bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methodology for Recovery and Identification of Enteropathogenic Escherichia coli
Authors: Mehlman Ira J , Sanders Arvey C , Simon Nicholas T , Olson Joseph C 
Published: February 2020

Abstract
Pathogenic biotypes of E. coli have been incriminated in food-borne illness. Sensitivity to elevated temperature and atypical behavior precluded assessment of their incidence. A tentative recovery procedure involves direct streak, preenrichment in MacConkey broth at 35°C and transfer to lauryl tryptose broth with incubation at 44°C, and pre-enrichment in nutrient broth at 35°C and transfer to enteric enrichment broth with incubation at 41.5°C. Serological examination of enrichment simplifies analysis. Levine's eosin methylene blue agar is recommended for rapid lactose fermenters; MacConkey's agar should be used for slow fermenters. Primary screening reactions include H2S, arabinose, urease, o-nitrophenyl-β-D-galactosidase, and indole. Secondary reactions comprise lysine decarboxylase, Voges-Proskauer (at 22°C), and other tests required to differentiate E. coli from Citrobacter diver sus, C. freundii, Enterobacter hafniae, Klebsiella pneumoniae, and Shigella species. Slide and tube agglutination reactions are necessary for identification of somatic and capsular antigens. Enhancement of motility by serial passage in a semisolid medium is essential for recognition of flagellar antigen. Confirmatory reactions include nitrate reduction, cytochrome oxidase, and Gram stain. Potentiality for quantitation, applicability to animal pathogens, and ecological samples are discussed.
Thin Layer Chromatography and in situ Fluorometry for the Quantitative Determination of Dimethoate and Malathion in Lettuce
Authors: Macneil James D , Maclellan Brian L , Frep Roland W 
Published: February 2020

Abstract
Dimethoate and malathion in spiked lettuce extracts are separated by thin layer chromatography on silica gel followed by in situ fluorometric determination. Fluorescence is produced by spraying the developed chromatogram with a palladium chloride-calcein reagent. A ligand exchange occurs in which the palladium complexes preferentially with the sulfur in the pesticide, releasing the metal-fluorochromic indicator calcein. For dimethoate, a linear response is obtained for 10—100 ng/spot and the need for a preliminary cleanup procedure is eliminated.
Qualitative Determination of Coal Tar Dyes in Alcoholic Products by Thin Layer Chromatography
Authors: Martin Glenn E , Figert Donald M 
Published: February 2020

Abstract
Thin layer chromatography can be used to determine coal tar dyes in alcoholic products. Hie dyes most commonly found in distilled spirits are FD&C Yellow No. 5, FD&C Red No. 2, and FD&C Red No, 4.
Determination of Siduron in Fertilizers by Flame Ionization Gas-Liquid Chromatography
Authors: Ealy Daniel B , Gorman Robert R , Kaiser Francis R , Scroggs Robert E 
Published: February 2020

Abstract
Siduron is formulated with fertilizers at about 2.4%. The herbicide is extracted with CHC13, using a magnetic stirrer, p,p'-methoxychlor is added as an internal standard, and the relative GLC peak heights are determined. The GLC column is 3% JXR on Gas-Chrom Q, and the mode of detection is hydrogen flame ionization.
Spectroscopic and Chromatographic Identification of Dimethoxyamphetamines
Authors: Bailey Keith , Legault Donald , Verner Denise 
Published: February 2020

Abstract
The qualitative analysis of the 6 isomeric dimethoxyamphetamines and their hydrochloride salts is described. Their ultraviolet spectra are insufficiently different for distinction, but mass, proton magnetic resonance, and infrared spectra allow a positive identification to be made, and reference spectra are provided. The application of gas-liquid and thin layer chromatographic systems for the analysis is discussed.
Spectrophotometric Method for Simultaneous Determination of Anthocyanogens and Catechins (Tanninogens)
Authors: Dadic Miroslav 
Published: February 2020

Abstract
An earlier method for the simultaneous determination of anthocyanogens and catechins (tanninogens) in beer, wine, and brewing materials has been modified to include Polyclar AT and Polyamide Woelm 400 as the adsorbents. The results are presented, along with the values obtained using Nylon-66 for comparison. Nylon-66 and Polyamide Woelm 400 are the adsorbents of choice, yielding similar results, while Polyclar AT gives lower tanninogen values. The method is further applied to determine the anthocyanogen and catechin contents of solids, without the use of tanninogen adsorbents. Lyophilized beer, “testinic acid,„ and humic acid samples were thus analyzed. The present method is recommended for the simultaneous determination of catechins and anthocyanogens in any tanninogen-containing materials.
Improved Colorimetric Determination for Furfural in Citrus Juices
Authors: Dinsmore Howard L , Nagy Steven 
Published: February 2020

Abstract
An improved colorimetric method for furfural in citrus juices, which is based on the well known aniline-acetic acid reaction with furfural (Stenhouse reaction), is described. Addition of SnCl2 and HCl yielded higher intensity and improved color stability. The reagent giving the best results contained 1% SnCl2, 0.6N HCl, and 10% aniline in glacial acetic acid.
Determination of Pentachlorophenol in Natural and Waste Waters
Authors: Chau Alfred S Y , Coburn John A 
Published: February 2020

Abstract
A sensitive and reliable method suitable for routine determination of pentachlorophenol (PCP) in natural and waste waters is reported. PCP is extracted from the preserved sample with benzene and from the benzene into a potassium carbonate solution. The addition of acetic anhydride to the aqueous solution produces the acetate derivative of PCP, which is extracted in hexane and analyzed by electron capture gas-liquid chromatography. The analysis of PCP in lake water and sewage effluent is presented, along with the retention times of 17 other phenolic acetates. By this procedure, as little as 0.01 ppb PCP in 1 L water can be determined.
Confirmation of Pesticide Residue Identity. VI. Derivative Formation in Solid Matrix for Confirmation of Heptachlor and Endosulfan Isomers
Authors: Chau Alfred S Y , Terry Ken 
Published: February 2020

Abstract
An alternative method for the confirmation of heptachlor residue identity is described. This method entails derivation in a solid matrix prepared from alumina and sulfuric acid to obtain a single derivative in almost quantitative yield.
Gas-Liquid Chromatographic Determination of Sodium Fluoroacetate
Authors: Stahr Henry M , Buck William B , Ross Paul F 
Published: February 2020

Abstract
Sodium fluoroacetate is extracted from biological samples, esterified, and determined by GLC, using a Resoflex column. The identity of the rodenticide is confirmed by a fluoride electrode procedure or by GLC/MS. The method can detect as low as 0.1 μg sodium fluoroacetate.
Rapid Screening Method for Analysis of Chlorinated Pesticide and Polychlorinated Biphenyl Residues in Fish
Authors: Ronald Erney D 
Published: February 2020

Abstract
Ground fish is dried with anhydrous Na2S04, packed into a chromatographic column, and extracted with petroleum ether. An aliquot of extract is cleaned up on miniature chromatographic columns of Florisil and silica gel. GLC analyses of a variety of fish samples by both the proposed procedure and multipesticide residue methods gave comparable results. The described procedure is rapid, economical, and applicable to routine analysis of fish samples.
Confirmation of Pesticide Residue Identity. VII. Solid Matrix Derivation Procedure for the Simultaneous Confirmation of Heptachlor and Endrin Residues in the Presence of Large Quantities of Polychlorinated Biphenyls
Authors: Chau Alfred S Y 
Published: February 2020

Abstract
Heptachlor is converted almost quantitatively (90%) to 1-hydroxychlordene, and endrin is converted to the ketone in 75% yield. Because of the diversity in polarity of these derivatives and the unreacted polychlorinated biphenyls, they are clearly separated. This procedure has been applied routinely to extracts obtained from fish, sediment, and water samples.
Colorimetric Method for Estimation of Carbaryl and Its Residues on Grains
Authors: Rangaswamy Jois R , Majumder Suvendu K 
Published: February 2020

Abstract
A new colorimetric method for the estimation of carbaryl, 1-naphthyl JV-methylcarbamate, based on its reaction with diazotized o-toluidine, has been described. The absorption maximum of the red color formed is measured at 520 nm. The method is sensitive to 0.1 fig carbaryl/20 g sample, with an estimation limit of 1 /ig, and can be applied to 10% dust formulations of carbaryl.
Quantitative Gas-Liquid Chromatographic Determination of Ethyl Esters and Isoamyl Acetate in Whiskies and Rums and Confirmation by Mass Spectrometry
Authors: Martin Glenn E , Dyer Randolph H , Buscemi Peter C 
Published: February 2020

Abstract
A gas chromatographic method is described for determining isoamyl acetate and the ethyl esters caproate, caprylate, caprate, laurate, myristate, and palmitate in whiskies (Scotch and bourbons, light and Canadian) and rums (Caribbean and New England). A 4 0% ethanol solution saturated with salt was reduced to 5—10% ethanol by adding a saturated salt solution and extracting 3 times with pentane. For whiskies, the isoamyl acetate ranged from none detected (ND) to 4.5 ppm, ethyl caproate from ND to 3.9 ppm, ethyl caprylate from 0.9 to 16 ppm, ethyl caprate from 1.1 to 20.6 ppm, ethyl laurate from ND to 7.5 ppm, ethyl myristate from ND to 10.0 ppm, ethyl palmitate from ND to 8.0 ppm, and ethyl acetate from 69.4 to 717 ppm. The Caribbean rums showed the lowest concentration of ethyl esters and the New England rum showed the greatest concentration of these ethyl esters (C6 through C16). This method did not detect below 0.1 ppm. The identity of these esters was confirmed by gas-liquid chromatography- mass spectrometry.
Collaborative Study of the Determination of Lead in Alkyd and Latex Paints
Authors: Porter Warren K 
Published: February 2020

Abstract
A collaborative study was conducted on the determination of lead in alkyd and latex paints by atomic absorption spectrophotometry after nitric acid digestion. Fourteen samples of blank paints and paints with known additions of lead were analyzed by 10 collaborators. Coefficients of variation from 4 to 16% were obtained for 0.33 to 0.02% lead in the paint solids. The statistical analysis indicates minimal bias and adequate precision for the analysis of lead in paints at the current regulatory limit (0.5% in the paint solids or dry paint film). The method has been adopted as official first action.
Collaborative Study of the Infrared Spectrophotometric Determination of Aldicarb in Formulations
Authors: Mcdermott William H 
Published: February 2020

Abstract
An infrared method for the determination of aldicarb in formulations was studied collaboratively. The carbamate carbonyl infrared absorption band at 5.75 μm of the aldicarb is measured after extraction of the aldicarb from the formulation with methylene chloride in a Soxhlet extractor. A statistical evaluation of the data by the technique of matched pairs at the 10% level shows a random standard deviation of 0.21%, a systematic standard deviation of 0.26%, and an overall standard deviation of 0.43%. The method has been adopted as official first action.
Determination of Carbaryl in Pesticide Formulations and Fertilizers by High-Pressure Liquid Chromatography
Authors: Colvin Billy M , Engdahl Barbara S , Hanks Alan R 
Published: February 2020

Abstract
A simple and rapid method is described for the determination of carbaryl in pesticide formulations by high-speed liquid chromatography. Carbaryl is extracted with 10% methanol in chloroform and pentachlorophenol is added as an internal standard. The sample extract is injected into a liquid chromatograph, and peak height ratios are used for quantitative measurement. Chromatography is complete in 8 min. The method compares favorably with infrared, near infrared, and colorimetric procedures for carbaryl.
Use of the AOAC Fluorometric Method for Selenium in Plants for the Analysis of Papers and Tobaccos
Authors: Leisure Orie W , Olson Oscar E 
Published: February 2020

Abstract
Additional studies of the AOAC fluorometric method for selenium, 3.074—3.078, were undertaken to determine if the method is applicable to paper and processed tobacco samples. The recovery of added selenium, the use of oxygen flask combustion, and neutron activation analysis without chemical separation of the element were studied. The studies all indicate that the results with the fluorometric method are not too low. It is concluded that this method is satisfactory for the analysis of processed tobaccos. It is less useful for the analysis of paper, since its selenium content is often about 0.02 ppm, the lower limit of the sensitivity of the method.
Absorption-Elution Testing for ABO Blood Group Factors: Preliminary Collaborative Study
Authors: Fox Richard H 
Published: February 2020

Abstract
Four laboratories participated in a study of an absorption-elution method for the determination of ABO factors in dried human blood. In the method studied, normal saline solution is used for the incubation for elution and whole blood cells are added after incubation; thus, the whole cells are not subjected to excessive temperature for a prolonged period of time. Each collaborator received 5 dried stains of human blood on clean cotton cloth. Three of the 4 collaborators correctly typed each of the 5 samples submitted to them. The fourth did not report the A factor but did report the B factor of an AB blood stain. The data show no false grouping report. Based on the results of this study, it is recommended that the absorption-elution test be subjected to a larger collaborative study.
Isolation, Identification, and Quantitation of o-Toluenesulfonamide, a Major Impurity in Commercial Saccharins
Authors: Stavric Bozidar , Lacombe Richard , Watson Jim R , Munro Ian C 
Published: February 2020

Abstract
o-Toluenesulfonamide (o-TS) was found to be a major impurity in 9 of 10 different saccharin samples used for carcinogenicity tests in animals in various laboratories. Isolation of o-TS from sodium saccharin was achieved by extraction with ethyl acetate, and separation was accomplished by using thin layer chromatography. Saccharin samples obtained in the free acid form were first converted to their sodium salts. o-TS was identified by Rf and ultraviolet, infrared, and mass spectra. Quantitative determination of o-TS was performed by gas chromatography. The concentration of o-TS in the samples ranged from 2.5 to 5050 ppm.
Extraction and Thin Layer Chromatographic Confirmation of Urine Residues from Food Packaging Materials
Authors: Thrasher Joel J 
Published: February 2020

Abstract
A collaborative study has been conducted on a modified method for the extraction and thin layer chromatographic identification of urine residues on food packaging materials. The modifications involve changes in sample extraction equipment, prewash solvent, sample extract spotting, and plate development. In the collaborative study, 41 of 42 spiked and blank samples were identified correctly. The method has been adopted as official first action.
Gas Chromatographic Measurement of Benzoyl Peroxide (as Benzoic Acid) in Cheese
Authors: Karasz Albert B , DeCocco Frank , Maxstadt John J 
Published: February 2020

Abstract
Benzoyl peroxide bleach, added to cheese, is estimated by gas chromatographic determination of benzoic acid, its principal reduction product. Copper is added to the acidified ether extract of the cheese to reduce the residual bleach, and solvent partitioning and permanganate treatment are used for purification. The benzoic acid is transferred to chloroform containing lauric acid as an internal standard and determined by flame ionization gas chromatography, with a column containing 5% FFAP + 0.5% H3PO4 on Chromosorb W. The average recovery of added benzoyl peroxide was 82.0% and the standard deviation was 0.0128. The occurrence of benzoic acid of microbial origin in cheese poses a problem in accurately determining added benzoyl peroxide from the benzoic acid found in a sample.
Influence of Brand of Dialysis Tubing on a Quantitative Technique for Determining Alkaline Phosphatase Activity of Milk
Authors: Kleyn Dick H , Jakubowski Joseph 
Published: February 2020

Abstract
A study was conducted to determine the influence of brand of dialysis tubing on the official first action method for alkaline phosphatase activity of milk, 16.B01—16.B05. Two brands of tubing were compared: seamless regenerated cellulose tubing and membrane tubing. Analyses were performed in quintuplet on 8, 5, and 5 samples of milk containing about 0.10, 0.25, and 0.50% raw milk, respectively. Two trials were also conducted to compare the rates of dialysis, using about 0.25% raw milk. An analysis of variance of the data showed that the brand of tubing did have a significant ( P&lt; 0.05) influence on resulting absorbance values, particularly at the higher levels of phosphatase activity. Rates of dialysis were found to agree within ± 0.07 μg phenolphthalein/hr during the 3 hr incubation specified. The modified method has been adopted as official final action.
Stability-Indicating Spectrophotometry Determination of Morphine in Injectable Solutions Containing Bisulfite
Authors: Hundley Harvey K , Castillo Gabriel D 
Published: February 2020

Abstract
Morphine in injectable preparations mar undergo reaction with bisulfite when this is used as an antioxidant in the formulation. A simple chromatographic procedure has been developed for the separation of morphine from its oxidation products and from the morphine-bisulfite interaction products. Neutral or acidic impurities are removed from a pH 4.3 buffered sample by elution of a partition chromatographic column with ether. An ether solution of di-(2- ethylhexyl) phosphoric acid is then used to elute the morphine as the cationic component of the ion pair. This fraction is extracted with dilute sulfuric acid to dissociate the ion pair and transfer the morphine to the acid solution for spectrophotometric determination. Multiple analyses of a commercial morphine sulfate formulation gave 101.2±0.3% of declared. Assays by 5 analysts of another commercial preparation and a laboratory preparation gave, respectively, an average of 99.6±2.7% of declared and an average recovery of 90.4±0.5%. The latter, containing 7 mg bisulfite/ml, or 7 times as much as the commercial formulations, shows significant bisulfite-induced decomposition.
Rapid Screening Method for Examining Corn and Corn-Derived Products for Possible Aflatoxin Contamination
Authors: Barabolak Roman , Colburn Charles R , Smith Robert J 
Published: February 2020

Abstract
Aflatoxins were extracted from the sample by high-speed blending with aqueous acetone, purified with ammonium sulfate, re-extracted into benzene, evaporated to dryness, and redissolved in chloroform-acetone. The final solution was subjected to descending minicolumn chromatography through successive layers of alumina, silica gel, and Florisil, and the aflatoxin band was visualized by fluorescence. The method requires only 35—40 min, and results are semiquantitative.
Determination of Chlorophenoxy Acids in Formulations by Gas-Liquid Chromatography of Their Trimethylsilyl Derivatives
Authors: Collier Richard H , Grimes Gregory S 
Published: February 2020

Abstract
A rapid, precise, and specific method for the analysis of free acid and amine salt formulations of chlorophenoxy acids has been developed. Samples containing the amine salts are prepared by addition of dioxane and removal of the water/dioxane azeotrope by rotary evaporation. The trimethylsilyl esters are prepared by incubation of free acids or the above dry residues with N,O-his (trimethylsilyl) acetamide. The esters are chromatographed on 5% SE-30 on 80–100 mesh Chromosorb W with column temperature programming, using pyrene as an internal standard. The method has undergone a ruggedness test which showed very little sensitivity to changes in many of the chromatographic and derivatization conditions. The method was compared to the official final action infrared method for 2,4-D amine salt formulations, 6.A15–6.A19, and to a modified infrared method using the C–CI stretching band at 15.6 μm for measurement. The official method gave a relative standard deviation of 9%, while the modified infrared method and the gas chromatographic method gave relative standard deviations of 1.2 and 1.0%, respectively. The gas chromatographic method resulted in values not significantly different from those of the official method. With the modified infrared method, high results were obtained for some samples, presumably due to the presence of chlorine-containing compounds other than 2,4-D. Recovery of acids and amine salts for the gas chromatographic method is 100.5±1.0%. The method distinguishes between MCPA, MCPP, 2,4-D, 2,4- 5-T, silvex, and 2,4-DB.
Universal Chromatographic-Colorimetric Method for the Determination of Trace Amounts of Polyvinylpyrrolidone and Its Copolymers in Foods, Beverages, Laundry Products, and Cosmetics
Authors: Frauenfelder Lewis J 
Published: February 2020

Abstract
A chromatographic-colorimetric method has been developed for the determination of trace amounts of polyvinylpyrrolidone (PVP) and its copolymers in foods, beverages, laundry products, and cosmetics. Products containing the PVP are passed through a chromatographic column and the PVP is adsorbed at the top of the column. The column is prepared from silica gel if the sample is soluble in 40% acetic acid solution while Micro-Cel E is used when the sample is soluble in a 50% ethanol solution. The PVP adsorbed on the column is then treated with Vital Red dye and the PVP-dye complex thus formed is eluted with TV-methyl pyrrolidone and measured colorimetrically. From the data obtained it is apparent that the method can detect as little as 0.1 ppm with a reproducibility of ±5% of the amount present.
Chemical Analysis of Tetracycline Residues in Animal Tissues
Authors: Ryan John Joseph , Dupont Jo Anne 
Published: February 2020

Abstract
The common tetracyclines (TCs) which are used in agriculture, tetracycline, oxytetracycline, and chlortetracycline, are analyzed in animal tissues by using chemical-physical methods. Tissue from chicken, beef, pork, or fish is blended in aqueous HC1 and centrifuged. The supernate is adsorbed on an Amberlite X AD-2 column, the column is washed with water, and the TCs are eluted with methanol. For levels of TCs greater than 0.5 ppm in tissues and milk, the concentrated residue is spotted on a thin layer plate coated with kiesclguhr. The amount of TCs present on the developed plate is estimated by comparison of the fluorescence with standards spotted concurrently. Recovery of all 3 TCs from samples fortified at levels of 0.5-2 ppm is 45-80%. For levels less than 0.5 ppm, the residue from the Amberlite column is dissolved in pH 9 aqueous solution containing calcium ions and barbital, TCs are extracted into chloroformethanol, and the concentration is estimated on thin layer plates. Recoveries of TCs from various tissues at levels of 0.1–0.5 ppm are 10–35%.
Nuclear Magnetic Resonance Analysis of Pharmaceuticals. XIII. Carbromal and Bromural in Tablets
Authors: Turczan John W 
Published: February 2020

Abstract
A new procedure for a rapid quantitative analysis of carbromal and bromural in tablets is described. The method is based on measurement of the nuclear magnetic resonance (NMR) signal of each compound in a carbon tetrachloride- pyridine solvent mixture (2+1), with hexamethylcyclotrisiloxane as an internal standard. A standard deviation of 0.7% for carbromal and 0.5% for bromural was obtained on synthetic mixtures. The NMR spectrum provides a specific means of identification for these 2 compounds.