bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Nitrate in Feeds
Authors: Hatcher D W , Schall E D 
Published: February 2020

Abstract
Attempts to measure nitrate at the low levels found in feeds by existing methods failed due to interferences from the soluble organic matter extracted from the samples along with the nitrate. The difficulties increased as the nitrate level decreased. A method for low-level materials was developed in which nitrate was isolated from interfering substances by thin-layer chromatography, eluted quantitatively from the absorbent, and measured colorimetrically by a modification of the 3,4-xylenol method. The procedure will determine nitrate accurately down to 10 ppm or less.
Collaborative Study of a Method for Multiple Chlorinated Pesticide Residues in Fatty Foods
Authors: Johnson Loren Y 
Published: February 2020

Abstract
Twenty lahoratories took part in a collaborative study of a method for chlorinated pesticide residues in which gas chromatography is used for the quantitative measurements of the residues. Butterfat and evaporated milk were the sample products; heptachlor epoxide and dieldrin were the pesticides. The results of the study have the precision and accuracy expected of the method. The average recovery was 113% with a standard deviation of ± 0.039 ppm at the 0.29 ppm level for heptachlor epoxide, and 95.9% with a standard deviation of ± 0.052 ppm at the 0.26 ppm level for dieldrin.
Colorimetric Determination of Procaine Penicillin in Mixed Feeds
Authors: Stone Loyal R 
Published: February 2020

Abstract
Procaine penicillin is determined by a rapid colorimetric procedure based on conversion of penicillin to penicillamine which turns blue with arsenomolybdic acid reagent. The presence of other antibiotics and chemotherapeutic agents in the feed does not interfere. The method is suitable over the range 10–100 g procaine penicillin per ton of feed.
Determination of Trimethylamine Nitrogen in Extracts and in Volatile Fractions of Fish
Authors: Bethea Sammie , Hillig Fred 
Published: February 2020

Abstract
Dyer’s colorimetric procedure was applied to the determination of trimethylamine nitrogen (TMA-N) in distillates from frozen cod and frozen haddock. Studies show that a more accurate estimate of the TMA-N contained in fish is obtained when this colorimetric method is applied to the distillates rather than to the extract. The method is also shortened by the elimination of one distillation, two oxidations, and two titrations.
Dichlone Residues on Foods
Authors: Miller George A 
Published: February 2020

Abstract
A collaborative study was conducted to evaluate a colorimetric method for the determination of residues of the fungicide dichlone. The fruit or vegetable is stripped with benzene; the extract is cleaned up on an activated Florisil column and eluted with 1% acetone in benzene. The dimethylamine reaction product is then read spectrophotometrically. The results of 10 collaborators in the 0.5–4.0 ppm range were: peaches, 78–112%; tomatoes, 88–110%; strawberries, 80–105%. The method is rapid; sensitivity is 0.25 ppm. The method has been adopted as official, first action.
Determination of Sodium Cis-3-Chloroacrylate Residues in Cottonseed and Root Crops
Authors: Johnson D P , Stansbury H A 
Published: February 2020

Abstract
Residues of sodium cis-3-chloroacrylate are determined in cottonseed and root crops by measuring the color produced when the compound is reacted with pyridine and sodium hydroxide. It is extracted by first converting it to free cis-3-chloroacrylic acid and then blending the tissue with l-butanol. The extract is cleaned up by liquid-liquid partitioning of aqueous buffered solutions with ethyl ether and l-butanol, followed by chromatography on alumina. The method sensitivity is about 0.05 ppm and recoveries average 91.9 ± 1.6%. Residues ranging from 0.05 to 2.83 ppm were found in cottonseed from crops treated with 1.5–5 lb per acre. The hulk of the residue was in the lint-hulls-motes fraction of the seed; only 0.1–0.2 ppm was in the meal. Residues were not found in either the crude or refined oil. Both onions and potatoes were free of residues after treatment with up to 5 lb per acre. The half-life in soil was about 3 days.
N-1-Naphthylphthalamic Acid Residues on Food Crops
Authors: Johnson Raymond H 
Published: February 2020

Abstract
The method of Lane, et al. for N-l-naphtliylphthalamic acid was modified as follows: The distillation of the freed l-naphthylamine was changed to provide for a true steam distillation that lessened decomposition losses of the amine in the strong alkali; the color development conditions were modified to yield a more stable solution for measurement. With the modified method, recoveries of 80–100% were obtained on cabbage, asparagus, and alfalfa meal fortified with 0.10–1.1 ppm N-1-naphthylphthalamic acid.
Determination of Chlorine in DDT by the Use of Dispersed Sodium
Authors: Berges Herman H 
Published: February 2020

Abstract
An accurate method for the determination of chlorine in DDT employs dispersed sodium to convert the organic chlorine to inorganic chlorine; this reduces the reaction time to 2–3 minutes, compared to 1–1½ hours for the official method. Otherwise this procedure is identical to the official procedure. No special equipment is needed.
Determination of Phosphatase in Dairy Products by Dialysis
Authors: Perlmutter Sam H , Lewis Lossie M 
Published: February 2020

Abstract
A method for determination of phosphatase, the enzyme naturally present in raw milk, hascd on a dialysis technique, was evaluated by a collahorative test among seven laboratories. Results indicate that the method is accurate and reproducible, and it was adopted as official, first action.
Direct Micro determination of Mercury in Color Additives by the Photometric-Mercury Vapor Procedure
Authors: Wenninger John A 
Published: February 2020

Abstract
A direct method has been developed for the determination of submicrogram amounts of mercury in inorganic and organic color additives. Samples are pyrolyzed at 650°C, generating mercury vapor from the mercury compounds present in the sample. The pyrolysate is passed over heated copper oxide and swept through a series of traps that remove interfering substances. The mercury content of the gas stream is determined with a commercially available mercury vapor meter. The method requires no pretreatment of the sample, such as digestion and isolation of mercury. Amounts of mercury as low as 0.01 μg can be detected. Samples as large as 25 mg (organic colors) or 250 mg (inorganic colors) may be used. Mercury at a concentration of 0.50 ppm in organic colors and 0.05 ppm in inorganic colors can be determined to within ± 2 0 % . About 5 minutes is required per analysis. The method is not suitable for the determination of mercury in samples containing organically bound iodine.
Total Diet Study: Content of Ten Minerals—Aluminum, Calcium, Phosphorus, Sodium, Potassium, Boron, Copper, Iron, Manganese, and Magnesium
Authors: Zook Elizabeth G , Lehmann Joanna 
Published: February 2020

Abstract
Ten mineral elements were determined by emission spectroscopy in 20 subsamples of the Food and Drug Administration “total diet” described in earlier publications. Radioactivity residues from fallout, proximate composition, selected vitamins, pesticide residues, and carbohydrate fractions were previously determined on these samples. On a dry, fat-free basis, aluminum content of these diets varied considerably (14-fold). In view of the normal range of mineral content in individual foods, minerals other than aluminum were remarkably uniform (2-fold variation). Minerals and their ranges per 100 g dry, fat-free solids were as follows: aluminum, 0.54–7.40 mg; calcium, 223–323 mg; phosphorus, 296–398 mg; sodium, 968–1147 m g ; potassium, 686–899 mg; boron, 0.290–0.593 mg; copper, 0.330–0.733 mg; iron, 3.80–6.18 mg; manganese, 0.54–1.30 mg; and magnesium, 60.4–102.8 mg. Data on a 4200 calorie daily intake are also presented.
Determination of Available Lysine in Food Materials
Authors: Lyman Carl M , Thomas M C 
Published: February 2020

Abstract
The major problems in the determination of available lysine in samples of high carbohydrate content are: (1) the destruction of e-dinitrophenyl lysine by carbohydrate decomposition products, and (2) the formation of interfering colored materials during hydrolysis of the samples. A procedure based on a modification of the Sanger reaction is described. Since this procedure is too involved and too intricate to be generally useful, collaborative study has been delayed and our efforts have been directed toward development of a simpler method.
Application of Chemical Kinetics to Assay of Phenobarbital and Pentobarbital Mixtures
Authors: Chafetz Lester , Robinson J Rocky , Petrick Robert J 
Published: February 2020

Abstract
An assay of mixtures of phenobarbital and pentobarbital is described which exploits the difference in rate of degradation of the drugs in alkali. The procedure entails measurement of peak absorbance of dilutions (pH 10) of phenobarbital and a mixture of the drugs before and after heating them in 0.1M trisodium phosphate for 15 minutes. In four trials of the procedure on replicated samples, the average recovery of the phenobarbital was 97.3% (range 89.5–105.2%) and of the pentobarbital 98.1% (range 94.0–101.0%). Synthetic tablet mixtures containing phenobarbital-pentobarbital combinations were assayed with satisfactory results after chromatographic separation of the barbiturates from the mixture.
Analysis of Vanilla Powders
Authors: Fitelson J 
Published: February 2020

Abstract
A number of the official methods for vanilla extracts have been adapted for use with vanilla powders, including lead number, vanillin, ethyl vanillin, organic acids by paper chromatography, and resins. Results on authentic samples compared well with results for extracts or concentrates. The direct paper chromatographic method for foreign plant material was not adaptable to powders.
Extraction p-Values of Pesticides and Related Compounds in Six Binary Solvent Systems
Authors: Bowman Malcolm C , Beroza Morton 
Published: February 2020

Abstract
The extraction p-values (fraction of solute partitioning into upper phase of an equivolume two-phase system) of 131 pesticides and related compounds in six solvent systems have been determined to aid in pesticide analysis and identification. The 85 compounds whose p-values were determined by electron-capture gas chromatography have been tabulated in order of increasing retention times alongside their p-values to allow the best choice of the six solvent systems to be made for identification purposes. Remaining p-values were determined gravimetrically. Mathematical formulas are given for calculating from the p-value the fractional amount extracted after repeated extractions. Graphs are presented which allow the specificity of a given p-value in a given system to be determined readily.
Determination of Carbaryl in Crops by Oscillographic Polarography
Authors: Gajan Raymond J , Benson Walter R , Finocchiaro Josephine M 
Published: February 2020

Abstract
The insecticide carbaryl can be determined quantitatively in the presence of a-naphthol by means of oscillographic polarography. A characteristic peak for the hydrolysis product of nitrosated carbaryl is obtained which has a peak potential of –0.45 ± .05 v vs. a mercury pool reference electrode. Using a modified cleanup method, as little as 0.2 ppm of carbaryl residues on certain fruils and vegetables has been determined. Recoveries from fortified crops averaged 95.3% ± 9 . 0% at the 0.2, 5.0, and 10.0 ppm levels. Among those pesticides tested, only o-phenylphenol interfered.
Gas-Liquid Chromatographic Method for Determination of Fat-Soluble Vitamins. III. Evaluation of a Vacuum Distillation Procedure for Vitamin E Isolation, Using C-14 Labelled Alpha-Tocopheryl Acetate
Authors: Sheppard A J , Ford L A , Boehne J W , Libby D A 
Published: February 2020

Abstract
Alpha-tocopheryl acetate, carbon-14 labelled in the methyl group at the two position, was used to determine the stability and recovery of the vitamin during vacuum distillation (140–160°C, and 0.020 mm Hg pressure, 60 minutes). Evaluation was based on measurements of radioactivity with a liquid scintillation spectrometer and a lowbackground Geiger counter. Recoveries of 20 mg of the pure compound were nearly quantitative (97%). Recoveries of the tocopheryl ester added to lard, “stripped” of vitamin E, at 0.5 mg/g or less and to butter at 0.1 mg/g were 98 and 82%, respectively. Results of the differential counting technique suggest that the ester is increasingly unstable at temperatures exceeding 160° and that a molecular rearrangement probably takes place.
Human Bioassay Techniques for Determining Availability of Vitamins from Preparations Resistant to In Vitro Disintegration
Authors: Libby David A , Schertel Max E , Loy Henry W 
Published: February 2020

Abstract
The human bioassay method has been utilized to determine the availability of certain vitamins from preparations which did not pass the official USP disintegration test. Urinary riboflavin recoveries from the test preparation were compared to urinary recoveries from equivalent quantities of a riboflavin reference standard. Tablets which traversed the entire digestive tract and were recovered intact were assayed for specific vitamins. Multiple vitamin dosage forms which did not disintegrate during the USP in vitro disintegration test were found to be also significantly resistant to human digestive action. Vitamin availabilities from these forms as determined by urinary excretion were seriously impaired. Extreme individual variations were noted in tests of the same product. Several preparations were found to be totally unavailable to certain individuals.
Wick Trough and Thin Layer Chromatography Developments
Authors: Wilkie John B 
Published: February 2020

Abstract
A wick trough system was developed which permits chromatographing in the horizontal, ascending, or descending position. This system will chromatograph large samples with good resolution in approximately 30 minutes. It was applied to a nonsaponifiable fraction of a feed extract containing vitamin A. The system satisfactorily separated xanthophyll, vitamin A, carotene, and the extraneous material.
Micro thin layer plates were adapted to the wick system. Trial runs with a dye mixture gave promising results.
Determination of DDVP in DDVP-Dipterex Formulations by Gas Chromatography
Authors: Ellis John , Bates John 
Published: February 2020

Abstract
In the analyses of commercial fly-bait samples for DDVP (0,0-dimethyI-2,2-dichloro vinyl phosphate), containing Dipterex (0,0-dimethyl-2,2,2-trichloro - 1 - hydroxyethyl phosphonate) as a guaranteed ingredient, interferences were observed at 9.9– 10.4/t with the current spectrophotometric methods. These samples were analyzed by an electron capture gas chromatographic method, and the results showed no interference from Dipterex or other substances. A selected group of samples was analyzed by gas chromatography and spectrophotometry, and the results were compared.
Applicability of an Isotope Exchange Method for the Determination of Milligram and Microgram Quantities of Organic Mercurials. I. Pharmaceutical and Agricultural Mercurials
Authors: Davis Sidney , Arnold Alphonso 
Published: February 2020

Abstract
The isotope exchange technique was applied to the analysis of milligram and microgram quantities of organic mercurials, with emphasis on pharmaceuticals and fungicides of an agricultural nature. Average recovery was 98.48 ± 1.12% for Hg-203 in equilibrium with chemical mercury. In comparison studies, the isotope exchange procedure showed essential agreement with standard techniques for mercury determination. At low levels, traces of mercury via glassware contamination were observed to interfere. The digestion system was found to be applicable to most organic mercurials studied except ethyl mercuric phosphate and three commercial fungicides.
II. Rapid Extraction Method for Crops
Authors: Watts Randall R , Storherr Robert W 
Published: February 2020

Abstract
An ethyl acetate extraction method for organophosphate pesticide residues on crop samples requires about 40 minutes for extraction and preparation of sample. This procedure eliminates the lengthy acetonitrile concentration and reduces the volume of solvent used in the acetonitrile procedure. Dimethoate, diazinon, Trithion, Guthion, Phosdrin, and parathion were easily extracted from field-sprayed kale by the ethyl acetate extraction method.
4-(p-Nitrobenzyl) pyridine, A New Chromogenic Spray Reagent for the Organophosphate Pesticides
Authors: Watts Randall R 
Published: February 2020

Abstract
This paper describes p-nitrobenzyl pyridine as a chromogenic spray reagent for detection of organophosphate pesticides on paper and thin layer chromatograms. The chromogenic spray is equally sensitive for thio and nonthio organophosphate pesticides. All 20 organophosphate pesticides tested on paper and thin layer chromatograms gave distinct and persistent spots with the spray procedure. The lower sensitivity limit is 0.5 μg of pesticide on paper chromatograms and 0.5–2.0 μg of pesticide on thin layer chromatograms.
Rapid Visual Technique for Recovery of Mold from Beverages and Therapeutic Liquids
Authors: Miller Bob J 
Published: February 2020

Abstract
A visual method is presented that enables the analyst to isolate clumps of mold from dark solutions and from colored and irregular bottles and to examine the material microscopically. The solutions to be examined are passed through a glass tube for visual examination, and any observed extraneous material is deposited directly onto a slide. Physical characteristics are not altered, and all visible mold clumps can be accurately counted and measured.
A Rapid Method of Carbon Analysis for Biological Materials
Authors: Smith L W , Flatt W P , Barnes K A , Soest P J Van 
Published: February 2020

Abstract
An induction furnace and a gasometric analyzer have been adapted for the analysis of carbon in biological materials. Samples for analysis must not exceed 70 mg carbon. The number of analyses which can be routinely performed for carbon in an eight-hour day has been increased from 8, by wet combustion, to 50, by the induction furnace method. Hay, concentrate, dried feces, wet feces, milk, and urine have been analyzed by this method with iron, cupric oxide, molybdenum trioxide, and silicic acid used as reagents. Silver phosphate and vanadium pentoxide were required to obtain satisfactory analyses of dried milk. Liquid urine was analyzed successfully by the same methods employed for dried samples except for minor modifications of the combustion tube and catalysts. Analyses on sodium carbonate, glucose, and potassium hydrogen phthalate yielded carbon recoveries of essentially 100%.
Rapid Method for the Determination of Insect Fragments from Cocoa
Authors: Stein Richard , Ferrera Robert S , Brown Robert F 
Published: February 2020

Abstract
A rapid screening method for determining insect fragments in cocoa uses a 5 g sample of cocoa and requires only 10 minutes for extraction, as compared with the 50 g samples in the official method. The new method shows approximately eqvial recoveries and good agreement between determinations and analysts.
Effects of Neutral Salts on the Activity of Iodine, Bromine, and Chlorine as Swimming Pool Water Disinfectants
Authors: Koski T A , Beloian A , Stuart L S 
Published: February 2020

Abstract
Potassium iodide, potassium bromide, and potassium chloride materially slow down the bacteria killing rates of iodine, bromine, and chlorine, respectively, in distilled water. The germicidal activity of elemental iodine in water does not increase as the pH is increased from pH 5.8 (the mean value fovind in unbuffered water containing 2.0 ppni free iodine) to 8.0 as might be expected if the germicidal activity of iodine could be attributed to hypoiodous acid. Chlorine is considerably less effective as a disinfectant for sea water than for fresh water when judged by activity against the gram-positive test organism S. faecalis. While this can be attributed, in part, to interference by the neutral chloride salts present in sea water, the presence of an initial high chlorine demand and difficulties encountered in maintaining available chlorine residuals after this demand has apparently been satisfied make it impossible to conclude that this is the only factor involved.
Efficiency of Several Selective Media for Isolating Coagulase-Positive Staphylococci From Food Products
Authors: Baer Edward F , Franklin Marquitta K , Gilden Mildred M 
Published: February 2020

Abstract
The relative efficiency of several selective media recommended for detecting coagulasepositive staphylococci was determined during the course of random food sample examination. Media compared were: cooked meat broth containing 10% NaCl, Trypticase soy broth containing 10% NaCl, sorbic acid broth, staphylococcus medium No. 110, polymyxin-B agar, Vogel and Johnson agar, tellurite glycine agar, and mannitol egg agar. Results indicate that Trypticase soy broth containing 10% NaCl combined with Vogel and Johnson agar as the plating medium was the most efficient media system.
Thiabendazole in Feeds
Authors: Szalkowski C R 
Published: February 2020

Abstract
Two methods for thiabendazole, 2-(4′-thiazoyl)-benzimidazole, in feeds were studied collaboratively. Method I is applicable to all feeds. Method II is applicable to cattle supplements and premixes containing &gt; 1% thiabendazole. Thiabendazole is extracted from the feed with 0.1N HCl; any interferences are removed with sodium citrate and chloroform extraction. The thiabendazole is re-extracted with 0.1N HCl and treated with a zinc slurry in 30% glycerol containing p-phenylenediamine. Oxidation with ferric sulfate yields a blue complex which is extracted with n-butanol and measured at 605 mμ. The methods are recommended for adoption as official, first action.
Rapid Detection of Chlorinated Pesticide Residues by an Improved TLC Technique: 3¼ × 4″ Micro Slides
Authors: Kovacs Martin F 
Published: February 2020

Abstract
Submicrogram quantities of as many as 26 chlorinated pesticides can be resolved in 5–10 minutes and identified on 3¼ × 4″ micro slides coated with either aluminum oxide G or MN-silica gel G-HR. Plates are developed in 800 ml beakers with one of three solvent systems: n-heptane + 1% acetone; n-heptane; or iso-octane with 25% dimethylformamide. Rf values are presented. A 3¼ × 4″ micro plate combines the speed and economy of a 1 × 3″ microscope slide with the capacity and efficiency of an 8 × 8″ plate for TLC analysis.
Determination of Tranid Residues in Fresh Fruits, Vegetables, and Cottonseed
Authors: Johnson D P , Stansbury H A 
Published: February 2020

Abstract
Tranid, 3-exo-chloro-6-endo-cyano-2-norbornanone O-(methylcarbamoyl)oxime, is an acaricide effective against both resistant and nonresistant strains of red and citrvis mites. Residvies of Tranid are determined in fresh frviit and vegetables as well as cottonseed by a combination of base- and acid-catalyzed hydrolysis to form hydroxylamine. The latter is then oxidized to nitrous acid which is determined colorimetrically. The compound is extracted from the crop with benzene and cleaned up by liquid partitioning. The method is sensitive to abovit 0.03 ppm of Tranid, and recoveries from all crops tested averaged 91.5 ± 4.4% over the range 0.05–3 ppm.
Determination of the Substituted Urea Herbicides Linuron, Monuron, Diuron, Neburon, and Fenuron in Surface Waters
Authors: Katz Stanley E 
Published: February 2020

Abstract
A quantitative method has been developed for the substituted urea herbicides in surface waters. The herbicide is extracted from water with chloroform and hydrolyzed under reflux conditions with 6N HCl. The resulting aniline is diazotized and condensed with N-(l-naphthyl) ethylenediamine to form a magenta dye, which is extracted with n-butanol and measured colorimetrically at 555 μ. Qualitative determination is made by thin layer chromatography. The herbicide is extracted from water with chloroform, and the volume is reduced. After development, the chromatograms are sprayed with ninhydrin and visualized.