bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Norflurazon Residues in Mixed Crop Matrices
Authors: Winkler Victor W , Patel Jayanti R , Januszanis Mary , Colarusso Marjorie 
Published: February 2020

Abstract
A method for determining norflurazon residues in mixed crop matrices is described. The method includes methanol Soxhlet extraction, hexane wash, addition of 10% saline, methylene chloride extraction, concentration, preparative thin layer chromatography of 10% sample aliquot, and resuspension of sample zone for gas-liquid chromatographic analysis. The lower level of electron capture detection is 0.01 ppm. Recoveries for 0.08 ppm spiked samples of cottonseed; soybean seed and foliage; peanut seed plus hulls and foliage,; orange and tangerine; lemon; apple and peach; and soil are generally greater than 80%.
Thin Layer Chromatographic Determination of Methyl Parathion as Paraoxon by Cholinesterase Inhibition
Authors: Bhaskar Sana Udaya , Kumar Nanguneri V Nanda 
Published: February 2020

Abstract
A simple, sensitive, and rapid method is described for the quantitative estimation of nanogram amounts of methyl parathion (O,O-dimethyl O-p-nitrophenyl phosphorothioate) as methyl paraoxon (O,O-dimethyl O-p-nitrophenyl phosphate) on thin layer chromatograms. Methyl paraoxon is detected by pig liver acetone powder cholinesterase inhibition, using p-nitrobenzenediazoniumfluoroborate as the chromogenic reagent. Commercial pig liver acetone powder is more advantageous than raw liver sources because it is readily available and can be preserved indefinitely. About 0.1 ng methyl parathion can be detected, and amounts from 5 to 50 ng can be quantitatively estimated.
Comparison of Three Methods for Determination of Sulfamethazine in Swine Tissues: Collaborative Study
Authors: Malanoski Anthony J , Barnes Charlie J , Fazio Thomas 
Published: February 2020

Abstract
An interlaboratory study of 3 methods for the determination of sulfamethazine in swine muscle and liver tissue was conducted. A gas chromatographic (GC), a combined gas chromatographic-mass spectrometric (GC/MS), and a colorimetric method were evaluated. Four fortified and 2 incurred levels of sulfamethazine ranging from 0.00 to 0.45 ppm were studied. The study revealed that the GC/MS procedure provides the most reliable data and that the GC method provides acceptable data w i t h the incorporation of appropriate controls. The recoveries for the GC/MS method typically ranged from 90 to 100% for swine liver and muscle. The GC and GC/MS methods have been adopted official first action.
Liquid and Gas Chromatographic Analysis of Diethyl Phthalate in Water and Sediment
Authors: Payne William R , Benner Jacquelyn E 
Published: February 2020

Abstract
Diethyl phthalate was determined in water and sediment by high performance liquid chromatography (HPLC) and in water by gas-liquid chromatography with electron capture detection (GLC-ECD). Water samples were extracted with hexane, using a high-speed homogenizer-ultrasonic apparatus and a test tube mixer. Sediments were Soxhlet-extracted using acetonitrile. For HPLC, diethyl phthalate was determined in normal phase mode using a Zorbax-CN column, a 2% isopropanol-hexane solvent system, and a UV variable wavelength detector. For GLC-ECD, a 3% SE-30 Gas-Chrom Q column with a 63Ni electron capture detection system was used. Recoveries from fortified samples ranged from 93.9 to 98.0% for water atO.Ol-0.50 ppm, and from 90.0 to 93.6% for sediment atO.2-2.Oppm.
Spectrophotometric Determination of Menadione and Menadione Sodium Bisulfite
Authors: Sidhom Madiha B , El-Kommos Michel E 
Published: February 2020

Abstract
A spectrophotometric method is described for the determination of menadione and menadione sodium bisulfite in bulk and in solution for injection. The method measures the intensity of the violet color (λmax 540 nm) developed when menadione reacts with thiosemicarbazide in alkaline medium. Beer's law is obeyed in the concentration range 4-40 μg/m L (r = 0.9995). The method is simple, sensitive, and particularly suited for routine analysis of official menadione sodium bisulfite injection. Results are comparable with the USP method.
Spectrophotometric Determination of Oxazepam and Dipyridamole in Two-Component Mixtures
Authors: Korany Mohamed A , Haller Rolf 
Published: February 2020

Abstract
The λpj method is applied to simultaneous determination of oxazepam and dipyridamole in 2-component mixtures. Authentic mixtures and tablets containing oxazepam and dipyridamole were assayed by measuring the absorbances in 0.1N H2SO4 and 0.05M borax solutions and calculating the λp2 at 2 wavelength sets: 272-312 nm (at 8 nm intervals) and 288-328' nm (at 8 nm intervals). The concentration is evaluated by solving a pair of simultaneous equations. The results obtained are reasonably reproducible with a coefficient of variation less than 2%. The proposed method is compared with the λA modification of Vierordt's method of 2-component analysis. The λpj method gave more accurate and precise results.
Derivatization and Cleanup Improvements in Determination of Residues of Glyphosate and Aminomethylphosphonic Acid in Blueberries
Authors: Guinivan Richard A , Thompson Neal P , Wheeler Willis B 
Published: February 2020

Abstract
A new method based on development of the 2-chloroethyl N-heptafluorobutyryl derivatives of glyphosate and its major metabolite aminomethylphosphonic acid is reported for fortified blueberry samples. The concentrated aqueous extract is chromatographed on a gel permeation column in a low pH eluant. Under these conditions, sugar is eliminated by permeation and pigments are strongly adsorbed. Additional sugar is eliminated with a small cation exchange column and then the sample is easily dried and derivatized. The derivatized compounds are extracted from an aqueous environment with hexane and analyzed by gas chromatography with electron capture detection. This procedure requires significantly less sample handling time and provides greater sensitivity for glyphosate than the commonly used procedure recommended by EPA.
Automated High Pressure Liquid Chromatographic System for Determination of Mannitol, Sorbitol, and Xylitol in Chewing Gums and Confections
Authors: Samarco Eugene C , Parente Ernest S 
Published: February 2020

Abstract
A rapid, precise, and reproducible automated high pressure liquid chromatographic method was developed to determine xylitol in the presence of mannitol and sorbitol in chewing gums and confectionery products. A mobile phase of water and methanol elutes the polyols simultaneously from a cation-exchange column without pretreatment or derivatization. Injections into the liquid chromatograph were made by an autosampler, and data reduction was performed with a programmable electronic integrator. Average recoveries for one level each of mannitol, sorbitol, and xylitol in 6 replicate samples prepared by the standard addition technique were 102.5,100.5, and 100.7%, respectively.
Recovery of Eggs of Two Parasitic Nematodes, Ascaris sp. and Trichuris sp.: Interlaboratory Study
Authors: Rude Richard A , Bier Jeffrey W , Jackson George J , McClure Foster D 
Published: February 2020

Abstract
An interlaboratory study was conducted to determine the effectiveness of the Nacconol ether centrifugation method for recovering parasitic nematode eggs from 3 contaminated products: a crop (cabbage), a sludge fertilizer (Milorganite), and a sewage effluent (Minneapolis). Six replicate samples for each of the 3 products were seeded with eggs at 3 different levels: 200 Ascaris suis and 8 Trichuris muris; 15 A. suis and 15 T. muris; 8 A. suis and 180 T. muris. Recovery was low for all samples except sewage effluent, in which recoveries greater than 100% in 2 samples resulted from the misidentification of arthropod eggs as Ascaris sp. The average mean percent recovery for the other samples was 22.53. Repeatability for replicate samples and reproducibility of results by individual laboratories were poor, and the method is not recommended for quantitative estimates of nematode egg contamination of foods and food-contact materials. However, the Nacconol ether centrifugation method can be used as an all-or-none test. (Only 13% of 1146 counts were falsely negative.) Of 69 samples, only 4 were falsely negative for A. suis eggs and only 1 was falsely negative for T. muris eggs in counts of 6 replicates.
Accuracy of Pesticide Reference Standard Solutions. Part II. Chemical Stability Under Four Storage Conditions
Authors: Hodgson David W , Thompson John F , Watts Randall R 
Published: February 2020

Abstract
A study was undertaken to assess the long-term chemical stability of dilute standard pesticide solutions of 4 compound classes. The solutions were studied under 4 storage conditions: freezer at —15°C; refrigerator at 3°C; ambient temperature in the dark; and ambient temperature on the bench top exposed to fluorescent and natural light. Pesticide compounds including 27 organochlorines, 20 organophosphates, 10 triazines, and 13 carbamates were monitored for periods of 6 months to 2 years. Most of the compounds were stable (&lt;10% decomposition) under all conditions for the full length of the study. Solutions of CDEC, butylate, and disulfoton, however, decomposed when stored under all storage conditions. Solutions of carbaryl, methiocarb, and carbofuran decomposed when stored at ambient laboratory temperature with exposure to light. Recommendations are made for formulating solvents, storage, and practical shelf life of high concentration stock solutions and dilute gas chromatographic working standards representing 4 pesticide classes
Microbial Hazards Associated with Bean Sprouting
Authors: Andrews Wallace H , Mislivec Philip B , Wilson Clyde R , Bruce Verneal R , Poelma Paul L , Gibson Regina , Trucksess Mary W , Young Kathryn 
Published: February 2020

Abstract
The behavior of microorganisms was studied in mung beans and alfalfa seeds before and after germination in modified, commercially available bean-sprouting kits. The microorganisms were enumerated by the aerobic plate count (APC) and by total yeast and mold count procedures. Salmonella species were artificially inoculated into selected samples and were enumerated by the most probable number (MPN) method. After germination of the beans or seeds into mature sprouts, significant increases were noted in APCs and in MPN values of Salmonella species. Although counts of yeasts and molds did not increase significantly after germination, these samples showed an increase in toxic Aspergillus flavus and potentially toxic Alternaria species. The presence of toxic Penicillium cyclopium molds also increased substantially in 5 samples of a single brand of mung beans. Analysis of selected sprout samples, however, showed no presence of aflatoxin.
Analytical Methods for Microbiology in the Next Decade
Authors: Feldman John 
Published: February 2020

Abstract
As microbiologists develop and modify methods and turn to automated equipment to decrease analysis time, the precision and accuracy of the methods must be ensured through collaborative study. Rapid, validated methods are needed in many areas. Sterility testing and the use of biological indicators are among subjects of interest to FDA and industry. These groups are also studying particulate analysis. The limulus amebocyte lysate test is being considered for use in detecting endotoxins in drugs and medical devices, in diagnosing illness, and in assessing the microbiological quality of foods and water. Reliable methods are needed for detecting viruses in foods to assure a safe food supply. Studies are needed on the Vibrionaceae to better understand the mechanisms of invasiveness and host response. Methods must also be developed to study pathogens in the water and food supply.
High Pressure Liquid Chromatographic Determination of Glycyrrhizic Acid or Glycyrrhizic Acid Salts in Various Licorice Products: Collaborative Study
Authors: Vora Peter S ,   Collaborators:, Estes H , Grigor Dr , Hodge B , Hurst W J , LeBlanc D , Shuford C , Walker K , Zimmermann M 
Published: February 2020

Abstract
A collaborative study determining glycyrrhizic acid or glycyrrhizic acid salts content of various licorice products has been conducted using high pressure liquid chromatography (HPLC). Five samples containing various concentrations of glycyrrhizic acid were analyzed in blind replicates by 8 collaborators. The results indicate excellent repeatability and reproducibility with coefficients of variation less than 7.5%. In addition, this method allows the determination of glycyrrhizic acid in less than 15 min compared with 3 days for the conventional gravimetric and colorimetric methods. The method has been adopted official first action.
Evaluation of Silica and Polar Bonded Columns for Liquid Chromatographic Analysis of Temephos Formulations
Authors: Mount Dwight L , Miles James W 
Published: February 2020

Abstract
In the course of development of an HPLC method for determination of temephos in technical grade temephos and its formulations, a variety of columns and solvent systems were evaluated. Three satisfactory methods evolved and were evaluated for reproducibility, convenience, cost, and optimum resolution of active ingredient from possible impurities. After consideration of advantages and disadvantages of each system, a method based on the use of a silica gel column eluted with ethyl acetate-hexane (10 + 90) and p-nitrophenyl p-nitrobenzoate as internal standard was selected for testing in an international collaborative trial.
Gas Chromatographic Determination of Synthetic Musk (7-Acetyl-6-Ethyl-1,1,4,4-Tetramethyltetralin) in Fragrances
Authors: Wisneski Harris H , Yates Ronald L , Davis Henry M 
Published: February 2020

Abstract
A gas chromatographic method has been developed for the determination of the synthetic fragrance musk, 7-acetyl-6-ethyl-1,1,4,4-tetramethyltetralin (AETT). The fragrance is first added to water and extracted with ether to separate the fragrance oil from the water-alcohol mixture. The AETT, present in the ether-soluble fraction, is purified further by preparative high pressure liquid chromatography (HPLC). The AETT in the collected HPLC fraction is then determined by gas chromatography using external standardization. Recoveries from samples spiked with AETT at levels ranging from 100 to 1000 μg/mL varied from 80 to 96% with an average of 90%. AETT was verified in each sample by gas chromatography/mass spectrometry.
High Performance Liquid Chromatographic Determination of Vitamin D in Fortified Milks, Margarine, and Infant Formulas
Authors: Thompson James N , Hatina George , Maxwell William B , Duval Suzanne 
Published: February 2020

Abstract
Fortified milks were saponified overnight at room temperature with 1% ethanolic pyrogallol and KOH. The digest was extracted with hexane after adding water and ethanol, and the extract was washed consecutively with 5% KOH, water, and 55% aqueous ethanol to remove polar lipids. After evaporation, the residue was first chromatographed on a column of 5 μm silica. A fraction containing vitamin D was collected, evaporated, and rechromatographed on a reverse phase column for the separation and quantitation of vitamins D2 and D3. Recovery was 96-99% and the coefficient of variation was 3% (8 replicates). Infant formula was diluted and then saponified and extracted as in the analysis of milk. Margarine was saponified by shaking overnight with 1% ethanolic pyrogallol and 80% KOH. Water and ethanol were added to the digest before extraction. Extracts from formula and margarine were chromatographed as milk except, before HPLC, the extract was dissolved in isopropanol-hexane (1 + 99) and passed through 5 cm alumina in a Pasteur pipet, and the concentration of isopropanol in the first high performance liquid chromatographic (HPLC) solvent system was halved to improve the separation of vitamin D from other absorbing lipids. Usually several peaks were obtained during the final HPLC analysis, and the identification of vitamins D2 and D3 was less certain than in the analysis of milk. The coefficients of variation for formula and margarine were 6% (5 replicates) and 9% (6 replicates), respectively.
Screening Test for Sulfamethazine and Sulfathiazole in Swine Liver
Authors: Parks Owen W 
Published: February 2020

Abstract
A screening method is described for estimation of sulfamethazine and sulfathiazole residues in swine livers. Tissues are homogenized with CHCl3-ethyl acetate (1 + 1). The drugs are extracted from the organic solvent with pH 10 carbonate buffer and back-extracted into dichloromethane, as an ion-pair with tetrabutylammonium hydroxide, without pH adjustment. Following evaporation of the solvent, the residue is dissolved in methanol, subjected to thin layer chromatography, and detected by the Bratton- Marshall reaction. Recoveries of sulfamethazine and sulfathiazole, determined by high pressure liquid chromatography, were 50.8 and 42%, respectively, with coefficients of variation of 4.2 and 4.7%.
Simple, Low-Cost Method for Determination of Selected Chlorinated Pesticides in Fat Samples
Authors: Waliszewski Stefan M , Szymczyński Grzegorz A 
Published: February 2020

Abstract
A method is described for the quantitative and qualitative determination of selected chlorinated pesticides in fat samples. Pesticide residues are extracted with petroleum ether and separated from fat with concentrated H2SO4 instead of the commonly used adsorbents Florisil, alumina, or silica gel. Residues were analyzed by gas chromatography with electron capture detection. Recoveries of fortified samples were approximately 100%.
Gas-Liquid Chromatographic-Thermal Energy Analyzer Determination of N-Nitrosodimethylamine in Beer: Collaborative Study
Authors: Sen Nrisinha P , Seaman Stephen , Bickis Mikelis ,   Collaborators:, Castegnaro M , Ellen G , Fazio T , Fiddler W , Fine D H , Herwig W C , Issenberg P , Lacey A B , Massey R , O’Brien T , Scanlan R , Thomas G , Thomsen J 
Published: February 2020

Abstract
The GLC/TEA method for N-nitrosodimethylamine (NDMA) in beer was studied collaboratively by 13 laboratories from 7 countries. Collaborators were asked to analyze a total of 10 randomly labeled samples of beer consisting of the following duplicates: a naturally contaminated commercial beer; a beer extremely low (ca 0.1 ppb) in NDMA; and the low NDMA beer spiked with 0.5,1.9, and 5.0 ppb NDMA. The pooled repeatability and reproducibility coefficients of variation (CV) for all samples were 17% and 27%, respectively. However, when data from 2 laboratories (outliers) were omitted, the corresponding CV values improved considerably (11% and 15%, respectively). Variance analysis showed the presence of a significant laboratory-sample interaction when all data were used for analysis, but this interaction disappeared when data from the 2 outlying laboratories were excluded. The pooled percent recovery of the overall method (omitting outliers) was 101.4 ± 3.5. All the laboratories detected NDMA in the low NDMA beer. The method was adopted official first action.
Adsorption of 2,4-Dichlorophenoxyacetic Acid on Glassware as Source of Error in 2,4-D Analysis
Authors: Kan Gordon Y P , Mah Fred T S , Wade Norman L 
Published: February 2020

Abstract
Loss of 2,4-dichlorophenoxyacetic acid (2,4-D) by adsorption on Pyrex evaporating flasks and flint glass bottles was studied. 2,4-D may be quantitatively recovered by direct methylation with diazomethane in Pyrex evaporating flasks; it may also be desorbed with methylene chloride in the presence of strong H2SO4. This step must be taken when 2,4-D is transferred from one glass vessel to another to ensure accuracy of data.
International Mycotoxin Check Sample Program: Part I. Report on Laboratory Performance for Determination of Aflatoxins B1, B2, G1, and G2 in Raw Peanut Meal, Deoiled Peanut Meal, and Yellow Corn Meal
Authors: Friesen Marlin D , Garren Liliane 
Published: February 2020

Abstract
Three aflatoxin-contaminated samples (raw peanut meal, deoiled peanut meal, and yellow corn meal) were analyzed by 121 laboratories in 31 countries. Sufficient data were obtained to permit a statistical comparison of the performance of laboratories using the BF, CB, and EEC methods and those using high performance liquid chromatography (HPLC) for quantitation. No significant differences were found between means for laboratories using these 4 methods for the analysis of raw peanut meal or yellow corn meal. However, for deoiled peanut meal, means were significantly different for laboratories using the BF method compared with the CB or EEC methods for B1 and B2, and for laboratories using the CB method compared with HPLC methods for G2.
High Performance Liquid Chromatographic Quantitation of Aflatoxin Metabolites in Animal Tissues
Authors: Gregory Jesse F 
Published: February 2020

Abstract
A previously reported reverse phase high performance liquid chromatographic (HPLC) procedure was modified to permit the determination of the parent aflatoxins and various free and conjugated metabolites in animal tissues. The modified procedure was based on HPLC analysis of duplicate portions of a sample extract which had been prepared with and without treatment with trifluoroacetic acid (TFA). TFA catalyzes the conversion of aflatoxins G1, B1, M1, and Q1 to the fluorescent derivatives G2a, B2a M2a, and Q2a. Aflatoxicol, which exhibited a sharp fluorescent peak in its native state, eluted as a tailing peak with weaker fluorescence following TFA treatment. Acid hydrolysis of the aqueous phase of tissue samples permitted the analysis of water-soluble conjugated forms of the various aflatoxins. Analysis of fluorescence spectra of manually collected HPLC fractions qualitatively supported the accuracy of the method. Representative data on the distribution of aflatoxins in turkey liver following ingestion of an experimentally contaminated ration are presented.
Gas-Liquid Chromatographic Determination of Nonpolar Organochlorine Pesticide Residues in a Crude Vegetable Oil and Its Refinery By-Products
Authors: Young Susan J V , Kamps Laverne R 
Published: February 2020

Abstract
A crude soybean oil, several of its refinery by-products (described as soapstock, deodorizer distillate, and clabber stock), and the completely refined oil were analyzed for pesticide residues. Fourteen organochlorine pesticides and pesticide metabolites were found in the deodorizer distillate; 5 of these were also found in the clabber stock. Levels in these byproducts ranged from 0.3 to 8 ppm. Only endrin and dieldrin were detected in the crude oil at levels of 0.01 and 0.05 ppm, respectively. Forty to 150 times these levels were found in the deodorizer distillate and clabber stock. Pesticide residues were not detected in the refined oil or in the soapstock at limits of detection for dieldrin of about 0.01 and 0.1 ppm, respectively. The method used by the Food and Drug Administration to analyze fats and oils for multiple organohalogen pesticide residues was inadequate for the extraction of pesticide residues from vegetable oil refinery by-products. The method used to analyze the crude vegetable oil and the refinery by-products involved dissolution of the oil samples in ethyl acetate- toluene, filtration if necessary, cleanup by gel permeation chromatography, and then Florisil column chromatography. The oil was isolated from aqueous-oil mixtures by extraction with hexane before analysis. The crude soybean oil was fortified with 12 organohalogen pesticides and Aroclor 1254 at levels of 0.5-3.7 ppm. Recoveries ranged from 83 to 102%.