bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-Performance Thin-Layer Chromatographic Analysis of Selected Organophosphorous Pesticide Residues in Tea
Authors: Yue Yongde , Zhang Rong , Fan Wei , Tang Feng 
Published: February 2020

Abstract
The separation of 9 organophosphates (monocrotophos, quinalphos, triazophos, parathion-methyl, isofenphos-methyl, temephos, parathion, phoxim-ethyl, and chlorpyrifos) by high-performance thin-layer chromatography (HPTLC) with automated multiple development was studied. The HPTLC method was developed and validated for analysis of residues of phoxim-ethyl and chlorpyrifos in tea. The sample was extracted with acetonitrile and cleaned up by ENVI-CARB solid-phase extraction. The extract was directly applied as bands to glass-backed silica gel 60F254 HPTLC plates. The plates were developed with dichloromethanehexane (1 1, v/v) in a glass twin-trough chamber. Evaluation of the developed HPTLC plates was performed densitometrically. The results indicated that the detection limits of phoxim and chlorpyrifos were 5.0 109 and 1.0 108 g, respectively. Recoveries of the pesticides from tea by this analytical method were 90.7105.5%, and relative standard deviations were 7.313.5%. The precision and accuracy of the method were generally satisfactory for analysis of pesticide residues in tea.
High-Performance Thin-Layer Chromatography/Mass Spectrometry for Rapid Analysis of Neutral Glycosphingolipids
Authors: Miyazaki Masao , Yonesige Azusa , Matsuda Junko , Kuroda Yasuhiro , Kojima Naoya , Suzuki Akemi 
Published: February 2020

Abstract
Direct coupling of high-performance thin-layer chromatography (HPTLC) to matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MS) was shown to be a reliable and reproducible method to obtain structural information and fundamental properties of glycosphingolipids (GSLs).We report a protocol for the preparation of neutral GSL extracts frommouse tissues and demonstrate the applicability of HPTLC/MS to these preparations. The protocol consists of lipid extraction and ion exchange chromatography followed by a mild alkaline treatment and a reversed-phase cartridge extraction. Possible structures for each GSL are proposed based on HPTLC/MS analyses. This fast and simple method can be used to screen neutral GSL extracts obtained from tissues and cells without isolation and purification into individual GSLs.
Effect of Selected Metal Ions on the Photodegradation of Ciprofloxacin in the Solid Phase
Authors: Hubicka Urszula , Krzek Jan 
Published: February 2020

Abstract
The photodegradation of ciprofloxacin in the solid phase was investigated by using the chromatographic-densitometric method in the presence and absence of selected metal ions. It was shown that both ion concentration and ion type have an effect on the degradation process that leads to the generation of 2 new products with Rf values of approximately 0.45 and 0.56, which are different from the Rf of approximately 0.68 for ciprofloxacin. It was found that Cu2 and Fe3 ions have the strongest effect on ciprofloxacin photodegradation compared with photodegradation carried out without these ions and also with photodegradations carried out in the presence of Zn2, Cr3, Ni2, and Co2 ions. To identify the photodegradation products, we used amine-specific chromatographic reactions, UV spectra recorded directly from the chromatograms, and proton nuclear magnetic resonance and IR spectroscopic methods. The chemical structures of the degradation products were found to be 7-[(2-aminoethyl)amino]-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-quinoline-3-carboxylic acid and 7-amino-1-cyclopropyl-6- fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid.
Determination of Ergot Alkaloids: Purity and Stability Assessment of Standards and Optimization of Extraction Conditions for Cereal Samples
Authors: Krska Rudolf , Berthiller Franz , Schuhmacher Rainer , Nielsen Kristian F , Crews Colin 
Published: February 2020

Abstract
Results obtained from a purity study on standards of the 6 major ergot alkaloids ergometrine, ergotamine, ergosine, ergocristine, ergocryptine, and ergocornine and their corresponding epimers are discussed. The 6 ergot alkaloids studied have been defined by the European Food Safety Authority as those that are the most common and physiologically active. The purity of the standards was investigated by means of liquid chromatography with diode array detection, electrospray ionization, and time-of-flight mass spectrometry (LC-DAD-ESI-TOF-MS). All of the standards assessed showed purity levels considerably above 98 apart from ergocristinine (94), ergosine (96), and ergosinine (95). Also discussed is the optimization of extraction conditions presented in a recently published method for the quantitation of ergot alkaloids in food samples using solid-phase extraction with primary secondary amine (PSA) before LC/MS/MS. Based on the results obtained from these optimization studies, a mixture of acetonitrile with ammonium carbonate buffer was used as extraction solvent, as recoveries for all analyzed ergot alkaloids were significantly higher than those with the other solvents. Different samplesolvent ratios and extraction times showed just minor influences in extraction efficacy. Finally, the stability of the ergot alkaloids in both raw cereals and cereal-based processed food extracts was studied. According to these studies, extracts should be prepared and analyzed the same day or stored below ambient temperatures. Barley and rye extracts, which were stored at 4 and 15C after PSA cleanup, proved to be stable overnight. However, storage over a period of 14 days at 4C resulted in significant epimerization, which was most pronounced in rye and particularly for ergocornine, ergocryptine, and ergocristine.
ASimple 2-Directional High-Performance Thin-Layer Chromatographic Method for the Simultaneous Determination of Curcumin, Metanil Yellow, and Sudan Dyes in Turmeric, Chili, and Curry Powders
Authors: Dixit Sumita , Khanna Subhash K , Das Mukul 
Published: February 2020

Abstract
A method using simple extraction and 2-directional high-performance thin-layer chromatography (HPTLC) was developed for the simultaneous determination of curcumin, metanil yellow, and sudan dyes in turmeric, chili, and various mixed curry powder formulations. The method offers resolution (Rf) of turmeric pigments, namely, curcumin (0.77), demethoxycurcumin (0.69), bis(demethoxy)curcumin (0.61), and the synthetic dye metanil yellow (0.05) by the first-directional mobile phase, chloroformmethanol (9 1, v/v). The resolution (Rf) of sudan I (0.30) and sudan IV (0.23) was achieved by the second-directional mobile phase, toluenehexaneacetic acid (50 50 1, v/v/v). Natural pigments of both turmeric and chili showed no interference in the detection and quantification of synthetic colors. The limit of detection and limit of quantification values for curcumin, metanil yellow, sudan I, and sudan IV were 17.39, 42.90, 15.45, and 7.01 and 52.71, 130.0, 46.80, and 21.24 ng/spot, respectively. Analysis of a few market samples showed the presence of metanil yellow (1.54.6 mg/g), sudan I (4.812.1 mg/g), and sudan IV (0.92.0 mg/g) in loose turmeric and chili samples, whereas the curcumin content in turmeric and mixed curry powder samples ranged from 6.5 to 36.4 and from 0.3 to 1.9 mg/g, respectively. The method is relatively simple, offers reasonable sensitivity, and can be used to screen a large number of samples.
Determination of Trace Amounts of Cu2, Ni2, and Mn2 Ions After Preconcentration onto PAN-Immobilized Organo Nanoclay as a New Sorbent
Authors: Afzali Daryoush , Mostafavi Ali 
Published: February 2020

Abstract
The application of organo nanoclay 1-(2-pyridylazo)-2-naphthol (PAN)-immobilized as a new, easily prepared, and stable solid sorbent for preconcentration of trace amounts of Cu2, Ni2, and Mn2 ions in aqueous solution is presented. The organo nanoclay was prepared by adding tetradecyldimethylbenzylammonium chloride onto montmorillonite and then saturating with PAN. A simple, rapid, selective, sensitive, and economical method was developed for the simultaneous separation of trace amounts of copper, nickel, and manganese in aqueous medium using PAN as an analytical reagent. The sorption was quantitative in the pH range of 69.5, and quantitative desorption occurred instantaneously with 5.0 mL 3 M HNO3. Linearity was maintained at 0.2637 ng/mL for copper, 152 ng/mL for nickel, and 0.221 ng/mL for manganese in the original solution. The detection limits were 0.04 ng/mL for Cu(II), 0.15 ng/mL for Ni(II), and 0.03 ng/mL for Mn(II) in the original solution (2bl; standard deviation and bl blank). Various parameters, such as the effect of pH, breakthrough volume, and interference of a large number of anions and cations, have been studied, and the proposed method was used to determine these metal ions in water and standard samples. Determination of these metal ions in standard samples showed that the proposed method has good accuracy.
Determination of Aconitum Alkaloids in Dietary Supplements and Raw Botanical Materials by Liquid Chromatography/UV Detection with Confirmation by Liquid Chromatography/Tandem Mass Spectrometry: Collaborative Study
Authors: Wong Siu-Kay ,   Collaborators:, Che C T , Guo H-Z , Ji S , Kim J-H , Leung K S Y , Lo C K , Richards A , Schaneberg B T , Sudberg; S , Sullivan D , Wang W , Wong Y C , Zhang L-X , Zheng F-Y 
Published: February 2020

Abstract
An interlaboratory study was conducted to evaluate a method for the determination of 3 Aconitum alkaloids, viz., aconitine, mesaconitine, and hypaconitine, in raw botanical material and dietary supplements. The alkaloids were extracted with diethyl ether in the presence of ammonia. After cleanup by solid-phase extraction to remove matrix interferences, the alkaloids were determined by reversed-phase liquid chromatography (LC)/UV detection at 235 nm with confirmation by LC/tandem mass spectrometry (MS/MS). A total of 14 blind duplicates were successfully analyzed by 12 collaborators. For repeatability, the relative standard deviation (RSDr) values ranged from 1.9 to 16.7, and for reproducibility, the RSDR values ranged from 6.5 to 33. The HorRat values were all &lt;2 with only one exception at 2.3. All collaborating laboratories had calibration curves with correlation coefficients of &gt;0.998. In addition, 6 collaborators performed the confirmation and were able to verify the identities of the alkaloids by using LC/MS/MS.
Spectrophotometric Determination of Doxazosin Mesylate in Tablets by Ion-Pair and Charge-Transfer Complexation Reactions
Authors: Aydomu Zeynep , Barla Asli 
Published: February 2020

Abstract
Two accurate, easy spectrophotometric methods for the determination of doxazosin mesylate were described. The first method was based on the formation of ion-pair complexes with the acidic sulfophthalein dyes bromocresol purple (BCP) and bromophenol blue (BPB) in pH 3.3 and 4.5 citratephosphate buffer, respectively. The formed complexes were extracted into dichloromethane, and their absorbance was measured at 403 and 410 nm for BCP and BPB, respectively. The second method was based on the charge transfer reaction of the drug as an n-electron donor with either 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or 7,7,8,8-tetracyanoquinodimethane (TCNQ) as -acceptors, to give colored radical anions. The absorbances of products were measured at 457 nm in acetonitrile and 838 nm in methanol for DDQ and TCNQ, respectively. Under the optimum reaction conditions, Beer's law was obeyed with a good correlation coefficient (r = 0.99970.9999) in the concentration ranges 3.018.0, 3.020.0, 15.095.0, and 10.0100.0 g/mL for the BCP, BPB, DDQ, and TCNQ methods, respectively. Limits of detection of the BCP, BPB, DDQ, and TCNQ methods were 0.314, 0.408, 1.935, and 1.610 g/mL, respectively. The limits of quantification were 1.045, 1.360, 6.449, and 5.367 g/mL, respectively. The parameters molar absorptivity, precision, accuracy, recovery, robustness, and stability constant were studied. The proposed methods were successfully applied for determination of the drug in tablets with good accuracy and precision. Statistical comparison of the results with those obtained by a reported method showed good agreement and indicated no significant difference in accuracy and precision.
Multiresidue Mycotoxin Analysis in Corn Grain by Column High-Performance Liquid Chromatography with Postcolumn Photochemical and Chemical Derivatization: Single-Laboratory Validation
Authors: Ofitserova Maria , Nerkar Sareeta , Pickering Michael , Torma Laszlo , Thiex Nancy 
Published: February 2020

Abstract
A multiresidue method was developed and validated for simultaneous analysis of 5 families of mycotoxins in corn grain. Deoxynivalenol (DON); aflatoxins B1, B2, G1, G2; ochratoxin A; zearalenone; and fumonisins FB1 and FB2 are extracted from corn grain samples with watermethanol, and extracts are cleaned up using immunoaffinity and solid-phase extraction columns. The column high-performance liquid chromatographic method uses postcolumn photochemical derivatization for detection of aflatoxins and derivatization with o-phthalaldehyde for detection of fumonisins. Mean recoveries and relative standard deviation values () over studied fortification levels for the chosen matrixes were: DON 89.9, 8.7; aflatoxin B1 85, 9.4; aflatoxin B2 82.4, 9.7; aflatoxin G1 74.8, 13.5; aflatoxin G2 79.2, 10.0; fumonisin B1 96.2, 8.0; fumonisin B2 84.5, 6.4; zearalenone 91.7, 11.5; and ochratoxin A 87.4, 15.8. The method performance criteria, including specificity, accuracy, repeatability, operational range, and detection limits, were found to be within specifications set by the Feed Additives and Contaminants Group of the AOAC Agricultural Materials Community.
Validated Column High-Performance Liquid Chromatographic Method for Determination of Aspirin and Clopidogrel in Combined Tablets in the Presence of Degradation Products Formed Under ICHRecommended Stress Conditions
Authors: Kachhadia Pankaj K , Doshi Ashish S , Joshi Hitendra S 
Published: February 2020

Abstract
The development and validation of a column high-performance liquid chromatographic assay method for the determination of aspirin and clopidogrel in tablet formulation are described. The combination formulation was subjected to International Conference on Harmonization-recommended stress conditions. Separation of the drugs from the degradation products formed under stress conditions was achieved on an octasilyl (C8) column using 0.3 orthophosphoric acidacetonitrile (65 + 35, v/v) mobile phase. The method was validated for specificity, linearity, limits of detection and quantification, precision, accuracy, and robustness. The method was found to be specific against placebo interference and during the forced degradation. The response was linear in the concentration range of 30.0120.0 g/mL for aspirin and 15.060.0 g/mL for clopidogrel, with a correlation coefficient of 0.9999 for both. The relative standard deviation values for intra- and interday precision were &lt;2.0. The accuracy was between 99.12 and 99.83 for aspirin and 98.20 and 100.35 for clopidogrel. Stress testing showed degradation products that were well-separated from the parent compound, confirming the stability-indicating capacity of the method.
Estimation of Pitavastatin Calcium in Tablet Dosage Forms by Column Liquid Chromatography and Ultraviolet Spectrophotometry
Authors: Panchal Hiral J , Suhagia Bhanubhai N , Patel Madhabhai M , Patel Bhavesh H 
Published: February 2020

Abstract
Two simple and accurate methods for the determination of pitavastatin calcium (PIT) in tablet dosage forms were developed and validated using column liquid chromatography (LC) and UV spectrophotometry. The LC separation was achieved on a Phenomenex Luna C18 column (250 mm, 4.6 mm id, 5 m) in the isocratic mode using acetonitrilewatertriethylamine (80 + 19.8 + 0.2, v/v/v), adjusted to pH 3.5 0.05 with orthophosphoric acid, as the mobile phase at a flow rate of 1.5 mL/min. The retention time was 5.70 min. Both the methods were performed at 238 nm, the wavelength of maximum absorbance of PIT in methanol. In the LC method, quantification was achieved with a photodiode array detector over the concentration range of 0.12.5 g/mL with a mean recovery of 100.26 0.75. In the UV method, quantification was achieved over the concentration range of 220 g/mL with mean recovery of 99.65 1.24. Both methods were validated, and the results were compared statistically. They were found to be simple, specific, accurate, and precise. The methods were successfully applied for the determination of PIT in tablet dosage form without any interference from common excipients.
Determination of Deoxynivalenol in Soft Wheat by Immunoaffinity Column Cleanup and LC-UV Detection: Interlaboratory Study
Authors: Neumann Gary , Lombaert Gary A , Kotello Susan , Fedorowich Nicole ,   Collaborators:, Abdelaal E , Cea J , Kurz K , Malone B , Marley E , Mischke C , Panzarini G , Patel S , Roscoe M , Savard M , Solfrizzo M , Trelka R , Vargas E 
Published: February 2020

Abstract
An interlaboratory study was conducted to assess the applicability of a previously validated method for the analysis of deoxynivalenol (DON) in cereal and cereal products to soft wheat in the range of &gt;0.13.0 g/g. The study evaluated a generic method to determine DON at levels that bracket the existing Canadian guidelines for DON in soft wheat destined for use in baby foods and nonstaple foods. Collaborators selected one of 2 approved brands of DON immunoaffinity column for cleanup and their choice of qualified C18 liquid chromatographic (LC) column. Separation was by LC with UV detection. Blind duplicates from 5 levels of naturally contaminated wheat and a pair of spiked wheat samples were successfully analyzed by 12 laboratories in 8 countries. For samples naturally contaminated with DON from &lt;0.12.2 g/g, the relative standard deviation of repeatability (RSDr) ranged from 3.1 to 14.8. For reproducibility, the RSDR ranged from 21.0 to 32.9 and the HorRat range was 1.0 to 1.9. Recoveries of 0.5 g/g DON spiked into wheat ranged from 66 to 98, with an average of 84. The RSDr was 5.4, the RSDR was 12.6, and the HorRat value was 0.7.
Determination of Oxytetracycline/Oxytetracycline Hydrochloride in Animal Feed, Fish Feed, and Veterinary Medicinal Products by Liquid Chromatography with Fluorescence Detection: Collaborative Study
Authors: Thiex Nancy J , Larson Richard ,   Collaborators:, Ahmed M S , Albert K , Babin Y , Campbell H , Campbell M , DeAtley A , Eigen S , Elson K , Farrow M , Firman M , Jamieson J , Jobin D , Kibbey J , Kirby P , Larson R , Marshall D , Mathis J , McManus K , Menefee L , Olson L , Panagiotis S , Raines J , Rowe D , Sabbatini J Z , Singh D , Smith C , Stenske M A , van Rhijn H , Williams S M 
Published: February 2020

Abstract
A method for determining oxytetracycline (OTC) in animal feed, fish feed, and veterinary medicinal products at medicated use and contamination levels was collaboratively studied. The method is applicable to the analysis of animal feeds and mineral premixes containing levels 2 mg/kg, and fish feed containing levels 10 mg/kg. Oxytetracycline hydrochloride (OTC.HCl) is extracted from ground feed material in acidmethanol solution using mechanical agitation. After centrifugation for 5 min at 1230 g, an aliquot of the extract is diluted with water and/or acidmethanol so that the concentration of OTC.HCl is approximately the same as that in the working standard, and the solutions contain at least 50 water. Injectable veterinary medicinal materials (also called animal remedy materials) are diluted with water and/or extractant to reach the target concentration. The extracts are filtered and analyzed by reversed-phase liquid chromatography with fluorescence detection with excitation at 390 nm and emission at 512 nm. Twenty-eight test samples of medicated feeds, supplements, and drug premixes, including 4 test samples for trace-level analysis, were sent to 17 collaborators in Canada, The Netherlands, and the United States. Results were received from 11 laboratories. The RSDr values (within-laboratory repeatability) ranged from 1.26 to 9.21; RSDR values (among-laboratory reproducibility) ranged from 2.14 to 12.9, and HorRat values ranged from 0.54 to 3.02. It is recommended that this method be adopted AOAC Official First Action.
Determination of 17-Ethynylestradiol, Carbamazepine, Diazepam, Simvastatin, and Oxybenzone in Fish Livers
Authors: Kwon Jeong-Wook , Armbrust Kevin L , Vidal-Dorsch Doris , Bay Steven M , Xia Kang 
Published: February 2020

Abstract
A method using liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed for the determination of 17-ethynylestradiol in fish liver; a second method using LC/MS was developed for the determination of carbamazepine, diazepam, simvastatin, and oxybenzone in fish liver. The fish liver samples were extracted and cleaned up by using liquid-liquid extraction and solid-phase extraction before the extracts were analyzed by LC/MS or LC/MS/MS with electrospray negative and positive ionization. Recoveries of the 5 target compounds from spiked catfish liver ranged from 72 2 to 100 3. Limits of quantification for the 5 compounds were between 4.2 and 12.3 ng/g (wet weight). Ten turbot (Pleuronichthys verticalis) liver samples were analyzed; levels of 17-ethynylestradiol, carbamazepine, simvastatin, and oxybenzone were below the detection limits. Diazepam was detected in all 10 fish liver samples at concentrations ranging from 23 to 110 ng/g (wet weight).
Evaluation of Analytical Methods for the Determination of Moisture, Crude Protein, Crude Fat, and Crude Fiber in Distillers Dried Grains with Solubles
Authors: Thiex Nancy 
Published: February 2020

Abstract
A number of analytical methods for constituents commonly measured in distillers dried grains (DDG) are practiced in laboratories serving the agricultural sector. A large interlaboratory variability among results has been observed in the industry. Methods for moisture, crude fat, and crude fiber are empirical, thus part of this variability can be attributed to the use of different methods of analysis. A study was organized and supported by the American Feed Industry Association, the Renewable Fuels Association, and the National Corn Grain Association to evaluate the efficacy, applicability, and the intralaboratory variation of a number of methods for moisture, crude protein, crude fat, and crude fiber in DDG with solubles (DDGS). The moisture methods included in the study are AOAC 930.15, AOAC 934.01, AOAC 935.29, AOAC 2003.06, and National Forage Testing Association (NFTA) 2.2.2.5; the crude protein methods studied are AOAC 990.03 and AOAC 2001.13; the crude fat methods studied are AOAC 945.16, AOAC 954.02, AOAC 2003.05, and AOAC 2006.06; and the crude fiber methods studied are AOAC 978.10 and AOCS Ba 6a-05. A second study was undertaken to assess existing interlaboratory variation of the same methods in 23 laboratories. Based on the results of these studies, the sponsoring associations established recommended reference methods for use in commercial trade of DDGS. The reference methods selected are NFTA 2.2.2.5 for moisture, AOAC 990.03 and AOAC 2001.11 for crude protein, AOAC 945.16 for crude fat, and AOAC 978.10 for crude fiber.