Flight Mass Spectrometry Tue, 28 Nov 2017 00:00:00 +0000 Two analytical platforms, gas chromatography (GC) coupled to quadrupole-time-of-flight (QTOF) mass spectrometry (MS) and reversed-phase ultrahigh performance liquid chromatography (UHPLC) coupled to diode array (DAD) and QTOF detection, were applied in order to study the alkaloid profile of Fumaria capreolata. The use of these mass analyzers enabled tentatively identifying the alkaloids by matching their accurate mass signals and suggested molecular formulae with those previously reported in libraries and databases. Moreover, the proposed structures were corroborated by studying their fragmentation pattern obtained by both platforms. In this way, 8 and 26 isoquinoline alkaloids were characterized using GC-QTOF-MS and RP-UHPLC-DAD-QTOF-MS, respectively, and they belonged to the following subclasses: protoberberine, protopine, aporphine, benzophenanthridine, spirobenzylisoquinoline, morphinandienone, and benzylisoquinoline. Moreover, the latter analytical method was selected to determine at 280 nm the concentration of protopine (9.6 ± 0.7 mg/g), a potential active compound of the extract. In conclusion, although GC-MS has been commonly used for the analysis of this type of phytochemicals, RP-UHPLC-DAD-QTOF-MS provided essential complementary information. This analytical method can be applied for the quality control of phytopharmaceuticals containing Fumaria extracts currently found in the market. María del Mar Contreras, Noureddine Bribi, Ana María Gómez-Caravaca, Julio Gálvez, and Antonio Segura-Carretero Copyright © 2017 María del Mar Contreras et al. All rights reserved. Recent Studies on the Speciation and Determination of Mercury in Different Environmental Matrices Using Various Analytical Techniques Mon, 20 Nov 2017 00:00:00 +0000 This paper reviews the current research on the speciation and determination of mercury by various analytical techniques, including the atomic absorption spectrometry (AAS), voltammetry, inductively coupled plasma optical emission spectrometry (ICP-OES), ICP-mass spectrometry (MS), atomic fluorescence spectrometry (AFS), spectrophotometry, spectrofluorometry, and high performance liquid chromatography (HPLC). Approximately 96 research papers on the speciation and determination of mercury by various analytical instruments published in international journals since 2015 were reviewed. All analytical parameters, including the limits of detection, linearity range, quality assurance and control, applicability, and interfering ions, evaluated in the reviewed articles were tabulated. In this review, we found a lack of information in speciation studies of mercury in recent years. Another important conclusion from this review was that there were few studies regarding the concentration of mercury in the atmosphere. Lakshmi Narayana Suvarapu and Sung-Ok Baek Copyright © 2017 Lakshmi Narayana Suvarapu and Sung-Ok Baek. All rights reserved. Infrared Drying as a Quick Preparation Method for Dried Tangerine Peel Sun, 19 Nov 2017 00:00:00 +0000 To establish the most convenient and effective method to dry tangerine peels, different methods (sun drying, hot-air drying, freeze drying, vacuum drying, and medium- and short-wave infrared drying) were exploited. Our results indicated that medium- and short-wave infrared drying was the best method to preserve nutraceutical components; for example, vitamin C was raised to 6.77 mg/g (D.W.) from 3.39 mg/g (sun drying). Moreover, the drying time can be shortened above 96% compared with sun drying. Importantly, the efficiency of DPPH radical scavenging was enhanced from 26.66% to 55.92%. These findings would provide a reliable and time-saving methodology to produce high-quality dried tangerine peels. Mingyue Xu, Guifang Tian, Chengying Zhao, Aftab Ahmad, Huijuan Zhang, Jinfeng Bi, Hang Xiao, and Jinkai Zheng Copyright © 2017 Mingyue Xu et al. All rights reserved. Comparison of Attenuated Total Reflectance Mid-Infrared, Near Infrared, and 1H-Nuclear Magnetic Resonance Spectroscopies for the Determination of Coffee’s Geographical Origin Wed, 01 Nov 2017 00:00:00 +0000 The sensorial properties of Colombian coffee are renowned worldwide, which is reflected in its market value. This raises the threat of fraud by adulteration using coffee grains from other countries, thus creating a demand for robust and cost-effective methods for the determination of geographical origin of coffee samples. Spectroscopic techniques such as Nuclear Magnetic Resonance (NMR), near infrared (NIR), and mid-infrared (mIR) have arisen as strong candidates for the task. Although a body of work exists that reports on their individual performances, a faithful comparison has not been established yet. We evaluated the performance of 1H-NMR, Attenuated Total Reflectance mIR (ATR-mIR), and NIR applied to fraud detection in Colombian coffee. For each technique, we built classification models for discrimination by species (C. arabica versus C. canephora (or robusta)) and by origin (Colombia versus other C. arabica) using a common set of coffee samples. All techniques successfully discriminated samples by species, as expected. Regarding origin determination, ATR-mIR and 1H-NMR showed comparable capacity to discriminate Colombian coffee samples, while NIR fell short by comparison. In conclusion, ATR-mIR, a less common technique in the field of coffee adulteration and fraud detection, emerges as a strong candidate, faster and with lower cost compared to 1H-NMR and more discriminating compared to NIR. Jessica Medina, Diana Caro Rodríguez, Victoria A. Arana, Andrés Bernal, Pierre Esseiva, and Julien Wist Copyright © 2017 Jessica Medina et al. All rights reserved. Detailed Componential Characterization of Extractable Species with Organic Solvents from Wheat Straw Wed, 01 Nov 2017 00:00:00 +0000 Componential analysis of extractives is important for better understanding the structure and utilization of biomass. In this investigation, wheat straw (WS) was extracted with petroleum ether (PE) and carbon disulfide (CS2) sequentially, to afford extractable fractions and , respectively. Detailed componential analyses of and were carried out with Fourier transform infrared (FTIR) spectroscopy, gas chromatography/mass spectrometry (GC/MS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy dispersive spectrometry (EDS), and electron probe microanalysis (EPMA). Total extractives were quantified 4.96% by weight compared to the initial WS sample. FTIR and GC/MS analyses results showed that PE was effective for the extraction of ketones and waxes derived compounds; meanwhile CS2 preferred ketones and other species with higher degrees of unsaturation. Steroids were enriched into and with considerable high relative contents, namely, 64.52% and 79.58%, respectively. XPS analysis showed that most of the C atoms in extractives were contained in the structures of C-C, C-COOR, and C-O. TEM-EDS and EPMA analyses were used to detect trace amount elements, such as Al, Si, P, S, Cl, and Ca atoms. Detailed characterization of extractable species from WS can provide more information on elucidation of extractives in biomass. Yong-Chao Lu, Yao Lu, Zhao-Lin Lu, and Xian-Yong Wei Copyright © 2017 Yong-Chao Lu et al. All rights reserved. Development of a Rapid and Simple Method to Remove Polyphenols from Plant Extracts Mon, 23 Oct 2017 00:00:00 +0000 Polyphenols are secondary metabolites of plants, which are responsible for prevention of many diseases. Polyvinylpolypyrrolidone (PVPP) has a high affinity towards polyphenols. This method involves the use of PVPP column to remove polyphenols under centrifugal force. Standards of gallic acid, epigallocatechin gallate, vanillin, and tea extracts (Camellia sinensis) were used in this study. PVPP powder was packed in a syringe with different quantities. The test samples were layered over the PVPP column and subjected to centrifugation. Supernatant was tested for the total phenol content. The presence of phenolic compounds and caffeine was screened by HPLC and measuring the absorbance at 280. The antioxidant capacity of standards and tea extracts was compared with the polyphenol removed fractions using DPPH scavenging assay. No polyphenols were found in polyphenolic standards or tea extracts after PVPP treatment. The method described in the present study to remove polyphenols is simple, inexpensive, rapid, and efficient and can be employed to investigate the contribution of polyphenols present in natural products to their biological activity. Imali Ranatunge, Subshini Adikary, Piumi Dasanayake, Chamira Dilanka Fernando, and Preethi Soysa Copyright © 2017 Imali Ranatunge et al. All rights reserved. The Hazard Content of Cadmium, Lead, and Other Trace Elements in Some Medicinal Herbs and Their Water Infusions Thu, 19 Oct 2017 00:00:00 +0000 54 samples belonging to 23 herbal species (15 individuals and 8 mixtures) were analyzed for their contents of heavy metals in the raw materials and in their water infusions. Trace and toxic elements in these samples were determined by using inductively coupled plasma-atomic emission spectrometry (ICP-OES) following acid digestion. The order of decreasing mean metal concentrations in raw materials (mg/kg) was found to be as follows: Fe (440) > Mn (162) > Zn (45.8) > Cu (12) > Pb (10.4) > Ni (5.4) > Cr (2.9) > Co (0.91) > Cd (0.5). It was found that 21% of the analyzed samples contain both Cd and Pb above their permissible limits. However, the infusions produced from these plants were found to contain fewer amounts of metals than the raw materials. Studied metals had the following mass transfer percentages to the infusion solutions (Fe: 3.5%, Cd: 14%, Cr: 15%, Pb: 20%, Co: 29%, Ni: 31%, Zn: 36%, Cu: 48%, and Mn: 53%). The estimated daily intake calculated for the toxic elements Pb and Cd through the consumption of herbal infusions was far below the tolerable daily intake set by the World Health Organization (WHO). Fuad A. Ababneh Copyright © 2017 Fuad A. Ababneh. All rights reserved. Simple Quantification of Pentosidine in Human Urine and Plasma by High-Performance Liquid Chromatography Wed, 18 Oct 2017 00:00:00 +0000 Pentosidine is an advanced glycation end-product (AGE) and fluorescent cross-link compound. A simple high-performance liquid chromatographic (HPLC) method was developed for the detection and quantification of pentosidine in human urine and plasma. The mobile phase used a gradient system to improve separation of pentosidine from endogenous peaks, and chromatograms were monitored by fluorescent detector set at excitation and emission wavelengths of 328 and 378 nm, respectively. The retention time for pentosidine was 24.3 min and the lower limits of quantification (LLOQ) in human urine and plasma were 1 nM. The intraday assay precisions (coefficients of variation) were generally low and found to be in the range of 5.19–7.49% and 4.96–8.78% for human urine and plasma, respectively. The corresponding values of the interday assay precisions were 9.45% and 4.27%. Accuracies (relative errors) ranged from 87.9% to 115%. Pentosidine was stable in a range of pH solutions, human urine, and plasma. In summary, this HPLC method can be applied in future preclinical and clinical evaluation of pentosidine in the diabetic patients. Ji Sang Lee, Yoon-Sok Chung, Sun Young Chang, Yi-Sook Jung, and So Hee Kim Copyright © 2017 Ji Sang Lee et al. All rights reserved. Dispersive Solid Phase Extraction for the Analysis of Veterinary Drugs Applied to Food Samples: A Review Wed, 18 Oct 2017 00:00:00 +0000 To achieve analytical success, it is necessary to develop thorough clean-up procedures to extract analytes from the matrix. Dispersive solid phase extraction (DSPE) has been used as a pretreatment technique for the analysis of several compounds. This technique is based on the dispersion of a solid sorbent in liquid samples in the extraction isolation and clean-up of different analytes from complex matrices. DSPE has found a wide range of applications in several fields, and it is considered to be a selective, robust, and versatile technique. The applications of dispersive techniques in the analysis of veterinary drugs in different matrices involve magnetic sorbents, molecularly imprinted polymers, carbon-based nanomaterials, and the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method. Techniques based on DSPE permit minimization of additional steps such as precipitation, centrifugation, and filtration, which decreases the manipulation of the sample. In this review, we describe the main procedures used for synthesis, characterization, and application of this pretreatment technique and how it has been applied to food analysis. Gabriela Islas, Israel S. Ibarra, Prisciliano Hernandez, Jose M. Miranda, and Alberto Cepeda Copyright © 2017 Gabriela Islas et al. All rights reserved. Hollow-Fibre-Supported Dispersive Liquid-Liquid Microextraction for Determination of Atrazine and Triclosan in Aqueous Samples Wed, 11 Oct 2017 00:00:00 +0000 We report the application of the dispersive liquid-liquid microextraction coupled to hollow-fibre membrane-assisted liquid-phase microextraction and its application for extraction of atrazine and triclosan. Under optimum conditions, namely, 25 μL of a 1 : 4 chlorobenzene : ethyl acetate mixture dispersed in 1 mL of aqueous sample, 10% (m/v) NaCl, a magnetic stirrer speed at 600 rpm, and 10 minutes’ extraction time with toluene-filled fibre as the acceptor phase, the method demonstrates sufficient figures of merit. These include linearity ( ≥ 0.9975), intravial precision (%RSD ≤ 7.6), enrichment factors (127 and 142), limits of detection (0.0081 and 0.0169 µg/mL), and recovery from river water and sewerage (96–101%). The relatively high detection limits are attributed to the flame ionization detector which is less preferred than a mass spectrometer in trace analyses. This is the first report of a homogenous mixture of the dispersed organic solvent in aqueous solutions and its employment in extraction of organic compounds from aqueous solutions. It therefore adds yet another candidate in the pool of miniaturised solvent microextraction techniques. Thabiso Letseka and Mosotho J. George Copyright © 2017 Thabiso Letseka and Mosotho J. George. All rights reserved. Using Odd-Alkanes as a Carbon Source to Increase the Content of Nutritionally Important Fatty Acids in Candida krusei, Trichosporon cutaneum, and Yarrowia lipolytica Tue, 10 Oct 2017 00:00:00 +0000 We investigated the possibility of utilizing unusual carbon sources by three yeast strains: Candida krusei DBM 2136, Trichosporon cutaneum CCY 30-5-10, and Yarrowia lipolytica CCY 30-26-36. These strains are characterized by high biomass yield, ability to accumulate high amounts of lipids, and their potential as producers of dietetically important fatty acids. The aim of this work was the production of nutritionally important fatty acids by utilization of n-alkanes with an odd number of carbon atoms, alone and in combination with glucose and subsequent analysis of microbial lipids accumulation and fatty acid profile. All three yeast strains were able to grow and produce high amounts of the fatty acids of interest. Yarrowia lipolytica was found as the most suitable strain for the growth on n-alkanes (n-pentadecane and n-heptadecane) as the only source of carbon. The addition of biosurfactants rhamnolipids into the cultivation increased the ratio of heptadecenoic acid (up to 17.9% of total FAs in Y. lipolytica CCY 30-26-36, 14.9% in T. cutaneum CCY 30-5-10, and 17.5% in C. krusei DBM 2136) and the total biomass yield. The results show that, by manipulation of the initial cultivation conditions, the ratio of important fatty acids may be increased. Olga Matatkova, Lucia Gharwalova, Michal Zimola, Tomas Rezanka, Jan Masak, and Irena Kolouchova Copyright © 2017 Olga Matatkova et al. All rights reserved. Application of HPTLC with Densitometry for Evaluation of the Impact of External Factors on Contents of Diphenhydramine in Its Solutions Mon, 18 Sep 2017 09:34:24 +0000 The subject of durability of drugs is a very important problem investigated by researches. The method of accelerated aging is very often used for stability testing. It involves the influence of temperature, humidity, and light exposure. The aim of this work is estimation of contents of diphenhydramine in its standard solutions undergoing the impact of external factors, that is, temperature and UV light. The standard solutions of diphenhydramine were prepared in distilled water. The analysis of contents of compound investigated was carried out by use of HPTLC. Adsorption thin layer chromatography was performed on aluminum HPTLC plates precoated with silica gel 60F254 using mixture of ammonia, methanol, and ethyl acetate as mobile phase. The solutions investigated were exposed to UV light as well as being heated in 40°C. The contents of diphenhydramine were measured in initial solution and during experiment. The additional peaks on densitograms as well as changes in color of solution were observed as a result of exposure to UV light which can give information about new substances, degradation products of diphenhydramine, which were created during experiment. Katarzyna Bober Copyright © 2017 Katarzyna Bober. All rights reserved. Analysis of Three Compounds in Flos Farfarae by Capillary Electrophoresis with Large-Volume Sample Stacking Tue, 05 Sep 2017 07:49:50 +0000 The aim of this study was to develop a method combining an online concentration and high-efficiency capillary electrophoresis separation to analyze and detect three compounds (rutin, hyperoside, and chlorogenic acid) in Flos Farfarae. In order to get good resolution and enrichment, several parameters such as the choice of running buffer, pH and concentration of the running buffer, organic modifier, temperature, and separation voltage were all investigated. The optimized conditions were obtained as follows: the buffer of 40 mM NaH2P04-40 mM Borax-30% v/v methanol (pH 9.0); the sample hydrodynamic injection of up to 4 s at 0.5 psi; 20 kV applied voltage. The diode-array detector was used, and the detection wavelength was 364 nm. Based on peak area, higher levels of selective and sensitive improvements in analysis were observed and about 14-, 26-, and 5-fold enrichment of rutin, hyperoside, and chlorogenic acid were achieved, respectively. This method was successfully applied to determine the three compounds in Flos Farfarae. The linear curve of peak response versus concentration was from 20 to 400 µg/ml, 16.5 to 330 µg/mL, and 25 to 500 µg/mL, respectively. The regression coefficients were 0.9998, 0.9999, and 0.9991, respectively. Hai-xia Yu, Zeng-Yan Hao, Lu Li, Ya-yun Huang, Hong-Fen Zhang, and An-jia Chen Copyright © 2017 Hai-xia Yu et al. All rights reserved. Sensitive Wavelengths Selection in Identification of Ophiopogon japonicus Based on Near-Infrared Hyperspectral Imaging Technology Sun, 27 Aug 2017 10:21:14 +0000 Hyperspectral imaging (HSI) technology has increasingly been applied as an analytical tool in fields of agricultural, food, and Traditional Chinese Medicine over the past few years. The HSI spectrum of a sample is typically achieved by a spectroradiometer at hundreds of wavelengths. In recent years, considerable effort has been made towards identifying wavelengths (variables) that contribute useful information. Wavelengths selection is a critical step in data analysis for Raman, NIRS, or HSI spectroscopy. In this study, the performances of 10 different wavelength selection methods for the discrimination of Ophiopogon japonicus of different origin were compared. The wavelength selection algorithms tested include successive projections algorithm (SPA), loading weights (LW), regression coefficients (RC), uninformative variable elimination (UVE), UVE-SPA, competitive adaptive reweighted sampling (CARS), interval partial least squares regression (iPLS), backward iPLS (BiPLS), forward iPLS (FiPLS), and genetic algorithms (GA-PLS). One linear technique (partial least squares-discriminant analysis) was established for the evaluation of identification. And a nonlinear calibration model, support vector machine (SVM), was also provided for comparison. The results indicate that wavelengths selection methods are tools to identify more concise and effective spectral data and play important roles in the multivariate analysis, which can be used for subsequent modeling analysis. Zhengyan Xia, Chu Zhang, Haiyong Weng, Pengcheng Nie, and Yong He Copyright © 2017 Zhengyan Xia et al. All rights reserved. NMR Confirmation and HPLC Quantification of Javamide-I and Javamide-II in Green Coffee Extract Products Available in the Market Wed, 23 Aug 2017 00:00:00 +0000 Javamide-I/javamide-II are phenolic amides found in coffee. Recent reports suggested that they may contain several biological activities related to human health. Therefore, there is emergent interest about their quantities in coffee-related products. Green coffee extract is a powder extract made of unroasted green coffee beans, available as a dietary supplement. However, there is little information about the amounts of javamide-I/javamide-II in green coffee extract products in the market. Therefore, in this paper, javamide-I/javamide-II were extracted from green coffee extract products and their identifications were confirmed by NMR. After that, the amounts of javamide-I/javamide-II were individually quantified from seven different green coffee extract samples using the HPLC method coupled to an electrochemical detector. The HPLC method provided accurate and reliable measurement of javamide-I/javamide-II with excellent peak resolution and low detection limit. In all seven green coffee extract samples, javamide-II was found to be between 0.28 and 2.96 mg/g, but javamide-I was detected in only five samples in the concentration levels of 0.15–0.52 mg/g, suggesting that green coffee extract products contain different amounts of javamide-I/javamide-II. In summary, javamide-I/javamide-II can be found in green coffee extract products sold in the market, but their amounts are likely to be comparatively different in between green coffee extract brands. Jae B. Park Copyright © 2017 Jae B. Park. All rights reserved. Separation Process of Fine Coals by Ultrasonic Vibration Gas-Solid Fluidized Bed Sun, 06 Aug 2017 09:01:07 +0000 Ultrasonic vibration gas-solid fluidized bed was proposed and introduced to separate fine coals (0.5–0.125 mm fraction). Several technological methods such as XRF, XRD, XPS, and EPMA were used to study the composition of heavy products to evaluate the separation effect. Results show that the ultrasonic vibration force field strengthens the particle separation process based on density when the vibration frequency is 35 kHz and the fluidization number is 1.8. The ash difference between the light and heavy products and the recovery of combustible material obtain the maximum values of 47.30% and 89.59%, respectively. The sulfur content of the heavy product reaches the maximum value of 6.78%. Chemical state analysis of sulfur shows that organic sulfur (-C-S-), sulfate-sulfur (-SO4), and pyrite-sulfur (-S2) are confirmed in the original coal and heavy product. Organic sulfur (-C-S-) is mainly concentrated in the light product, and pyrite-sulfur (-S2) is significantly enriched in the heavy product. The element composition, phase composition, backscatter imagery, and surface distribution of elements for heavy product show concentration of high-density minerals including pyrite, quartz, and kaolinite. Some harmful elements such as F, Pb, and As are also concentrated in the heavy product. Shuai Wang, Yaqun He, Hua Wei, and Weining Xie Copyright © 2017 Shuai Wang et al. All rights reserved. Phenolics in Primula veris L. and P. elatior (L.) Hill Raw Materials Tue, 01 Aug 2017 00:00:00 +0000 Primula veris L. and Primula elatior (L.) Hill represent medicinal plants used for the production of herbal teas and preparations with antioxidant and expectorant activity. Flowers and roots of both species possess the same biological activity. In the presented study, raw materials of wild growing P. veris and P. elatior were compared in terms of the content and composition of phenolic compounds using a fast and simple HPLC-DAD method. The study showed that flowers of both species were rich in flavonoids. However, P. veris flowers were characterized with a distinctly higher content of isorhamnetin-3-O-glucoside, astragalin, and (+)-catechin, whereas P. elatior occurred to be a richer source of rutoside and isorhamnetin-3-O-rutinoside. Hyperoside was found exclusively in P. elatior flowers. Phenolic glycosides (primverin and primulaverin) were identified only in the roots. Their content was about ten times higher in P. veris in comparison with P. elatior underground organs. The obtained results clearly show that both Primula species differ distinctly in terms of the content and composition of phenolic compounds. The compounds differentiating both species to the highest degree (hyperoside, in flowers, as well as primverin and primulaverin, in the roots) may be useful chemical markers in the identification and evaluation of both species. Katarzyna Bączek, Jarosław L. Przybył, Małgorzata Mirgos, Olga Kosakowska, Izabela Szymborska-Sandhu, and Zenon Węglarz Copyright © 2017 Katarzyna Bączek et al. All rights reserved. In Vitro Dissolution Profile of Dapagliflozin: Development, Method Validation, and Analysis of Commercial Tablets Mon, 31 Jul 2017 07:55:53 +0000 Dapagliflozin was the first of its class (inhibitors of sodium-glucose cotransporter) to be approved in Europe, USA, and Brazil. As the drug was recently approved, there is the need for research on analytical methods, including dissolution studies for the quality evaluation and assurance of tablets. The dissolution methodology was developed with apparatus II (paddle) in 900 mL of medium (simulated gastric fluid, pH 1.2), temperature set at °C, and stirring speed of 50 rpm. For the quantification, a spectrophotometric ( nm) method was developed and validated. In validation studies, the method proved to be specific and linear in the range from 0.5 to 15 μg·mL−1 (). The precision showed results with RSD values lower than 2%. The recovery of 80.72, 98.47, and 119.41% proved the accuracy of the method. Through a systematic approach by applying Factorial 23, the robustness of the method was confirmed (). The studies of commercial tablets containing 5 or 10 mg demonstrated that they could be considered similar through , , and dissolution efficiency analyses. Also, the developed method can be used for the quality evaluation of dapagliflozin tablets and can be considered as a scientific basis for future official pharmacopoeial methods. Rafaela Zielinski Cavalheiro de Meira, Aline Biggi Maciel, Fabio Seigi Murakami, Paulo Renato de Oliveira, and Larissa Sakis Bernardi Copyright © 2017 Rafaela Zielinski Cavalheiro de Meira et al. All rights reserved. Effect of Isopropyl Alcohol Concentration and Etching Time on Wet Chemical Anisotropic Etching of Low-Resistivity Crystalline Silicon Wafer Mon, 31 Jul 2017 07:26:49 +0000 A micropyramid structure was formed on the surface of a monocrystalline silicon wafer (100) using a wet chemical anisotropic etching technique. The main objective was to evaluate the performance of the etchant based on the silicon surface reflectance. Different isopropyl alcohol (IPA) volume concentrations (2, 4, 6, 8, and 10%) and different etching times (10, 20, 30, 40, and 50 min) were selected to study the total reflectance of silicon wafers. The other parameters such as NaOH concentration (12% wt.), the temperature of the solution (81.5°C), and range of stirrer speeds (400 rpm) were kept constant for all processes. The surface morphology of the wafer was analyzed by optical microscopy and atomic force microscopy (AFM). The AFM images confirmed a well-uniform pyramidal structure with various average pyramid sizes ranging from 1 to 1.6 μm. A UV-Vis spectrophotometer with integrating sphere was used to obtain the total reflectivity. The textured silicon wafers show high absorbance in the visible region. The optimum texture-etching parameters were found to be 4–6% vol. IPA and 40 min at which the average total reflectance of the silicon wafer was reduced to 11.22%. Eyad Abdur-Rahman, Ibrahim Alghoraibi, and Hassan Alkurdi Copyright © 2017 Eyad Abdur-Rahman et al. All rights reserved. Hexavalent Chromium Removal from Model Water and Car Shock Absorber Factory Effluent by Nanofiltration and Reverse Osmosis Membrane Thu, 27 Jul 2017 00:00:00 +0000 Nanofiltration and reverse osmosis are investigated as a possible alternative to the conventional methods of Cr(VI) removal from model water and industrial effluent. The influences of feed concentration, water recovery, pH, and the coexisting anions were studied. The results have shown that retention rates of hexavalent chromium can reach 99.7% using nanofiltration membrane (NF-HL) and vary from 85 to 99.9% using reverse osmosis membrane (RO-SG) depending upon the composition of the solution and operating conditions. This work was also extended to investigate the separation of Cr(VI) from car shock absorber factory effluent. The use of these membranes is very promising for Cr(VI) water treatment and desalting industry effluent. Spiegler-Kedem model was applied to experimental results in the aim to determine phenomenological parameters, the reflection coefficient of the membrane , and the solute permeability coefficient . The convective and diffusive parts of the mass transfer were quantified with predominance of the diffusive contribution. Amine Mnif, Imen Bejaoui, Meral Mouelhi, and Béchir Hamrouni Copyright © 2017 Amine Mnif et al. All rights reserved. Effectiveness of Liquid-Liquid Extraction, Solid Phase Extraction, and Headspace Technique for Determination of Some Volatile Water-Soluble Compounds of Rose Aromatic Water Sun, 16 Jul 2017 10:33:29 +0000 Steam distillation is used to isolate scent of rose flowers. Rose aromatic water is commonly used in European cuisine and aromatherapy besides its use in cosmetic industry for its lovely scent. In this study, three different sampling techniques, liquid-liquid extraction (LLE), headspace technique (HS), and solid phase extraction (SPE), were compared for the analysis of volatile water-soluble compounds in commercial rose aromatic water. Some volatile water-soluble compounds of rose aromatic water were also analyzed by gas chromatography mass spectrometry (GCMS). In any case, it was concluded that one of the solid phase extraction methods led to higher recoveries for 2-phenylethyl alcohol (PEA) in the rose aromatic water than the liquid-liquid extraction and headspace technique. Liquid-liquid extraction method provided higher recovery ratios for citronellol, nerol, and geraniol than others. Ideal linear correlation coefficient values were observed by GCMS for quantitative analysis of volatile compounds (). Optimized methods showed acceptable repeatability (RSDs < 5%) and excellent recovery (>95%). For compounds such as α-pinene, linalool, β-caryophyllene, α-humulene, methyl eugenol, and eugenol, the best recovery values were obtained with LLE and SPE. Hale Seçilmiş Canbay Copyright © 2017 Hale Seçilmiş Canbay. All rights reserved. Quantification of Barbatusin and 3β-Hydroxy-3-deoxybarbatusin in Plectranthus Species by HPLC-DAD Mon, 03 Jul 2017 07:43:31 +0000 The concentration of diterpenes barbatusin (1) and 3β-hydroxy-3-deoxybarbatusin (2) in the extracts from leaves of Plectranthus grandis, P. barbatus, P. ornatus, and P. amboinicus was evaluated by HPLC-DAD analysis on a Luna C-18 column, using isocratic mixtures of water and acetonitrile as eluents. The regression equations were obtained with good linearity (r2 > 0.99) and limit of quantifications was higher than 0.1 µg/mL. The precision (lower than 3.5%, within day) and accuracy (higher than 81.7% and lower than 107.6%) of the methods were adequate. Barbatusin (1) was detected in P. grandis (15.432 ± 2.28 mg/g) and P. barbatus (5.198 ± 3.45 mg/g) extracts, while compound 2 was detected in P. grandis (4.068 ± 3.34 mg/g), P. barbatus (0.654 ± 5.86 mg/g), P. amboinicus (0.160 ± 7.25 mg/g), and P. ornatus (0.763 ± 5.10 mg/g). The evaluated validation parameters were satisfactorily achieved, and the developed methodology represents a suitable tool for application in the quantification of barbatusin (1) and 3β-hydroxy-3-deoxybarbatusin (2) in Plectranthus species. Maria Goretti de Vasconcelos Silva, Leandro Bezerra Lima, Maria da Conceição Ferreira de Oliveira, Marcos Carlos de Mattos, and Jair Mafezoli Copyright © 2017 Maria Goretti de Vasconcelos Silva et al. All rights reserved. Geochemical Characteristics and Origins of the Crude Oil of Triassic Yanchang Formation in Southwestern Yishan Slope, Ordos Basin Sun, 02 Jul 2017 00:00:00 +0000 Biomarker compounds that derived from early living organisms play an important role in oil and gas geochemistry and exploration since they can record the diagenetic evolution of the parent materials of crude oil and reflect the organic geochemical characteristics of crude oil and source rocks. To offer scientific basis for oil exploration and exploitation for study area, gas chromatography-mass spectrometry method is applied to study the biomarker compounds of crude oil in Southwestern Yishan Slope of Ordos Basin, through qualitatively and quantitatively analyzing separated materials. The crude oil of Yanchang Formation and the source rocks of Yan’an and Yanchang Formation were collected in order to systematically analyze the characteristics of the biomarker compounds in saturated hydrocarbon fractions and clarify the organic geochemical characteristics of crude oil. The distribution and composition of various types of hydrocarbon biomarker compounds in crude oil suggest that the parent materials of crude oil are composed of hydrobiont and terrigenous plants, and the crude oil is mature oil which is formed in the weak reducing fresh water environment. Oil source correlation results show that the crude oil of Yanchang Formation in Yishan Slope is sourced from the source rocks of Chang 7 subformation. Xiaoli Zhang, Jinxian He, Yande Zhao, Hongchen Wu, and Zeqiang Ren Copyright © 2017 Xiaoli Zhang et al. All rights reserved.