bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collaborative Study of a Gas Chromatographic Method for the Analysis of Prometryne
Authors: Murphy R T , Hofberg A H , Buser H R 
Published: February 2020

Abstract
A gas chromatographic method for the determination of prometryne in wettable powder formulations containing about 80% active ingredient was collaboratively studied, using a matched pair scheme. The prometryne was extracted from the powder with chloroform containing dieldrin as an internal standard and chromatographed on Carbowax 20M, using a flame ionization detector. Determinations on the 2 samples by 12 collaborators using peak height measurements show an overall coefficient of variation of 1.4%, coefficient of variation of random error of 1.3%, and for systematic error, 0.4%. Application of the F-test shows the systematic error not to be significant. The method has been adopted as official first action.
Collaborative Study of a Method for the Determination of Trimethylamine Nitrogen in Fish
Authors: Boland Frederick E , Paige Dorothy D 
Published: February 2020

Abstract
Dyer’s method for the determination of trimethylamine was collaboratively studied. Six samples of fish extract and one standard solution were sent to each of 9 collaborators. The results from one laboratory differed significantly from the remainder and were not included in the statistical analysis. The results from the remainder of the collaborators were generally in good agreement. Results clearly differentiate between the acceptable and decomposed samples which were used in this study. The method for determining trimethylamine nitrogen in fish has been adopted as official first action.
Rapid Determination of Mercury in Fish
Authors: Bache Carl A , McKone Colin , Lisk Donald J 
Published: February 2020

Abstract
Successful oxygen flask combustion of samples of high oil or fat content has been particularly difficult in the past. A method is described for analysis of mercury in fish by modified Schöniger combustion and colorimetric determination of mercuric dithizonate. The recovery of mercury added to fish at the 0.5 ppm level was satisfactory.
IR Detection of False Positives for Gums in Mayonnaise Due to Mustard Flour
Authors: Krinitz Benjamin 
Published: February 2020

Abstract
A number of samples of mayonnaise were examined for added gums by first the precipitation of the protein with trichloroacetic acid and then the alcohol precipitation of water-soluble “gum.” Although the hydrolyzed precipitate gave a positive copper reduction and Molisch test, positive identification of gum could not be made. The IR spectrum confirmed the fact that the false positive for gums was due to the presence of mustard flour in the mayonnaise.
Determination of Moisture and Oil Concentrations in Feedstuffs by Four Different Methods
Authors: Crook Lynn , Williams W P 
Published: February 2020

Abstract
The moisture content of feedstuffs was determined by 4 methods: drying (1) over sulfuric acid to constant weight and (2) in vacuo 5 hr at 95°C, and direct extraction with (3) ethyl and (4) petroleum ether, assuming that the difference between weight loss of the moist sample upon extraction and the oil recovered represented the moisture content. Statistical analysis (P &lt;0.5) indicated that 1 &gt; 2 &gt; 4 ⊁ 3. The oil content of feedstuffs was determined by petroleum and ethyl ether extractions of moist samples and samples dried by 1 and 2. No significant difference existed between the corresponding petroleum and ethyl ether extractions. However, the oil extracted from samples dried by 2 was significantly less than that extracted from moist samples or samples dried by 1. The quantity of nitrogen extracted was not significantly different for petroleum and ethyl ether extractions, but may be large enough to significantly affect crude protein or amino acid analysis.
Gas-Liquid Chromatography–Mass Spectrometry Characterization of Polychlorinated Biphenyls (Aroclors) and 36Cl-Labeling of Aroclors 1248 and 1254
Authors: Stalling David L , Huckins James N 
Published: February 2020

Abstract
The isomer composition of the Aroclor 1200 series was characterized by GLC-MS, using temperature programming and SE-30 support-coated, open-tubular capillary columns. A method is described for the preparation and purification of 36Cl-labeled Aroclors 1248 and 1254. Neutron irradiation of the commercial material was used to prepare the 36Cl-labeled material. Purification of the irradiated product was accomplished by silicic acid column chromatography. Yields of the purified product were between 63 and 99%, with no detectable alteration of the isomer composition; 10% of the 36C1 produced was associated with the unchanged PCB isomers and the remaining radioactivity was contained in polychlorinated terphenyls. The terphenyls were produced by irradiation polymerization, and they were easily separated from the PCB components. Mass spectrometry, utilizing either temperature programmed GLC or direct probe sample introduction, was used to characterize the irradiation products. The radioactive materials are being utilized in experiments to determine uptake and metabolism of PCB by aquatic organisms.
Simultaneous Polarographic Determination of p-Nitro-2-acetamido-3-hydroxypropiophenone and 1-p-Nitrophenyl-2-amino-1,3-propanediol
Authors: Dumanović D , Volke J , Jovanović R 
Published: February 2020

Abstract
The reduction of p-nitro-2-acetamido-3-hydroxypropiophenone is one of the steps in the synthesis of chloramphenicol by the Parke-Davis process. A simultaneous polarographic determination of the 2 compounds in the reaction mixture after the reduction of p-nitro-2-acetamido-3-hydroxypropiophenone has been proposed. The determination can be carried out in Britton-Robinson universal buffers over the pH range from 2 to 10. The polarographic behavior of the 3 compounds is described.
Comparison of Paints by Neutron Activation Analysis. II. Colored Paints
Authors: Snow K B , Washington W D 
Published: February 2020

Abstract
A study of colored paints was made to determine to what extent individual paint samples can be characterized by neutron activation analysis. Approximately 300 samples of red, white, blue, and green paints from the major manufacturers in the United States were examined. It was found that paints of the same color produced by different manufacturers could be distinguished by this technique. Batch-to-batch variations between paints from the same manufacturer were observed, and it was found that in a small number of cases no differences were detected.
Fluorimetric Characteristics of Some Narcotic and Dangerous Drugs
Authors: DeZan Paul , Canaff Roger F , Bianchi Robert 
Published: February 2020

Abstract
Spectrophotofluorimetry is one of the most sensitive analytical techniques available to the forensic scientist. An extensive amount of data has been published regarding the use of this technique in the analysis of various drugs. The object of this paper is to compile data involving the fluorimetric analysis of narcotic and dangerous drugs. This basically includes emission and excitation maxima, solvents employed, and sensitivity.
Extraction and Microbiological Assay of Erythromycin in Feeds. II. Collaborative Study
Authors: Nyman Melvin A , Winkler Victor W 
Published: February 2020

Abstract
Eight laboratories participated in a collaborative study of a method for determining low levels of erythromycin in commercially prepared mash and pelleted feeds. Erythromycin was extracted from 10 or 40 g milled feed samples (100 vs. 10 and 5 g/ton, respectively) with a novel methylal-methanol-water extraction system (65 + 15 + 20, v/v/v). The extractant was diluted directly by phosphate buffer for bioassay. The average recovery values for the 5, 10, and 100 g/ton feed samples were 3.9-2.6, 8.6-8.1, and 105.8-84.1 g/ton (mash vs. pellet).
Improved Method for Determination of Chlorophenoxy Acid Residues in Total Diet Samples
Authors: Yip George 
Published: February 2020

Abstract
Modifications to an earlier procedure for chlorophenoxyacetic acid residues are introduced to provide better recoveries, cleaner samples, and sensitivities down to 0.02 ppm. These changes include (1) extracting with acetonitrile or CHCI3, (2) more effective methylation of the acids, (3) Florisil chromatography to separate PCP from the other herbicides, and (4) isothermal gas chromatography by electron capture or microcoulometric detection. The improved procedure was compared with the previous one, using several total diet composites at fortification levels of 0.01–0.05 ppm. Results showed that usable chromatograms were obtainable only with the improved procedure. Recovery studies were made on all commodity groups except for fats, oils, and shortenings. Microcoulometric results were good. Compounds studied were MCP, 2,4-D, 2,4,5-T, 2,4,5-TP, 2,4-DB, PCP, and 2,3,6-TBA.
Determination of Malonaldehyde as an Index of Rancidity in Nut Meats
Authors: Holland David C 
Published: February 2020

Abstract
Distillation of ground walnut meats from a slightly acidified concentrated NaCl solution gives a high per cent recovery of malonaldehyde which is associated with rancidity in nut meat products. Heating an aliquot of the distillate in an acetic acid solution of 2-thiobarbituric acid yields an intense red color with a maximum absorbance at about 532 nm. As little as 0.1 μg malonaldehyde/ml can be measured. Nuts judged to be slightly rancid by a taste panel showed the presence of approximately 40 μg malonaldehyde/g nul meat. Recoveries of malonaldehyde added to samples ranged from 92 to 97%. No malonaldehyde was detected in fresh nut meats.
Sensitivity of Chicks to Ochratoxins
Authors: Chu Fun Sun , Chang Chi C 
Published: February 2020

Abstract
The acute toxicity of ochratoxin A and its derivatives in day-old chicks has been studied. The LD50 was 166 and 216 μg per assay for ochratoxins A and C, respectively. No toxic effect was demonstrated when chicks were fed with up to 500 μg/chick of the hydrolyzed product, i.e., dihydroisocoumarin. Based on the results reported, the day-old chick assay is valid as a confirmatory test for ochratoxin.
Quantitative Determination of Tremortins in Agricultural Commodities
Authors: Hou C T , Ciegler A , Hesseltine C W 
Published: February 2020

Abstract
The procedure described for the quantitative determination of tremortins in agricultural commodities involves extracting the agricultural commodity with chloroform-methanol (2 + 1), followed by thin layer chromatography and colorimetric assay. This procedure was successfully applied to the analysis of tremortin A added to grains and the production of tremortins A and B on various commodities.
Colorimetric Determination of Carbaryl Residues in Field-Treated Corn
Authors: Dhal P , Lal Rattan 
Published: February 2020

Abstract
The colorimetric procedure outlined by Johnson was followed with some modifications for the analysis of carbaryl residues in corn. Recoveries from fortified samples were 77.2-99.3%. Carbaryl applied as granules in furrows at planting was translocated to the leaves. Carbaryl in the root and leaf was 16.25–27.50 and 17.24–27.62 ppm, respectively, 35 days after application. When applied as a water-suspension spray, 1.04 ppm carbaryl was detected in the leaves 21 days after application. It was not detectable in grain, stover, or silk, although 0.86 ppm was found in husks. In winter, 8.57 ppm carbaryl was detected 60 days after application. It was not detected in grain, stover, silk, and inner husks, but wrapper husks contained 24.23 ppm 27 days after application.
Colorimetric Method for Estimation of Zineb
Authors: Rangaswamy J R , Poornima P , Majumder S K 
Published: February 2020

Abstract
Zineb can be determined colorimetrically after reaction with cupric acetate in HC1. The copper salt formed is measured at 370 nm. This method has been applied successfully to the analysis of zineb formulations and zineb on grains and peanut pods.
Chromous Chloride Reductions. VI. Derivative Formation for the Simultaneous Identification of Heptachlor and Endrin Pesticide Residues by Gas Chromatography
Authors: Chau Alfred S Y , Cochrane W P 
Published: February 2020

Abstract
A chromous chloride reaction followed by GLC analysis is described for the simultaneous confirmation of heptachlor and endrin residues. This procedure constitutes a convenient method for the routine confirmation of heptachlor and endrin residues as low as 0.01 and 0.04 ppm, respectively, in 10 g sample extracts. An alternative method for the confirmation of heptachlor, using zinc and acetic acid, is also described.
Microcolorimetrie Estimation of Sulfur Dioxide in Fruits and Fruit Products
Authors: Nagaraja K V , Manjrekar S P 
Published: February 2020

Abstract
A simple and rapid microcolorimetric method, which is based on the reduction of yellow colored peroxodisulfato titanic acid to colorless titanium oxysulfate, has been developed for the determination of sulfur dioxide in dried fruit, fruit sirups, beverages, and liquid concentrates. The reduction in intensity of the yellow color is directly proportional to the concentration of sulfur dioxide over the range of 0-30 μg/ml.
Identification of Acetic, Propionic, and Sorbic Acids in Bakery Products by Thin Layer Chromatography
Authors: Tjan G H , Jansen J Th A 
Published: February 2020

Abstract
A rapid and sensitive thin layer chromatographic method has been described for detecting acetic, propionic, and sorbic acids in bakery products. Acetic, propionic, and sorbic acids were steam distilled from an acidified mixture of the samples into a solution of NaOH. After concentration of the alkaline solutions, samples were spotted on a thin layer plate; the chromatoplate was developed and the acids were identified by spraying with bromcresol purple.
Analysis of Nitrite- and/or Nitrate-Processed Meats for N-Nitrosodimethylamine
Authors: Fazio T , White R H , Howard J W 
Published: February 2020

Abstract
A total of 51 samples of various meat products was analyzed for N-nitrosodimethylamine with a method demonstrated to be sensitive to 10 ppb. The identity of the amine in one ham sample was confirmed by mass spectrometry at the 5 ppb level, the highest quantity detected in the various samples by GLC analysis. The presence of N-nitrosodimethylamine in the other samples could not be definitely established, since the apparent levels were too low for confirmatory analysis.
Analytical Profile of Straight Bourbon Whiskies
Authors: Schoeneman Robert L , Dyer Randolph H , Earl Elaine M 
Published: February 2020

Abstract
In this study 162 straight bourbon whiskies representing 2-, 4-, 6-, and 8-year-old samples were characterized by both chemical and physical analyses. Determinations using official AOAC methods were made on the components commonly used in characterizing distilled spirits. In addition, sodium, potassium, calcium, and magnesium were determined by atomic absorption spectrophotometry. Certain congeners were significantly correlated with age, while others were not.
Thin Layer Chromatographic-Gravimetric Determination of O,O-Diethyl S-(N-Isopropylcarbamoylmethyl) Phosphorothiolothionate (Prothoate) in Technical Products and Liquid Formulations
Authors: Bazzi B , Fabbrini R , Radice M 
Published: February 2020

Abstract
A method, based on phosphorus determination after thin layer chromatographic separation, has been developed for the analysis of O,O-diethyl S-(N-isopropylcarbamoylmethyl) phosphorothiolothionate in both technical products and liquid formulations. The insecticide or a convenient amount of an insecticidal preparation is dissolved in benzene and the solution is spotted on a thin layer chromatographic plate. After the plate is developed and sprayed with the chromogenic reagent, the portion containing prothoate is scraped off and the pesticide is eluted with methanol. The quantity of the active ingredient in the eluate is obtained by estimation of phosphorus as quinoline phosphomolybdate and the concentration of prothoate in the original sample can be calculated.
Conversion of Monuron to Ethyl-N-p-chlorophenyl Carbamate by Soxhlet Extraction of Plant Tissue with Ethanol
Authors: Lee Shaw S , Fang S C 
Published: February 2020

Abstract
Soxhlet extraction of plant materials with alcohol converted monuron residue to carbamate. Although this conversion will not affect the accuracy of monuron determination by the Bratton-Marshall reaction, it will undoubtedly affect the accuracy if the measurement is carried out by thin layer or paper chromatography. Diuron, fenuron, and chloroxuron, which contain 1,1-dimethyl substitution, were also converted to the corresponding carbamates, while siduron, neburon, linuron, monomethyl monuron, monomethyl diuron, and p-chlorophenyl urea were not. When monuron was refluxed with other alcohols such as methanol, isopropanol, and n-butanol, monuron was also converted to other products.
Identification of Crystalline Derivatives of Butyrophenones by X-Ray Diffraction: Examination of Pure Compounds and Active Substances in Pharmaceutical Formulations
Authors: Okkerse E , Leenheer A De , Heyndrickx A 
Published: February 2020

Abstract
Isolation and crystallization procedures have been developed for butyrophenones as free substances and from pharmaceutical formulations, namely ampoules, coated tablets, drops, and tablets. Crystallization as free bases, picrates, picrolonates, chlorhydrates, bromates, sulfates, and phosphates was attempted for all compounds. For the crystalline derivatives, the X-ray diffraction data were obtained by the Debye-Scherrer powder technique with photographic recording. The products have been classified according to their X-ray data, using “Hanawalt’s three strongest lines index” and the “innermost line index” systems. The butyrophenones could be identified with certainty by direct comparison of the X-ray diffraction patterns of compounds isolated from dosage forms with reference patterns.
Ultraviolet Spectrophotometric Determination of Propylthiouracil in Assays and Dissolution Studies of Tablets and Capsules
Authors: Hom Foo Song , Veresh Stephen A , Miskel John J 
Published: February 2020

Abstract
An ultraviolet Spectrophotometric method is reported for the determination of propylthiouracil in tablets or capsules. The accuracy and precision of the method are comparable to those achieved with the official USP assay procedure for tablets. In addition, the proposed method is simpler and more rapid, consequently providing an advantage where large numbers of determinations are indicated, e.g., in the determinations of individual dose variations and in dissolution rate studies. The method presently reported is suggested as an alternative to the official USP XVIII procedure.
Thin Layer Chromatographic Separation of Two Chlorodibenzo-p-Dioxins from Some Polychlorinated Biphenyls and Organochlorine Pesticides
Authors: Williams D T , Blanchfield B J 
Published: February 2020

Abstract
A thin layer chromatographic procedure is described for isolating 2,3,7,8-tetrachlorodibenzo-p-dioxin and octachlorodibenzo-p-dioxin. This method separates these compounds from polychlorobiphenyls and organochlorine pesticides. After isolation by thin layer chromatography, the chlorodibenzo-p-dioxins are analyzed by using electron capture gas chromatography. The application of the method to corn oil is discussed.
Electron Capture Gas Chromatographic Determination of Melengestrol Acetate in Animal Feed Supplements
Authors: Davis R A , Koshy K T , Ogilvie M L , Stahl G L , Callahan W A 
Published: February 2020

Abstract
Gas-liquid chromatographic methods are described for the determination of melengestrol acetate (MGA) in cattle feed supplements containing 0.000011–0.000220% MGA (0.05–1.0 mg/lb). A sample is extracted with hexane in a continuous liquid-liquid extractor and, if necessary, the extract is purified by treatment with activated carbon, solvent partition from hexane into aqueous methanol and then into methylene chloride, followed by column chromatography with alumina and silica columns. MGA in liquid feed and a few dry feed supplements may be determined directly in the initial extract by GLC. MGA in most dry feed supplements may be determined using only the solvent parition cleanup step; a few samples containing a low level of MGA and a large amount of co-extracted material may require all of the cleanup steps. MGA is measured by GLC, using a 1% OV-17 column, a 63Ni electron affinity detector, and cholesteryl chloroacetate as an internal standard. Recovery of MGA averages better than 90% with a coefficient of variation on the order of 7% for the feed supplements studied.
Determination of Canthaxanthin in Concentrates and Feeds
Authors: Osadca M , Araujo M , Ritter E De 
Published: February 2020

Abstract
Methods are presented for determining canthaxanthin as a 10% concentrate in beadlet form as such and in feed premixes and finished feeds. Canthaxanthin is liberated from the beadlets by hot aqueous solution and extracted into an organic solvent. In the case of feeds, separation from naturally occurring carotenoids in the extract is achieved by successive column and thin layer chromatography. Canthaxanthin in the final solution is isomerized to equilibrium with iodine and measured spectrophotometrically at 480±2 nm.
Collaborative Study of a Chromatographic Method for Sodium Diphenylhydantoin in Capsules
Authors: Cunningham C G , Brunner Charlotte A , Levine Joseph 
Published: February 2020

Abstract
A column chromatographic method is described for the determination of sodium diphenylhydantoin in capsules. A collaborative study was performed, using a synthetic mixture and a composite of a commercial preparation as samples. The average recovery for the synthetic mixture was 100.2 ±1.6%, and the average value for the commercial preparation was 96.2±1.6% of the labeled content. It is recommended that this method be adopted as official first action.
Elution Solvent System for Florisil Column Cleanup in Organochlorine Pesticide Residue Analyses
Authors: Mills Paul A , Bong Barbara A , Kamps La Verne R , Burke Jerry A 
Published: February 2020

Abstract
An elution solvent system is presented which can replace the currently used mixtures of ethyl ether-petroleum ether in the Florisil column chromatographic cleanup for pesticide residue analyses. Three eluants consisting of different mixtures of methylene chloride, hexane, and acetonitrile give greatly improved cleanup for extracts of fats and oils and recover pesticide chemicals of a greater range of polarity than do the ethyl ether-petroleum ether eluants. Fifty chemicals are known to be essentially completely recovered. Data are presented on fractional elution of representative compounds and on efficiency of removal of fatty substances. The proposed system has performed satisfactorily as a replacement for the ethyl ether-petroleum ether eluants in the analyses of a variety of representative foods for organochlorine pesticides.
Method for Preparing Dehydrated Tomato Powder for Examination by the Howard Mold Count Method
Authors: Parran Hamilton M , Douglas Ruth G , Eisenberg William V 
Published: February 2020

Abstract
Two methods were compared for preparing dehydrated tomato powder for the Howard mold count method in a collaborative study. One method requires hand-mixing the powder with water to obtain a sample within a specific refractive index range. The other involves a standard suspension based on a weight/volume dilution prepared under specified blending conditions. Standardizing these parameters eliminates some of the variables that affect the accuracy of results. It is recommended that the blending method be adopted as official first action.