bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Method for Speciation of Chromium: Coprecipitation Without Carrier Element by Using a Triazole Derivative
Authors: Duran Celal , Bulut Volkan N , Ozdes Duygu , Gundogdu Ali , Soylak Mustafa 
Published: February 2020

Abstract
A coprecipitation method has been established for speciation of chromium(III) and chromium(VI) in real samples. The procedure is based on the coprecipitation of Cr(III), by using a new organic coprecipitant, 3-phenyl-4-o-hydroxybenzylidenamino-4,5-dihydro-1,2,4-triazole-5-one, without adding any carrier element. After reduction of Cr(VI) by concentrated H2SO4 and ethanol, the method was applied to the determination of total Cr. The level of Cr(VI) was calculated by the difference of total Cr and Cr(III) levels. For optimum recovery of Cr(III), different analytical factors such as pH, amount of coprecipitant, centrifugation rate and time, and effect of sample volume, were investigated. The influences of some anions, cations, and transition metals on the recoveries were also investigated, and no significant interferences were observed. The preconcentration factor was 100. The detection limit based on 3 times standard deviation () of the blank (n = 10) for Cr(III) was 0.50 g/L. In order to evaluate the accuracy of the method, certified reference materials (CRM-TMDW-500 Drinking Water and National Institute of Standards and Technology Standard Reference Material 1573a Tomato Leaves) were analyzed, and the results obtained were in good agreement with certified values. The presented procedure was applied for Cr speciation in various solid and liquid samples with successful results.
Development and Validation of a Reversed-Phase High-Performance Liquid Chromatographic Method for the Simultaneous Determination of Amiloride Hydrochloride, Atenolol, Hydrochlorothiazide, and Chlorthalidone in Their Combined Mixtures
Authors: Elshanawane Abdalla A , Mostafa Samia M , Elgawish Mohamed S 
Published: February 2020

Abstract
A high-performance liquid chromatographic method was developed for the simultaneous determination of 2 ternary mixtures containing amiloride hydrochloride, atenolol, hydrochlorothiazide, and chlorthalidone used in hypertension therapy. The use of cyanopropyl column results in satisfactory separation of both mixtures. The mobile phase consisted of 10 mM KH2PO4 buffer (pH 4.5) and methanol in a ratio of (75 25 v/v), at a flow rate of 1 mL/min. UV detector was operated at 275 nm. Calibration graphs were linear in the concentration ranges of 210, 20200, 10100, and 550 g/mL for amiloride hydrochloride, atenolol, hydrochlorothiazide, and chlorthalidone, respectively. Intraday and interday precision values (relative standard deviation) were &lt;1.13 for mixture I (amiloride hydrochloride, atenolol, chlorthalidone), and &lt;0.93 for mixture II (amiloride hydrochloride, atenolol, hydrochlorothiazide). The method was successfully applied for the determination of the 2 combinations in laboratory-prepared mixtures and commercial pharmaceutical formulation with high accuracy and precision. Statistical comparison of the results with those of the published methods showed excellent agreement and indicates no significant difference between them.
Determination of Bromine in Regulated Foods with a Field-Portable X-Ray Fluorescence Analyzer
Authors: Anderson David L 
Published: February 2020

Abstract
A field-portable X-ray fluorescence analyzer, factory-calibrated for soil analysis, was used to measure bromine (Br) mass fractions in reference materials, flour, bakery products, malted barley, selected U.S. Food and Drug Administration Total Diet Study foods, and other food products. By using a calibration based on instrumental neutron activation analysis results for Br in reference materials, accurate quantitative results, confirmed by z-scores, could be obtained for mass fractions of about 255 mg/kg. These results confirmed accuracy of results (with larger uncertainties) obtained by applying a simple correction factor to the analyzer's output value. Results showed that very short analysis times (&lt;2 min) would be needed to screen foods for Br content at regulatory levels for brominated and enriched brominated flour (24 mg/kg Br) and whole wheat flour and bakery products (36 mg/kg Br). Feasibility for determination of Br in malted barley at the regulatory level (75 mg/kg Br) was demonstrated, but quantitative results at that level could not be assured because no reference material with a suitable mass fraction was available. Br mass fractions for all foods tested were well below regulatory levels.
Adsorptive Cathodic Stripping Voltammetric Determination of Dexamethasone in Formulations and Biological Fluids
Authors: Ghoneim Enass M , El-Attar Mona A , Ghoneim Mohamed M 
Published: February 2020

Abstract
The electrochemical behavior of dexamethasone at a hanging mercury drop electrode (HMDE) in a universal buffer series of pH 210 was studied using cyclic voltammetry. Based on the interfacial adsorptive character of dexamethasone onto the HMDE (electrode surface coverage 1.4 1010mol/cm2), a fully validated simple square-wave adsorptive cathodic stripping voltammetric method is described for its determination in bulk form with a limit of detection (LOD) of 3.1 109 M. The described method was successfully applied to analysis of dexamethasone in its pharmaceutical formulations (deltasone tablets and fortecortin ampule) and in spiked samples of human urine, bovine urine, and protein-free bovine milk. The achieved LODs of dexamethasone in human urine, bovine urine, and protein-free bovine milk were 1.5 108, 2 108, and 9 109 M, respectively. The mean percentage recoveries of 4 107 M dexamethasone in bulk form, spiked human urine, bovine urine, and bovine milk, based on the average of 3 replicate measurements, were 99.8 0.25, 100.4 0.96, 99.6 0.79, and 100.1 0.26, respectively.
Validated Method for Determination of Eight Banned Nitroimidazole Residues in Natural Casings by LC/MS/MS with Solid-Phase Extraction
Authors: Sun Hanwen , Wang Fengchi , Ai Lianfeng , Guo Chunhai , Chen Ruichun 
Published: February 2020

Abstract
A sensitive method based on solid-phase extraction-liquid chromatography-tandem mass spectrometry interfaced with electrospray ionization (SPE-LC-MS/MS-ESI) was developed for the simultaneous determination of 8 banned nitroimidazole (NOZ) drugs including metronidazole (MNZ), ronidazole (RNZ), dimetridazole (DMZ), tinidazole, ornidazole, secnidazole, metronidazole-OH (MNZOH, the metabolite of MNZ), and 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI, the metabolite of RNZ and DMZ) in natural casings. After extraction with ethyl acetate and evaporation, the NOZs were reconstituted in ethyl acetate and purified on a strong cation-exchange SPE column, and then LC/MS/MS analysis was performed by positive ESI applying multiple reaction monitoring of 2 transition reactions for each compound. The method was validated according to the European Union requirements (Commission Decision 2002/657/EC). Specificity, linearity, decision limit (CC), detection capability (CC), accuracy, and precision were determined. Average recoveries of the 8 NOZs from natural animal casing fortified at 3 levels (0.1, 0.5, and 1 g/kg) ranged from 87.3 to 116.5. The calculated CC for NOZs ranged from 0.029 to 0.049 g/kg, and CC ranged from 0.049 to 0.083 g/kg. Repeatability was in the range of 3.3510.1, and within-laboratory reproducibility was &lt;10.3.
Optimized HPLC Method for Analysis of Polar and Nonpolar Heterocyclic Amines in Cooked Meat Products
Authors: Gibis Monika 
Published: February 2020

Abstract
A simple, precise, and specific column high-performance liquid chromatographic (HPLC) method with UV absorption diode array and fluorescence detection has been developed by optimizing a previously described method for the simultaneous quantification of 15 polar and nonpolar heterocyclic amines (HAs) in fried meat products. The HPLC determination could be improved due to the application of a silica-based reversed-phase column with octadecyl groups (TSK-gel&lt;sup/&gt; Super ODS) and a particle size of 2 m. The separation of HAs in the complex meat matrix was performed with a 21 min mobile phase gradient. The method was validated for instrumental precision, repeatability, and selectivity and compared with a previously published method. After liquid adsorption of the basic sample mixture on diatomaceous earth, HAs were extracted with ethyl acetate. For cleanup, solid-phase extraction (silica propylsulfonic acid and octadecyl cartridges) and different washing steps were applied. Both nonpolar and polar HAs were determined in one fraction. The calibration curves of all HAs were linear for the applied detection system (correlation coefficient = 0.9900.995). The recoveries, with the exception of 3-amino-1-methyl-5H-pyrido [4,3-b]indole (Trp-P-2), were between 42 and 98 from meat samples spiked in a range of 1.5 to 3.3 ng/g for fluorescence-active and 4.3 to 8 ng/g for UV-active HAs. For quantification of HAs, the standard addition method was used for adjustment of different characteristics of HAs in the extraction. In fried meat samples (chicken breast and beef patties), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f] quinoxaline(4,8-DiMeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), norharmane, and harmane were found in a concentration range of 0.02 to 14.3 ng/g.
A Novel Method for the Quantification of Quinic Acid in Food Using Stable Isotope Dilution Analysis
Authors: Erk Thomas , Bergmann Hannah , Richling Elke 
Published: February 2020

Abstract
Organic acids play an important role in the flavor and taste of plant-derived foods. Quinic acid (QA) is one of the major acids. In the past, several methods like HPLC/UV, GC, and capillary electrophoresis were used for identification and quantification of QA. For the first time, a novel, sensitive, and selective method for the quantification of QA in food using stable isotope dilution analysis with HPLC/MS/MS has been established. Uniformly labeled 13C-QA was used as a standard to reduce sample preparations and to overcome matrix and ionization effects. The method was used to determine the QA content of red wines, instant coffees, and cloudy apple juices. QA contents of instant coffees were 64.4 and 63.6 g/kg powder. The concentrations in red wines were 24.0 and 25.1 mg/L, and 1493.3 and 1705.2 mg/L in cloudy apple juices.
Determination of Seven Flavonoids in Ixeridium gracile (DC.) Shih by High-Performance Liquid Chromatography
Authors: Chen Juan , Ma Xue-Mei , Shi Yan-Ping 
Published: February 2020

Abstract
A high-performance liquid chromatographic technique coupled with photodiode array detection was proposed for the simultaneous determination of 7 flavonoids, i.e., quercetin, kaempferol, 7-hydroxyflavanone, 7-methoxyflavanone, 2,4-dihydroxychalcone, 2,4-dihydroxydihydrochalcone, and 7,2-dihydroxy-3, 4-dimethoxyisoflavane, in extracts of the plant Ixeridium gracile. Optimum separation was obtained by using a reversed-phase C18 method. Because of the different UV characteristics of these components, 5 detection wavelengths were used for the quantitative analysis. All of the flavonoids showed good linearity (r &gt; 0.9999). The limit of detection and limit of quantitation values for the analytes ranged from 0.06 to 0.46 g/mL and from 0.18 to 1.48 g/mL, respectively. The method was validated by evaluating repeatability, precision, stability, and accuracy. Five different extraction and purification procedures were investigated for preparation of the sample solution. The optimized method was applied to the determination of flavonoids in I. gracile and was found to be efficient.
Automated Chemiluminometric Screening of Counterfeit Drugs of the Antituberculosis Agent Pyrazinamide
Authors: Prior João A V , Santos João L M , Lima José L F C 
Published: February 2020

Abstract
Finding counterfeit drugs presents a growing challenge in preventing these products from entering health systems and causing serious consequences for consumers, drug manufacturers, and governments. In this investigation a simple, low-cost, and expeditious chemiluminometric approach, relying on a fully automated multipumping flow system for screening pharmaceutical preparations of the antituberculosis drug pyrazinamide, was implemented. The developed chemiluminescent method was based on the scavenging effect of pyrazinamide on the oxidation of luminol by hydrogen peroxide in alkaline medium. For analytical signal monitoring, a homemade chemiluminescence detector relying on a photomultiplier module was developed. Linear calibration plots for pyrazinamide concentrations between 10 and 70 mg/L were obtained (R = 0.9931) with good precision (RSD &lt; 0.99; n = 21). The limit of detection was 5.79 mg/L, and the sampling rate was about 150 determinations per hour.
A Cloud Point Extraction Procedure for Preconcentration/Flame Atomic Absorption Spectrometric Determination of Silver, Zinc, and Lead at Subtrace Levels in Environmental Samples
Authors: Ghaedi Mehrorang , Shokrollahi Ardeshir , Niknam Khodabakhsh , Niknam Ebrahim , Derki Somayyeh , Soylak Mustafa 
Published: February 2020

Abstract
A cloud point extraction (CPE) procedure was presented for the preconcentration of silver, zinc, and lead ions in various samples. The complexes of these metal ions with 2-(((1H-benzo[d]imidazol-2-yl)methoxy)methyl)-1H-benzo[d]imidazole (BIMMBI) are quantitatively extracted into the Triton X-114-rich phase after centrifugation. A solution of 1.0 M HNO3 in methanol was added to the surfactant-rich phase as the effective eluant before analysis by flame atomic absorption spectrometry. The influence of effective parameters such as the concentrations of BIMMBI, Triton X-114, and HNO3, pH, bath temperature, centrifuge rate, and time on method sensitivity and efficiency was optimized. Detection limits of 2.8, 1.7, and 1.1 ng/mL for Pb2+, Ag+, and Zn2+, respectively, along with a preconcentration factor of 30 and enrichment factors of 33, 48, and 53 for Pb2+, Ag+, and Zn2+, respectively, were obtained. The present CPE method is suitable for accurate and precise determination of trace amounts of analyte ions in complex matrixes. The proposed CPE procedure was applied to the determination of these ions in biological, natural water, wastewater, soil, and blood samples.
Nontargeted Multicomponent Analytical Screening of Plastic Food Contact Materials Using Fast Interpretation of Deliverables via Expert Structure-Activity Relationship Software
Authors: Rothenbacher Thorsten , Schwack Wolfgang 
Published: February 2020

Abstract
Plastic packaging materials may release compounds into packed foodstuffs. To identify potential migrants of toxicological concern, resins, and multilayer foils (mainly polyethylene) intended for the production of food contact materials were extracted and analyzed by GC/mass spectrometry. To identify even compounds of low concentrations, AMDIS software was used and data evaluation was safeguarded by the Kovats retention index (RI) system. In this way, 46 compounds were identified as possible migrants. The expert structure-activity relationship software DEREK for Windows was utilized to evaluate all identified substances in terms of carcinogenicity, genotoxicity, thyroid toxicity, and miscellaneous endpoints for humans. Additionally, a literature search for these compounds was performed with Sci-Finder&lt;sup/&gt;, but relevant data were missing for 28 substances. Seven compounds with adverse toxicological effects were identified. In addition, the RIs of 24 commercial additive standards, measured with a GC capillary column of intermediate polarity, are given.
Validation Study of a Receptor-Based Lateral Flow Assay for Detection of Beta-Lactam Antibiotics in Milk
Authors: Abouzied Mohamed , Sarzynski Michael , Walsh Aaron , Wood Heather , Mozola Mark 
Published: February 2020

Abstract
Avalidation study designed tomeet the requirements of the AOAC Research Institute and the U.S. Food and Drug Administration (FDA), Center for Veterinary Medicine, was conducted for a receptor-based, immunochromatographic method (BetaStar US) for detection of beta-lactam antibiotic residues in raw, commingled bovine milk. The assay was found to detect amoxicillin, ampicillin, cephapirin, cloxacillin, and penicillin G at levels below the FDA tolerance/safe levels but above the maximum sensitivity thresholds established by the National Conference on Interstate Milk Shipments. Results of the Part I (internal) and Part II (independent laboratory) dose-response studies using spiked samples were in very close agreement for all five drugs tested, with differences between the Part I and Part II 90/95 sensitivity values ranging from 0 to 1 ppb. The test was able to detect all five drugs at the approximate 90/95 sensitivity levels when present as incurred residues in milk collected from cows that had been treated with the specific drug. Asixth drug, ceftiofur, was found to be undetectable at levels of 500 ppb (as total ceftiofur metabolites from incurred residues in milk samples). The selectivity of the assay was 100, because no false-positive results were obtained in tests of &gt;1000 control milk samples. The assay was found to be applicable to the testing of frozen raw milk samples. Results of ruggedness experiments established the operating parameter tolerances for the BetaStar US assay. Results of cross-reactivity testing established that the assay detects certain other beta-lactam drugs (dicloxacillin and ticarcillin), but it does not cross-react with any of 30 drugs belonging to other classes. Abnormally high bacterial or somatic cell counts in rawmilk produced no interference with the ability of the test to detect beta-lactams at tolerance/safe levels.
Simultaneous Determination of Five Benzimidazoles in Feeds Using High-Performance Capillary Electrophoresis
Authors: Shen Jianzhong , Tong Jing , Jiang Haiyang , Rao Qinxiong , Li Na , Guo Liming , Ding Shuangyang 
Published: February 2020

Abstract
A high-performance capillary electrophoretic method for determination of five benzimidazoles (thiabendazole, albendazole, fenbendazole, mebendazole, oxfendazole) in animal feeds was developed. Separation was carried out in an 80.5 cm 75 m id fused-silica uncoated capillary and injected by hydrodynamic injection (35 mbar 8 s) at a wavelength detection of 295 nm. The drugs were completely resolved in 50 mmol/L citric acid buffer (pH 1.9) with 30 kV at a temperature of 25C. Linear range was 180 g/mL; limits of detection for the analytes were less than 2 mg/kg; the overall recoveries for benzimidazoles were &gt;73, with coefficients of variation below 10.
High-Performance Liquid Chromatographic Fingerprint for Quality Control of Terminalia arjuna Containing Ayurvedic churna Formulation
Authors: Chitlange Sohan S , Kulkarni Prajakta S , Patil Dada , Patwardhan Bhushan , Nanda Rabindra K 
Published: February 2020

Abstract
Because Ayurvedic herbal preparations contain a myriad of compounds in complex matrixes, it is difficult to establish quality control standards for raw materials and to standardize finished Ayurvedic drugs. A novel, accurate, and valid fingerprint method was developed using HPLC for quality control of a traditional Ayurvedic Arjuna churna formulation, which is used as a cardiotonic drug. Comprehensive comparison of chromatograms of standardized formulation of Arjuna churna and marketed formulations revealed eight characteristic peaks in chromatograms, which unambiguously confirmed the presence of authentic raw material used in the formulation on the basis of their retention time values and UV data. An HPLC fingerprint was also developed for total sapogenins present in Terminalia arjuna. The six common peaks observed in chromatograms of isolated sapogenins, standardized formulations, and marketed formulations can serve as a quality control tool for qualitative estimation of total saponin glycosides present in an Arjuna churna formulation.
Construction of New Iodide Ion-Selective Electrodes Based on New Ionophores: Comparison of the Effect of Structures and Additives on Electrode Response
Authors: Shokrollahi Ardeshir , Ghaedi Mehrorang , Kianfar Ali Hossain , Montazerozohori Morteza , Najibzadeh Marziyeh 
Published: February 2020

Abstract
New iodide ion-selective electrodes based on bis(2-methyl-3-phenyl-propenylidene)1,2-propanediamine) mercury(II) bromide [Hg(BMPPMB)Br2], bis (5-bromo salicylaldehyde) ethylenediimine vanadyl(IV) [VO(5-Br Salen)], and bis(5-bromo salicylaldehyde) ethylenediimine uranyl(VI) [UO2(5-Br Salen)] carriers are described. The electrodes exhibited Nernstian slopes of 58.3 1.0, 58.5 1.4, and 59.0 1.2 mV/decade for Hg(BMPPMB)Br2, VO(5-Br Salen), and UO2(5-Br Salen) iodide ion concentration in the range of 1.0 1060.1 M, with detection limits of about 0.6, 0.5, and 0.3 M, respectively. The potentiometric responses of the electrodes were independent of pH over the range 1.710.6, 2.211.3, and 2.111.1, with satisfactory reproducibility. The electrodes had response times of 5 s and could be used for at least 84, 80, and 100 days for Hg(BMPPMB)Br2, VO(5-Br Salen), and UO2(5-Br Salen), respectively, without any considerable divergence in their potential responses.
Rapid Method for the Determination and Confirmation of Fluoroquinolone Residues in Catfish Using Liquid Chromatography/Fluorescence Detection and Liquid Chromatography-Tandem Mass Spectrometry
Authors: McMullen Sarah E , Schenck Frank J , Vega Victor A 
Published: February 2020

Abstract
A simplified method for the extraction and determination of four fluoroquinolone (FQ) residues (ciprofloxacin, enrofloxacin, sarafloxacin, and difloxacin) in catfish is presented. In this method, the FQ residues were extracted with acidified acetonitrile, and the extract was defatted with dispersive C18 solid-phase extraction (SPE) sorbent or hexane. A portion of the extract was evaporated and reconstituted in the mobile phase. The quantitative determination was accomplished with LC-fluorescence detection (FLD), and the confirmation was by LC-MS/MS. Fortifications of catfish tissue were carried out at 0.5x, x, 2x, and 4x, where x = 5 ppb (U.S. Food and Drug Administration current regulatory target level). Recoveries for the LC/FLD determination of five replicates (for both cleanup routes) at each level ranged from 64 to 98, with RSD values &lt;8. The method quantitation limits for all residues were &lt;1 ng/g. The LC-MS/MS analysis of the same extracts confirmed all FQ residues at all levels. This method is an improvement over existing methodologies since additional cleanup steps, such as cation exchange SPE column cleanup, are not utilized. The C18 dispersive SPE method represents a novel cleanup approach for FQs in fish tissue.