bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solid-Phase Extraction of Antimony Using Chemically Modified SiO2-PAN Nanoparticles
Authors: Kaur Anupreet , Gupta Usha 
Published: February 2020

Abstract
A new analytical method using 1-(2-pyridylazo)-2-naphthol (PAN)-modified SiO2 nanoparticles as solid-phase extractant has been developed for the preconcentration of trace amounts of Sb(III) in different water samples. Conditions of the analysis such as preconcentration factor, effect of pH, sample volume, shaking time, elution conditions, and effects of interfering ions for the recovery of the analyte were investigated. The adsorption capacity of nanometer SiO2-PAN was found to be 186.25 mol/g at optimum pH and the LOD (3) was 0.60 g/L. The extractant showed rapid kinetic sorption. The adsorption equilibrium of Sb(III) on nanometer SiO2-PAN was achieved in 10 min. Adsorbed Sb(III) was easily eluted with 4 mL 2 M hydrochloric acid. The maximum preconcentration factor was 62.20. The method was applied for the determination of trace amounts of Sb(III) in various water samples (tap, mineral water, and industrial effluents).
Fast Analysis of Polybrominated Diphenyl Ethers in Eggs Using Selective Pressurized Liquid Extraction Coupled with Online GPC-GC/MS
Authors: Liu Yin-Ping , Li Jing-Guang , Zhao Yun-Feng , Zhang Lei , Zhou Rui , Wu Yong-Ning , Zhu Ling-Yan 
Published: February 2020

Abstract
This article reports the applicability of online gel permeation chromatography (GPC)-GC/MS for the determination of seven predominant polybrominated diphenyl ethers (PBDEs) in eggs to effectively eliminate matrix interference. Selective pressurized liquid extraction using acidic alumina as a fat retainer was used for cleanup of the PBDEs in eggs. It was selected because of its advantages: simpler operation, minimum time spent on sample handing to get fat-free extracts, and low volume of solvent consumption. After concentration, the extract was directly injected for online GC/MS operated in the negative ion chemical ionization mode with a 15 m capillary column. Recoveries of spiked samples were between 75.1 and 102.0, with RSDs (n = 3) ranging from 3.6911.47 when spiked at levels of 2 and 20 ng/g, dry mass. The LOD varied from 0.2534 ng/g, dry mass. The proposed method was proven to be rapid, efficient, and reliable for the trace determination of PBDEs in eggs.
Modification and Validation of a High-Performance Liquid Chromatography Method for Quantification of Huperzine A in Huperzia Crispata
Authors: Yu Lijun , Shi Yunfeng , Huang Jianan , Gong Yushun , Liu Zhonghua , Hu Weixin 
Published: February 2020

Abstract
The present study describes a rapid and sensitive HPLC method for the quantification of huperzine A (HupA) in Huperzia Crispata (Huperziaceae). The sample extraction and preparation involved a simple, time-saving, single-solvent extraction, with each sample being analyzed within 12 min. The mobile phase was ammonium acetate (0.1 M, pH 6.0)methanol (64 + 36, v/v) at a flow rate of 1.0 mL/min. Detection was at 308 nm. The calibration curve was linear from 0.049 to 7.84 µg (R2 = 0.9997), with intraday and interday precision RSD of less than 2%. The extraction recovery rate was over 98.49%. Quantification of HupA was performed using this modified method, and the content of HupA was 1.86 times higher in the whole plant of H. crispata (218.17 ± 1.55 µg/g) than in that of H. serrata (117.03 ± 2.97 µg/g). In the whole plant of H. crispata, HupA mainly accumulated in the actively growing shoot tips, the apical bud, and the 10 youngest leaves, reaching 455.23 ± 2.97 µg/g. The content of HupA in the samples from sunshine-sheltered sites was 3.45 times higher than in that from sunshine-abundant sites. The satisfactory results indicate that this modified method can be applied in the quality control of large-scale Huperziaceae plant extracts and that changes should be made in the cultivation of H. crispata so as to maximize the production of HupA.
Comparison of Limulus Amebocyte Lysates with the United States Pharmacopeial Pyrogen Test and the Portable Test System for Radiopharmaceuticals
Authors: Santos-Oliveira Ralph 
Published: February 2020

Abstract
Radiopharmaceuticals play an important role in modern nuclear medicine, and 18F-FDG (2-[18F] fluoro-2-deoxy-D-glucose) is the most frequently used in imaging examinations today. The pyrogen test represents an important parameter for the quality of radiopharmaceuticals since most of them, 18F-FDG included, are injectable solutions. However, the standard test proposed by the U.S. Pharmacopeia using limulus amebocyte lysates takes too long (about 1 h). An alternative test is the Portable Test System, which takes no more than 15 min. In order to compare both tests, 10 batches of 18F-FDG produced in the Nuclear Engineering Institute, Rio de Janeiro, Brazil, were analyzed. The results showed that in 40% of the samples analyzed, different results were found. From the total analyzed, 20% showed totally diverging results, and 80% demonstrated partial similarity. These differences have a great impact in the choice of the test used for radiopharmaceutical injectable solutions and the importance of validation tests before the implementation in the daily routine.
Quantitative Structure-Retention Relationship Studies as an Analytical Tool in the Determination and Modeling of Pesticide Residues in Plant Organisms
Authors: Buszewski Bogusaw , Michel Monika 
Published: February 2020

Abstract
Crop models use mathematical equations to simulate the physical and chemical processes that generally control the uptake, translocation, and sorption of pesticides in all parts of plants. Our interest is focused on method optimization to determine the new compounds using stationary and mobile phases with different physicochemical properties. The work deals with five fungicides composed of nitrogen-containing heterocycles, 1,2,4-triazoles. The sample preparation liquid extraction and solid-phase-based methods are used to determine and model the pesticide residues in plants organisms. Analysis of these compounds is generally carried out by GC or HPLC coupled to different detectors, especially to mass spectrometers, in hyphenated techniques that have been extremely developed in recent years. The relationships between the chromatographic retention factor (k) and those physicochemical properties that are relevant in quantitative structure-retention relationship (QSRR) studies were investigated. The accuracy of the simple linear regressions between the chromatographic retention and the descriptors for all of the compounds was satisfactory (correlation coefficient 0.83 ≥ R2 ≥ 0.99). The QSRR models of these nitrogen-containing heterocyclic compounds could be predicted with a multiple linear regression equation having the statistical index R2 = 1.00. Evaluation of chromatographic properties of the new stationary phases and description of the molecular separation mechanism using the QSRR method, including molecular modeling, were performed. A universal model is presented that links the physicochemical parameters describing the fungicide compounds with the anatomical, physiological, and biochemical properties of the plant.
Application of HPLC and TLC with Diode Array Detection After SPE to the Determination of Pesticides in Water Samples from the Zemborzycki Reservoir (Lublin, Southeastern Poland)
Authors: Tuzimski Tomasz 
Published: February 2020

Abstract
The application of TLC with a diode array detector (TLC-DAD) and HPLC-DAD after SPE for identification and quantitative analysis of pesticides in water samples is demonstrated. The procedures described for the determination of compounds are inexpensive and can be applied to routine analysis of analytes in water samples after preliminary cleanup and concentration by SPE. Average recoveries for four different cartridges and three solvents by the proposed HPLC-DAD method after SPE also are presented. The efficiency of the SPE procedure was evaluated using real water samples from the Zemborzycki Reservoir, near Lublin, southeastern Poland. The method was validated for precision, repeatability, and accuracy.
Rapid Method for the Determination of Organochlorine Pesticides and PCBs in Fish Muscle Samples by Microwave-Assisted Extraction and Analysis of Extracts by GC-ECD
Authors: Wilkowska Angelika M , Biziuk Marek 
Published: February 2020

Abstract
A procedure for the multiresidue determination of organochlorine pesticides and polychlorinated biphenyls in fish muscle samples has been developed. The method is based on the microwave-assisted extraction (MAE) of food samples from an acetonitrilewater (95 5, v/v) mixture followed by SPE cleanup of the extracts and analysis by GC with an electron capture detector. MAE operational parameters, such as the extraction solvent, temperature, and time, were optimized with respect to the extraction efficiency of the target compounds from food samples with 1013 fat content. The chosen extraction technique allows reduction of the solvent consumption and extraction time when compared with methods already used. Acetonitrile is a good extraction solvent for low-fat matrixes (220 fat content), such as fish samples, because it does not significantly dissolve the highly polar proteins, salts, and sugars commonly found in food and gives high recoveries of a wide polarity range of analytes. For purification, SPE using LC-Florisil was shown to be sufficient for the removal of coextracted substances. Recoveries &gt;78 with RSD values &lt;15 were obtained for all compounds under the selected conditions. Method quantification limits were in the 510 g/kg range. The method was applied to the analysis of samples of herring (Clupea harengus) purchased at the local fish market. The method is rapid and reliable for the determination of organochlorine analytes in fish muscle.
Development and Validation of an HPLC/MS/MS Method for the Determination of Sufentanil and Morphine in Human Plasma
Authors: Manfio Josélia Larger , Santos Verônica Jorge , Lanchote Vera Lúcia , Santos Luciana M , Carmona Maria José C , Auler José Otavio , Junior Liberato Brum , Donaduzzi Carmen Maria , Santos Silvia R C J 
Published: February 2020

Abstract
A sensitive and fast HPLC/MS/MS method for measurement of sufentanil and morphine in plasma was developed and validated. A single liquid–liquid extraction in alkaline medium was used for the cleanup of plasma, and fentanyl was added as an internal standard (IS). The analyses were carried out using a C18 column and the mobile phase acetonitrile–5 mM ammonium acetate + 0.25% formic acid (70 + 30, v/v). The triple-quadrupole mass spectrometer equipped with an electrospray source in positive mode was set up in the selective reaction monitoring mode to detect precursor → product ion transition 387.0 &gt; 238.0, 285.7 &gt; 165.1, and 337.0 &gt; 188.0 for sufentanil, morphine, and IS, respectively. The method was linear in the 0.05 (LOQ) – 500 ng/mL range for sufentanil and 10 (LOQ) – 1000 ng/mL range for morphine. Good selectivity, linearity, precision, accuracy, and robustness were obtained for the HPLC/MS/MS method. The proposed method was successfully applied for the determination of sufentanil and morphine in patients undergoing cardiac surgery.
Qualitative PCR Method for Roundup Ready® Soybean: Interlaboratory Study
Authors: Kodama Takashi , Kasahara Masaki , Minegishi Yasutaka , Futo Satoshi , Sawada Chihiro , Watai Masatoshi , Akiyama Hiroshi , Teshima Reiko , Kurosawa Yasunori , Furui Satoshi , Hino Akihiro , Kitta Kazumi 
Published: February 2020

Abstract
Quantitative and qualitative methods based on PCR have been developed for genetically modified organisms (GMO). Interlaboratory studies were previously conducted for GMO quantitative methods; in this study, an interlaboratory study was conducted for a qualitative method for a GM soybean, Roundup Ready® soy (RR soy), with primer pairs designed for the quantitative method of RR soy studied previously. Fourteen laboratories in Japan participated. Each participant extracted DNA from 1.0 g each of the soy samples containing 0, 0.05, and 0.10% of RR soy, and performed PCR with primer pairs for an internal control gene (Le1) and RR soy followed by agarose gel electrophoresis. The PCR product amplified in this PCR system for Le1 was detected from all samples. The sensitivity, specificity, and false-negative and false-positive rates of the method were obtained from the results of RR soy detection. False-negative rates at the level of 0.05 and 0.10% of the RR soy samples were 6.0 and 2.3%, respectively, revealing that the LOD of the method was somewhat below 0.10%. The current study demonstrated that the qualitative method would be practical for monitoring the labeling system of GM soy in kernel lots.
Optimization of Detection Conditions and Single-Laboratory Validation of a Multiresidue Method for the Determination of 135 Pesticides and 25 Organic Pollutants in Grapes and Wine by Gas Chromatography Time-of-Flight Mass Spectrometry
Authors: Dasgupta Soma , Banerjee Kaushik , Dhumal Kondiba N , Adsule Pandurang G 
Published: February 2020

Abstract
This paper describes single-laboratory validation of a multiresidue method for the determination of 135 pesticides, 12 dioxin-like polychlorinated biphenyls, 12 polyaromatic hydrocarbons, and bisphenol A in grapes and wine by GC/time-of-flight MS in a total run time of 48 min. The method is based on extraction with ethyl acetate in a sample-to-solvent ratio of 1:1, followed by selective dispersive SPE cleanup for grapes and wine. The GC/MS conditions were optimized for the chromatographic separation and to achieve highest S/N for all 160 target analytes, including the temperature-sensitive compounds, like captan and captafol, that are prone to degradation during analysis. An average recovery of 80–120% with RSD &lt;10% could be attained for all analytes except 17, for which the average recoveries were 70–80%. LOQ ranged within 10–50 ng/g, with &lt;25% expanded uncertainties, for 155 compounds in grapes and 151 in wine. In the incurred grape and wine samples, the residues of buprofezin, chlorpyriphos, metalaxyl, and myclobutanil were detected, with an RSD of &lt;5% (n= 6); the results were statistically similar to previously reported validated methods.
RP-HPLC Analysis of Phenolic Acids of Selected Central European Carex L. (Cyperaceae) Species and Its Implication for Taxonomy
Authors: Bogucka-Kocka Anna , Szewczyk Katarzyna , Janyszek Magdalena , Janyszek Sławomir , Cieśla Łukasz 
Published: February 2020

Abstract
Eighteen species belonging to the Carex genus were checked for the presence and the amount of eight phenolic acids (p-hydroxybenzoic, vanillic, caffeic, syringic, protocatechuic, p-coumaric, sinapic, and ferulic) by means of HPLC. Both the free and bonded phenolic acids were analyzed. The majority of the analyzed acids occurred in the studied species in relatively high amounts. The highest concentrations found were caffeic acid and p-coumaric acid, for which the detected levels were negatively correlated. A very interesting feature was the occurrence of sinapic acid, a compound very rarely detected in plant tissues. Its distribution across the analyzed set of species can be hypothetically connected with the humidity of plants' habitats. Several attempted tests of aggregative cluster analysis showed no similarity to the real taxonomical structure of the genus Carex. Thus, the phenolic acids' composition cannot be considered as the major taxonomical feature for the genus Carex.
Development of a Method to Determine Albendazole and Its Metabolites in the Muscle Tissue of Yellow Perch Using High-Performance Liquid Chromatography with Fluorescence Detection
Authors: Yu Donglei , Rummel Nathan , Shaikh Badar 
Published: February 2020

Abstract
An HPLC method was developed for the determination of albendazole (ABZ) and its metabolites, a sulfoxide (ABZSO), a sulfone (ABZSO2), and albendazole-2-aminosulfone (ABZ-2-NH2SO2), from yellow perch muscle tissue with adhering skin. The muscle tissue samples were made alkaline with potassium carbonate and extracted with ethyl acetate, followed by a series of liquidliquid extraction steps. After solvent evaporation, the residue was reconstituted in the initial mobile phase combination of the gradient. The mobile phase consisted of a buffer, 50 mM ammonium acetate (pH 4.0) in 10 methanolwater, and 100 acetonitrile. The gradient was from 20 acetonitrile to 85 acetonitrile. The analytes were chromatographed on an RP Luna C18(2) column and detected by fluorescence with excitation and emission wavelengths of 290 and 330 nm, respectively. The average recoveries from fortified muscle tissue for ABZ (20100 ppb), ABZ-SO (20200 ppb), ABZSO2 (8100 ppb), and ABZ-2-NH2SO2 (20100 ppb) were 85, 95, 101, and 86, respectively, with corresponding CV values of 9, 3, 6, and 4, respectively. Their LOQ values were 10, 10, 1, and 10 ppb, respectively. The procedure was applied to determine ABZ and its major metabolites in the incurred muscle tissue of yellow perch obtained after orally dosing the fish with ABZ.
Gradient HPLC-Diode Array Detector Stability-Indicating Determination of Lidocaine Hydrochloride and Cetylpyridinium Chloride in Two Combined Oral Gel Dosage Forms
Authors: Belal Tarek S , Shaalan Rasha A , Haggag Rim S 
Published: February 2020

Abstract
A simple, rapid, and selective HPLC-diode array detector method was developed for the simultaneous determination of lidocaine hydrochloride (LD) and cetylpyridinium chloride (CPC) in two combined pharmaceutical formulations. Effective chromatographic separation was achieved on a Zorbax SB-C8 (4.6 250 mm, 5 m particle size) column with gradient elution using a mobile phase composed of 0.05 M phosphoric acid and acetonitrile. The gradient elution started with 25 (v/v) acetonitrile, ramped up linearly to 85 in 5 min, and then was constant until the end of the run. The mobile phase was pumped at a flow rate of 1.2 mL/min. The multiple wavelength detector was set at 214 and 258 nm, and quantification of the analytes was based on measuring their peak areas. The retention times for LD and CPC were about 3.4 and 7.3 min, respectively. The reliability and analytical performance of the proposed HPLC procedure were statistically validated with respect to linearity, range, precision, accuracy, selectivity, robustness, LOD, and LOQ. Calibration curves were linear in the range of 5200 and 10400 g/mL for LD and CPC, respectively, with correlation coefficients &gt;0.999. The proposed method was proven to be stability-indicating by the resolution of the two analytes from the related substance and potential impurity (2,6-dimethylaniline) as well as from forced-degradation products. The validated HPLC method was extended to the analysis of LD and CPC in two combined oral gel preparations for which the two analytes were successfully resolved from the pharmaceutical adjuvants and quantified with recoveries not less than 97.9.
A Highly Sensitive RP-HPLC-Fluorescence Method to Study Aldehyde Oxidase Activity
Authors: Rashidi Mohammad-Reza , Amini Kaveh , Khani Mohammad-Yaser , Faridi Akram , Hanaee Jalal , Sorouraddin Mohammad-Hossein 
Published: February 2020

Abstract
Aldehyde oxidase is a widely distributed enzyme that is involved in the metabolism of an extensive range of aldehydes and N-heterocyclic compounds with physiological, pharmacological, and toxicological relevance. In the present study, a highly sensitive RP-HPLC-fluorescence method based on the oxidation of phenanthridine to phenanthridinone has been developed and validated to assay aldehyde oxidase activity in biological samples. Determination of phenanthridinone was achieved on a C18 column using 10 mmol/L phosphate buffer (pH 5.0) containing 0.1 mmol/L EDTAacetonitrile (40 60, v/v) as the mobile phase. The fluorescence intensity of phenanthridinone was measured at 364 nm with excitation at 236 nm. The proposed method was precise, accurate, specific and rapid (analysis time, approximately 8 min) with a mean RSD of 2.54. Peak responses were linear from 0.5 to 100 nmol/L, with an LOD of 0.125 nmol/L. The applicability of the method was demonstrated by measurement of aldehyde oxidase activity in rat liver, kidney, ovary, and heart fractions.
Clospore: A Liquid Medium for Producing High Titers of Semi-purified Spores of Clostridium difficile
Authors: Perez Justo , Springthorpe V Susan , Sattar Syed A 
Published: February 2020

Abstract
Clostridium difficile continues to cause infections in healthcare and other settings. Its spores survive well indoors and require sporicidal chemicals for infection control. However, proper testing of disinfectants is impeded due to difficulties in obtaining viable spores of high enough quality and titers to meet current regulations for sporicidal claims. A new liquid medium (Clospore) has been developed, based on a systematic review of the compositions of 20 other available media. C. difficile spores grown in the new medium and treated with a mixture of lysozyme and trypsin yielded final suspensions with &gt;109 CFU/mL of viable spores, with a purity of &gt;91 as tested by spore-staining and phase-contrast microscopy. The spores showed a biological decay rate of about 0.1 log10/month when dried on metal disks and stored indoors (air temperature 23 2C; relative humidity 52.76 15.08). Heating the purified spore suspensions to 70C for 10 min to inactivate any vegetative cells showed no spore activation or inactivation. The spores could be stored for at least 14 months either refrigerated (4C) or frozen (20 or 80C) in 50 (v/v) ethanol with virtually no loss in viability. The resistance of the enzyme-treated spores to three levels of sodium hypochlorite (1000, 3000, and 5000 ppm), using a standardized quantitative carrier test, was almost identical to that of the spores concentrated by centrifugation alone. The described procedure has been successfully applied to four standard (ATCC) and six clinical strains of C. difficile.
Validation of an Oil-in-Water Microemulsion Liquid Chromatography Method for Analysis of Perindopril tert-Butylamine and Its Impurities
Authors: Mašković Marija , Dotsikas Yannis , Malenović Anđelija , Jančić-Stojanović Biljana , Ivanović Darko , Medenica Mirjana 
Published: February 2020

Abstract
This paper describes the development and validation of a microemulsion liquid chromatography (MELC) method for simultaneous determination of perindopril tert-butylamine and its impurities in bulk active substances and the pharmaceutical dosage form of tablets. An appropriate resolution with reasonable retention times was obtained for a microemulsion containing 0.24% (w/v) butyl acetate, 0.30% (w/v) ethyl acetate, 2% (w/v) sodium dodecyl sulfate, 7.75% (w/v) n-butanol, and 20.0 mM potassium dihydrogen phosphate, the pH of which was adjusted to 3.70 with 85% orthophosphoric acid. Separations were performed on a Nucleosil 120-5 butyl modified (C4), 250 × 4 mm, 5 μm particle size silica column at 40°C, with a mobile phase flow rate of 1.25 mL/min. UV detection was performed at 254 nm. The established method was subjected to method validation, and required validation parameters were defined. Robustness testing, an important part of method validation, was performed as well. Since robustness validation can be conducted using different experimental designs, the Plackett-Burman design was applied due to its possibility of testing many factors at the same time. The validated MELC method was found to be suitable for the simultaneous determination of perindopril tert-butylamine and its impurities in pharmaceuticals.