Journal of Analytical Methods in Chemistry The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. Uninformative Biological Variability Elimination in Apple Soluble Solids Content Inspection by Using Fourier Transform Near-Infrared Spectroscopy Combined with Multivariate Analysis and Wavelength Selection Algorithm Mon, 16 Oct 2017 09:54:56 +0000 Uninformative biological variability elimination methods were studied in the near-infrared calibration model for predicting the soluble solids content of apples. Four different preprocessing methods, namely, Savitzky-Golay smoothing, multiplicative scatter correction, standard normal variate, and mean normalization, as well as their combinations were conducted on raw Fourier transform near-infrared spectra to eliminate the uninformative biological variability. Subsequently, robust calibration models were established by using partial least squares regression analysis and wavelength selection algorithms. Results indicated that the partial least squares calibration models with characteristic variables selected by CARS method coupled with preprocessing of Savitzky-Golay smoothing and multiplicative scatter correction had a considerable potential for predicting apple soluble solids content regardless of the biological variability. Lin Zhang, Baohua Zhang, Jun Zhou, Baoxing Gu, and Guangzhao Tian Copyright © 2017 Lin Zhang et al. All rights reserved. Assessment of Availability and Human Health Risk Posed by Arsenic Contaminated Well Waters from Timis-Bega Area, Romania Sun, 15 Oct 2017 00:00:00 +0000 Mobilization of As from geological materials into ground and drinking water sources may represent an important threat to human health. The objective of this study was to assess the As concentration and availability in underground water used as drinking water sources. Water samples were collected from public and private wells in Timis-Bega area of Pannonian Basin, West Romania. Total-dissolved As measured after “classical” filtration of water samples was in the range of 0.10–168 μg L−1, thus exceeding the guideline value in majority of the samples. The aim of this study was also to assess the “truly dissolved” concentrations of As considered as available concentrations, in well waters, after passive sampling by Diffusive Gradients in Thin-films (DGT). The results showed that over 70% of total-dissolved As is in available forms. The obtained data were used to evaluate the risks of using the wells as drinking water source. Hazard quotients for ingestion and dermal pathways and hazard index (HI) for exposure to As were calculated. The HI values > 1 found that majority of samples indicated a health risk for local residents. Marin Senila, Erika Levei, Oana Cadar, Lacrimioara Ramona Senila, Marius Roman, Ferenc Puskas, and Mihaela Sima Copyright © 2017 Marin Senila et al. All rights reserved. Thermal Emission of Alkali Metal Ions from Al30-Pillared Montmorillonite Studied by Mass Spectrometric Method Sun, 08 Oct 2017 00:00:00 +0000 The thermal emission of alkali metal ions from Al30-pillared montmorillonite in comparison with its natural form was studied by mass spectrometry in the temperature range 770–930 K. The measurements were carried out on a magnetic mass spectrometer MI-1201. For natural montmorillonite, the densities of the emission currents () decrease in the mass spectrum in the following sequence (T = 805 K, A/cm2): K+ (4.55 · 10−14), Cs+ (9.72 · 10−15), Rb+ (1.13 · 10−15), Na+ (1.75 · 10−16), Li+ (3.37 · 10−17). For Al30-pillared montmorillonite, thermionic emission undergoes temperature-time changes. In the low-temperature section of the investigated range (770–805 K), the value of increases substantially for all ions in comparison with natural montmorillonite (T = 805 K, A/cm2): Cs+ (6.47 · 10−13), K+ (9.44 · 10−14), Na+ (3.34 · 10−15), Rb+ (1.77 · 10−15), and Li+ (4.59 · 10−16). A reversible anomaly is observed in the temperature range 805–832 K: with increasing temperature, the value of of alkaline ions falls abruptly. This effect increases with increasing ionic radius of M+. After a long heating-up period, this anomaly disappears and the dependence acquires a classical linear form. The results are interpreted from the point of view of the dependence of the efficiency of thermionic emission on the phase transformations of pillars. V. B. Motalov, N. S. Karasev, N. L. Ovchinnikov, and M. F. Butman Copyright © 2017 V. B. Motalov et al. All rights reserved. Ratiometric Sensing of Hydrogen Peroxide Utilizing Conformational Change in Fluorescent Boronic Acid Polymers Thu, 28 Sep 2017 12:05:15 +0000 We demonstrate that the copolymers containing boronic acid and pyrene units can be utilized for the fluorometric sensing of hydrogen peroxide (H2O2) in aqueous solutions. The copolymer exists in a relatively extended conformation in the absence of H2O2, whereas the polymer chain is contracted by the reaction of boronic acid moieties with H2O2 to form phenol groups. This conformational change induces aggregation of the originally isolated pyrene groups. As a result, relative intensity of excimer emission with respect to monomer emission increases with H2O2 concentration. Accordingly, the present methodology enables us to measure H2O2 by means of ratiometric fluorescence change in the range of 0–30 μM. Kan Takeshima, Kanako Mizuno, Hitoshi Nakahashi, Hiroshi Aoki, and Yasumasa Kanekiyo Copyright © 2017 Kan Takeshima et al. All rights reserved. SPE-UHPLC-FLD Method for the Simultaneous Determination of Five Anthraquinones in Human Urine Using Mixed-Mode Bis(tetraoxacalix[2]arene[2]triazine) Modified Silica as Sorbent Thu, 28 Sep 2017 00:00:00 +0000 The five anthraquinones compounds (including aloe-emodin, emodin, physcion, chrysophanol, and rhein) are regarded as the main effective ingredients in rhubarb (Dahuang in Chinese, one of the commonly used Chinese herbal medicines). In this work, a simple and effective solid phase extraction (SPE) method based on bis(tetraoxacalix[2]arene[2]triazine) modified silica gel as adsorbent was developed. Coupled with UHPLC-FLD, the developed method was successfully applied for the measuring of main anthraquinones in human urine after oral administration of the extracts of rhubarb. To obtain the highest recoveries of the five anthraquinones in the SPE process, the main parameters which may affect extraction efficiency were optimized. The optimized sorbent amount, sample loading pH, sample loading rate, washing solution, and eluent condition were obtained. The developed method showed good linearity in 0.012–1.800 μg mL−1 for the five anthraquinones with correlation coefficients more than 0.9993. The investigated LOD values ranged from 3.9 to 5.7 ng mL−1, while the LOQs were between 12.0 and 18.2 ng mL−1. The recoveries of the method were also investigated, which were in the range of 94.8–106.6%. The application of the mixed-mode SPE materials in the proposed method was feasible and simple, and suitable for the enrichment of anthraquinones in urine samples. Kai Hu, Yonghui Qiao, Zhifen Deng, Mingxia Wu, and Wei Liu Copyright © 2017 Kai Hu et al. All rights reserved. Development of a LC-MS/MS Method for the Simultaneous Detection of Tricarboxylic Acid Cycle Intermediates in a Range of Biological Matrices Mon, 18 Sep 2017 00:00:00 +0000 It is now well-established that perturbations in the tricarboxylic acid (TCA) cycle play an important role in the metabolic transformation occurring in cancer including that of the prostate. A method for simultaneous qualitative and quantitative analysis of TCA cycle intermediates in body fluids, tissues, and cultured cell lines of human origin was developed using a common C18 reversed-phase column by LC-MS/MS technique. This LC-MS/MS method for profiling TCA cycle intermediates offers significant advantages including simple and fast preparation of a wide range of human biological samples. The analytical method was validated according to the guideline of the Royal Society of Chemistry Analytical Methods Committee. The limits of detection were below 60 nM for most of the TCA intermediates with the exception of lactic and fumaric acids. The calibration curves of all TCA analytes showed linearity with correlation coefficients . Recoveries were >95% for all TCA analytes. This method was established taking into consideration problems and limitations of existing techniques. We envisage that its application to different biological matrices will facilitate deeper understanding of the metabolic changes in the TCA cycle from in vitro, ex vivo, and in vivo studies. Omar Al Kadhi, Antonietta Melchini, Richard Mithen, and Shikha Saha Copyright © 2017 Omar Al Kadhi et al. All rights reserved. Polymorphism in Commercial Sources of Fusidic Acid: A Comparative Study of the In Vitro Release Characteristics of Forms I and III from a Marketed Pharmaceutical Cream Sun, 17 Sep 2017 00:00:00 +0000 A comparison of the polymorphic forms of 3 commercial sources of fusidic acid using FTIR and XRPD techniques has been performed in this study. It has been demonstrated that polymorphic Forms I and III are currently available on the commercial market. The influence of the observed polymorphism on the stability of the drug substance in bulk form has been investigated through stability and stress testing according to current ICH guidelines. Significant differences were detected between commercial sources with regard to the stability of the bulk substance under photolytic and humidity stress conditions. When properly packaged in an inert atmosphere, fusidic acid from all 3 manufacturers showed a comparable stability. The effects of the observed polymorphic differences on the intrinsic dissolution rate of the drug substance and its in vitro release from the marketed drug product Fusicutan® plus Betamethasone cream have been investigated. Results indicated that the release rate of the drug substance is similar for polymorphic Forms I and III, allowing both forms to be used during manufacture without affecting the safety or efficacy of the drug product. Jonathan Byrne, Robert Reinhardt, and Trinidad Velasco-Torrijos Copyright © 2017 Jonathan Byrne et al. All rights reserved. Molecular Marker Study of Particulate Organic Matter in Southern Ontario Air Sun, 17 Sep 2017 00:00:00 +0000 To study the origins of airborne particulate organic matter in southern Ontario, molecular marker concentrations were studied at Hamilton, Simcoe, and York Gateway Tunnel, representing industrial, rural, and heavy traffic sites, respectively. Airborne particulate matter smaller than 10 m in aerodynamic diameter was collected on quartz filters, and the collected samples were analyzed for total carbons, 5-6 ring PAHs, hopanes, n-alkanes (C20 to C34), and oxygenated aromatic compounds. Results showed that PAH concentrations at all three sites were highly correlated, indicating vehicular emissions as the major source. Meanwhile, in the scatter plots of ,-hopane and trisnorhopane, concentrations displayed different trends for Hamilton and Simcoe. The slopes of the linear regressions for Hamilton and the tunnel were statistically the same, while the slope for Simcoe was significantly different from those. Comparison with literature values revealed that the trend observed at Simcoe was explained by the influence from coal combustion. We also found that the majority of oxygenated aromatic compounds at both sites were in the similar level, possibly implying secondary products contained in the southern Ontario air. Regardless of some discrepancies, absolute principal component analysis applied to the datasets could reproduce those findings. Satoshi Irei, Jacek Stupak, Xueping Gong, Tak-Wai Chan, Michelle Cox, Robert McLaren, and Jochen Rudolph Copyright © 2017 Satoshi Irei et al. All rights reserved. Comparison Study of Voltammetric Behavior of Muscle Relaxant Dantrolene Sodium on Silver Solid Amalgam and Bismuth Film Electrodes Wed, 13 Sep 2017 06:53:51 +0000 Voltammetric behavior of muscle relaxant dantrolene sodium (DAN) was studied and the voltammetric methods for its determination using polished and mercury meniscus modified silver solid amalgam electrodes (p-AgSAE and m-AgSAE) as well as using bismuth film electrode (BiFE, ex situ plating on GCE) have been proposed. These working electrodes represent the most commonly used alternatives to mercury ones which come wrongfully into disfavor because of alleged toxicity of mercury. Within this work, the obtained results of DAN determination have been completed by corresponding statistical parameters and also some electrochemical characteristics of AgSAEs and BiFE were assessed, especially in comparison with the mercury electrodes. Renáta Šelešovská, Pavlína Martinková, Michaela Štěpánková, Tomáš Navrátil, and Jaromíra Chýlková Copyright © 2017 Renáta Šelešovská et al. All rights reserved. Transfer and Metabolism of Triadimefon Residues from Rape Flowers to Apicultural Products Wed, 06 Sep 2017 08:10:42 +0000 This paper presents a study on the transfer and metabolism of triadimefon residues from rape flowers to apicultural products. In the field trials, honeybee colonies were placed in four rape greenhouses treated with triadimefon on standard dosage. Apicultural products (pollen, honey, and royal jelly) were collected on a regular basis. Sample preparation and extraction procedure were established. HPLC/ESI-MS/MS method was validated. The respective residues of triadimefon and metabolite triadimenol were  mg/kg and  mg/kg in pollen on the 18th day, and both had reached the limits of detection in honey on the 24th day, while they were  mg/kg and  mg/kg in royal jelly on the 22nd day. Mathematical curve fitting studies were further investigated. On the basis of recommended dosage, the degradation half-lives of triadimefon in pollen, honey, and royal jelly were about 0.7, 12.5, and 19.5 days, respectively. Transfer of triadimefon residues from rape flowers to apicultural products diminished over spraying time. The residues of triadimefon and metabolite triadimenol in pollen were about 10 times higher than those in honey and jelly. Time to attain the maximum permissible limit of pollen in the European Union was 14.9 days, predicted from the index function. Ying-Hong Li, Bei-Lei Zhou, Ming-Rong Qian, Qiang Wang, and Hu Zhang Copyright © 2017 Ying-Hong Li et al. All rights reserved. Quality of Ceftriaxone Sodium in Lyophilized Powder for Injection Evaluated by Clean, Fast, and Efficient Spectrophotometric Method Tue, 05 Sep 2017 00:00:00 +0000 Ceftriaxone sodium, an antimicrobial agent that plays an important role in clinical practice, is successfully used to treat infections caused by most Gram-positive and Gram-negative organisms. Since there are few rapid analytical methods for ceftriaxone analysis to use in the pharmaceutical routine, the aim of this research was to develop a new method able to quantify this cephalosporin. Therefore, a sensitive, rapid, simple UV spectrophotometric method for the determination and quantification of ceftriaxone sodium was proposed. The UV detector was set at 241 nm. Beer’s law obeyed the concentration range of 10–20 µg mL−1. Statistical comparison of the results with a well-established reported method showed excellent agreement and proved that there is no significant difference in the accuracy and precision. Intra- and interday variability for the method were less than 2% relative standard deviation. The proposed method was applied to the determination of the examined drugs in pharmaceutical formulations and the results demonstrated that the method is equally accurate, precise, and reproducible as the official methods. Patrícia Vidal de Aléssio, Ana Carolina Kogawa, and Hérida Regina Nunes Salgado Copyright © 2017 Patrícia Vidal de Aléssio et al. All rights reserved. A Simple, Fast, and Inexpensive Simultaneous Determination of Trace Bismuth(III) and Lead(II) in Water Samples by Adsorptive Stripping Voltammetry Mon, 28 Aug 2017 06:59:41 +0000 A simple, fast, and inexpensive voltammetric method for the simultaneous determination of trace bismuth(III) and lead(II) using (Hg(Ag)FE) as a working electrode was optimized. For adsorptive stripping voltammetric determination of Bi(III) and Pb(II) in a single scan, the cupferron was applied as a complexing agent. Experimental conditions under which these elements can be simultaneously detected include 0.1 mol L−1 acetate buffer (pH = 4.6), 1 × 10−4 mol L−1 cupferron, accumulation potential −0.05 V, and accumulation time 30 s. The experiments were performed without deaeration of the solutions. The calibration graph was linear from 2 × 10−9 mol L−1 to 1 × 10−7 mol L−1 for the simultaneous presence of bismuth and lead. The detection limits for preconcentration time of 30 s were 6.7 × 10−10 mol L−1 and 8.8 × 10−10 mol L−1 for bismuth and lead, respectively. The application of this procedure was tested by analyzing certified reference material (SPS-WW1 Wastewater) and Lake Zemborzyce water (eastern areas of Poland). Malgorzata Grabarczyk and Marzena Adamczyk Copyright © 2017 Malgorzata Grabarczyk and Marzena Adamczyk. All rights reserved. Extraction of Phosphate from Polluted Waters Using Calcium Alginate Beads Doped with Active Carbon Derived from A. aspera Plant as Adsorbent Mon, 28 Aug 2017 00:00:00 +0000 An adsorbent prepared by entrapping active carbon derived from the stems of Achyranthes aspera plant in the calcium alginate beads (CABAA) has been investigated for its adsorption nature towards the removal of phosphate by varying various physicochemical parameters. Surface morphological studies are made using FTIR, XRD, FESEM, and EDX. The sorption mechanism is analyzed using Freundlich, Langmuir, Dubinin-Radushkevich, and Temkin adsorption isotherms. The adsorption kinetics is found to follow the pseudo-second-order model. Thermodynamic parameters are analyzed and found that the adsorption is endothermic and nonspontaneous in nature. The maximum amount of phosphate adsorbed onto CABAA is found to be 133.3 mg/g of active carbon and, furthermore, the adsorbent is highly selective. The methodology developed is successfully applied to polluted water samples. Ravulapalli Sujitha and Kunta Ravindhranath Copyright © 2017 Ravulapalli Sujitha and Kunta Ravindhranath. All rights reserved. UHPLC-PDA Assay for Simultaneous Determination of Vitamin D3 and Menaquinone-7 in Pharmaceutical Solid Dosage Formulation Mon, 21 Aug 2017 08:08:57 +0000 A newly developed method based on ultrahigh performance liquid chromatography (UHPLC) was optimized for the simultaneous determination of vitamin D3 and menaquinone-7 (MK-7) in tablet formulation in the present study. UHPLC separation of vitamin D3 and MK-7 was performed with ACE Excel 2 C18-PFP column (2 m, 2.1 100 mm) at 0.6 mL min−1 flow rate, whereas the mobile phase consisted of methanol/water (, v/v, phase A) and isopropyl alcohol (99.9%, phase B) containing 0.5% triethylamine. Isocratic separation of both the analytes was performed at 40°C by pumping the mobile phases A and B in the ratio of (v/v, pH, 6.0). Both analytes were detected at a wavelength of 265 nm and the injection volume was 1.0 L. The overall runtime per sample was 4.5 min with retention time of 1.26 and 3.64 min for vitamin D3 and MK-7, respectively. The calibration curve was linear from 5.0 to 100 g mL−1 for vitamin D3 and MK-7 with a coefficient of determination () 0.9981, while repeatability and reproducibility (expressed as relative standard deviation) were lower than 1.46 and 2.21%, respectively. The proposed HPLC method was demonstrated to be simple and rapid for the determination of vitamin D3 and MK-7 in tablets. Muhammad Jehangir, Mahmood Ahmed, Muhammad Imtiaz Shafiq, Abdul Samad, and Iftikhar-ul-Haq Copyright © 2017 Muhammad Jehangir et al. All rights reserved. A Liquid Chromatography-Tandem Mass Spectrometry Method for Evaluation of Two Brands of Enalapril 20 mg Tablets in Healthy Human Volunteers Tue, 15 Aug 2017 08:22:10 +0000 Enalapril is an angiotensin-converting enzyme inhibitor used for treatment of hypertension and chronic heart disease. Enalaprilat is its active metabolite responsible for the activity. This study aimed to develop and validate a method for enalapril and enalaprilat analysis and to determine the bioequivalence of two tablet formulae of enalapril. LC-MS/MS bioanalytical method was developed and validated and then applied to evaluate the bioavailability of two enalapril formulae. Antihyperglycemic sitagliptin was used as internal standard (IS). The method was accurate for the within- and between-days analysis, and precise CV% was <5%, being linear over the calibration range 1.0–200.0 ng/ml. Stability was >85% and the LOD was 0.907 and 0.910 ng/ml for enalapril and enalaprilat, respectively, and LLOQ was 1 ng/ml. The pharmacokinetic parameters , , , and values of enalapril and enalaprilat of the two formulae were calculated and nonsignificant differences were found. A linearity, specific, accurate, and precise method was developed and applied for the analysis of enalapril and enalaprilat in human plasma after oral administration of two formulae of enalapril 20 mg tablets in healthy volunteers. Depending on the statistical analysis it was concluded that the two enalapril formulae were bioequivalent. Wael Abu Dayyih, Mohammed Hamad, Ahmad Abu Awwad, Eyad Mallah, Zainab Zakarya, Alice Abu Dayyih, and Tawfiq Arafat Copyright © 2017 Wael Abu Dayyih et al. All rights reserved. Stereospecific Assay of (R)- and (S)-Goitrin in Commercial Formulation of Radix Isatidis by Reversed Phase High-Performance Liquid Chromatography Tue, 15 Aug 2017 08:09:46 +0000 Radix isatidis (Banlangen) is a widely used traditional Chinese medicine for treating fever and removing toxic heat. Pharmacological studies have indicated that (R)-goitrin (epigoitrin) is one of the main constituents accounting for its antiviral activity, while (S)-goitrin (goitrin) is known as an antithyroid factor. To better control the quality of radix isatidis and its formulations, it is imperative to enantiomerically determine the contents of R- and S-goitrin. In this study, an enantioselective method based on reversed phase chromatography was developed for the assay of (R, S)-goitrin enantiomers. Optimum separation was obtained on an S-Chiral A column (4.6 mm × 250 mm, 5 μm) using methanol/water (30 : 70, v/v) as the mobile phase. After validation, the method was applied to quantify the enantiomers in Banlangen granules, which is the most prescribed commercial formulation of radix isatidis. Compared to enantioselective resolution approaches based on normal phase chromatography, the new method could be conveniently performed using regular reversed phase high-performance liquid chromatography (RP-HPLC) equipment and was found to be more suitable for the enantioselective quality control of water-extracted and soluble medicines. Lixing Nie, Zhong Dai, and Shuangcheng Ma Copyright © 2017 Lixing Nie et al. All rights reserved. Chromatographic Characterization and Method Development for Determination of Levetiracetam in Saliva: Application to Correlation with Plasma Levels Mon, 07 Aug 2017 09:22:28 +0000 Levetiracetam (LVT) is a widely used antiepileptic drug (AED). A less invasive sampling method for therapeutic drug monitoring (TDM) would be very useful particularly for children. Saliva has been shown as an adequate sample for TDM of some AEDs. Due to the high hydrophilicity of LVT its separation on common stationary phases is quite a challenge so that previous methods for determination of LVT in saliva employed either gradient high performance liquid chromatographic (HPLC) system or mass spectrometer as a detector. In this study the retention behavior of LVT on some common stationary phases was examined, with C8 being the most retentive. A simple isocratic HPLC method that is based on simple protein precipitation was developed and validated for the determination of LVT in saliva. The method was applied to a sample group of epileptic children for the purpose of assessing potential correlation with plasma LVT levels and to investigate patient’s compliance. The results confirmed a reasonable correlation between plasma and salivary levels of LVT ( = 0.9) which supports the use of saliva for TDM of LVT. The study also revealed a significant percentage of epileptic patients having LVT levels below the estimated therapeutic range. Imad I. Hamdan, Mervat Alsous, and Amira Taher Masri Copyright © 2017 Imad I. Hamdan et al. All rights reserved. Extraction of Illegal Dyes from Red Chili Peppers with Cholinium-Based Deep Eutectic Solvents Mon, 31 Jul 2017 05:57:27 +0000 Deep eutectic solvents (DESs) as a new kind of green solvents have been used to extract bioactive compounds but there are few applications in extracting chrysoidine dyes. In this study, we developed an ultrasonic-assisted extraction method with choline chloride/hydrogen bond donor (ChCl/HBD) DES for the extraction of chrysoidine G (COG), astrazon orange G (AOG), and astrazon orange R (AOR) in food samples. Some experimental parameters, such as extraction time, raw material/solvent ratio, and temperature, were evaluated and optimized as follows: the ratio of ChCl/HBD, 1 : 2 (v/v); the ratio of sample/DES, 1 : 10 (g/mL); extraction time, 20 min; extraction temperature, 50°C. Under the optimized conditions, the limits of detection (μg/mL) were 0.10 for COG and 0.06 for AOG and AOR. The relative standard deviations were in the range of 1.2–2.1%. The recoveries of the three dyes were in the range of 80.2–105.0%. By comparing with other commonly used solvents for extracting chrysoidine dyes, the advantages of DESs proved them to be potential extraction solvents for chrysoidine G, astrazon orange G, and astrazon orange R in foods. Shuqiang Zhu, Dongling Liu, Xinyue Zhu, Along Su, and Haixia Zhang Copyright © 2017 Shuqiang Zhu et al. All rights reserved. Electrochemical Evaluation of trans-Resveratrol Levels in Red Wine Based on the Interaction between Resveratrol and Graphene Thu, 27 Jul 2017 00:00:00 +0000 trans-Resveratrol is often considered as one of the quality standards of red wine, and the development of a sensitive and reliable method for monitoring the trans-resveratrol levels in red wine is an urgent requirement for the quality control. Here, a novel voltammetric approach was described for probing trans-resveratrol using a graphene-modified glassy carbon (GC) electrode. The proposed electrode was prepared by one-step electrodeposition of reduced graphene oxide (ERGO) at a GC electrode. Compared with the bare GC electrode, the introduced graphene film on the electrode surface dramatically improved the sensitivity of the sensor response due to the π-π interaction between the graphene and trans-resveratrol. The developed sensor exhibited low detection limit of 0.2 μM with wide linear range of 0.8–32 μM and high stability. For the analysis of trans-resveratrol in red wine, the high anti-interference ability and the good recoveries indicated the great potential for practical applications. Lantao Liu, Yanli Zhou, Yiyu Kang, Haihong Huang, Congming Li, Maotian Xu, and Baoxian Ye Copyright © 2017 Lantao Liu et al. All rights reserved. Spectrophotometric Methods for Simultaneous Determination of Oxytetracycline HCl and Flunixin Meglumine in Their Veterinary Pharmaceutical Formulation Mon, 24 Jul 2017 00:00:00 +0000 Four precise, accurate, selective, and sensitive UV-spectrophotometric methods were developed and validated for the simultaneous determination of a binary mixture of Oxytetracycline HCl (OXY) and Flunixin Meglumine (FLU). The first method, dual wavelength (DW), depends on measuring the difference in absorbance (ΔA 273.4–327 nm) for the determination of OXY where FLU is zero while FLU is determined at ΔA 251.7–275.7 nm. The second method, first-derivative spectrophotometric method (1D), depends on measuring the peak amplitude of the first derivative selectively at 377 and 266.7 nm for the determination of OXY and FLU, respectively. The third method, ratio difference method, depends on the difference in amplitudes of the ratio spectra at ΔP 286.5–324.8 nm and ΔP 249.6–286.3 nm for the determination of OXY and FLU, respectively. The fourth method, first derivative of ratio spectra method (1DD), depends on measuring the amplitude peak to peak of the first derivative of ratio spectra at 296.7 to 369 nm and 259.1 to 304.7 nm for the determination of OXY and FLU, respectively. Different factors affecting the applied spectrophotometric methods were studied. The proposed methods were validated according to ICH guidelines. Satisfactory results were obtained for determination of both drugs in laboratory prepared mixture and pharmaceutical dosage form. The developed methods are compared favourably with the official ones. Hanan A. Merey, Mahmmoud S. Abd-Elmonem, Hagar N. Nazlawy, and Hala E. Zaazaa Copyright © 2017 Hanan A. Merey et al. All rights reserved. Synthesis, Characterization, and Adsorptive Properties of Fe3O4/GO Nanocomposites for Antimony Removal Thu, 20 Jul 2017 08:25:23 +0000 A magnetic Fe3O4/GO composite with potential for rapid solid-liquid separation through a magnetic field was synthesized using GO (graphene oxide) and Fe3O4 (ferriferous oxide). Characterization of Fe3O4/GO used scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR), and Vibrating Sample Magnetometer (VSM). A number of factors such as pH and coexisting ions on adsorbent dose were tested in a series of batch experiments. The results showed that GO and Fe3O4 are strongly integrated. For pH values in the range of 3.0~9.0, the removal efficiency of Sb(III) using the synthesized Fe3O4/GO remained high (95%). The adsorption showed good fit to a pseudo-second-order and Langmiur model, with the maximum adsorption capacity of 9.59 mg/g maintained across pH 3.0–9.0. Thermodynamic parameters revealed that the adsorption process was spontaneous and endothermic. Analysis by X-ray photoelectron spectroscopy (XPS) showed that the adsorption process is accompanied by a redox reaction. Xiuzhen Yang, Tengzhi Zhou, Bozhi Ren, Zhou Shi, and Andrew Hursthouse Copyright © 2017 Xiuzhen Yang et al. All rights reserved. Simultaneous Determination of 11 Compounds in Gualou Guizhi Granule and Pharmacokinetics Study by UPLC-MS/MS Thu, 20 Jul 2017 07:25:28 +0000 A rapid and sensitive ultrafast performance liquid chromatography-tandem mass spectrometry method (UPLC-MS/MS) was developed for the simultaneous determination of 11 compounds in Gualou Guizhi Granule (GLGZG), including liquiritin, isoliquiritin, liquirtin apioside, isoliquiritin apioside, liquiritigenin, isoliquiritigenin, glycyrrhizic acid, glycyrrhetinic acid, paeoniflorin, albiflorin, and paeoniflorin sulfonate in rat plasma. UPLC-MS/MS assay with negative ion mode was performed on a Waters CORTECS C18 (2.1 × 100 mm, 1.6 μm) with the mobile phase consisting of 0.1% aqueous formic acid (A) and acetonitrile (B) in gradient elution at a flow rate of 0.25 mL·min−1. The method was linear for all analytes within the detection range (). The inter- and intraday precision (RSD) were 2.21–6.41% and 1.67–6.18%; the inter- and intraday accuracy (recover) were 92.48–114.03% and 90.23–112.04%. And the recovery rate ranged from 81.30% to 108.22%. The matrix effect values obtained for analytes ranged from 88.91% to 113.32%. This validated method was successfully applied to a pharmacokinetics study in rats after oral administration of GLGZG. Chengtao Sun, Wen Xu, Yuqin Zhang, Lishuang Yu, Miao Ye, Kedan Chu, Wei Xu, and Yu Lin Copyright © 2017 Chengtao Sun et al. All rights reserved. Solidified Floating Organic Drop Microextraction for the Detection of Trace Amount of Lead in Various Samples by Electrothermal Atomic Absorption Spectrometry Thu, 20 Jul 2017 06:41:45 +0000 A novel method was developed for determination of trace amounts of lead in water and food samples. Solidified floating organic drop microextraction was used to preconcentrate the lead ion. After the analyte was complexed with 1-(2-pyridylazo)-2-naphthol, undecanol and acetonitrile were added as extraction and dispersive solvent, respectively. Variables such as pH, volumes of extraction and dispersive solvents, and concentration of chelating agent were optimized. Under the optimum conditions, the detection limit of Pb (II) was determined as 0.042 µg L−1 with an enrichment factor of 300. The relative standard deviation is <10%. Accuracy of the developed procedure was evaluated by the analysis of certified reference material of human hair (NCS DC 73347) and wastewater (SPS-WW2) with satisfactory results. The developed procedure was then successfully applied to biscuit and water samples for detection of Pb (II) ions. Oya Aydın Urucu, Şeyda Dönmez, and Ece Kök Yetimoğlu Copyright © 2017 Oya Aydın Urucu et al. All rights reserved. Synthesis and Characterization of Mixed Iron-Manganese Oxide Nanoparticles and Their Application for Efficient Nickel Ion Removal from Aqueous Samples Wed, 19 Jul 2017 08:28:33 +0000 Mixed iron-manganese oxide nanoparticles, synthesized by a simple procedure, were used to remove nickel ion from aqueous solutions. Nanostructures, prepared by using different weight percents of manganese, were characterized by transmission electron microscopy, selected area diffraction, X-ray diffraction, Raman spectroscopy, and vibrating sample magnetometry. Adsorption/desorption isotherm curves demonstrated that manganese inclusions enhance the specific surface area three times and the pores volume ten times. This feature was crucial to decontaminate both aqueous samples and food extracts from nickel ion. Efficient removal of Ni2+ was highlighted by the well-known dimethylglyoxime test and by ICP-MS analysis and the possibility of regenerating the nanostructure was obtained by a washing treatment in disodium ethylenediaminetetraacetate solution. Alessandro Buccolieri, Antonio Serra, Giuseppe Maruccio, Anna Grazia Monteduro, Sanosh Kunjalukkal Padmanabhan, Antonio Licciulli, Valentina Bonfrate, Luca Salvatore, Daniela Manno, Lucio Calcagnile, and Gabriele Giancane Copyright © 2017 Alessandro Buccolieri et al. All rights reserved. Research on the Characteristics and Mechanism of the Cumulative Release of Antimony from an Antimony Smelting Slag Stacking Area under Rainfall Leaching Tue, 18 Jul 2017 00:00:00 +0000 We aimed to study the characteristics and the mechanism of the cumulative release of antimony at an antimony smelting slag stacking area in southern China. A series of dynamic and static leaching experiments to simulate the effects of rainfall were carried out. The results showed that the release of antimony from smelting slag increased with a decrease in the solid-liquid ratio, and the maximum accumulated release was found to be 42.13 mgSb/kg waste and 34.26 mgSb/kg waste with a solid/liquid ratio of 1 : 20; the maximum amount of antimony was released within 149–420 μm size fraction with 7.09 mg/L of the cumulative leaching. Also, the antimony release was the greatest and most rapid at pH 7.0 with the minimum release found at pH 4.0. With an increase in rainfall duration, the antimony release increased. The influence of variation in rainfall intensity on the release of antimony from smelting slag was small. Bozhi Ren, Yingying Zhou, Andrew S. Hursthouse, and Renjian Deng Copyright © 2017 Bozhi Ren et al. All rights reserved. Magnetic Solid-Phase Extraction Using Fe3O4@SiO2 Magnetic Nanoparticles Followed by UV-Vis Spectrometry for Determination of Paraquat in Plasma and Urine Samples Mon, 17 Jul 2017 07:26:13 +0000 A rapid and simple method was optimized and validated for the separation and quantification of paraquat, a frequently used herbicide and a leading cause of fatal poisoning worldwide, at trace levels with UV-Vis spectrophotometry in plasma and urine samples by direct magnetic solid-phase extraction. Fe3O4@SiO2 nanoparticles (NPs) were used as the magnetic solid-phase extraction agents and the paraquat absorbed on NPs was eluted using NaOH and ascorbic acid. Upon optimization, paraquat could be extracted and concentrated from various samples by 35-fold. The linear range, limit of detection (LOD), correlation coefficient (), and relative standard deviation (RSD) could reach 15.0–400.0 μg/L, 12.2 μg/L, 0.9987, and 0.65% (, = 40.0 μg/L), respectively. The Fe3O4@SiO2 NPs could be reused up to five times. The method was successfully applied to the determination of paraquat in urine and plasma at different hemoperfusion numbers in a local hospital for the patient of paraquat poisoning. The experiment result could not only enable immediate medical intervention but also benefit patients’ survival. Ou Sha, Yu Wang, Xin Yin, Xiaobing Chen, Li Chen, and Shujun Wang Copyright © 2017 Ou Sha et al. All rights reserved. SPE/TLC/Densitometric Quantification of Selected Synthetic Food Dyes in Liquid Foodstuffs and Pharmaceutical Preparations Mon, 17 Jul 2017 00:00:00 +0000 Selected synthetic food dyes (tartrazine, Ponceau 4R, Brilliant Blue, orange yellow, and azorubine) were isolated from liquid preparations (mouthwashes and beverages) by Solid Phase Extraction on aminopropyl-bonded silica with diluted aqueous sodium hydroxide as an eluent. The extraction step was followed by thin layer chromatography on silica gel 60 with chloroform-isopropanol-25% aq. ammonia 1 : 3 : 1 (v/v/v) as mobile phase and the densitometric quantification of dyes was achieved using quadratic calibration plots (; = 0.04–0.09 μgspot−1). The overall recoveries for all studied dyes were at the average level of over 90% and the repeatability of the proposed procedure (CV ≤ 4.1%) was sufficient to recommend it for the routine quantification of the aforementioned dyes in liquid matrices. Anna W. Sobańska, Jarosław Pyzowski, and Elżbieta Brzezińska Copyright © 2017 Anna W. Sobańska et al. All rights reserved. Analytical Method for the Validation of Three Polyphenols as a Marker Compound for the Standardization of Solidago virgaurea subsp. gigantea Extracts and Antiadipogenesis of Harvesting Time and Location Wed, 12 Jul 2017 00:00:00 +0000 Protocatechuic acid (PC), chlorogenic acid (CA), and kaempferol-3-O-rutinoside (K-O-R), isolated from the Solidago virgaurea subsp. gigantea (SV) extract, were quickly and efficiently separated using HPLC. Our chromatographic method was found to effectively separate PC, CA, and K-O-R at retention times of 5.36, 8.22, and 17.04 min, respectively. Linearity of PC, CA, and K-O-R was found to be in the range of 4.85–485.00, 47.5–1900.00, and 8.50–850.00 μg/ml. Recoveries ranged between 101.32 and 103.30%, 95.82 and 100.25%, and 96.18 and 99.37%, for PC, CA, and K-O-R, respectively. The antiadipogenesis activity of SV extracts collected from five different months and from seven different regions was evaluated using an Oil Red O staining assay in 3T3-L1 cells. Extract from SV collected in April from the Ulleung Island produced over 106.89% inhibition of adipogenesis without cytotoxicity at 50 μg/ml. This extract had a high amount of PC and K-O-R. The developed HPLC method was found to be fast, accurate, precise, and reproducible and could be applied to qualitative and quantitative analysis of three bioactive compounds in SV extracts. The SV extract collected in April from Ulleung Island can be used as a functional food ingredient preventing obesity. Seung Hwan Hwang, Ju Hee Kim, Zhiqiang Wang, Jae-Yong Lee, and Soon Sung Lim Copyright © 2017 Seung Hwan Hwang et al. All rights reserved. Development and Validation of a Stability-Indicating HPLC Method for the Simultaneous Determination of Florfenicol and Flunixin Meglumine Combination in an Injectable Solution Tue, 11 Jul 2017 09:56:04 +0000 The combination of the powerful antimicrobial agent florfenicol and the nonsteroidal anti-inflammatory flunixin meglumine is used for the treatment of bovine respiratory disease (BRD) and control of BRD-associated pyrexia, in beef and nonlactating dairy cattle. This study describes the development and validation of an HPLC-UV method for the simultaneous determination of florfenicol and flunixin, in an injectable preparation with a mixture of excipients. The proposed RP-HPLC method was developed by a reversed phase- (RP-) C18e (250 mm × 4.6 mm, 5 μm) column at room temperature, with an isocratic mobile phase of acetonitrile and water mixture, and pH was adjusted to 2.8 using diluted phosphoric acid, a flow rate of 1.0 mL/min, and ultraviolet detection at 268 nm. The stability-indicating method was developed by exposing the drugs to stress conditions of acid and base hydrolysis, oxidation, photodegradation, and thermal degradation; the obtained degraded products were successfully separated from the APIs. This method was validated in accordance with FDA and ICH guidelines and showed excellent linearity, accuracy, precision, specificity, robustness, LOD, LOQ, and system suitability results within the acceptance criteria. Nidal Batrawi, Hani Naseef, and Fuad Al-Rimawi Copyright © 2017 Nidal Batrawi et al. All rights reserved. Simultaneous Analysis of Ursolic Acid and Oleanolic Acid in Guava Leaves Using QuEChERS-Based Extraction Followed by High-Performance Liquid Chromatography Tue, 11 Jul 2017 06:43:45 +0000 In this paper, a novel method of QuEChERS-based extraction coupled with high-performance liquid chromatography has been developed for the simultaneous determination of ursolic acid (UA) and oleanolic acid (OA) in guava leaves. The QuEChERS-based extraction parameters, including the amount of added salt, vortex-assisted extraction time, and absorbent amount, and the chromatographic conditions were investigated for the analysis of UA and OA in guava leaves. Under the optimized conditions, the method showed good linearity over a range of 1–320 μg mL−1, with correlation coefficients above 0.999. The limits of detection of UA and OA were 0.18 and 0.36 μg mL−1, respectively. The intraday and interday precision were below 1.95 and 2.55%, respectively. The accuracies of the UA and OA determinations ranged from 97.4 to 111.4%. The contents of UA and OA in the guava leaf samples were 2.50 and 0.73 mg g−1, respectively. These results demonstrate that the developed method is applicable to the simultaneous determination of UA and OA in guava leaves. Chang Xu, Yiyi Liao, Chunyan Fang, Makoto Tsunoda, Yingxia Zhang, Yanting Song, and Shiming Deng Copyright © 2017 Chang Xu et al. All rights reserved.