bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid Chromatographic Determination of Amphotericin B in Different Pharmaceuticals
Authors: Lue Louis P , Hadman Susan T , Vancura Ales 
Published: February 2020

Abstract
Amphotericin B (AmB) is one of the most potent antifungal agents and the drug of choice in the treatment of serious fungal infections. A liquid chromatographic (LC) method was developed to determine AmB in pharmaceutical formulations for injection, tissue culture, cream, and lotion. μBondapak C18 reversed-phase column and a simple mobile phase consisting of acetonitrile–water–acetic acid (40 + 54 + 6, v/v) was used. The flow rate was 1.8 mL/min and the effluent was monitored at 405 nm. The developed LC method uses piroxicam as an internal standard and has a limit of detection of 10 ng/mL, a limit of quantitation of 30 ng/mL, and the assay is linear from 0.01 to 100 μg/mL. AmB and piroxicam elute with retention times of 12.4 and 4.0 min, respectively, and the resolution between AmB and piroxicam was 10.6. In comparison with the official United States Pharmacopeia microbial assay for AmB, this LC method is more rapid, selective, sensitive, and offers positive identification.
Development of the Infrared Hollow Waveguide Sampler for the Detection of Chlorophenols in Aqueous Solutions
Authors: Yang Jyisy , Lee Chung-Jay 
Published: February 2020

Abstract
A method based on the infrared hollow waveguide sampler was developed for sensing chlorophenols in aqueous solutions. This sampler was constructed by coating a suitable hydrophobic film onto the inner surface of an infrared hollow waveguide. By passing the aqueous solution through the hollow waveguide sampler, analytes can be absorbed into the hydrophobic layer. The adsorbed analytes can be sensed later by using Fourier transform infrared spectrometry. Six hydrophobic polymers were investigated for their performance in conjunction with the infrared hollow waveguide sampler for the detection of chlorophenols. Results indicated that poly(acrylonitrile-co-butadiene) was a most suitable hydrophobic material for absorption of chlorophenols in aqueous solutions. To further increase the detection sensitivity, factors such as sampling flow rate, sampling time, and thickness of the hydrophobic film were also investigated. Results indicated that the infrared signals were similar in the examined flow rates (2–30 mL/min), but that a higher flow rate tended to produce a higher analytical signal. Fast detection speed was an advantage of this method for the detection of chlorophenols, and the sampling/detection time can be &lt;10 min. In addition, analytical signals were nearly proportional to the thickness of the hydrophobic film coating the inside of the hollow waveguide. With the optimal conditions found in this work, detection limits based on 3 times the peak-to-peak noise level were around 300 ppb for the chlorophenols examined. A high degree of linearity in the standard curves was also observed for this method in the concentration range of 10–100 ppm. The typical regression coefficients were &gt;0.994 for the chlorophenols examined.
Gas Chromatographic/Mass Spectrometric Determination of Benzene and Its Alkyl Derivatives in Indoor and Outdoor Air in Fuji, Japan
Authors: Amagai Takashi , Ohura Takeshi , Sugiyama Tomohiko , Fusaya Masahiro , Matsushita Hidetsuru 
Published: February 2020

Abstract
An analytical method was established for the determination of benzene and 13 of its alkyl derivatives. The method was applied to a survey of indoor pollution that investigated the usefulness of the method, concentration levels, seasonal variations, profiles, correlations between compounds, and factors that affected indoor pollution by these compounds. The survey was performed in 21 houses in the summer of 1999 and 20 houses in the winter of 1999–2000 in Fuji, Japan. All the target compounds were detected in the indoor and outdoor air of all houses. Outdoor concentrations of benzene ranged from 0.779 to 3.17 μg/m3 in summer and from 1.35 to 6.04 μg/m3 in winter, whereas indoor concentrations of benzene ranged from 0.694 to 3.11 μg/m3 in summer and from 1.65 to 6.89 μg/m3 in winter. Indoor concentrations of the target compounds, except for benzene, were elevated, compared with outdoor concentrations. Because indoor and outdoor concentrations of benzene and its derivatives in summer were lower than in winter, the emission of these compounds may be increased by use of a heater and other variables present in winter. Profiles of the compounds, correlations between the compounds, and factors that affected indoor pollution (determined by multiple regression analysis) were investigated. These results suggested that indoor benzene predominantly penetrated from outdoors and that other benzene derivatives were emitted from indoor sources, such as paint solvents and kerosene heaters.
Evaluation of Platanus occidentalis and Pinus sylvestris as Bioindicators for Lead and Cadmium by Slurry Sampling-Electrothermal Atomic Absorption Spectrometry
Authors: Amoedo Luisa , Capelo J Luis , Lavilla Isela , Bendicho Carlos 
Published: February 2020

Abstract
Two higher plants (Platanus occidentalis and Pinus sylvestris) were used as bioindicators for assessment of contamination by Pb and Cd in an urban and industrialized area. Both toxic metals in plant tissue were determined by transverse-heated electrothermal atomic absorption spectrometry-longitudinal Zeeman background correction combined with automated ultrasonic slurry sampling. Twenty sampling points were established to observe a relationship between metal concentration in plant and traffic density. Screening optimization of variables influencing slurry preparations (sonication time, sonication power, and surfactant concentration) followed a fractional factorial design at 2 levels. No significant effects were observed in the interval of variables studied. Limits of detection of Pb and Cd in the plants were 0.28 and 0.025 μ/g (dry weight), respectively. Metal concentrations in the plants were in the range of 5–51 and 0.05–0.7 μg/g for Pb and Cd, respectively. Factor analysis to data of metal concentration in both plants, extractable metal content in soil, distance to traffic, and traffic density, showed a significant association between features such as concentration of Pb and Cd in leaves of P. occidentalis and traffic density, which accounted for the largest variance. Other features such as extractable metal contents in soil accounted for lesser variance, meaning that soils in the area investigated were less suitable than plants for monitoring metal pollution caused by vehicular traffic.
Determination of Mercury in Sewage Sludges by Slurry Sampling Electrothermal Atomic Absorption Spectrometry
Authors: López-García Ignacio , Sánchez-Merlos Mateo , Arroyo-Cortez Jesús , Hernández-Córdoba Manuel 
Published: February 2020

Abstract
An electrothermal atomic absorption spectrometric procedure was developed for the determination of mercury in sewage sludge, in which the samples were suspended in a solution containing hydrofluoric and nitric acids. Silver nitrate (4%, m/v) and potassium permanganate (3%, m/v) were incorporated as matrix modifiers, and aliquots were directly introduced into the graphite furnace. A fast-heating program with no conventional pyrolysis step was used. The detection limit for mercury in a 50 mg/mL suspension was 0.1 μg/g. Calibration was performed by using aqueous standards. An analysis of certified reference materials confirmed the reliability of the procedure.
Size Exclusion Chromatographic Cleanup for GC/MS Determination of Organophosphorus Pesticide Residues in Household and Vehicle Dust
Authors: Moate Thomas F , Furia Matthew , Curl Cynthia , Muniz Juan F , Yu Jianbo , Fenske Richard A 
Published: February 2020

Abstract
Size exclusion chromatography (SEC) was used as a cleanup method for the analysis of organophosphorus pesticides in household and vehicle dusts. The pesticides investigated were diazinon, methyl parathion, chlorpyrifos, malathion, phosmet, and azinphosmethyl. These compounds are of interest due to their use in agricultural tree fruit production and/or urban pest control. Pesticides were determined via gas chromatography/mass spectrometry with selected-ion monitoring and cool on-column injection. The lower limit of method validation was 0.20 μg/g. Method limits of detection in dust ranged from 0.012–0.055 μg/g. Dust samples were collected with vacuums from the homes and vehicles of people living and working in a rural agricultural region in the central part of Washington State. The analytes were extracted from the dust by sonication in acetone. The extracts were solvent-exchanged to cyclohexane, frozen, thawed, and centrifuged prior to SEC injection. Following SEC, the eluent was split into 2 fractions, concentrated, and injected on-column into the gas chromatograph. This method represents the first complete publication describing the SEC cleanup of organophosphorus pesticides in dusts. Recoveries of pesticides in dusts ranged from 63.5–110.8 ± 4.9–19.6% over a fortification range of 0.20–10.00 μg/g. This optimized, automated, and reproducible SEC method does not require further treatment or cleanup for trace determination of these organophosphorus pesticides.
Automatic Flow System Titration Based on Multicommutation for Spectrophotometric Determination of Total Acidity in Silage Extracts
Authors: Tumang Cristiane A , Paim Ana Paula S , Reis Boaventura F 
Published: February 2020

Abstract
A multicommutated flow titration procedure is proposed for the spectrophotometric determination of total acidity in silage extracts. The flow network comprises a set of 3-way solenoid valves, computer-controlled to provide facilities to handle the titrand, titrant, and carrier solutions by using a single pumping channel. The procedure is based on the volumetric fraction variation approach that maintains the same volume of titrand solution and varies the titrant solution step by step, to provide determination without the use of an analytical curve. The procedure is implemented by using phenolphthalein as an external indicator; the proposed algorithm was able to titrate silage extracts presenting different color intensities. Sample solutions with concentrations ranging from 10−3 to 10−1 mol/L total acidity could be analyzed by using 10−2 mol/L sodium hydroxide as the titrant solution. Other advantages include a relative standard deviation of &lt;1.0% (n = 4) for a typical silage extract solution containing 26 mmol/L total acidity; an analytical throughput of 16 determinations per hour was also achieved. Accuracy was assessed by processing a set of silage extract solutions and comparing the results with those obtained by using the conventional potentiometric titration procedure. No significant difference at the 95% confidence level was observed.
Virulence Testing of Listeria monocytogenes
Authors: Raybourne Richard B 
Published: February 2020

Abstract
A major problem in understanding foodborne listeriosis from both the basic science and regulatory perspectives revolves around the role played by virulence factors of Listeria monocytogenes and how these interact with host susceptibility to result in the observed incidence of disease. From a mechanistic perspective, this problem has been well investigated, and many virulence components of L. monocytogenes have been discovered. Deletion of these genes results in large reductions in virulence functions in vitro and in vivo. The clonal bacteria and genetically identical hosts necessary to solve the riddles associated with virulence mechanisms are not likely to reflect the natural diversity found among wild populations of L. monocytogenes, including those associated with food. These factors contribute to a major dilemma in risk assessment and risk management of foodborne listeriosis: Although low-level L. monocytogenes contamination of certain foods is relatively common, suggesting widespread exposure, illness is overwhelmingly associated with only a relatively small subpopulation (3 of the 13 L. monocytogenes serotypes) and occurs in only a small proportion of susceptible individuals. Virulence testing based on DNA probes for virulence genes is confounded by the widespread distribution of these genes in food isolates. In terms of the distribution of virulence factors among food isolates of L. monocytogenes, only listeriolysin is well characterized, because β-hemolysis is often used to confirm the presence of L. monocytogenes in foods. The presence of other virulence genes such as those involved in host cell invasion and cell-to-cell spread (inIA and actA) among food isolates has not been extensively investigated. How the presence of these components translates into functional virulence as measured in vivo and in vitro is also unknown. Animal studies and cell culture systems show a range of virulence among food isolates of L. monocytogenes. However, clinical isolates included in such studies are not consistently more virulent than food isolates with no known human disease association. Where multiple serotypes or ribotypes are compared, it has been difficult to demonstrate a consistent pattern of increased virulence associated with any subtype(s) in animal or in vitro studies. Development of model systems that adequately reflect the complexity of the host–pathogen relationship remains a challenge.
Simultaneous Determination of Promethazine, Chlorpromazine, and Perphenazine by Multivariate Calibration Methods and Derivative Spectrophotometry
Authors: Shamsipur Mojtaba , Hemmateenejad Bahram , Akhond Morteza 
Published: February 2020

Abstract
Partial least-squares (PLS) regression, singular value decomposition-based PLS, and an artificial neural network (ANN) were tested as calibration procedures for the simultaneous determination of promethazine, chlorpromazine, and perphenazine by both conventional and derivative spectrophotometry. Comparison of the results revealed that the application of the ANN to the derivative spectra is superior to the application of the 2 PLS methods used. Different binary and ternary synthetic mixtures of the phenothiazine drugs in pure form and in tablets were analyzed by the proposed method, and acceptable results were obtained.
Validation of a Gas Chromatographic Method for Determination of Fatty Alcohols in 10 mg Film-Coated Tablets of Policosanol
Authors: Sierra Roxana , González Víctor L , Magraner Juan 
Published: February 2020

Abstract
A gas chromatographic method using a packed column and 1-eicosanol as an internal standard was validated for the determination of the fatty alcohols that compose policosanol in 10 mg film-coated tablets. The alcohols were determined as trimethylsilyl derivatives, prepared with N-methyl-N-trimethylsilyltrifluoroacetamide. The method can detect degradation products with high retention times, without interfering with the peaks of the active principle. Good linearity (correlation coefficient = 0.9992) and accuracy (mean recovery = 100.27 ± 1.66%) were proven over a range of 25–200% of the nominal concentration. Within- and between-day precision at the nominal 100% value met the acceptance criteria (&lt;2%). Ruggedness was examined through an intralaboratory experimental study in which 6 operational changes were made; the changes were found to have no effect on quantitation, repeatability, resolution, and relative retention time. The method is suitable for the quality control process and stability studies of these tablets.
Monitoring of Five Postharvest Fungicides in Fruit and Vegetables by Matrix Solid-Phase Dispersion and Liquid Chromatography/Mass Spectrometry
Authors: Blasco Cristina , Picó Yolanda , Font Guillermina 
Published: February 2020

Abstract
A method was developed for monitoring dichloran, flutriafol, o-phenylphenol, prochloraz, and tolclofos-methyl in fruits and vegetables, using matrix solid-phase dispersion and liquid chromatography with mass spectrometry detection. The method was used to determine fungicide content in 200 samples of chards, onions, peppers, bananas, lemons, and oranges. Of the samples examined, 54% contained o-phenylphenol with concentrations ranging from 0.005 to 3.34 mg/kg and 35% showed prochloraz in the range of 0.06–1.95 mg/kg. Dichloran, flutriafol, and tolclofos-methyl were detected only occasionally. Only 4% of the samples exceeded the European Union maximum residue limits. The pesticides involved were tolclofos-methyl in 3 samples, o-phenylphenol and flutriafol in 2, and dichloran in one. The calculation of estimated daily intake from these monitoring data showed that dietary intakes were much lower than the acceptable daily intakes established by international agencies.
Differential Pulse Polarographic Determination of Procymidone in Formulations and Wine
Authors: Sreedhar Neelam Y , Babu Thommandru R , Samatha Kethamreddy , Sujatha Devarapalli , Thriveni Thenepalli 
Published: February 2020

Abstract
The dicarboximide fungicide procymidone was studied systematically by using direct current polarography, cyclic voltammetry, differential pulse polarography (DPP), controlled potential electrolysis, and millicoulometry in the universal buffer medium with dimethylformamide as the solvent. Procymidone exhibited a single well-defined polarographic wave in the pH range 2.0–6.0, leading to the formation of the hydroxy compound. The overall reduction process was diffusion-controlled and adsorption-free. The variation of half-wave potential with pH, the concentration of the analyte, and other experimental conditions are described. The reduction mechanism proposed is an overall 4-electron process, in which the dicarboximide group is reduced. DPP was used to determine procymidone in agricultural formulations and wine at the optimum conditions found; a detection limit of 2.4 × 10−9M was estimated. The results obtained by the proposed method were also compared with those obtained by other methods.
Spectrophotometric Determination of Caramel Content in Spirits Aged in Oak Casks
Authors: Boscolo Mauricio , Andrade-Sobrinho Luiz G , Lima-Neto Benedito S , Franco Douglas W , Ferreira Marcia Miguel Castro 
Published: February 2020

Abstract
A new methodology was developed for determination of caramel in spirits aged in oak casks. The method is based on differences between the electronic spectra of oak aqueous alcoholic extracts and caramel solutions in the same solvent. The data were treated by 2 different approaches: the simplest one was based on the plot of caramel concentration versus the ratio of absorbance at 210 and 282 nm; the other was based on a partial least squares (PLS) calibration model using the first derivative of the spectral data. Both methodologies were applied to analysis of 159 aged spirit samples. The mean caramel content of several Brazilian sugar cane spirits (cachaça) and all United States whiskies was smaller than that of Scottish whiskies and other brandies from several countries. Correlation was good between caramel concentrations for the same sample calculated by the 2 methods. The uncertainties following PLS and the absorbance ratio method were 0.01 and 0.03 g/L, respectively, for a sample containing 0.45 g/L caramel. Treatment of UV-VIS spectra by pattern recognition using hierarchical clustering analysis and principal components analysis allowed discrimination of the samples as a function of their caramel content. It was possible to distinguish U.S. whiskies from other whiskies, but a clear differentiation among Brazilian cachaças as a function of their geographic origin was not feasible. Small caramel quantities as low as 0.08 g/L were clearly detected by these methodologies.
Spectrophotometric Determination of Phenylephrine Hydrochloride in Pharmaceuticals by Flow Injection Analysis Exploiting the Reaction with Potassium Ferricyanide and 4-Aminoantipyrine
Authors: Rocha José R C , Galhardo Cristiane X , Natividade Maria Auxiliadora E , Masini Jorge C 
Published: February 2020

Abstract
This paper presents a method for the determination of phenylephrine hydrochloride in pharmaceuticals by spectrophotometric flow injection analysis exploiting the reaction with potassium ferricyanide and 4-aminoantipyrine, which leads to the formation of a condensation product with strong absorptivity at 500 nm. The linear dynamic range was between 0.95 and 9 mg/L, with a limit of detection of 0.2 mg/L and a sampling throughput of 120 samples per hour. The method was applied to eyewashes and nasal decongestant liquid medicines.
DNA Microarray Technology Used for Studying Foodborne Pathogens and Microbial Habitats: Minireview
Authors: Al-Khaldi Sufian F , Martin Scott A , Rasooly Avraham , Evans Jeff D 
Published: February 2020

Abstract
Microarray analysis is an emerging technology that has the potential to become a leading trend in bacterial identification in food and feed improvement. The technology uses fluorescent-labeled probes amplified from bacterial samples that are then hybridized to thousands of DNA sequences immobilized on chemically modified glass slides. The whole gene or open reading frame(s) is represented by a polymerase chain reaction fragment of double-strand DNA, approximately 1000 base pair (bp) or 20–70 bp single-strand oligonucleotides. The technology can be used to identify bacteria and to study gene expression in complex microbial populations, such as those found in food and gastrointestinal tracts. Data generated by microarray analysis can be potentially used to improve the safety of our food supply as well as ensure the efficiency of animal feed conversion to human food, e.g., in meat and milk production by ruminants. This minireview addresses the use of microarray technology in bacterial identification and gene expression in different microbial systems and in habitats containing mixed populations of bacteria.
Comparison of Visual Immunoassay and Chromogenic Culture Medium for the Presence of Listeria spp. in Foods
Authors: Istafanos Philip , James Lawrence 
Published: February 2020

Abstract
Two rapid screening methods [the TECRA™ Listeria Visual Immunoassay (LIS–VIS) kit, an AOAC-approved 48 h visual test, which detects Listeria through colorimetry, and BCM™ Listeria isolation and differentiation plating agar] were used to screen U.S. Food and Drug Administration-regulated commodities for the presence of Listeria spp. Seventy-four different food samples were screened for the presence of Listeria spp. by using both protocols. Test results for the TECRA LIS–VIA showed 66 negative samples and 1 false positive, with 4 confirmed as L. monocytogenes and 3 as L. innocua. With the BCM agar, 67 samples were negative, 4 were confirmed as L. monocytogenes, and 3 were confirmed as L. innocua. Both methods showed similar results and were effective screening tools for Listeria spp. in foods. The BCM agar method proved to be a rapid, sensitive, and excellent tool for early screening and differentiation of Listeria spp. present in foods.