International Journal of Analytical Chemistry http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Recent Advances in the Synthesis and Stabilization of Nickel and Nickel Oxide Nanoparticles: A Green Adeptness Sun, 19 Jun 2016 11:22:34 +0000 http://www.hindawi.com/journals/ijac/2016/3512145/ Green protocols for the synthesis of nanoparticles have been attracting a lot of attention because they are eco-friendly, rapid, and cost-effective. Nickel and nickel oxide nanoparticles have been synthesized by green routes and characterized for impact of green chemistry on the properties and biological effects of nanoparticles in the last five years. Green synthesis, properties, and applications of nickel and nickel oxide nanoparticles have been reported in the literature. This review summarizes the synthesis of nickel and nickel oxide nanoparticles using different biological systems. This review also provides comparative overview of influence of chemical synthesis and green synthesis on structural properties of nickel and nickel oxide nanoparticles and their biological behavior. It concludes that green methods for synthesis of nickel and nickel oxide nanoparticles are better than chemical synthetic methods. Muhammad Imran Din and Aneela Rani Copyright © 2016 Muhammad Imran Din and Aneela Rani. All rights reserved. Selective Sensing of Tyrosine Phosphorylation in Peptides Using Terbium(III) Complexes Wed, 08 Jun 2016 11:22:37 +0000 http://www.hindawi.com/journals/ijac/2016/3216523/ Phosphorylation of tyrosine residues in proteins, as well as their dephosphorylation, is closely related to various diseases. However, this phosphorylation is usually accompanied by more abundant phosphorylation of serine and threonine residues in the proteins and covers only 0.05% of the total phosphorylation. Accordingly, highly selective detection of phosphorylated tyrosine in proteins is an urgent subject. In this review, recent developments in this field are described. Monomeric and binuclear complexes, which emit notable luminescence only in the presence of phosphotyrosine (pTyr), have been developed. There, the benzene ring of pTyr functions as an antenna and transfers its photoexcitation energy to the ion as the emission center. Even in the coexistence of phosphoserine (pSer) and phosphothreonine (pThr), pTyr can be efficintly detected with high selectivity. Simply by adding these complexes to the solutions, phosphorylation of tyrosine in peptides by protein tyrosine kinases and dephosphorylation by protein tyrosine phosphatases can be successfully visualized in a real-time fashion. Furthermore, the activities of various inhibitors on these enzymes are quantitatively evaluated, indicating a strong potential of the method for efficient screening of eminent inhibitors from a number of candidates. Jun Sumaoka, Hiroki Akiba, and Makoto Komiyama Copyright © 2016 Jun Sumaoka et al. All rights reserved. Simultaneous Determination of Four Active Ingredients in Sargentodoxa cuneata by HPLC Coupled with Evaporative Light Scattering Detection Sun, 29 May 2016 14:15:55 +0000 http://www.hindawi.com/journals/ijac/2016/8509858/ A HPLC coupled with evaporative light scattering detection method had been developed for the simultaneous determination of 3,4-dihydroxyphenylethyl alcohol glycoside, salidroside, chlorogenic acid, and liriodendrin in the stem of Sargentodoxa cuneata. With a C18 column, the analysis was performed using acetonitrile and 0.2% formic acid aqueous solution as mobile phase in gradient program at a flow rate of 0.9 mL/min. The optimum drift tube temperature of evaporative light scattering detection was at 105°C with the air flow rate of 2.5 L/min. The calibration curves showed good linearity during the test ranges. This method was validated for limits of detection and quantification, precision, and reproducibility. The recoveries were within the range of 96.39%–104.64%. The relative standard deviations of intraday and interday precision were less than 2.90% and 3.30%, respectively. The developed method can be successfully used to quantify the four analytes in the stem of Sargentodoxa cuneata from various regions in China. Di-Hua Li, Yuan-Shan Lv, Jun-Hong Liu, Lei Yang, Yan Wang, Shu-Kun Zhang, and Yu-Zhen Zhuo Copyright © 2016 Di-Hua Li et al. All rights reserved. Morphological Analysis of White Cement Clinker Minerals: Discussion on the Crystallization-Related Defects Wed, 25 May 2016 06:32:16 +0000 http://www.hindawi.com/journals/ijac/2016/1259094/ The paper deals with a formation of artificial rock (clinker). Temperature plays the capital role in the manufacturing process. So, it is useful to analyze a poor clinker to identify the different phases and defects associated with their crystallization. X-ray fluorescence spectroscopy was used to determine the clinker’s chemical composition. The amounts of the mineralogical phases are measured by quantitative XRD analysis (Rietveld). Scanning electron microscopy (SEM) was used to characterize the main phases of white Portland cement clinker and the defects associated with the formation of clinker mineral elements. The results of a study which focused on the identification of white clinker minerals and defects detected in these noncomplying clinkers such as fluctuation of the amount of the main phases (alite (C3S) and belite (C2S)), excess of the free lime, occurrence of C3S polymorphs, and occurrence of moderately-crystallized structures are presented in this paper. Mohamed Benmohamed, Rabah Alouani, Amel Jmayai, Abdesslem Ben Haj Amara, and Hafsia Ben Rhaiem Copyright © 2016 Mohamed Benmohamed et al. All rights reserved. The Size of the Human Proteome: The Width and Depth Thu, 19 May 2016 17:15:16 +0000 http://www.hindawi.com/journals/ijac/2016/7436849/ This work discusses bioinformatics and experimental approaches to explore the human proteome, a constellation of proteins expressed in different tissues and organs. As the human proteome is not a static entity, it seems necessary to estimate the number of different protein species (proteoforms) and measure the number of copies of the same protein in a specific tissue. Here, meta-analysis of neXtProt knowledge base is proposed for theoretical prediction of the number of different proteoforms that arise from alternative splicing (AS), single amino acid polymorphisms (SAPs), and posttranslational modifications (PTMs). Three possible cases are considered: PTMs and SAPs appear exclusively in the canonical sequences of proteins, but not in splice variants; PTMs and SAPs can occur in both proteins encoded by canonical sequences and in splice variants; all modification types (AS, SAP, and PTM) occur as independent events. Experimental validation of proteoforms is limited by the analytical sensitivity of proteomic technology. A bell-shaped distribution histogram was generated for proteins encoded by a single chromosome, with the estimation of copy numbers in plasma, liver, and HepG2 cell line. The proposed metabioinformatics approaches can be used for estimation of the number of different proteoforms for any group of protein-coding genes. Elena A. Ponomarenko, Ekaterina V. Poverennaya, Ekaterina V. Ilgisonis, Mikhail A. Pyatnitskiy, Arthur T. Kopylov, Victor G. Zgoda, Andrey V. Lisitsa, and Alexander I. Archakov Copyright © 2016 Elena A. Ponomarenko et al. All rights reserved. Use of the Relaxometry Technique for Quantification of Paramagnetic Ions in Aqueous Solutions and a Comparison with Other Analytical Methods Tue, 17 May 2016 06:43:41 +0000 http://www.hindawi.com/journals/ijac/2016/8256437/ We have demonstrated that the relaxometry technique is very efficient to quantify paramagnetic ions during in situ electrolysis measurements. Therefore, the goal of this work was to validate the relaxometry technique in the determination of the concentration of the ions contained in electrolytic solutions, Cu2+, Ni2+, Cr3+, and Mn2+, and compare it with other analytical methods. Two different NMR spectrometers were used: a commercial spectrometer with a homogeneous magnetic field and a home-built unilateral sensor with an inhomogeneous magnetic field. Without pretreatment, manganese ions do not have absorption bands in the UV-Visible region, but it is possible to quantify them using relaxometry (the limit of quantification is close to 10−5 mol L−1). Therefore, since the technique does not require chemical indicators and is a cheap and robust method, it can be used as a replacement for some conventional quantification techniques. The relaxometry technique could be applied to evaluate the corrosion of metallic surfaces. Bruna Ferreira Gomes, Juliana Soares da Silva Burato, Carlos Manuel Silva Lobo, and Luiz Alberto Colnago Copyright © 2016 Bruna Ferreira Gomes et al. All rights reserved. Multianalytical Method Validation for Qualitative and Quantitative Analysis of Solvents of Abuse in Oral Fluid by HS-GC/MS Wed, 04 May 2016 13:41:24 +0000 http://www.hindawi.com/journals/ijac/2016/1029286/ The use of oral fluid as a biological matrix to monitor the use of drugs of abuse is a global trend because it presents several advantages and good correlation to the blood level. Thus, the present work aimed to develop and validate an analytical method for quantification and detection of solvents used as inhalants of abuse in oral fluid (OF), using Quantisal™ as collector device by headspace and gas chromatography coupled with a mass detector (HS-GC/MS). Chromatographic separation was performed with a ZB-BAC1 column and the total time of analysis was 11.8 min. The method showed good linearity (correlation coefficient higher than 0.99 for all solvents). The limits of detection ranged from 0.05 to 5 mg/L, while the lower limits of quantification ranged from 2.5 to 12.5 mg/L. Accuracy, precision, matrix effect, and residual effect presented satisfactory results, meeting the criteria accepted for the validation of bioanalytical methods. The method showed good selectivity considering that, for solvents coeluting at the same retention time, resolution was performed by the mass detector. The method developed proved to be adequate when applied in OF samples from users of drugs and may be used to monitor the abuse of inhalants in routine forensic analyses. Bruna Claudia Coppe, Bruna Tassi Borille, Taís Regina Fiorentin, Ana Laura Bemvenuti Jacques, Ana Claudia Fagundes, Stela Maris de Jezus Castro, Lysa Silveira Remy, Flavio Pechansky, and Renata Pereira Limberger Copyright © 2016 Bruna Claudia Coppe et al. All rights reserved. Comparison of Three Solid Phase Materials for the Extraction of Carboxylic Acids from River Water Followed by 2D GC × GC-TOFMS Determination Wed, 04 May 2016 13:39:05 +0000 http://www.hindawi.com/journals/ijac/2016/6396938/ The extraction and determination of aliphatic and aromatic carboxylic acids as well as their influence on the aromaticity and molecularity relationship of natural organic matter (NOM) in water are reported in this study. Three solid phase extraction (SPE) sorbents were used and their extraction efficiencies evaluated after chromatographic determinations (using gas chromatography with a time of flight mass spectrometer (GC × GC-TOFMS) and liquid chromatography with organic carbon detector (LC-OCD)). More than 42 carboxylic acids were identified in raw water from the Vaal River, which feeds the Lethabo Power Generation Station, South Africa, with cooling water. The aromatic carboxylic acid efficiency (28%) was achieved by using Strata™ X SPE while the highest aliphatic carboxylic acid efficiency (92.08%) was achieved by silica SPE. The hydrophobic nature of NOM in water depends on the nature of organic compounds in water, whether aromatic or aliphatic. The LC-OCD was used to assess the hydrophobicity levels of NOM as a function of these carboxylic acids in cooling water. The LC-OCD results showed that the aromatic nature of NOM in SPE filtered water followed the order Silica>Strata X>C-18. From the results, the hydrophobicity degree of the samples depended on the type and number of carboxylic acids that were removed by the SPE cartridges. G. O. Bosire, J. C. Ngila, and H. Parshotam Copyright © 2016 G. O. Bosire et al. All rights reserved. Determination of Natamycin in Turkish Yoghurt Tue, 03 May 2016 11:06:51 +0000 http://www.hindawi.com/journals/ijac/2016/8480963/ This study was aimed at developing RP-HPLC method for determination of natamycin in Turkish yoghurt. Chromatographic separation was achieved on a C8 column (150 mm × 4.6 mm × 5 µm) with a mobile phase of methanol : water : acetic acid (12 : 8 : 1 v/v/v), at 1 mL/min flow rate with a detection of 303 nm. Natamycin was spiked into handmade yoghurt samples and used for validation. The method has been fully validated according to ISO 9233-2, 2007 (IDF 140-2, 2007). It was successfully applied to determination of 28 different Turkish yoghurt products. Findings dealing with the presence of natamycin in cheese samples are presented. Dilek Bilgic Alkaya and Ozlem Karalomlu Copyright © 2016 Dilek Bilgic Alkaya and Ozlem Karalomlu. All rights reserved. Study on Colloidal Model of Petroleum Residues through the Attraction Potential between Colloids Tue, 19 Apr 2016 14:17:50 +0000 http://www.hindawi.com/journals/ijac/2016/4182164/ The samples of DaGang atmospheric residue (DG-AR), Middle East atmospheric residue (ME-AR), TaHe atmospheric residue (TH-AR), and their thermal reaction samples were chosen for study. All the samples were fractioned into six components separately, including saturates plus light aromatics, heavy aromatics, light resins, middle resins, heavy resins, and asphaltenes. The dielectric permittivity of the solutions of these components was measured, and the dielectric permittivity values of the components can be determined by extrapolation, which increased steadily from saturates plus light aromatics to asphaltenes. Moreover, the Hamaker constants of the components were calculated from their dielectric permittivity values. The Van der Waals attractive potential energy between colloids corresponding to various models could be calculated from the fractional composition and the Hamaker constants of every component. It was assumed that the cores of colloidal particles were formed by asphaltenes and heavy resins mainly; the other fractions acted as dispersion medium. For the three serials of thermal reaction samples, the Van der Waals attraction potential energy between colloids for this kind of model was calculated. For TH-AR thermal reaction samples, the Van der Waals attraction potential energy presented the maximum as thermal reaction is going on, which was near to the end of coke induction period. Long-li Zhang, Guo-hua Yang, Chao-he Yang, and Guo-he Que Copyright © 2016 Long-li Zhang et al. All rights reserved. Masking Agents Evaluation for Lead Determination by Flow Injection-Hydride Generation-Atomic Fluorescence Spectrometry Technique: Effect of KI, L-Cysteine, and 1,10-Phenanthroline Mon, 11 Apr 2016 14:32:14 +0000 http://www.hindawi.com/journals/ijac/2016/3095120/ Hydride generation (HG) of lead technique presents interferences from foreign ions of complex matrix samples. In order to minimize these interferences, the effect of masking agents such as KI, L-cysteine, and 1,10-phenanthroline was studied in the absence and in the presence of selected interfering species (As, Cr, Cu, and Fe). Different modes of addition of masking agents were accomplished, that is, to either sample or KBH4 reducing solution. The lead determinations were performed using a flow injection analysis (FIA) system coupled to HG and atomic fluorescence spectrometry (AFS). The linearity of calibration curves (1–10 μg Pb L−1) was not affected by the addition of the masking agents. The use of KI in the reducing solution diminished interferences from concentrations of As and Cu, while 1,10-phenanthroline showed a positive effect on the interference by As. Moreover, Cr and Cu appeared to be the most serious interfering ions for plumbane (PbH4), because they drastically reduced the analytical signal of lead. Fe did not present any interference under the employed experimental conditions, even at high levels. The accuracy was established through the analysis of certified reference material (i.e., BCR-610, groundwater) using KI as masking agent. The detection limit reached by FIA-HG-AFS proposed methodology was 0.03 μg Pb L−1. Blanca G. Beltrán, Luz O. Leal, Laura Ferrer, and Víctor Cerdà Copyright © 2016 Blanca G. Beltrán et al. All rights reserved. Core-Shell Columns in High-Performance Liquid Chromatography: Food Analysis Applications Sun, 10 Apr 2016 06:18:33 +0000 http://www.hindawi.com/journals/ijac/2016/3189724/ The increased separation efficiency provided by the new technology of column packed with core-shell particles in high-performance liquid chromatography (HPLC) has resulted in their widespread diffusion in several analytical fields: from pharmaceutical, biological, environmental, and toxicological. The present paper presents their most recent applications in food analysis. Their use has proved to be particularly advantageous for the determination of compounds at trace levels or when a large amount of samples must be analyzed fast using reliable and solvent-saving apparatus. The literature hereby described shows how the outstanding performances provided by core-shell particles column on a traditional HPLC instruments are comparable to those obtained with a costly UHPLC instrumentation, making this novel column a promising key tool in food analysis. Raffaella Preti Copyright © 2016 Raffaella Preti. All rights reserved. Measurement of Circulating 1,25-Dihydroxyvitamin D: Comparison of an Automated Method with a Liquid Chromatography Tandem Mass Spectrometry Method Tue, 05 Apr 2016 09:35:51 +0000 http://www.hindawi.com/journals/ijac/2016/8501435/ Background. The clinical relevance of circulating 1,25-dihydroxyvitamin D (1,25(OH)2D) is probably underappreciated, but variations in the measurement of this difficult analyte between different methods limit comparison of results. Methods. In 129 clinical samples, we compared a new automated assay with a commercially available liquid chromatography tandem mass spectrometry (LC-MS/MS) kit. Results. Median (interquartile range) 1,25(OH)2D concentrations with the automated assay and the LC-MS/MS method were 26.6 pg/mL (18.5–39.0 pg/mL) and 23.6 pg/mL (16.1–31.3 pg/mL), respectively (). Using the method-specific cut-offs for deficient 1,25(OH)2D levels (<20 pg/mL for the automated assay and <17 pg/mL for the LC-MS/MS method), the percentage of patients classified as 1,25(OH)2D deficient was 28.7% and 27.1%, respectively. However, concordance between the two methods for deficient levels was only 62% and the concordance correlation coefficient was poor (0.534). The regression equation resulted in an intercept of −1.99 (95% CI: −7.33–1.31) and a slope of 1.27 (95% CI: 1.04–1.52) for the automated assay. The mean bias with respect to the mean of the two methods was −3.8 (1.96 SD: −28.3–20.8) pg/mL for the LC-MS/MS method minus the automated assay. Conclusions. The two methods show only modest correlation and further standardization is required to improve reliability and comparability of 1,25(OH)2D test procedures. Armin Zittermann, Jana B. Ernst, Tobias Becker, Jens Dreier, Cornelius Knabbe, Jan F. Gummert, and Joachim Kuhn Copyright © 2016 Armin Zittermann et al. All rights reserved. Direct Analysis of Low-Volatile Molecular Marker Extract from Airborne Particulate Matter Using Sensitivity Correction Method Mon, 04 Apr 2016 08:30:49 +0000 http://www.hindawi.com/journals/ijac/2016/2834575/ Molecular marker analysis of environmental samples often requires time consuming preseparation steps. Here, analysis of low-volatile nonpolar molecular markers (5-6 ring polycyclic aromatic hydrocarbons or PAHs, hopanoids, and n-alkanes) without the preseparation procedure is presented. Analysis of artificial sample extracts was directly conducted by gas chromatography-mass spectrometry (GC-MS). After every sample injection, a standard mixture was also analyzed to make a correction on the variation of instrumental sensitivity caused by the unfavorable matrix contained in the extract. The method was further validated for the PAHs using the NIST standard reference materials (SRMs) and then applied to airborne particulate matter samples. Tests with the SRMs showed that overall our methodology was validated with the uncertainty of ~30%. The measurement results of airborne particulate matter (PM) filter samples showed a strong correlation between the PAHs, implying the contributions from the same emission source. Analysis of size-segregated PM filter samples showed that their size distributions were found to be in the PM smaller than 0.4 μm aerodynamic diameter. The observations were consistent with our expectation of their possible sources. Thus, the method was found to be useful for molecular marker studies. Satoshi Irei Copyright © 2016 Satoshi Irei. All rights reserved. Quantification of Sterol and Triterpenol Biomarkers in Sediments of the Cananéia-Iguape Estuarine-Lagoonal System (Brazil) by UHPLC-MS/MS Mon, 21 Mar 2016 08:11:08 +0000 http://www.hindawi.com/journals/ijac/2016/8361375/ Sterols and triterpenols present in sedimentary cores from 12 stations along the Cananéia-Iguape estuarine-lagoonal system were investigated by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Ten sterols and three triterpenols were identified and quantified, indicating both natural and anthropogenic sources. The relative distributions of sterol and triterpenol showed that the study area is submitted to organic matter (OM) from the Ribeira de Iguape River, seawater, surrounding vegetation, and plankton production. The contribution of these sources depends on the region of the estuarine-lagoonal system and the depth of sediment. Regarding anthropogenic sources, only the samples submitted to freshwater flow from the Ribeira de Iguape River presented concentration of coprostanol higher than the threshold value and diagnostic ratios, coprostanol/(coprostanol + cholestanol) and coprostanol/cholesterol, that indicate moderate contamination by domestic sewage in that area of the estuarine-lagoonal system. Therefore, the approach used herein identified the OM sources and its transport along the Cananéia-Iguape estuarine-lagoonal system (Brazil), which is a complex of lagoonal channels located in a United Nations Educational, Scientific and Cultural Organization (UNESCO) Biosphere Reserve. Giovana Anceski Bataglion, Hector Henrique Ferreira Koolen, Rolf Roland Weber, and Marcos Nogueira Eberlin Copyright © 2016 Giovana Anceski Bataglion et al. All rights reserved. Gas Chromatography/Atmospheric Pressure Chemical Ionization-Fourier Transform Ion Cyclotron Resonance Mass Spectrometry of Pyrolysis Oil from German Brown Coal Tue, 15 Mar 2016 09:46:56 +0000 http://www.hindawi.com/journals/ijac/2016/5960916/ Pyrolysis oil from the slow pyrolysis of German brown coal from Schöningen, obtained at a temperature of 500°C, was separated and analyzed using hyphenation of gas chromatography with an atmospheric pressure chemical ionization source operated in negative ion mode and Fourier transform ion cyclotron resonance mass spectrometry (GC-APCI-FT-ICR-MS). Development of this ultrahigh-resolving analysis method is described, that is, optimization of specific GC and APCI parameters and performed data processing. The advantages of GC-APCI-FT-ICR-MS hyphenation, for example, soft ionization, ultrahigh-resolving detection, and most important isomer separation, were demonstrated for the sample liquid. For instance, it was possible to separate and identify nine different propylphenol, ethylmethylphenol, and trimethylphenol isomers. Furthermore, homologous series of different acids, for example, alkyl and alkylene carboxylic acids, were verified, as well as homologous series of alkyl phenols, alkyl dihydroxy benzenes, and alkoxy alkyl phenols. Jan Zuber, Marius M. Kroll, Philipp Rathsack, and Matthias Otto Copyright © 2016 Jan Zuber et al. All rights reserved. Development and Validation of Chronopotentiometric Method for Imidacloprid Determination in Pesticide Formulations and River Water Samples Sun, 06 Mar 2016 11:48:50 +0000 http://www.hindawi.com/journals/ijac/2016/5138491/ A new electrochemical method for determination of imidacloprid using chronopotentiometry on thin film mercury and glassy carbon electrode was presented. The most important experimental parameters of chronopotentiometry were examined and optimized with respect to imidacloprid analytical signal. Imidacloprid provided well-defined reduction peak in Britton-Robinson buffer on thin film mercury electrode at −1.0 V (versus Ag/AgCl (KCl, 3.5 mol/L)) and on glassy carbon electrode at −1.2 V (versus Ag/AgCl (KCl, 3.5 mol/L)). The reduction time was linearly proportional to concentrations from 0.8 to 30.0 mg/L on thin film mercury electrode and from 7.0 to 70.0 mg/L on glassy carbon electrode. The detection limits were 0.17 mg/L and 0.93 mg/L for thin film mercury and glassy carbon electrode, respectively. The estimation of method precision as a function of repeatability and reproducibility showed relative standard deviations values lower than 3.73%. Recovery values from 97.3 to 98.1% confirmed the accuracy of the proposed method, while the constancy of the transition time with deliberated small changes in the experimental parameters indicated a very good robustness. A minor influence of possible interfering compounds proved good selectivity of the method. Developed method was applied for imidacloprid determination in commercial pesticide formulations and river water samples. Ana Đurović, Zorica Stojanović, Snežana Kravić, Nada Grahovac, Vojislava Bursić, Gorica Vuković, and Zvonimir Suturović Copyright © 2016 Ana Đurović et al. All rights reserved. Production of Palmitoleic and Linoleic Acid in Oleaginous and Nonoleaginous Yeast Biomass Sun, 28 Feb 2016 16:33:22 +0000 http://www.hindawi.com/journals/ijac/2016/7583684/ We investigated the possibility of utilizing both oleaginous yeast species accumulating large amounts of lipids (Yarrowia lipolytica, Rhodotorula glutinis, Trichosporon cutaneum, and Candida sp.) and traditional biotechnological nonoleaginous ones (Kluyveromyces polysporus, Torulaspora delbrueckii, and Saccharomyces cerevisiae) as potential producers of dietetically important major fatty acids. The main objective was to examine the cultivation conditions that would induce a high ratio of dietary fatty acids and biomass. Though genus-dependent, the type of nitrogen source had a higher influence on biomass yield than the C/N ratio. The nitrogen source leading to the highest lipid accumulation was potassium nitrate, followed by ammonium sulfate, which is an ideal nitrogen source supporting, in both oleaginous and nonoleaginous species, sufficient biomass growth with concomitantly increased lipid accumulation. All yeast strains displayed high (70–90%) content of unsaturated fatty acids in total cell lipids. The content of dietary fatty acids of interest, namely, palmitoleic acid and linoleic acid, reached in Kluyveromyces and Trichosporon strains over 50% of total fatty acids and the highest yield, over 280 mg per g of dry cell weight of these fatty acids, was observed in Trichosporon with ammonium sulfate as nitrogen source at C/N ratio 70. Irena Kolouchová, Olga Maťátková, Karel Sigler, Jan Masák, and Tomáš Řezanka Copyright © 2016 Irena Kolouchová et al. All rights reserved. Multiple Reaction Monitoring Mode Based Liquid Chromatography-Mass Spectrometry Method for Simultaneous Quantification of Brassinolide and Other Plant Hormones Involved in Abiotic Stresses Sun, 28 Feb 2016 14:21:29 +0000 http://www.hindawi.com/journals/ijac/2016/7214087/ Plant hormones are the key regulators of adaptive stress response. Abiotic stresses such as drought and salt are known to affect the growth and productivity of plants. It is well known that the levels of plant hormones such as zeatin (ZA), abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA), and brassinolide (BR) fluctuate upon abiotic stress exposure. At present, there is not any single suitable liquid chromatography-mass spectrometry (LC-MS) method for simultaneous analysis of BR and other plant hormones involved in abiotic stresses. In the present study, we developed a simple, sensitive, and rapid method for simultaneous analysis of five major plant hormones, ZA, ABA, JA, SA, and BR, which are directly or indirectly involved in drought and salt stresses. The optimized extraction procedure was simple and easy to use for simultaneous measurement of these plant hormones in Arabidopsis thaliana. The developed method is highly reproducible and can be adapted for simultaneous measurement of changes in plant hormones (ZA, ABA, JA, SA, and BR) in response to abiotic stresses in plants like A. thaliana and tomato. Deepak M. Kasote, Ritesh Ghosh, Jun Young Chung, Jonggeun Kim, Inhwan Bae, and Hanhong Bae Copyright © 2016 Deepak M. Kasote et al. All rights reserved. Development and Validation of HPLC Method for the Simultaneous Determination of Five Food Additives and Caffeine in Soft Drinks Wed, 17 Feb 2016 13:11:20 +0000 http://www.hindawi.com/journals/ijac/2016/2879406/ Box-Behnken design was applied to optimize high performance liquid chromatography (HPLC) conditions for the simultaneous determination of potassium sorbate, sodium benzoate, carmoisine, allura red, ponceau 4R, and caffeine in commercial soft drinks. The experimental variables chosen were pH (6.0–7.0), flow rate (1.0–1.4 mL/min), and mobile phase ratio (85–95% acetate buffer). Resolution values of all peak pairs were used as a response. Stationary phase was Inertsil OctaDecylSilane- (ODS-) 3V reverse phase column (250 × 4.6 mm, 5 μm) dimensions. The detection was performed at 230 nm. Optimal values were found 6.0 pH, 1.0 mL/min flow rate, and 95% mobile phase ratio for the method which was validated by calculating the linearity (), accuracy (recoveries ≥ 95.75%), precision (intraday variation ≤ 1.923%, interday variation ≤ 1.950%), limits of detection (LODs), and limits of quantification (LOQs) parameters. LODs and LOQs for analytes were in the range of 0.10–0.19 μg/mL and 0.33–0.63 μg/mL, respectively. The proposed method was applied successfully for the simultaneous determination of the mixtures of five food additives and caffeine in soft drinks. Bürge Aşçı, Şule Dinç Zor, and Özlem Aksu Dönmez Copyright © 2016 Bürge Aşçı et al. All rights reserved. Liquid Chromatography with Electrospray Ionization and Tandem Mass Spectrometry Applied in the Quantitative Analysis of Chitin-Derived Glucosamine for a Rapid Estimation of Fungal Biomass in Soil Tue, 09 Feb 2016 13:45:23 +0000 http://www.hindawi.com/journals/ijac/2016/9269357/ This method employs liquid chromatography-tandem mass spectrometry to rapidly quantify chitin-derived glucosamine for estimating fungal biomass. Analyte retention was achieved using hydrophilic interaction liquid chromatography, with a zwitter-ionic stationary phase (ZIC-HILIC), and isocratic elution using 60% 5 mM ammonium formate buffer (pH 3.0) and 40% ACN. Inclusion of muramic acid and its chromatographic separation from glucosamine enabled calculation of the bacterial contribution to the latter. Galactosamine, an isobaric isomer to glucosamine, found in significant amounts in soil samples, was also investigated. The two isomers form the same precursor and product ions and could not be chromatographically separated using this rapid method. Instead, glucosamine and galactosamine were distinguished mathematically, using the linear relationships describing the differences in product ion intensities for the two analytes. The m/z transitions of 180 72 and 180 84 were applied for the detection of glucosamine and galactosamine and that of 252 126 for muramic acid. Limits of detection were in the nanomolar range for all included analytes. The total analysis time was 6 min, providing a high sample throughput method. Madelen A. Olofsson and Dan Bylund Copyright © 2016 Madelen A. Olofsson and Dan Bylund. All rights reserved. Enantioseparation of Citalopram by RP-HPLC, Using Sulfobutyl Ether-β-Cyclodextrin as a Chiral Mobile Phase Additive Tue, 05 Jan 2016 08:32:23 +0000 http://www.hindawi.com/journals/ijac/2016/1231386/ Enantiomeric separation of citalopram (CIT) was developed using a reversed phase HPLC (RP-HPLC) with sulfobutylether-β-cyclodextrin (SBE-β-CD) as a chiral mobile phase additive. The effects of the pH value of aqueous buffer, concentration of chiral additive, composition of mobile phase, and column temperature on the enantioseparation of CIT were investigated on the Hedera ODS-2 C18 column (250 mm × 4.6 mm × 5.0 um). A satisfactory resolution was achieved at 25°C using a mobile phase consisting of a mixture of aqueous buffer (pH of 2.5, 5 mM sodium dihydrogen phosphate, and 12 mM SBE-β-CD), methanol, and acetonitrile with a volumetric ratio of 21 : 3 : 1 and flow rate of 1.0 mL/min. This analytical method was evaluated by examining the precision (lower than 3.0%), linearity (regression coefficients close to 1), limit of detection (0.070 µg/mL for ()-CIT and 0.076 µg/mL for ()-CIT), and limit of quantitation (0.235 µg/mL for ()-CIT and 0.254 µg/mL for ()-CIT). Yangfeng Peng, Quan Sophia He, and Jiang Cai Copyright © 2016 Yangfeng Peng et al. All rights reserved. Micellar Enhanced Spectrofluorimetric Method for the Determination of Ponatinib in Human Plasma and Urine via Cremophor RH 40 as Sensing Agent Thu, 31 Dec 2015 16:33:28 +0000 http://www.hindawi.com/journals/ijac/2015/210503/ An impressively simple and precise spectrofluorimetric procedure was established and validated for ponatinib (PTB) quantitation in biological fluids such as human plasma and human urine. This method depends on examining the fluorescence characteristics of PTB in a micellar system of Cremophor RH 40 (Cr RH 40). Cr RH 40 enhanced the intrinsic fluorescence of PTB distinctly in aqueous water. The fluorescence spectra of PTB was recorded at 457 nm following its excitation at 305 nm. Maximum fluorescence intensity was attained by addition of 0.7 mL of Cr RH 40 and one mL of phosphate buffer to PTB aliquots and then dilution with distilled water. There is a linear relationship between the fluorescence intensity of PTB and its concentration over the range 5–120 ngmL−1, with limit of detection and limit of quantification equal to 0.905 ngmL−1 and 2.742 ngmL−1, respectively. The accuracy and the precisions of the proposed method were checked and gave adequate results. The adopted method was applied with a great success for PTB quantitation in different biological matrices (spiked human plasma and urine) giving high recovery values. Hany W. Darwish, Ahmed H. Bakheit, Ali Saber Abdelhameed, and Amer S. AlKhairallah Copyright © 2015 Hany W. Darwish et al. All rights reserved. Near-Infrared Spectroscopy as an Analytical Process Technology for the On-Line Quantification of Water Precipitation Processes during Danhong Injection Tue, 29 Dec 2015 13:08:42 +0000 http://www.hindawi.com/journals/ijac/2015/313471/ This paper used near-infrared (NIR) spectroscopy for the on-line quantitative monitoring of water precipitation during Danhong injection. For these NIR measurements, two fiber optic probes designed to transmit NIR radiation through a 2 mm flow cell were used to collect spectra in real-time. Partial least squares regression (PLSR) was developed as the preferred chemometrics quantitative analysis of the critical intermediate qualities: the danshensu (DSS, (R)-3, 4-dihydroxyphenyllactic acid), protocatechuic aldehyde (PA), rosmarinic acid (RA), and salvianolic acid B (SAB) concentrations. Optimized PLSR models were successfully built and used for on-line detecting of the concentrations of DSS, PA, RA, and SAB of water precipitation during Danhong injection. Besides, the information of DSS, PA, RA, and SAB concentrations would be instantly fed back to site technical personnel for control and adjustment timely. The verification experiments determined that the predicted values agreed with the actual homologic value. Xuesong Liu, Chunyan Wu, Shu Geng, Ye Jin, Lianjun Luan, Yong Chen, and Yongjiang Wu Copyright © 2015 Xuesong Liu et al. All rights reserved. Separation and Analysis of Boron Isotope in High Plant by Thermal Ionization Mass Spectrometry Thu, 24 Dec 2015 13:55:17 +0000 http://www.hindawi.com/journals/ijac/2015/364242/ Knowledge of boron and its isotope in plants is useful to better understand the transposition and translocation of boron within plant, the geochemical behavior in the interface between soil and plant, and the biogeochemical cycle of boron. It is critical to develop a useful method to separate boron from the plant for the geochemical application of boron and its isotope. A method was developed for the extraction of boron in plant sample, whose isotope was determined by thermal ionization mass spectrometry. The results indicated that this method of dry ashing coupled with two-step ion-exchange chromatography is powerful for the separation of boron in plant sample with large amounts of organic matters completely. The ratios of boron isotope composition in those plant tissue samples ranged from to (total range: ) with a mean value of SD. The stem and root isotopic compositions were lower than those in flower and leaf. The molecular mechanism of boron isotope may be responsible for the observed variation of boron isotopic composition and are considered as a useful tool for the better understanding of boron cycling process in the environment and for the signature of living systems. Qingcai Xu, Yuliang Dong, Huayu Zhu, and Aide Sun Copyright © 2015 Qingcai Xu et al. All rights reserved. High Performance Liquid Chromatographic Assay for the Simultaneous Determination of Posaconazole and Vincristine in Rat Plasma Tue, 22 Dec 2015 08:34:09 +0000 http://www.hindawi.com/journals/ijac/2015/743915/ Purpose. Developing a validated HPLC-DAD method for simultaneous determination of posaconazole (PSZ) and vincristine (VCR) in rat plasma. Methods. PSZ, VCR, and itraconazole (ITZ) were extracted from 200 μL plasma using diethyl ether in the presence of 0.1 M sodium hydroxide solution. The organic layer was evaporated in vacuo and dried residue was reconstituted and injected through HC-C18 (4.6 × 250 mm, 5 μm) column. In the mobile phase, acetonitrile and 0.015 M potassium dihydrogen orthophosphate (30 : 70 to 80 : 20, linear gradient over 7 minutes) pumped at 1.5 mL/min. VCR and PSZ were measured at 220 and 262 nm, respectively. Two Sprague Dawley rats were orally dosed PSZ followed by iv dosing of VCR and serial blood sampling was performed. Results. VCR, PSZ, and ITZ were successfully separated within 11 min. Calibration curves were linear over the range of 50–5000 ng/mL for both drugs. The CV% and % error of the mean were ≤18% and limit of quantitation was 50 ng/mL for both drugs. Rat plasma concentrations of PSZ and VCR were simultaneously measured up to 72 h and their calculated pharmacokinetics parameters were comparable to the literature. Conclusion. The assay was validated as per ICH guidelines and is appropriate for pharmacokinetics drug-drug interaction studies. Hadeel A. Khalil, Ahmed F. El-Yazbi, Tarek S. Belal, and Dalia A. Hamdy Copyright © 2015 Hadeel A. Khalil et al. All rights reserved. A New HPLC-ELSD Method for Simultaneous Determination of N-Acetylglucosamine and N-Acetylgalactosamine in Dairy Foods Tue, 15 Dec 2015 13:39:09 +0000 http://www.hindawi.com/journals/ijac/2015/892486/ A rapid high performance liquid chromatographic method with evaporative light scattering detection (HPLC-ELSD), using a carbohydrate column, was developed for simultaneous determination of N-acetylglucosamine (GlcNAc) and N-acetylgalactosamine (GalNAc) in dairy foods. Sample preparation was performed by precipitation using acetonitrile. The limits of detection were 2.097 mg/L for GlcNAc and 3.247 mg/L for GalNAc. The limits of quantification were 6.043 mg/L for GlcNAc and 9.125 mg/L for GalNAc. Accuracy ranged from 96.4 to 105.7% for GlcNAc and from 97.1 to 104.1% for GalNAc. The precision of the method was <1.7% for GlcNAc and <2.2% for GalNAc. The mean recovery of the method was measured by spiking samples with 30.0–120.0 mg/L GlcNAc or 12.5–50.0 mg/L GalNAc and was found to be 95.1–105.5% for GlcNAc and 99.5–105.9% for GalNAc. The stability test results of standard solutions stored at 4, 20, and 40°C were 96.2–104.7% for GlcNAc and 98.0–106.5% for GalNAc. This study determined GlcNAc and GalNAc in dairy foods using HPLC-ELSD method. This rapid, simultaneous quantitation method might be useful as a mean of convenient quality control of dairy foods. Ho Jin Kim, In Kyung Bae, Min Hee Jeong, Hye Jin Park, Jin Sil Jung, and Jang Eok Kim Copyright © 2015 Ho Jin Kim et al. All rights reserved. Development and Validation of Simple RP-HPLC Method for Intracellular Determination of Fluconazole Concentration and Its Application to the Study of Candida albicans Azole Resistance Wed, 09 Dec 2015 07:57:45 +0000 http://www.hindawi.com/journals/ijac/2015/576250/ Candida albicans (strains NCTC-885-653 and ATCC-10231) long-term cultivated in the presence of antifungal agent fluconazole (FLC) and classical microbiological methods for determination of minimal inhibitory concentration (MIC) were used in this study. A simple and sensitive method based on reverse-phase high-performance liquid chromatography (RP-HPLC) has been developed for the determination of FLC intracellular concentration in C. albicans using tinidazole as an internal standard. Following extraction with dichloromethane, the chromatographic separation was achieved on a Machery-Nagel EC250/2 Nucleodur-100-3 C18 column by gradient elution using the mobile phase consisting of (A) 0.01 M ammonium acetate buffer, pH = 5.00, and (B) acetonitrile. Different analytical performance parameters such as linearity, precision, accuracy, limit of quantification (LOQ), and robustness were determined according to US DHHS FDA and EMEA guidelines. The method was linear for FLC ranging from 100 to 10000 ng/mL. The intraday and interday precisions (relative standard deviation) were within 2.79 and 2.64%, respectively, and the accuracy (relative error) was less than 2.82%. The extraction recovery ranged from 79.3 to 85.5%. The reliable method was successfully applied to C. albicans azole-resistance study and it was shown that intracellular concentration of FLC correlated with a yeast drug susceptibility profile and MIC values. Tigran K. Davtyan, Levon A. Melikyan, Nune A. Nikoyan, Hripsime P. Aleksanyan, and Nairi G. Grigoryan Copyright © 2015 Tigran K. Davtyan et al. All rights reserved. Simultaneous Detection and Estimation of Catechol, Hydroquinone, and Resorcinol in Binary and Ternary Mixtures Using Electrochemical Techniques Tue, 01 Dec 2015 10:08:24 +0000 http://www.hindawi.com/journals/ijac/2015/862979/ Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were performed with a glassy carbon electrode (GCE) modified with polyglutamic acid (PGA) on the three dihydroxybenzene isomers, catechol (CT), hydroquinone (HQ), and resorcinol (RS). At bare GCE, these isomers exhibited voltammograms with highly overlapped redox peaks that impeded their simultaneous detection in binary and ternary mixtures. On the contrary, at PGA modified GCE binary and ternary mixtures of the dihydroxybenzene isomers showed well-resolved redox peaks in both CV and DPV experiments. This resolving ability of PGA modified GCE proves its potential to be exploited as an electrochemical sensor for the simultaneous detection of these isomers. Md. Uzzal Hossain, Md. Toufiqur Rahman, and Md. Qamrul Ehsan Copyright © 2015 Md. Uzzal Hossain et al. All rights reserved. Highly Sensitive Immunochromatographic Identification of Tetracycline Antibiotics in Milk Wed, 25 Nov 2015 12:04:28 +0000 http://www.hindawi.com/journals/ijac/2015/347621/ A rapid immunochromatographic assay was developed for the control of tetracycline (TC). The assay is based on the competition between immobilized TC-protein conjugate and TC in a tested sample for binding with polyclonal anti-TC antibodies conjugated to colloidal gold during the flow of the sample along a membrane strip with immobilized reactants. Conjugation of colloidal gold and the total immunoglobulin (IgG) fraction of polyclonal antibodies was used to increase the assay sensitivity to ensure low content of specific antibodies in the conjugate. This allowed effective inhibition of free TC and conjugate binding in the strip test zone. Photometric marker registration allows control of the reduction of binding, thereby enhancing detection sensitivity. The proposed assay allows TC to be detected at concentrations up to 20 ng/mL, exceeding the limit of detection of the known analogues, in a wide working range (more than two orders) of 60 pg/mL to 10 ng/mL, ensured through the use of polyclonal antibodies. The assay time is 10 min. The efficiency of the designed assay is shown to identify TC in milk; the degree of recovery of TC ranges from 90 to 112%. The precision of the concentrations measurements was no more than 10%. N. A. Taranova, A. S. Kruhlik, E. A. Zvereva, V. V. Shmanai, I. I. Vashkevich, D. A. Semyonov, S. A. Eremin, A. V. Zherdev, and B. B. Dzantiev Copyright © 2015 N. A. Taranova et al. All rights reserved.