bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thin Layer Chromatographic Determination of Aflatoxins in Wine
Authors: Takahashi David M 
Published: February 2020

Abstract
A thin layer chromatographic (TLC) method is described for the determination of aflatoxins B1, B2, G1, and G2 in wine. Aflatoxins are extracted from wine with methylene chloride and the concentrated sample extract is subsequently cleaned up on a silica gel-alumina column prior to TLC analysis. The recoveries of B1, B2, G1, and G2 from 13 samples of various wines at the spiked levels of 2 μg/L (B1 and G1) and 0.4 μg/L (B2 and G2) were approximately 90–100%, as measured visually. The proposed method is sensitive to at least 0.25 μg aflatoxin/ L wine.
Vitamin A in Mixed Feeds, Premixes, and Foods: Development of Method
Authors: Parrish Donald B 
Published: February 2020

Abstract
The present official final action method for determining vitamin A in feeds, 39.008–39.013, was simplified where possible and modified to provide alternative procedures so that it could be used to analyze different types of feed and food products. Among the changes were the following: making fewer extractions, solution transfers, and dilutions to volume; using smaller aliquots; and eliminating chromatography. There was less change in the method for samples of low vitamin A content and those containing carotenoid pigments. A biopotency test was added to provide a basis for converting analytical values of vitamin A stated in μg to USP units.
Polarographic Determination of Niacinamide in Multivitamin Preparations
Authors: Taira Albert Y 
Published: February 2020

Abstract
Niacinamide is extracted from multivitamin preparations with sodium bicarbonate solution. The extract is mixed with Celite and packed into a chromatographic column. The vitamin is eluted with 10% re-propanol in ether and the eluate is evaporated to dryness in the presence of hydrochloric acid. The residue is dissolved in potassium chloride solution and diluted to volume. The polarogram, from –1.40 to –1.90 v, is recorded on a polarograph equipped with a dropping mercury electrode and an H-cell with a saturated calomel reference cell. Additional assays with chemical and microbiological methods showed comparable results. The method is sensitive to 2 mg niacinamide.
Collaborative Study of Clopidol in Chicken Tissues and Eggs, Using Gas-Liquid Chromatography
Authors: Leroy Bjerke E , Herman James L 
Published: February 2020

Abstract
Ten collaborators participated in a study of an improved method for determining residues of the coccidiostat clopidol (3,5-dichloro-2,6- dimethyl-4-pyridinol) in chicken tissues and eggs. Tissues are extracted with methanol and the extract is cleaned up with columns of alumina and anion exchange resin. After methylation with diazomethane reagent, clopidol methyl ether is determined by gas chromatography with electron capture detection. The method is applicable to levels as low as 0.1 ppm in chicken tissues and 0.05 ppm in eggs. Results from 9 collaborators gave an average recovery of 84% from muscle, 90% from liver, and 84% from eggs. Results from an unknown sample of each substrate were excellent. The method has been adopted as official first action.
Fluorometric Determination of Diethylstilbestrol at Low Levels in Animal Feeds
Authors: Ponder Carl 
Published: February 2020

Abstract
A fluorometric method has been developed to determine diethylstilbestrol (DES) at the 5 ppb level in liquid and dry animal feeds. DES is extracted from the feeds, using a mixture of acetone-isoamyl alcohol (1+1) after an initial treatment with acetic acid-ethylene glycol (1+4). Solvent partitioning further isolates the DES which is irradiated in a buffered solution with ultraviolet light to form the neutral phenanthrenedione derivative. The dione is extracted from an alkaline solution and converted to the phenolic phenanthrenediol derivative in an acidified bisulfite solution. The diol derivative is further isolated by solvent partitioning and is determined fluorometrically in methanol. Recoveries on 7 samples (examined by 5 analysts) spiked with SO ppb DES ranged from 70 to 117%. Recoveries on 2 samples spiked at 5.5 and 5.9 ppb were 89 and 100%, respectively. The recoveries on 2 samples of commercial feed, prepared to contain 5.6 ppb DES by adding a calculated amount of blank feed, were 91 and 95%.
Evaluation of Hektoen Enteric Agar for the Detection of Salmonella in Foods and Feeds
Authors: Bisciello Neil B , Schrade John P 
Published: February 2020

Abstract
Over the past 2 years in our laboratory, Hektoen enteric (HE) agar was evaluated as a medium for the detection of salmonellae in foods and feeds. HE agar was used in conjunction with brilliant green, bismuth sulfite, and Salmonella-Shigella agars, according to AOAC methods. More than 2000 samples representing over 40 different products were tested and the cultural results on all media were compared. HE agar was more efficient than the other media for recovery of salmonellae in contaminated samples and showed a lower number of false positives. HE agar is a highly selective medium for Salmonella species and we recommend that it be evaluated for incorporation into the AOAC methods.
Automated Method for the Analysis of Thiamine in Milk, with Application to Other Selected Foods
Authors: Kirk James R 
Published: February 2020

Abstract
An automated method for the determination of thiamine in milk and food products is described. The procedure involves the oxidation of thiamine to thiochrome, extraction into isobutanol, and fluorescence measurement. The automated procedure gave a mean recovery value of 92.7% and a standard deviation of ±0.7%, compared to 83.3±2.5% for the manual procedure. The procedure is simple, rapid, and accurate, and markedly shortens the average time for analysis.
Isolation, Detection, and Quantitation of Zearalenone in Maize and Barley
Authors: Mirocha Chester J , Schauerhamer Beth , Pathre Sadanand V 
Published: February 2020

Abstract
A versatile method for the detection of zearalenone is described, employing options of either thin layer chromatography (TLC), gas-liquid chromatography (GLC), ultraviolet chromatography, GLC-mass spectrometry, or combinations of all of these. Zearalenone is extracted with either a Soxhlet apparatus or the more rapid and convenient batch extraction technique with equal efficiency. Cleanup of the extract involves either a base (NaOH) treatment and partition with water or an acetonitrile- petroleum ether partition. A chloroformethanol (97+3) solvent system is used for analysis by TLC with confirmation by fluorescent properties. The limit of detection on the TLC plate is 0.1 μg, while the sensitivity for the TLC method is about 50 ppb. Best quantitative results are obtained by analytical procedures involving GLC. The limit of sensitivity by GLC is less than 50 ppb. The derivatives dimethoxyzearalenone and methyl oxime-di- TMS-ether-zearalenone are prepared to confirm the presence of zearalenone. Zearalenone can also be analyzed both qualitatively and quantitatively by ultraviolet spectrophotometry. For quantitation, a standard curve is constructed of the absorption at 274 nm. The limit of detection is between 0.1 and 0.5 μg/ml. Analysis by combination GLC and mass spectroscopy is also described along with analysis by multiple ion detection. Per cent recovery is 83.5±7. The method described is suitable for analysis of the concentrations of zearalenone normally encountered in nature and thought to be significant.
Spectrophotometric Determination of Piperazine in Pharmaceutical Preparations
Authors: Baggi Tulsidas R , Mahajan Surinder N , Ramana Rao G 
Published: February 2020

Abstract
A solution of piperazine or its salts is heated with 2,6-dichloroquinonechlorimide, and the color produced is measured at 525 nm to obtain the concentration of piperazine. The color developed obeys Beer’s law in the concentration range of 6.4–51.2 μg piperazine/ml. The results of the proposed method agree with those of the official methods within ± 1.0% for piperazine and its salts and ± 2.0% for formulations. The method is rapid and precise and gives reproducible results. It is suitable for the analytical control of piperazine or its salts and their formulations.
Identification of Impurities in Illicit Methamphetamine Samples
Authors: Barron Robert P , Kruegel Alice V , Moore James M , Kram Theodore C 
Published: February 2020

Abstract
Three impurities have been identified in illicit methamphetamine samples. One of these, N-formylmethamphetamine (N-methyl-N-(α-methylphenethyl) formamide), is an intermediate in the synthesis of methamphetamine by the Leuckart reaction. The remaining 2, ,α,α’-trimethyldiphenethylamine and α-benzyl-N-methylphenethylamine, are by-products of methamphetamine synthesis. Ultraviolet, infrared, nuclear magnetic resonance, and gas chromatographic- mass spectral techniques were used to identify these compounds. The data obtained are discussed and synthetic pathways are postulated to explain the presence of each compound in samples of methamphetamine.
U.S. Department of Agriculture Nutrient Data Bank
Authors: Murphy Elizabeth W , Watt Bernice K , Rizek Robert L 
Published: February 2020

Abstract
As part of its long-standing program for providing representative data on the nutrient composition of foods, the U.S. Department of Agriculture is developing a Nutrient Data Bank which, compared with the past, will have a far greater input of data from industry, an increase in the amount of data available for computer use, and an increase in the speed of releasing data to the public. A data submission form has been developed for use by those wishing to contribute data to the data bank. A coding system for classifying and retrieving data is in preparation. When operational, the Data Bank should provide information of use in food labeling. To help in evaluating data to be included in the Data Bank, a comparison of analytical methods used in determining minerals was made. This review showed that results by emission spectroscopy frequently did not agree well with data from other methods. Proper calibration and care in making determinations are needed for all methods, and especially for emission spectroscopy. There is a need for more certified reference samples of foods, to be used in establishing the accuracy of analytical procedures.
Introductory Study of Scanning Electron Microscopy of Elytral Fragments of Stored Product Beetles
Authors: Brickey Paris M , Gecan John S 
Published: February 2020

Abstract
Eleven stored product beetles were examined for surface features of the beetle elytron, using a scanning electron microscope. The 3 characteristics, sculpturing pattern, setae, and setal pits, were well defined and could be used to distinguish the species examined. The scanning electron microscope can give 3-dimensional images at magnifications up to 20,000 ×, in contrast with the light microscope which has a maximum magnification of 1000 ×.
Determination of N-(4-Chlorophenyl)-N´-(2,6-difluorobenzoyl)-urea in Milk by High-Speed Liquid Chromatography
Authors: Corley Calvin , Miller Richard W , Hill Kenneth R 
Published: February 2020

Abstract
A rapid and sensitive method of analysis in which high-speed liquid chromatography was used with ultraviolet absorption detection was developed for determining residues of Thompson- Hayward TH 6040 (N-(4-chlorophenyl)-N'- (2,6-dinuorobenzoyl)urea) in cows' milk. The larvicide is extracted from whole milk with ethyl acetate, and the lipids are removed by partitioning between hexane and acetonitrile. After evaporation of the acetonitrile, the residue is dissolved in ethanol, and aliquots are injected into a liquid chromatograph, using methanol-water (1+1) as the mobile phase in a packed column. Recovery of TH 6040 from cows' milk is essentially quantitative, and no interfering substances appear on the chromatogram. The lowest detectable level was 10 ng. Milk from a cow fed 1 mg larvicide/kg body weight daily in the diet was analyzed by this procedure, and no detectable residues (&lt;0.1 ppm) were found over a 15 week sampling interval.
Determination of 2-Propanol Residue in Some Fruits Dewaxed with Alcohol Vapors
Authors: Calhoun Mary JO , Dellamonica Edward S 
Published: February 2020

Abstract
A quantitative method is described for the determination of 2-propanol in apples and grapes exposed to alcohol vapors. This method was also applied to eggplants. The procedure includes the following: homogenizing the product in a blender and filtering the slurry; weighing an aliquot of the filtrate into a serum bottle containing 1-propanol, the internal standard; equilibrating the liquid and gas phases; sampling the headspace vapor and analyzing by gas-solid chromatography (GSC). A time-temperature study using model alcohol systems indicated that equilibration at 65 °C for 60 min gave the most constant peak area ratios of 2- propanol: 1-propanol as measured by GSC. The peak area ratio was directly proportional to the concentration of 2-propanol over the range 0舓180 ppm. The recovery of 2-propanol added to untreated apple juice was excellent within this range.
Protein Analysis of Feeds, Using a Block Digestor
Authors: Hambleton Larry G , Noel Rodney J 
Published: February 2020

Abstract
A method for the determination of proteins in feeds, utilizing the Technicon® BD-20 block digestor, has been developed. Twenty feed samples are weighed directly into the 250 ml tubes and digested for 35 min after clearing. The temperature of the solution during the digestion and the uniformity of temperature between various holes in the block were determined. The effect of air currents over the tubes was also studied. Six replicate determinations on cottonseed meal, blood meal, soybean meal, tryptophan, and 2 feed samples are reported and compared to results on the same sample analyzed by the official final action Kjeldahl method; good agreement was shown between the methods. The accuracy of the block digestor was confirmed by analyzing 40 routine feed samples by both the block digestor and Kjeldahl methods; results did not show a significant difference when compared by Student's t-test at the 5% level.
Determination of Moisture in Molasses by the Karl Fischer Method, Using Formamide as the Solvent
Authors: Kviesitis Boris 
Published: February 2020

Abstract
The use of formamide as a solvent for the determination of moisture in molasses by the Karl Fischer method reduces the time required for titration which, in turn, increases the accuracy of the method. Formamide has the advantage of dissolving molasses without increasing its water content. It is recommended that the use of formamide in the determination of moisture by the Karl Fischer method be submitted to collaborative study.
Correlation Between Physical Properties and Field Performance of Insecticidal Emulsion Sprays
Authors: El-Refai Abd R , El-Attal Zakaria M , Said Ali A A 
Published: February 2020

Abstract
Commercial and laboratory-prepared insecticide emulsiliable concentrates were tested in the laboratory and in the field to study their physical and chemical characteristics. Distribution of spray emulsion and retained deposits of active ingredients on leaf surfaces are directly related to emulsion stability, amount of emulsifier, and droplet size of spray emulsion. Thus the laboratory tests described for the measurement of the latter 3 properties can be performed before extensive field trials are conducted.
Colorimetric Determination of Mestranol in Combination with Ethynodiol Diacetate
Authors: Wu John Y P 
Published: February 2020

Abstract
Mestranol in combination with ethynodiol diacetate, an oral contraceptive formulation, is isolated from the sample on a partition chromatographic column prior to colorimetric determination. The color reaction which is specific for estrogens is formed by shaking an aliquot of the heptane eluate of mestranol with a 30% methanol-sulfuric acid solution. A collaborative study of the method gave results of 99.8% of added mestranol for the simulated mix and 100.7% of labeled mestranol for the commercial tablet. The method has been adopted as official first action.
Methodology for Enteropathogenic Escherichia coli
Authors: Mehlman Ira J , Simon Nicholas T , Sanders Arvey C , Fishbein Morris , Olson Joseph C , Read Ralston B 
Published: February 2020

Abstract
Pathogenic biotypes of Escherichia coli grow poorly at temperatures greatly different from that of the host. Percentages quantitatively recovered at 42.0, 44.0, 44.5, and 45.5°C in lauryl tryptose broth were 100, 76, 76, and 42, respectively. Corresponding values for 175 strains of varied origin were 98, 89, 82, and 65%. Maximal growth temperature is dependent upon medium. Lauryl tryptose and elevated coliform broths were equivalent in the recovery of small inocula (100 cells/ml) at 41.5–44.5°. Mac-Conkey, enteric enrichment, and Gram-negative broths were inhibitory at corresponding values. Growth at elevated temperature in nutrient broth is enhanced by carbohydrate. Standard lactose enrichment media fail to recover slow lactose fermenters. An acidified glutamic acid medium was unsuitable for recovery of E. coli. The data suggest modification of standard temperatures for the recovery of pathogenic biotypes. Previously recommended analytical methods have been simplified and supplemented. The enhancement of motility in indole-nitrite broth at 35°C is recommended. A 4-tube semiquantitative test is offered for tentative identification of somatic and capsular antigens. Inclusion of Alkalescens-Dispar strains is warranted by their pathogenic behavior. Examination in Shigella and Alkalescens-Dispar sera is required to cover the dysentery-like biotypes. Pathogenic potential cannot be inferred from serotype.
Collaborative Study of Wet and Dry Ashing Techniques for the Elemental Analysis of Plant Tissue by Atomic Absorption Spectrophotometry
Authors: Isaac Robert A , Johnson William C 
Published: February 2020

Abstract
Seven laboratories participated in a collaborative study of wet ashing of plant material with a nitric-perchloric acid mixture and dry ashing at 500°C in order to determine the elements calcium, copper, iron, magnesium, manganese, potassium, and zinc by atomic absorption spectrophotometry. Five different homogeneous leaf tissue samples were analyzed and a synthetic standard solution containing all of the elements studied was included to evaluate sample preparation errors independent of instrument errors. The results indicated that plant tissue preparation by either wet or dry ashing gave similar elemental composition results for the tissues analyzed. The wet and dry ashing techniques have been adopted as official first action.
Limited Collaborative Study of an Optional Method for the Isolation of Light Filth from Fig and Fruit Paste
Authors: Kvenberg John E , Eisenberg William V , King Alfred C 
Published: February 2020

Abstract
The present official first action method for the isolation of light filth from fig and fruit paste, 44.083(a), occasionally yields excessive plant debris on filter papers, which causes difficulty in effectively counting insect filth. The proposed method provides the option of an additional flotation of trapped off material in a Corning percolator. This revision has been adopted as official first action as an alternative to 44.083(a).
Removing the Interference of DDT and Its Analogs in the Analysis for Residues of Poly chlorinated Biphenyls
Authors: Trotter William J 
Published: February 2020

Abstract
A micro scale procedure is described for quantitatively separating polychlorinated biphenyls (PCBs) from DDT and its analogs. DDT and TDE are initially dehydrochlorinated with ethanolic KOH to their respective olefins, DDE and TDE-olefin (l-chloro-2,2-bis(p-chlorophenyl) ethylene). The olefins are then oxidized by Cr03 in acetic acid to the more polar dichlorobenzophenone. PCBs are eluted from a micro Florisil column with petroleum ether. Typical recoveries in the ppm range (based on a 5 g sample) were &gt;80% for Aroclors 1254 and 1260. Recoveries generally were poorer with Aroclors of lower chlorine content and decreased with decreasing quantity of Aroclor present. The DDT group was not quantitatively determined; recoveries averaged ≥60% for the DDT group in the ppm range (based on a 5 g sample). The procedure was successfully applied to samples of Lake Michigan chubs containing residues of PCBs and the DDT group and to extracts of human serum fortified with Aroclors and the DDT group.
Limitation on the Use of Antimony Pentachloride for Perchlorination of Poly chlorinated Biphenyls
Authors: Trotter William J , Young Susan J V 
Published: February 2020

Abstract
Two contaminants are present in commercially available antimony pentachloride (SbCl5) used to perchlorinate polychlorinated biphenyls (PCBs) to decachlorobiphenyl (DCB). DCB is found in the SbCl5 perchlorination reaction blank in which no PCBs were added. Bromononachlorobiphenyl (BNCB) is found after use of SbCl5 to perchlorinate PCBs. Levels of DCB found in the SbCl5 reaction blanks from various distributors ranged from 8 to 972 ng DCB/ml SbCl5. The relationship of the formation of BNCB to amounts of various PCB Aroclors perchlorinated is examined.
Fluorometric Determination of Nitrite in Cured Meats
Authors: Coppola Elia D , Wickroski Alphonse F , Hanna J. Gordon 
Published: February 2020

Abstract
An indirect fluorometric method for determining sodium nitrite in meat products is presented. The extracted sodium nitrite is consumed in a diazotization reaction with a measured excess of sulfanilic acid. Fluorescamine, which acts selectively with primary amines such as sulfanilic acid, is a fluorogenic reagent for the excess amine. The amine consumed, calculated by difference from the total originally present, is directly related to the sodium nitrite content of the sample. Interferences from amino acids and soluble proteins in the meat extract are eliminated by judicious use of a secondary peak in the fluorescence spectra (436 nm excitation, 495 nm fluorescence) combined with measurement at low pH (3.30). The recoveries of sodium nitrite ranged from 83.2 to 99.6% with an average of 93.4% and a standard deviation of ±5.28% for 11 determinations.
Crude Fiber Analysis Without Asbestos
Authors: Holst David O , Gehrke Charles W 
Published: February 2020

Abstract
Hoist reported on new filtration equipment that incorporates a vacuum manifold with an air metering device that provides the operator precise control over the vacuum applied. This equipment, which eliminated asbestos, was used in a study on acid-detergent fiber, cellulose, and lignin determinations. Improved precision and good accuracy were obtained with less time involved for each analysis. One analyst can complete 72 determinations in an 8 hr day. The data were in good agreement with the official AOAC method. Ten collaborative Association of American Feed Control Officials check feed samples (1973) were analyzed independently twice with this method and the results were in good agreement with the reported grand average of the data for the check feed samples. An average range of 0.066% fiber was obtained with an average difference from the reported grand average of +0.0195% fiber. In other experiments, over a 3 week period, 5 forage samples with a fiber content of 3–30% were analyzed singly each week by the reported method and the official final action AOAC method, 7.050–7.054. The average range for the AOAC method was 0.54% and for the crude fiber method without asbestos 0.29%. Important advantages of this method are precision, accuracy, rapidity, and the elimination of asbestos fibers and the hazardg associated with their inhalation.