bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectra-Structure Correlations of Some Heterocyclic Pharmaceuticals
Authors: Hayden Alma L , Maienthal Millard 
Published: February 2020

Abstract
The results of a study of the relationship between spectra and structure of zoxazolamine, methimazole, and some related compounds are presented. Group frequency assignments of the infrared spectra were clarified or confirmed by comparisons with ultraviolet, near infrared, and nuclear magnetic resonance data.
The Determination of Methimazole by Infrared Spectrophotometry
Authors: Hayden Alma L , Brannon Wilson L 
Published: February 2020

Abstract
A method for the determination of methimazole by column chromatography and infrared spectrophotometry was subjected to collaborative study in four district laboratories. Although the results were favorable, they were not sufficiently precise nor accurate to recommend the method for adoption. Further study of the method is recommended.
The Role of Nuclear Magnetic Resonance in the Analysis of Pharmaceuticals
Authors: Alexander Thomas G , Koch Stanley A 
Published: February 2020

Abstract
The applications anticipated for nuclear magnetic resonance (NMR) in pharmaceutical analysis include the identification of compounds, elucidation of unknown structures, determination of sample purity, and quantitative analysis. “Fingerprint” identification of a sample is often readily possible with the aid of spectra catalogs. Examples are shown of how NMR aided in the structure elucidation of several compounds, particularly that of anthralin. Only in certain cases can NMR sensitively detect impurities; the necessary conditions and limitations for such detection are discussed. Comparisons are made of the ease with which impurities in selected phenothiazine drugs were detected by IR and NMR. Two different methods for quantitatively determining the relative amounts of components in a mixture are discussed. Future avenues of collaborative studies are indicated.
An Approach to the Separation, Identification, and Determination of at Least Ten Organophosphate Pesticide Residues in Raw Agricultural Products
Authors: McCaulley Donald F 
Published: February 2020

Abstract
This paper describes the preliminary development of a method that permits relatively rapid qualitative determination of residues of a number of common phosphate pesticide compounds. Extraction is followed by vacuum sublimation, gas-liquid chromatography, and infrared analysis. A wide variety of vegetables and fruits can be analyzed by the general procedure.
Screening Procedure for Organothiophosphate Pesticide Residues on Fruits and Vegetables Using Microcoulometric Gas Chromatography
Authors: Nelson Richard C 
Published: February 2020

Abstract
A screening procedure for the thiophosphates, previously adapted from the Mills- Onley-Gaither method for organic chloride pesticides, has been extended to include a total of 16 parent compounds and 25 crops. Two columns were studied: a 6 ft 15% DC-200 silicone oil column on 30/60 mesh Chromosorb P, which was used in all recovery work, and a fluorinated silicone column, 4 ft 10% QF-1 on HMDS-treated 60/80 mesh Chromosorb W. Sample sizes for injection were increased to 10 g and recoveries were run as low as 0.1 ppm. Over-all method recoveries on all thiophosphates tested, except dimethoate, Guthion, and Systox, were 70% or better; recoveries of these three were considerably improved by substituting benzene instead of petroleum ether in the shake-out step. Multilinear temperature programming was tried with the DC-200 column, and found to be promising. The QF-1 column was found to be useful in separating pesticide combinations not resolved by the DC-200 column.
Analysis of Lipids in Fish Meal
Authors: Parks Paul F , Hummel Mildred E 
Published: February 2020

Abstract
The lipid fraction of fish meal was extracted by four different solvent systems: diethyl ether, chloroform, the official AOAC method for fat in fish meal, 22.037, and a binary mixture of methanol-acetone. The lipid extracted by each solvent was partitioned into a triglyceride-fatty acid-sterol fraction (TFS) and a phospholipid fraction. The amount of material extracted by the different solvents was in the following descending order: methanol-acetone &gt; official AOAC method 22.037 &gt; chloroform &gt; diethyl ether. The increased extraction of the binary mixture over the official AOAC method is partly due to a marked increase in the extraction of phospholipids from fish meal by the methanol-acetone mixture. The fatty acid composition of the TFS fraction from the methanol-acetone, chloroform, and diethyl ether extractions was similar. However, the TFS fraction extracted with acetone after acid hydrolysis (AOAC method 22.037) was higher in palmitic and stearic acids and lower in myristic and palmitoleic acids than the TFS fraction extracted by the other methods.
Infrared Determination of Sorbic Acid in Foods
Authors: Calloway George F , Schwartzman George 
Published: February 2020

Abstract
Preliminary study of an infrared method for determination of sorbic acid in foods gave promising results. The procedure consists of steam distillation of the food product, extraction of the distillate with chloroform, and measurement of the infrared absorbance of the chloroform extract at 10 μ. Recoveries from 92 to 110% were obtained from 14 food samples spiked with 0.05–0.15% sorbic acid. A collaborative study is recommended.
Gas Chromatographic Identification of Ethyl Esters of Fatty Acids in Domestic and Imported Rums
Authors: Stevens Robert K 
Published: February 2020

Abstract
Classical gas chromatographic techniques were used to identify the following ethyl esters in domestic and imported rum: ethyl caprylate, ethyl caprate, ethyl laurate, ethyl myristate, and ethyl palmitate. Quality of the rum may be related to the amounts of these esters present.
Collaborative Studies of Methods for Butterfat in Homogenized and Chocolate Milk
Authors: Mitchell D J 
Published: February 2020

Abstract
The AOAC Roese-Gottlieb, Babcock, and rapid detergent (TeSa) methods for the determination of butterfat were compared in a collaborative study on ten samples of homogenized milk by each of five laboratories. The Roese-Gottlieb and rapid detergent methods were also compared on ten samples of chocolate milk by the same collaborators. Each collaborator obtained the samples in his own area. The Babcock method gave low results for homogenized milk as expected. Comparing the TeSa method with the Roese-Gottlieb method, it appears that more developmental work on the rapid detergent method for homogenized milk and chocolate milk is necessary.
Evaluation of Protein Quality (Biological Method)
Authors: Derse Philip H 
Published: February 2020

Abstract
When casein, soy grits, white bread, or protein bread is tested individually for protein quality with sucrose or starch as the added carbohydrate, the over-all results obtained are in good agreement. Either carbohydrate gives good results and appears to contribute little effect on the 28 day assay period. Shorter assay periods may be possible, depending on the type of carbohydrate employed.
Polarographic Determination of Selenium in Biological Materials
Authors: Christian Gary D , Knoblock Edward C , Purdy William C 
Published: February 2020

Abstract
Polarography has been applied to the determination of selenium in biological materials. The direct determination described requires as little as 30 minutes for a single analysis. To increase the sensitivity, the selenium is isolated by one of two methods: The element is isolated by filtering through a Millipore filter, digesting the filter plus selenium, and obtaining a polarogram; or the selenium-diaminobenzidine complex is formed directly in the acid digest and then is extracted into a mixture of chloroform and ethylene chloride, the complex is backextracted into 2M perchloric acid, and a polarogram is obtained. Polarographic revalues are reported for the two selenium-DAB waves. As little as 0.2 µg selenium can be determined in a 1–2 g wet weight sample. Recoveries of organoselenium compounds from two different acid-digestion mixtures were comparable. A modification of the digestion mixture described by Cummins, et al. is given. Most procedures described require 2 hours or less analysis time for a single sample.
Gas Chromatographic Determination of Thiouracils in Feeds
Authors: Fravolini Arnaldo , Begliomini Alfredo 
Published: February 2020

Abstract
A gas-liquid chromatographic method has been used to determine thiouracils added to feeds. The chromatographic separation is carried out on alkylated compounds. A column of SE-30 polymer methyl silicone was used. Recoveries averaged between 92 and 103%. The procedure is simple and brief.
Rapid Colorimetric Method for Determining Vanillin
Authors: Fitelson J 
Published: February 2020

Abstract
A simple and reliable colorimetric method for vanillin, based on the color produced with indole, has been developed for the use of laboratories that lack the equipment needed for the official method. Results average about 0.02% higher than those by the official method. Five laboratories obtained good agreement with the colorimetric method.
Preliminary Studies on Weathering of Chlordane Residues
Authors: Thruston Alfred D 
Published: February 2020

Abstract
The qualitative and quantitative determination of chlordane residues on raw agricultural products has been best achieved by gas chromatography techniques. While good recoveries (90–100% at the 0.1 ppm level) have been obtained from plant extracts with added standard chlordane, weathered chlordane residues show changes in number and size of gas chromatographic peaks. Chlordane at the 50 µg level, when exposed to the air at room temperature over a period of time, showed progressive decomposition and loss of the many components that make up chlordane.
Diphenylamine-Zinc Chloride as a Chromogenic Agent for the Detection of a Mixture of DDT, Chlordane, and Toxaphene on Thin Layer Chromatograms
Authors: Faucheux Lewis J 
Published: February 2020

Abstract
Diphenylamine-ZnCL2 has been evaluated as a chromogenic agent for detection of toxaphene, DDT, and chlordane on A12O3 thin layer plates. Characteristic colors were obtained for these pesticides; a lower level of about 5 µg was detectable. Color reactions of 34 pesticides at the 20 µg level are presented.
Various Components of Bourbon Whisky by Thin Layer and Gas-Liquid Chromatography
Authors: Martin Glenn E , Schmit John A , Schoeneman Robert L 
Published: February 2020

Abstract
By using various techniques such as thin layer chromatography and gas-liquid chromatography, with the assistance of silyl ether derivatives, the following seven compounds have been identified in bourbon whisky: vanillin, syringaldehyde, citric acid, alphaand beta-D-glucose, and alpha- and beta-D-fructose.
Chromatographic and Extraction Techniques for Vitamin C Assay
Authors: Ritter Elmer De 
Published: February 2020

Abstract
A review is presented of chromatographic procedures used in the assay of vitamin C. Paper, thin layer, and column chromatography have been used to advantage for separating interfering substances. Even the closely related erythorbic acid, which has no vitamin C activity, can be separated from ascorbic acid by various techniques on paper. Total vitamin C can be determined chromatographically after reduction of dehydroascorbic acid with H2S or after oxidation of the reduced form to dehydroascorbic acid. A combination of column and thin layer chromatography on silica gel of the dinitrosazone formed by reaction of dehydroascorbic acid with 2,4-dinitrophenylhydraiine is recommended as an effective method for achieving specificity in vitamin C assays of foods and feeds where the level of interference is high. Efficient extraction procedures are described for determining added ascorbic acid in feeds and mineral premixes.
A Critical Evaluation of the Ammonium Molybdophosphate Method for Phosphorus
Authors: Duncan R D , Srabson J A 
Published: February 2020

Abstract
The official ammonium molybdophosphate method for phosphorus is subject to both positive and negative errors. The solubility of the precipitate in the precipitation medium is negligible, but its solubility in water is high enough to introduce significant error if washing of the precipitate is excessive or prolonged. The precipitate contains only 97% of the stoichiometric amount of ammonia, a deficiency which results in a positive error of 3 parts per thousand in the conventional titration. High temperatures in the titration medium also result in positive errors from volatilization of ammonia. The errors resulting from deficiencies of ammonia are avoided in the formaldehyde modification of the method.
Determination of Minor Nutrients in Fertilizers by Atomic Absorption Spectrophotometry: Second Collaborative Study
Authors: Mcbride C H 
Published: February 2020

Abstract
The atomic absorption method studied last year was re-examined and extended to include calcium and sodium. The procedures were submitted to 16 collaborators for determination of Ca, Cu, Fe, Mg, Mn, Na, and Zn. Results for Ca and Na were discouraging; further study is recommended.
Rapid Quantitative Vatside Check Test for Chlorinated Hydrocarbons in Aqueous Emulsions: Methoxychlor, DDT, Dieldrin, and Chlordane
Authors: Czech Fred P 
Published: February 2020

Abstract
Field tests for certain chlorinated hydrocarbons in aqueous emulstions used for the eradication of ectoparasites in livestock were previously described. Pertinent parameters for the vatside determination of methoxychlor, DDT, dieldrin, and chlordane are given in this report in tabular form.
An Improved Method for Cleanup of Brassica for Parathion Analysis
Authors: Beckman Herman , Bevenue Arthur , Gauer W O , Erro Felix 
Published: February 2020

Abstract
An improved cleanup procedure has been developed for the recovery of parathion from crops, with special reference to cole crops. Parathion is separated from many chlorinated hydrocarbon pesticides that could cause interfering gas chromatographic responses. Electron capture techniques were used to detect the chlorinated hydrocarbon pesticides, and colorimetry and electron capture were used to determine parathion.
Gas Chromatographic Determination of Phenolic Pesticides and Residues
Authors: Gutenmann W H , Lisk D J 
Published: February 2020

Abstract
Polar phenolic pesticides often tail badly when direct gas chromatography is attempted. Rapid conversion of the phenolic group to the corresponding methyl ether eliminates tailing. Chromatography of DNOC, DNOSBP, ioxynil, and bromoxynil have been performed by this procedure. Determination of DNOC, DNOSBP, and ioxynil in agricultural samples is reported.
Determination of Total Choline in Feeds
Authors: Fritz James C 
Published: February 2020

Abstract
Five feed samples were analyzed for choline by a modified reineckate method following extraction with acid methanol. One sample was the basal diet for the chick vitamin D assay; the other four samples had known quantities of choline chloride added to this basal diet. The results obtained by 12 collaborating laboratories gave an average value of 863 ± 259 mg choline chloride/kg of the basal diet. The average recovery of added choline in the other samples ranged from 90.2 to 96.6%. The larger percentage variation in the lower potency samples suggested a need for further study of the extraction procedure.
Analysis of Organo-Metallic Fungicides and Related Compounds by Atomic Absorption Spectroscopy
Authors: Gudzinowicz B J , Luciano V J 
Published: February 2020

Abstract
A method is proposed for the analysis of organo-metallic fungicides (derivatives of thiocarbamic acids) and related compounds by atomic absorption spectroscopy. The effect of chloride and nitrate anions on absorption and sensitivity was investigated. The differences in the results by use of a single Zeiss or three Beckman burners with the spectrometer’s 5-pass optical system were negligible. Yellow wax bean and cucumber leaves were stripped with chloroform and with pyridine and analyzed for their external cation content. The standard recoveries of zinc added to the leaf extract were 95–100% with chloroform and 100–102% with pyridine. Calibration curves were established for the determination of the metal content of maneb (manganous ethylenebisdithiocarbamate), manganous acetylacetonate, ferbam (ferric dimethyldithiocarbamate), iron acetylacetonate, ziram (zinc dimethyldithiocarbamate), zineb (zinc ethylenebisdithiocarbamate), and zinc acetylacetonate. The most favorable concentration ranges for the analysis of zinc, iron, and manganese (10–50% absorption) are 0.07–0.50, 0.70–5.0, and 0.4–2.0 ppm, respectively.
Comparative Evaluation of a Direct Plating Procedure and an Enrichment Isolation Procedure for Detecting Coagulase-Positive Staphylococci in Foods
Authors: Gilden Mildred M , Baer Edward F , Franklin Marquitta K 
Published: February 2020

Abstract
Coagulase-positive staphylococci were detected in 160 of 663 frozen food samples examined. The organism was detected by both a direct plating procedure and an enrichment isolation procedure in 32 (20%) of the samples. Detection was made by the enrichment isolation procedure (but not by the direct plating procedure) in 118 samples (73.8%), and by the direct plating procedure (but not by the enrichment isolation procedure) in 10 (6.2%) of the samples found to contain coagulase-positive staphylococci.
Reliability of Several Diagnostic and Determinative Tests in the Identification of Coagulase-Positive Staphylococci
Authors: Franklin Marquitta K , Baer Edward F , Gilden Mildred M 
Published: February 2020

Abstract
Five diagnostic and fovir determinative tests applied to the identification of S. aureus were evaluated on the basis of their correlation with the tube coagulase test. The rate of correlation for the diagnostic tests was so low that these tests are unsuitable as substitutes for the tube coagulase test. The rate of correlation for the determinative tests exceeded 90%. These tests could be useful in augmenting the tube coagulase test to differentiate S. aureus from other coagulase-positive organisms.
Comparison of the Official Method for Total Phosphorus (Volumetric) and the Gravimetric Quinoline Molybdate Method for Total Phosphorus—1965 Collaborative Study
Authors: Whitley Voyce P 
Published: February 2020

Abstract
The official method for total phosphorus (volumetric), 2.026–2.028, and the gravimetric quinoline molybdate method for total phosphorus were collaboratively studied and compared. Analyses were made on alfalfa, wheat, cherries, raspberries, and eggs by seven collaborators. Differences between the methods were insignificant, and the quinoline molybdate method is recommended for adoption as official, first action.
Ion Exchange Resin Separation of Metals Occurring in Plant Material
Authors: Breault Eugene A 
Published: February 2020

Abstract
The study of the separation of metallic chlorides on Amberlite CG-120 (200–400 mesh) cation exchange resin was continvied. Na, K, Mo, Al, Ca, and Fe have been separated by hydrochloric acid solutions and determined by polarography or flame photometry. Semimicro quantities of these metals can be separated from each other with a minimum of eluting agent, small resin beds, and simple equipment. Mechanical grading of the air-dried resin was used to obtain more uniform particles. The ion exchange separation scheme offers advantages over present official procedures, and it should provide a unified method for the analysis of metals in mixtures. Further study is recommended.
Furazolidone and Nitrofurazone in Feeds
Authors: Stone Loyal R 
Published: February 2020

Abstract
Collaborative studies were continued on a rapid method for furazolidone in feeds where the drug is isolated by column chromatography and measured in aqueous solution. This procedure was extended to determine both furazolidone and nitrofurazone separately in feeds medicated with bifuran and was studied collaboratively. The activity of the aluminum oxide adsorbent in these procedures is critical. However, with a suitable lot of adsorbent, these proposed procedures are more rapid and specific than the official methods.
Determination of Temik Residues in Raw Fruits and Vegetables
Authors: Johnson D P , Stansbury H A 
Published: February 2020

Abstract
Temik, 2-methyl-2-(methylthio) propionaldehyde O-(methylcarbamoyl)oxime, is a systemic pesticide effective both by topical application to the plant and by systemic translocation from treated soil. The method developed for residues of Temik in crops is based on extraction of the crops with chloroform, followed by cleanup involving both coagulation and liquid partitioning techniques. The analysis involves both base- and acid-catalyzed hydrolysis to liberate hydroxylamine, which is then oxidized by iodine to nitrous acid; the latter is determined by diazotization (a modification of the Griess test for nitrites). The method is sensitive to about 0.03 ppm; average recovery from 8 crops is 96.3 ± 3.2%. Other current commercial pesticides do not interfere in the analysis.
Characteristic Infrared Absorption Spectra and Frequencies of Carbamate Pesticides
Authors: Chen Jo-Yun T , Benson Walter R 
Published: February 2020

Abstract
The infrared spectra of 32 carbamate pesticides and model compounds in liquid (CS2) and solid (KBr) phases are presented. The characteristic infrared absorption frequencies and associated structures are tabulated in a summary and presented in a correlation chart. The carbonyl absorption frequencies of carbamates containing the N—H group are shifted to higher frequencies by approximately 35 cm-1 in going from the solid to the liquid phase. This shift is attributed to a loss of hydrogen bonding. In general the N,N-disubstituted carbamates show no such shift.
Collaborative Study of a Method for Multiple Chlorinated Pesticide Residues in Leafy and Cole-Type Vegetables
Authors: Gaul Jean 
Published: February 2020

Abstract
Sixteen collaborators representing eight laboratories studied an electron capture gas chromatography method for lindane, heptachlor, and TDE residues in leafy (endive) and cole-type (cauliflower) vegetables. Average recoveries for lindane at the 10 ppm level were 91.7% from endive and 95.7% from cauliflower; at the 1 ppm level, 93.6% from endive and 88.3% from cauliflower. Average recoveries for heptachlor at the 0.1 ppm level were 82% on endive and 94% on cauliflower; at the 0.05 ppm level, 88% on endive and 82% on cauliflower. Average recoveries for TDE at the 7 ppm level were 78.6% on endive and 85.4% on cauliflower; at the 1 ppm level, 86.1% on endive and 86.4% on cauliflower.
Collaborative Study of a Rapid Method for Multiple Chlorinated Pesticide Residues in Small Fruits
Authors: Davidson Arthur W 
Published: February 2020

Abstract
Twelve collaborators from six laboratories used gas-liquid and thin layer chromatography to measure BHC, p,p′-DDT, and endrin residues on apricots and strawberries. Recoveries for both crops by gas chromatography averaged: BHC, 104 ± 23 %; p,p′-DDT, 102 ± 10%; endrin, 96 ±14%. Recoveries for both crops by thin layer chromatography averaged: BHC, 98 ± 29%; p,p′-DDT, 97 ± 18%; and endrin, 96 ± 16%.
Potentiometric Determination of Chlorides in Wine, Distilled Spirits, and Wine Vinegar
Authors: Hubach Clifford E 
Published: February 2020

Abstract
Collaborative study of the Pro method for determining chlorides in wines and distilled spirits by direct titration with silver nitrate followed by potentiometric reading of the end point gave accurate and reproducible results. The procedure is suitable for repetitious analyses in control laboratories, and it is also adaptable to determinations requiring a high degree of precision. Recoveries of chloride added to samples averaged 99.7%. The method is recommended for adoption as official, first action.