bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Chelating Resin for Preconcentration and Determination of Mn(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II) by Flame Atomic Absorption Spectrometry
Authors: Maheswari Mohan A , Subramanian Mandakolathur S 
Published: February 2020

Abstract
A new polychelatogen, AXAD-16-1, 2-diphenylethanolamine, was developed by chemically modifying Amberlite XAD-16 with 1, 2-diphenyl-ethanolamine to produce an effective metal-chelating functionality for the preconcentration of Mn(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II) and their determination by flame atomic absorption spectrometry. Various physiochemical parameters that influence the quantitative preconcentration and recovery of metal were optimized by both static and dynamic techniques. The resin showed superior extraction efficiency with high-metal loading capacity values of 0.73, 0.80, 0.77, 0.87, 0.74, and 0.81 mmol/g for Mn(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II), respectively. The system also showed rapid metal-ion extraction and stripping, with complete saturation in the sorbent phase within 15 min for all the metal ions. The optimum condition for effective metal-ion extraction was found to be a neutral pH, which is a great advantage in the preconcentration of trace metal ions from natural water samples without any chemical pretreatment of the sample. The resin also demonstrated exclusive ion selectivity toward targeted metal ions by showing greater resistivity to various complexing species and more common metal ions during analyte concentration, which ultimately led to high preconcentration factors of 700 for Cu(II); 600 for Mn(II), Ni(II), and Zn(II); and 500 for Cd(II) and Pb(II), arising from a larger sample breakthrough volume. The lower limits of metal-ion detection were 7 ng/mL for Mn(II) and Ni(II); 5 ng/mL for Cu(II), Zn(II), and Cd(II), and 10 ng/mL for Pb(II). The developed resin was successful in preconcentrating metal ions from synthetic and real water samples, multivitamin-multimineral tablets, and curry leaves (Murraya koenigii) with relative standard deviations of &lt;3.0% for all analytical measurements, which demonstrated its practical utility.
New Refractive Index Method for Measurement of Alcoholic Strength of Small Volume Samples
Authors: Gerogiannaki-Christopoulou Maria , Kyriakidis Nikolaos V , Athanasopoulos Panagiotis E 
Published: February 2020

Abstract
A study of the correlation between the refractive index (RI) method adopted by the European Community (EC) and a reference pycnometric method for the measurement of alcoholic strength was undertaken. A new RI method with greater accuracy was also developed. Alcoholic strength measured by both RI methods presented a relatively constant negative bias compared with results by the pycnometric method. Differences found between the RI methods and the pycnometric method were 0.6–0.9% (v/v) when RI was measured by the EC method and 0.4–0.5% (v/v) when the new RI method developed in our laboratory was used. Statistical analysis of the results showed that differences between the 2 RI methods and the reference pycnometric method were statistically significant at the 95% confidence level. Correction factors are proposed for the accurate use of measurements of alcoholic strength obtained for small volume samples.
Inductively Coupled Plasma-Mass Spectrometry for the Determination of Elements and Elemental Species in Food: A Review
Authors: Cubadda Francesco 
Published: February 2020

Abstract
Inductively coupled plasma-mass spectrometry (ICP-MS) has definitely emerged as a powerful technique for total element determination and as a sensitive and selective detector in hyphenated methods for speciation analyses of elements in foods. In this review, the analytical challenges of elemental analysis of food and agricultural matrixes are discussed and several applications are examined. Selected examples illustrate the analytical approaches being used so far to address specific issues in various areas of food and nutrition research. The applications discussed include studies on dietary intake, element metabolism in man, transfer of elements through the food chain, effects of food processing and domestic preparation, and authenticity and origin assessment. The use of ICP-MS in the field of analytical quality assurance, food control, evaluation of food contact materials, and radionuclide contamination is also examined. Finally, the hyphenated techniques with ICP-MS detection used for elemental speciation in food are reviewed, and an overview of the main applications currently in the literature is presented. Throughout, recent trends and analytical developments likely to have a major impact on food-related areas are highlighted.
Quantitative Analysis of Iron-Containing Protein Myoglobin in Different Foodstuffs by Liquid Chromatography Coupled to High-Resolution Inductively Coupled Plasma Mass Spectrometry
Authors: Harrington Chris F , Elahi Selvarani , Merson Sheila A , Ponnampalavanar Punitha 
Published: February 2020

Abstract
Quantitative determination was made of the iron-containing protein myoglobin in a range of different foods, including meat, processed meat, fish, and shellfish, by liquid chromatography coupled to a double-focusing sector field inductively coupled plasma mass spectrometry (ICP–MS). The concentration of myoglobin determined in the samples ranged from 0 to 6.5 mg/kg, and the analytical precision (coefficient of variation) for the analysis of 8 replicate raw steak extracts was 2.1%. By using a double-focusing ICP–MS instrument, direct on-line detection of the most abundant iron isotope 56Fe was possible without interference from a major polyatomic interference (40Ar16O). Separation of myoglobin from other iron-containing compounds was facilitated by use of a gel filtration column (TSK Gel G2000SW) and Tris buffer (pH 7.2). The chromatographic column was coupled directly to the nebulizer of the ICP–MS instrument by a short piece of PEEK® tubing. To ensure sufficient quality control throughout the study, a raw beefsteak sample was developed as an in-house reference material. The concentration of the heme-iron-containing protein myoglobin in this sample was determined by the developed method and independently by a conventional spectrophotometric method. The agreement between the 2 analytical techniques was very good. The detection limit (3 times the signal/noise ratio for a blank) of the reported method for myoglobin was 0.85 ng Fe/L.
Confirmatory Determination of Six Penicillins in Honey by Liquid Chromatography/Electrospray Ionization–Tandem Mass Spectrometry
Authors: Wang Jian 
Published: February 2020

Abstract
A confirmatory method for 6 penicillin antibiotics (amoxicillin, ampicillin, penicillin G, oxacillin, cloxacillin, and dicloxacillin) in honey is presented that allows determination and confirmation of identity of the antibiotics at trace levels. The method includes the use of a stable isotope-labeled internal standard benzyl (d7-phenyl) penicillate and removal of sugar and other substances by solvent and solid-phase extraction. The honey extracts are then analyzed for penicillin residues by liquid chromatography/electrospray ionization–tandem mass spectrometry. Mass spectral acquisition was achieved in an electrospray positive ion mode by applying multiple reaction monitoring of 2 or 3 fragment ion transitions to provide a high degree of sensitivity and specificity. Typical recoveries of 6 penicillins at fortification levels of 6, 16, 40, and 80 μg/kg ranged from 51.4 to 132.9%. The recoveries varied with the individual penicillins and were affected by different honey matrixes. The ion ratios were consistent and could be used for confirmation of identity of the penicillins. The method limits of detection (μg/kg) were 0.25 for amoxicillin, 0.19 for ampicillin, 0.068 for penicillin G, 0.028 for oxacillin, 0.052 for cloxacillin, and 0.085 for dicloxacillin. The method limits of confirmation (μg/kg) were 0.44 for amoxicillin, 0.52 for ampicillin, 0.23 for penicillin G, 0.14 for oxacillin, 0.14 for cloxacillin, and 0.15 for dicloxacillin when a sample size of 5 g honey was used.
Determination of Tylosin in Feeds by Liquid Chromatography with Solid-Phase Extraction
Authors: Gramse Matthew J , Jacobson Paul E , Selkirk James C 
Published: February 2020

Abstract
A method was developed for the determination of tylosin in feeds. The method involves extraction of tylosin with methanol, concentration under a stream of nitrogen, and cleanup using Phenomenex C18 solid-phase extraction cartridge. Analyte separation and quantitation were achieved by gradient reversed-phase liquid chromatography and UV absorbance at 285 nm with a reference wavelength of 320 nm with column temperature of 45°C. Average spike recoveries for samples prepared at 4 spiking levels (22.7, 181, 907, and 1000 g/ton) were 111.0, 94.9, 96.2, and 98.6%, respectively. The overall method precision at each of the 4 spiking levels was ≤ 7.85% relative standard deviation. The limits of detection and quantitation (g/ton) were 2.16 and 7.20 g/ton, respectively.
Determination of Fluquinconazole, Pyrimethanil, and Clofentezine Residues in Fruits by Liquid Chromatography with Ultraviolet Detection
Authors: Navickiene Sandro , Ribeiro Maria Lúcia 
Published: February 2020

Abstract
A simple method was developed for the determination of fluquinconazole, pyrimethanil, and clofentezine in whole fruit; peel; and pulp of mango, apple, and papaya. These compounds were extracted from fruit samples with a mixture of ethyl acetate-n-hexane (1 + 1, v/v). An aliquot (2 mL) of the extract was evaporated to near dryness under a stream of nitrogen, and the residue was dissolved with 2 mL methanol. The analysis was performed by means of liquid chromatography with ultraviolet detection at 254 nm using a gradient solvent system. The method was validated with fortified fruit samples at concentration levels of 0.05, 0.10, 0.20, and 0.50 mg/kg. Average recoveries (4–8 replicates) ranged from 80 to 95% with relative standard deviations between 3.5 and 12.7%. Detection limits ranged from 0.03 to 0.05 mg/kg for fruit pulp and 0.03 mg/kg for whole fruit. The quantitation limits ranged from 0.05 to 0.10 mg/kg for fruit pulp and 0.05 mg/kg for whole fruit. The analytical method was applied to fruit samples obtained from local markets.
Determination of Plant Sterol Oxidation Products in Plant Sterol Enriched Spreads, Fat Blends, and Plant Sterol Concentrates
Authors: Louter Arjan J H 
Published: February 2020

Abstract
Plant sterols (PS) are very stable molecules but may undergo oxidation due to the presence of a double bond in the ring structure. In order to assess whether this occurs during heating and storage, an analytical procedure was developed for the determination of concentration levels and identity of PS oxidation products in functional food ingredients and products. The method is based on cold saponification, solvent extraction of unsaponifiables, isolation of sterol oxidation products by means of liquid chromatography, and final analysis by gas chromatography (GC) with flame ionization detection. Identification of the key PS oxidation products was performed by means of GC-mass spectrometry (GC-MS). Isotope dilution MS was used to verify the absence of the formation of potential artifacts by the method. The method described is applicable to spreads (containing 20–65% water), oils, sterol esters, pure sterols, and fat extracts from food. The between-day reproducibility of the total content of sterol oxidation products in control samples sample was 8%, and of individual sterol oxidation products, 6–15%. The recovery of sterol oxidation products was 91%. The limit of detection was 0.1 mg/kg.
Cholesterol Oxidation in Meat-Based Baby Foods
Authors: Evangelisti Filippo , Zunin Paola , Boggia Raffaella , Calcagno Claudio 
Published: February 2020

Abstract
Cholesterol oxidation in commercial meat-based homogenized and freeze-dried baby foods was examined. The 7 major products of this reaction were determined by gas chromatography coupled with mass spectrometry (GC-MS). As far as single cholesterol oxidation products (COP) are concerned, 7-ketocholesterol was the major product of direct cholesterol oxidation in the 2 groups of analyzed samples, and this study confirmed that it is a useful marker of the whole cholesterol oxidation process. Nevertheless, the amounts of cholesterol-5β,6β-epoxide were often similar to and sometimes higher than the amounts of 7-ketocholesterol, thus showing a strong development of both direct and indirect cholesterol oxidation pathways. Total COP content was significantly higher in freeze-dried than in homogenized products. Moreover, in freeze-dried samples, the COP content per serving was quite variable and, in 2 samples, it was close to or even higher than 500 μg. The greater development of cholesterol oxidation in the freeze-dried samples was confirmed by their highest total COP/cholesterol percent ratios. A constant correlation between the fatty acid composition and the development of cholesterol oxidation was not found, although a positive correlation between unsaturated fatty acid content and total COP content occasionally exists in samples of the same brand.
Determination of Diazepam in Cream Biscuits by Liquid Chromatography
Authors: Ghosh Priyankar , Reddy Mudiam Mohanakrishna , Rao Beedu Sashidhar , Sarin Rajendra Kumar 
Published: February 2020

Abstract
An analytical procedure was developed for the detection and quantitation of diazepam in cream biscuits, which were used to commit crime. The method involves the extraction of diazepam with ethanol at room temperature, and the extract is filtered, evaporated to dryness, and redissolved in the mobile phase, methanol–acetonitrile–tetrahydrofuran–water (15 + 55 + 4 + 26, v/v). The separation is achieved on a C18 reversed-phase column with the mobile phase and diode array detection (λmax) at 230 nm. Medazepam is used as the internal standard is for quantification. The calibration plot for the determination of diazepam is based on linear regression analysis (y = 0.6687x + 0.0372; r2 = 0.995). The limit of detection for diazepam in the biscuit samples was estimated as 600 ng/mL. The limit of quantitation for diazepam was estimated as 1.75 μg/mL. The diazepam detected per piece of biscuit was found to be in the range of 0.27–0.45 mg. Pure diazepam was added to biscuit samples at 3 levels (100 and 500 μg/g, and 1 mg/g), and the recoveries were found to be 95%. The mean retention time of diazepam was 2.7 min and that of medazepam (IS) was 4 min. The relative standard deviations of the diazepam level in the biscuit samples were estimated to be 0.4% for retention time and 1.02% for peak area in intraday analysis, whereas the corresponding values were and 0.61 and 2.34% in interday analysis. The method is rapid and reliable for qualitative and quantitative analysis of cream biscuits laced with diazepam, and it can be used by law enforcement laboratories for routine analysis.
Relationships Between LC Retention, Octanol–Water Partition Coefficient, and Fungistatic Properties of 2-(2,4-Dihydroxyphenyl)benzothiazoles
Authors: Matysiak Joanna , Niewiadomy Andrzej , Senczyna Bogdan , Żabińska Anna , Rózyło Jan K 
Published: February 2020

Abstract
The retention behavior of newly synthesized compounds with antimycotic activity from the 2-(2,4-dihydroxyphenyl)benzothiazole group by high-performance liquid chromatography has been investigated. RP-18 stationary phase and methanol–acetate buffer aqueous mobile phases at pH 4 and 7.4 have been used. In the case of the mobile phase at pH 7.4, higher concentrations of water can be applied than at pH 4. The studied compounds showed regular retention behavior, their log k values decreasing linearly with an increasing concentration of methanol in the mobile phase. On the basis of these relationships, the lipophilicity (log kw), specific hydrophobic surface area (S), and isocratic chromatographic hydrophobicity index (φ0) were determined. Similar log kw values and sensitivity to changes in the structure of compounds studied for both mobile phases have been found. Moderate correlations between the chromatographic parameters and the calculated octanol-water log P values were found. Finally, the lipophilicity parameters were compared with the fungistatic properties of compounds expressed by log MIC (minimum inhibitory concentration) values to find quantitative structure activity relationship equations.
Determination of Thiabendazole in Orange Juice and Rind by Liquid Chromatography with Fluorescence Detection and Confirmation by Gas Chromatography/Mass Spectrometry After Extraction by Matrix Solid-Phase Dispersion
Authors: Albero Beatriz , Sánchez-Brunete Consuelo , Tadeo José L 
Published: February 2020

Abstract
A method was developed for the determination of thiabendazole (TBZ) in orange juice and rind based on matrix solid-phase dispersion (MSPD). TBZ was extracted with ethyl acetate and the extract was subsequently cleaned up on a solid-phase extraction column. Fungicide residues were determined by liquid chromatography with fluorescence detection. Recoveries through the method ranged from 87 to 97% with relative standard deviations ≤11%. The detection and quantitation limits were 0.15 and 0.50 μg/kg, respectively. The confirmation of TBZ residues in positive samples was performed by solid-phase microextraction followed by gas chromatography with mass spectrometric detection using selected ion monitoring. The developed method was applied to determine TBZ levels in commercial orange juices and in juice and rind of fresh oranges. The influence of storage and washing of fruits on TBZ residues was also studied.
Selected Uses of Enzymes with Critical Fluids in Analytical Chemistry
Authors: Turner Charlotta , King Jerry W , McKeon Thomas 
Published: February 2020

Abstract
The use of enzymes coupled with supercritical fluid (SF)-based analytical techniques, such as supercritical fluid extraction (SFE), provides a safer environment platform for the analytical chemist and reduces the use of organic solvents. Incorporation of such techniques not only reduces the use of solvent in analytical laboratories, but it can also lead to overall method simplification and time savings. In this review, some of the fundamental aspects of using enzymes in the presence of SF media are discussed, particularly the influence of extraction (reaction) pressure, temperature, and water content of the extracting fluid and/or the sample matrix. Screening of optimal conditions for conducting reactions in the presence of SF media can be readily accomplished with automated serial or parallel SFE instrumentation, including selection of the proper enzyme. Numerous examples are cited, many based on lipase-initiated conversions of lipid substrates, to form useful analytical derivatives for gas chromatography, liquid chromatography, or SF chromatography analysis. In certain cases, enzymatic-aided processing of samples can permit the coupling of the extraction, sample preparation, and final analysis steps. The derived methods/techniques find application in nutritional food analyses, assays of industrial products, and micro analyses of specific samples.
Determination of Trimetazidine Dihydrochloride in the Presence of Its Acid-Induced Degradation Products
Authors: Bebawy Lories I , El Tarras Mohammed F , El Sabour Samah A 
Published: February 2020

Abstract
Three methods are presented for the determination of trimetazidine dihydrochloride in the presence of its acid-induced degradation products. The first method was based on measurement of first-derivative D1 value of trimetazidine dihydrochloride at 282 nm over a concentration range of 8.00–56.00 μg/mL with mean percentage accuracy of 99.80 ± 1.17. The second method was based on first derivative of the ratio spectra DD1 at 282 nm over the same concentration range with the percentage accuracy of 99.14 ± 0.68. The third method was based on separation of trimetazidine dihydrochloride from its acid-induced degradation products followed by densitometric measurement of the spots at 215 nm. The separation was performed on silica gel 60 F254 using methanol–ammonia (100 + 1.5, v/v) as mobile phase. This method was applicable for determination of the intact drug in the presence of its degradation products over a concentration range of 2.00–9.00 μg/spot with mean percentage accuracy of 99.86 ± 0.92. The proposed methods were successfully applied for the determination of trimetazidine dihydrochloride in bulk powder, laboratory-prepared mixtures containing different percentages of degradation products, and pharmaceutical dosage forms. The validity of results was assessed by applying the standard addition technique. The results obtained agreed statistically with those obtained by the reported method.
Application of the Wavelet Method for the Simultaneous Quantitative Determination of Benazepril and Hydrochlorothiazide in Their Mixtures
Authors: Dinç Erdal , Baleanu Dumitru 
Published: February 2020

Abstract
The discrete and continuous wavelet transforms were applied to the overlapping signal analysis of the ratio data signal for simultaneous quantitative determination of the title subject compounds in samples. The ratio spectra data of the binary mixtures containing benazepril (BE) and hydrochlorothiazide (HCT) were transferred as data vectors into the wavelet domain. Signal compression, followed by a 1-dimension continuous wavelet transform (CWT), was used to obtain coincident transformed signals for pure BE and HCT and their mixtures. The coincident transformed amplitudes corresponding to both maximum and minimum points allowed construction of calibration graphs for each compound in the binary mixture. The validity of CWT calibrations was tested by analyzing synthetic mixtures of the investigated compounds, and successful results were obtained. All calculations were performed within EXCEL, C++, and MATLAB6.5 softwares. The obtained results indicated that our approach was flexible and applicable for the binary mixture analysis.
Application of Derivative Spectrophotometry for Simultaneous Determination of Quinapril and Hydrochlorothiazide in the Combination Tablets
Authors: Kowalczuk Dorota , Hopkała Hanna 
Published: February 2020

Abstract
A new second-order-derivative spectrophotometric method using zero-crossing technique measures quinapril (QUI) and hydrochlorothiazide (HYD) in 2-component mixtures. The procedure does not require prior separation of components from the sample. QUI was determined at a wavelength of 211.6 nm (zero-crossing wavelength point of HYD). Similarly, HYD was measured at 270.8 nm (zero-crossing wavelength point of QUI). Calibration graphs were constructed over the concentration range of 4.0 to 24.0 μ/mL for QUI and 2.5 to 15.0 μg/mL for HYD. Detection and quantitation limits were 0.85 and 2.5 μg/mL for QUI and 0.12 and 0.4 μg/mL for HYD, respectively. The accuracy (recovery 100.5–102%), precision (relative standard deviation less than 3.5% for QUI and 1.5% for HYD), selectivity, and sensitivity of the elaborated methods were satisfactory. The proposed method was applied successfully for the determination of both drugs in QUI-HYD tablets.