bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Liquid Chromatographic Determination of Neomycin B in Bovine Kidney
Authors: Shaikh Badar , Jackson Jean 
Published: February 2020

Abstract
An improved liquid chromatographic (LC) method was developed for the determination of neomycin B in bovine kidney tissue. The tissue is homogenized twice in phosphate buffer; homogenate is centrifuged, and the supernatant is deproteinated by heat. The extract is acidified and mixed with ionpair concentrate, and neomycin B is determined by an LC system consisting of an ion-pairing mobile phase, a reversed-phase ODS column, postcolumn derivatization with o-phthalaldehyde reagent, and fluorometric detection. Average recoveries of neomycin B from kidney tissues spiked at 3,6, and 12 ppm were 103, 99, and 104%, with 9.7,7.9, and 3.7% intralaboratory coefficients of variation, respectively, using a standard curve prepared in buffer. The method was used to determine neomycin B in kidney tissue obtained from a calf killed 14 days after intramuscular dosing with neomycin (5 mg/lb). The tissue was found to contain about 3 ppm neomycin B. The LC conditions were also used to assay control samples of muscle, liver, milk, plasma, and urine. No interfering peaks were noted at the elution position of neomycin B.
Optimization of a Liquid Chromatographic Method for Determination of Oxytetracycline, Tetracycline, and Chlortetracycline in Milk
Authors: White C R , Moats W A , Kotula K L 
Published: February 2020

Abstract
A liquid chromatographic (LC) method was developed for the simultaneous identification and quantitation of oxytetracycline, tetracycline, and chlortetracycline in milk. Milk samples (5 mL) were deproteinized by adding 1 mL 1N HCI and 24 mL acetonitrile, and filtering. Dichloromethane and hexane were added to 15 mL filtrate to separate the water layer. The organic layer was washed with 1 mL deionized water, and the combined water layers were diluted to 4 mL. Sample aliquots of 1000 μL were then injected directly and analyzed on an LC system. The sensitivity limit of the method is 5 ppb for each antibiotic; no interferences are present at their retention times. Mean recoveries from milk spiked at 0.01-1 ppm ranged from 87 to 99%, and precision was good.
Liquid Chromatographic Determination of Abamectin in Fruits and Vegetables
Authors: Chamkasem Narong , Papathakis Michael L , Lee S Mark 
Published: February 2020

Abstract
A simplified extraction and cleanup procedure was developed for determining abamectin in fruits and vegetables. Abamectin is extracted from sample matrices by acetonitrile, and the acetonitrile phase is separated from the aqueous phase by saturating the extract with sodium chloride. Abamectin is then partitioned into hexane from the acetonitrile, and the hexane layer is cleaned up with an aminopropyl solid-phase extraction (SPE) system. The fluorescent abamectin derivative is formed by dehydration with trifluoroacetic anhydride-1-methylimidazole in dimethylformamide for 1 h at 30°C and with methanolic ammonium hydroxide for another 30 min at 30°C. The derivatized residues are separated from the reaction mixture by a silica SPE. The abamectin derivative is determined by reversedphase liquid chromatography with a fluorescence detector. The method yields recoveries of 85-97% at fortification levels of 10 and 50 μg/kg for orange, pears, spinach, and celery.
Organochlorine Pesticides and Polychlorinated Biphenyl Congeners in Commercial Fish from the Great Lakes
Authors: Newsome W Harvey , Andrews Paul 
Published: February 2020

Abstract
Fillets from 11 species of commercial fish from the Great Lakes were analyzed for residues of 39 polychlorinated biphenyl (PCB) congeners and 24 other organochlorine compounds. Eel and trout contained the highest amount of PCB (753 and 633 ppb wet weight, respectively) and other organochlorines (607 and 1404 ppb, respectively); perch and carp contained the lowest residues. The pentaand hexachlorinated PCBs were the major congeners in all species except whitefish, in which the tetrachlorinated congeners predominated. Toxaphene was the most abundant organochlorine pesticide in trout; p,p′ -DDE was the major component of this class in eel. Residue concentrations in commercial carp were compared with residues present in carp from a fishery closed to commercial operation. Although both PCB and organochlorine pesticide levels in carp were among the lowest for all commercial fish samples, levels from the contaminated area were among the highest.
Detection of Salmonella in Dry Foods Using Refrigerated Pre-Enrichment and Enrichment Broth Cultures: Interlaboratory Study
Authors: D’Aoust Jean-Yves , Sewell Anne M , Greco Paula ,   Collaborators:, Benson J , Boleszczuk P , Brodsky M , Cirigliano M , Coignaud C , Fain A , Flowers R , Gour L , Hamann W T , Huszczynski G , Jesset K , Konkel P , Lacasse P , Laffey P J , Laperriere G , Mclntyre K , Morrow A , Oggel J , Philippe L M , Purvis U , Richter E R , Thomas M D , West W , Zandstra W 
Published: February 2020

Abstract
An interlaboratory study was performed in 11 laboratories to validate the use of pre-enrichment and tetrathionate brilliant green (TBG35) and selenite cystine (SC35) enrichment cultures refrigerated 72 h at 2-5°C for greater analytical flexibility in the detection of Salmonella in dry foods. Productivities of refrigerated pre-enrichment and enrichment cultures were compared with that of the AOAC/Bacteriological Analytical Manual (BAM) procedure using 4 food types: whole egg powder, milk chocolate, animal feed, and instantized skim milk powder. Uninoculated and inoculated samples were included in each food group. There was complete agreement between the results obtained by the standard AOAC/BAM procedure and the 2 refrigeration procedures. Of 660 samples tested, the AOAC/BAM procedure identified 393 contaminated samples that were readily detected from the corresponding refrigerated pre-enrichment cultures and from the combined productivity of homologous refrigerated TBG35 and SC35 cultures. Refrigeration (72 h) of preenrichment or enrichment cultures for greater analytical flexibility and laboratory productivity in the examination of dry foods is under review for adoption by AOAC International.
AutoMicrobic System for Biochemical Identification of Listeria Species Isolated From Foods: Collaborative Study
Authors: Harris Loralyn , Humber John ,   Collaborators:, Agin J , Black J , Boling R , Calicchia M , Cooper C , Dickinson S , Heisick J , Kelly M , Knight M , LaClair D , Marshall C , Newman S , Presla L , Romine A , Schulke M , Scott J , Scott T , Sivey C , Tardio J , Twohy C , Vorhies I , Wagner T , Wazenski T 
Published: February 2020

Abstract
A collaborative study was conducted to evaluate the performance of the AutoMicrobic System Gram- Positive Identification (GPI) and Gram-Negative Identification (GNI) test kits to biochemically characterize Listeria spp. Thirteen laboratories each tested 97 food and environmental isolates, representing the 7 species of Listeria, as well as 11 additional genera of Gram-positive rods. Each collaborator inoculated both a GPI and a GNI card with a pure culture of each organism. The AutoMicrobic System identified the isolates and printed out the biochemical results. The GPI card is used to obtain a species identification and a mannitol reaction result, and the GNI card is used to obtain rhamnose and xylose reaction results. Organisms are classified into species groups and can be further distinguished on the basis of hemolysis or nitrate reduction tests. The AutoMicrobic System method correctly classified 90.8% of the Listeria spp. isolates and 100% of the non-Listeria isolates. The AutoMicrobic System method was adopted first action by AOAC International for the biochemical characterization of Listeria spp. isolated from food and environmental sources.
Rapid and Accurate Method for Determination of Niclosamide Released from Molluscicidal Formulations
Authors: Emara Laila H 
Published: February 2020

Abstract
A rapid, simple, and reproducible method was developed for quantitative determination of niclosamide ethanolamine salt (NES) — the most widely used molluscicide against snail vectors of schistosomiasis — in both distilled and natural canal waters. The biocide is extracted completely from water samples by passing through Sep-Pak C18 cartridge and eluting the cartridge with methanol. The eluate is then analyzed directly for NES by UV/vis spectrophotometry at 330 nm. This method was found sensitive enough to detect 0.1–5 ppm, and it is highly reproducible (standard deviation, 0.006–0.012). The standard curve obeyed Beer’s law. The method also successfully measured the release rate of NES from controlled-release elastomeric formulations. The release study suggests that NES loading and certain rubber additives are not the key factors that govern the release of the biocide.
Evaluation of Soxtec Extraction Procedure for Extracting Organic Compounds from Soils and Sediments
Authors: Lopez-Avila Viorica , Bauer Karin , Milanes June , Beckert Werner F 
Published: February 2020

Abstract
A study was carried out to evaluate the Soxtec extraction of 29 target compounds (7 nitroaromatic compounds, 3 haloethers, 7 chlorinated hydrocarbons, and 12 organochlorine pesticides) from spiked sandy clay loam and clay loam. The study also compared 2 solvent mixtures (hexane–acetone (1 + 1) and methylene chloride–acetone (1 + 1)) and investigated the effect on method recovery of 5 factors (matrix type, spike level, anhydrous sodium sulfate addition, total extraction time, and immersion/ extraction time ratio), their 2-way interactions, and a 3-way interaction (matrix × spike × time). Of the 5 factors investigated, matrix type, spike level, and total extraction time had a significant effect on method performance at the 5% significance level for 16 of the 29 target compounds (4 compounds were not recovered at all, and analysis of variance was not significant at the 5% significance level for 9 compounds). Anhydrous sodium sulfate addition and immersion/extraction time ratio had insignificant effects for all but one of the target compounds. This effect may have been a random occurrence. The data indicate that the 2 solvents performed equally well and 4 compounds were not recovered at all. These 4 compounds were apparently lost from the spiked matrix. Experiments were performed to determine compound recovery at each step in the extraction procedure. Limited experimental work was performed with 64 basic/neutral/acidic compounds spiked onto clay loam and with 3 standard reference materials certified for polynuclear aromatic hydrocarbons. From the 64 compounds spiked onto clay loam at 6 mg/kg, 20 had recoveries of greater than 75%, 22 had recoveries from 50 to 74%, 12 had recoveries from 25 to 49%, and 10 had recoveries of less than 25%.
Liquid Chromatographic Method for Determination of Diquat and Paraquat Herbicides in Potatoes: Collaborative Study
Authors: Worobey Brian L ,   Collaborators:, Béraldin F , Bruns G , Embleton J , Heck A , King R , McLeod K , Ward R 
Published: February 2020

Abstract
A liquid chromatographic (LC) method for the determination of diquat and paraquat herbicides/desiccants in potatoes was collaboratively studied in 6 laboratories. Analytes are extracted from 5 g sample with dilute acid by using a microreflux procedure; the hydrolysate is adjusted to pH 9–10 and passed through a disposable silica cartridge for rapid cleanup and preconcentration. Analytes are separated on a reversed-phase LC column and are measured as their heptanesulfonate ion pairs by UV detection. Each collaborator determined diquat and paraquat at 4 levels (0.05,0.1,0.5, and 1.0 ppm) in blind duplicate samples plus 2 blind negative control samples. Potatoes, obtained from each participant’s region, were spiked by the collaborators with unknown aqueous solutions containing no analyte or a mixture of diquat and paraquat standards. Repeatability and reproducibility relative standard deviations (RSDr and RSDR) averaged 17.1 and 29.0%, respectively, for determination of diquat and 10.8 and 29.5%, respectively, for paraquat. For analysis of standard solutions, RSDr and RSDR values were 6.3 and 12.0%, respectively, for diquat and 7.3 and 13.9%, respectively, for paraquat. Accuracy, measured by comparison with true spiking values (absolute recovery) averaged 77.6 and 76.2% for diquat and paraquat, respectively, and ranged from 71.8 to 88.0% for both compounds. The method was adopted first action by AOAC International.
Simple Method for Determination of Dietary Fiber in Frozen Foods
Authors: Al-Hasani Sami M , Hlavac Jan , Huntsman Mark A 
Published: February 2020

Abstract
A simple method was developed for the determination of dietary fiber in multicomponent foods. The method involves dispersing the sample into pH 7.4 phosphate buffer and adding bile and pancreatic enzyme as described. Results were comparable to AOAC methods with correlation coefficients of 86% for multicomponent dinners and 89% for breakfast foods. Coefficients of variation ranged from 7.4 to 20.0% for multicomponent foods and 1.0 to 3.6% for single component foods. In addition, blind duplicate samples had a correlation of 0.99. The described method required less time, labor, and manipulation than AOAC methods
A Simplified Alternative to the AOAC Official Method for Cholesterol in Multicomponent Foods
Authors: Thompson Raymond H , Merola George V 
Published: February 2020

Abstract
An AOAC official method for quantitating cholesterol in multicomponent foods, which was first published in the 13th edition of the Official Methods of Analysis, is rarely used. The method includes so many operations and manipulations—all described in excruciating detail—that most laboratories shun it altogether. Intent on finding an alternative, laboratories have developed their own methods for specific foods. As a result, new methods have proliferated, but still no practical method has been developed for the broader categories of multicomponent foods. The aim of AOAC, which is to promote greater accuracy and uniformity of analytical results primarily through collaborative testing, has not been well served under these circumstances. A different approach guided the work reported in the present paper. This approach was directed toward updating and dramatically simplifying the existing AOAC official method. The method's chloroformmethanol-water mixed-solvent extraction is preserved; however, all the remaining steps have been streamlined, updated, or eliminated by using newer technology. Cholesterol is quantitated with highly specific capillary gas-liquid chromatography using the internal standardization technique. The lipid extract is prepared for the chromatography step by a brief saponification carried out in a culture tube. The resulting method has been validated by using Standard Reference Materials and the standard addition method. Because a simplified method is now available for quantitating cholesterol in the lipid extracts, the expectation is that more attention can be given to the development of improved and efficient extraction methods. This step remains as the central difficulty in any number of methods of analysis for lipid analytes.
Gas Chromatographic/Electron Capture Detection Method for Determination of Chlorinated Acids in Water: Collaborative Study
Authors: Edgell Kenneth W , Erb Elizabeth J , Wesselman Raymond J , Longbottom James E ,   Collaborators:, Dodhiwala N , Fencl M , Hanisch R , Levan L , Manmade D , Neslund C , Wait D , Winslow M 
Published: February 2020

Abstract
A U.S. Environmental Protection Agency (USEPA) inter laboratory method validation study was conducted on USEPA Method 515.1, "Determination of Chlorinated Acids in Water by Gas Chromatography with an Electron Capture Detector. "This method is one of the 6 pesticide methods developed for the USEPA National Pesticide Survey (NPS). Method recovery and precision for analyses of sub-ppb to low-ppb concentrations of chlorinated acids were determined in reagent water and finished drinking waters. The analytes evaluated in the study included the 12 pesticides that were quantitatively measured in the National Pesticide Survey (bentazon, 2,4-D, 2,4-DB, 3,5-dichlorobenzoic acid, DCPA-diacid, dicamba, dichlorprop, 5-hydroxydicamba, pentachlorophenol, picloram, 2,4,5- T, and 2,4,5-TP) and 5 pesticides (acif luorfen, chloramben, dalapon, dinoseb, and 4-n it ro phenol) that were only qualitatively assessed in the National Pesticide Survey because of recognized method imprecision. The study design was based on Youden's nonreplicate plan for collaborative tests of analytical methods. The waters were spiked with 17 chlorinated acids, each at 6 concentration levels, prepared as 3 Youden pairs. Eight laboratories extracted the spiked test waters at pH &lt;2 with ethyl ether, performed a solvent exchange with methyl tert-butyl ether, prepared methyl esters of the extracted acids using diazomethane, and analyzed an aliquot of each derivatized extract by gas chromatography with electron capture detection. The submitted data were analyzed using a USEPA computer program, which measured recovery and precision for each of the 17 compounds and compared the performance of the method between water types. Method 515.1 was judged acceptable for the 12 NPS analytes recovered quantitatively; mean percent recoveries at 10-15 times the method detection limits ranged from 79 to 105% in reagent water and from 75 to 123% in finished drinking water. In reagent water, overall precision (reproducibility relative standard deviation, RSDR) ranged from 9.6 to 34.2% and in finished drinking water, the RSDR ranged from 11.9 to 37.0%. Single-analyst precision (RSD for repeatability, RSDr) ranged from 5.8 to 17.7% in reagent water and from 4.6 to 27.9% in drinking water. Results for the 5 other NPS analytes were too inaccurate or imprecise and, for these compounds, supported use of the method for qualitative measurements only; the 5 compounds are not included in the adopted method. The method has been adopted first action by AOAC INTERNATIONAL for determination of residues of 12 chlorinated acids in finished drinking water.
Determination of Methylene Chloride Acceptability and Its "Purification" for Ethylenethiourea Methodology
Authors: Sack Chris A , Kendall Donald C , Krause Richard T 
Published: February 2020

Abstract
A liquid chromatographic-electrochermcal method for the determination of ethylenethiourea (ETU) residues uses methylene chloride in the cleanup. Distilled-in-glass grade methylene chloride produced erratic ETU recoveries ranging from 0 to 106% for vacuum rotary evaporation of the solvent. ETU recoveries were found to be dependent on the bottle of methylene chloride used, not on supplier or lot. When GC2 grade methylene chloride from Burdick &Jackson Laboratories was used, ETU recoveries ranged from 92 to 110%. "Acceptable" ETU recoveries were defined as those values between 90 and 110%. Passing "unacceptable" methylene chloride through a column containing anhydrous sodium sulfate, sodium carbonate, and alumina was found to adequately purify methylene chloride. Treated methylene chloride provided acceptable ETU recoveries for up to 1 month after "purification."
Liquid Chromatographic Determination of Glyburide (Glibenclamide) and Its Related Compounds in Raw Materials
Authors: Beaulieu Normand , Graham Susan J , Lovering Edward G 
Published: February 2020

Abstract
A liquid chromatographic method has been developed for the determination of glyburide and 3 known related compounds in drug raw materials. The lower limit of quantitation of the related compounds is about 0.02%. Evaluation of 9 drug raw materials revealed total impurities ranging from 0.17 to 0.65%. The relative standard deviation of the assay method is &lt;1%.
Rapid Determination of Tryptophan in Intact Proteins by Derivative Spectrophotometry
Authors: Fletouris Dimitrios J , Botsoglou Nickos A , Papageorgiou Georgios E , Mantis Antonios J 
Published: February 2020

Abstract
A method for rapid determination of total tryptophan in intact proteins was developed. Sample is homogenized with 0.1 M sodium hydroxide, and the homogenate, if it contains suspended material, is centrifuged. Tryptophan is directly quantified in sample extract on the basis of its fourth-derivative UV absorption spectrum. Protein hydrolysis and/or extract purification is not required because the fourth-derivative transformation of the conventional analytical band around 285.5 nm virtually eliminates interferences arising from both tyrosine and other UV-absorbing components. When pure proteins were analyzed by the method, the values of tryptophan residues found coincided well with literature data based on sequence analysis. The applicability of the method was also tested on several food and feed ingredient samples selected to include a range of protein content and a variety of protein sources. Owing to its simplicity and reliability, the method is particularly recommended for everyday analysis of a large number of samples.
The Chinese Total Diet Study in 1990. Part II. Nutrients
Authors: Chen Junshi , Gao Junquan 
Published: February 2020

Abstract
This paper reports the intakes of 72 nutrients and their dietary sources obtained from the Chinese total diet study in 1990. Most of the nutrient intakes are close or equal to their corresponding recommended daily allowances (RDAs). Both the total energy intake (2203 kcal) and the proportions contributed by protein, fat, and carbohydrate meet the current Chinese RDAs and the World Health Organization (WHO) nutrient goals. The average protein intake was 64 g/day. The intake of essential amino acids all exceeded the Chinese RDA, and their proportions were generally consistent with the WHO recommended pattern. The average fat intake was 51.2 g/day (21.2% of the total energy intake). However, the dietary fat intake has been increasing significantly in the Chinese diet and the proportion of animal fat has reached 53% of the total fat intake. The total saturated:total monounsaturated:total polyunsaturated fatty acid ratio was 1.0:1.5:1.0. Although the average cholesterol intake was only 179 mg/day, it was 248 mg/day in the South 1 region. The intakes of thiamine and riboflavin were below the RDA. Retinol intakes in all the 4 regions were low. Most (80%) of the retinol (equivalent) intakes were from carotenoids. The average intake of total tocopherol was 89% of the RDA, and among the 4 regions, only the South 2 region has relatively low intake. The intakes of iron, copper, manganese, sodium, and phosphorus were adequate. The intakes of calcium, zinc, and potassium were insufficient, and intakes of selenium and magnesium were a little low. High sodium and low potassium intake is a traditional problem in the Chinese diet.