bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collaborative Study Using a ZDBT Colorimetric Method for the Determination of Copper in Alcoholic Products
Authors: Strunk Duane H , Andreasen A A 
Published: February 2020

Abstract
Results are given on a collaborative study in which a zinc dibenzyldithiocarbamate (ZDBT) colorimetric method is used to measure copper in alcoholic products such as high wine, spirits, gin, whisky, brandy, rum, and wine. In this method, the sample is made ca 0.SN with sulfuric acid, and carbon tetrachloride containing 0.2% ZDBT is added. The colored copper-ZDBT complex is extracted in the carbon tetrachloride and measured at 438 mμ against a similar carbon tetrachloride extract of a blank. Data show good precision, and it is recommended that the ZDBT method be adopted as official, first action.
Estimation of Afiatoxin M in Milk
Authors: Purchase I F H , Steyn M 
Published: February 2020

Abstract
The ability of various solvents, using a Soxhlet extractor and a mechanical shaker, to extract anatoxin M from freeze-dried milk powder was compared. Extraction is most efficient when the sample is extracted with an azcotropic mixture of acetone-chlo-roform-water in a Soxhlet apparatus.
Infrared Spectra of Carbophenothion (Trithion) and Some
of Its Possible Metabolic Products
Authors: Chen Jo-Yun T , Dority Roland W 
Published: February 2020

Abstract
The infrared spectra of carbophenothion and five of its possible metabolic products are interpreted and discussed in this paper. A table summarizing the characteristic infrared spectra of each compound accompanies the spectra. The infrared spectra of these six compounds are sufficiently different to serve as reference curves in the identification of organophosphorus pesticide residues
Collaborative Study of Microbiological Assay for Low
Chlortetracycline Concentrations in Final Feeds
Authors: Abbey Anthony 
Published: February 2020

Abstract
Two batches of commercial poultry feed containing low levels of chlortetracycline (CTC) activity (ca 10 ppm) were assayed collaboratively in 15 laboratories. The coefficients of variation for the individual batches were 10.0 and 9.2%, respectively; combining the data for both batches gave a coefficient of variation of 9.6%. The microbiological assay procedure, utilizing compensating CTC standard curves prepared with a diluent containing sodium hypochlorite- inactivated animal feed extracts, was found applicable in all 15 participating laboratories. The method is recommended for adoption as official, first action.
Evaluation of the Effects of Eleven Bleaching Agents on
Ground Cocoa Bean Tissue, Insect Fragments, and
Rodent Hairs
Authors: Gecan John S , Brickey P M 
Published: February 2020

Abstract
Eleven bleaching agents were used to decolorize cocoa tissues, and their effects on insect fragments and rodent hairs were studied. Gilorine bleaches, potassium permanganate, and hydrogen peroxide all result in good bleaching of ground cocoa. However, chlorine bleaches completely destroy rodent hair, and potassium permanganate is not effective for high fat products. Hydrogen peroxide decolorizes cocoa bean tissue very well and does not destroy rodent hairs nor decolorize insect fragments. A mechanical means of evaluating the amount of bleaching of cocoa bean tissues is also described. Future studies are planned on the use of hydrogen peroxide as a plant tissue bleaching agent
Uncombined Intermediates in FD&C Blue No. 1
Authors: Johnson Robert K 
Published: February 2020

Abstract
A collaborative study of the method derived from one proposed by Schumacher, This Journal, 48, 819-826 (1965), was sponsored by the Subcommittee on Analytical Methods, Certified Color Industry Committee. All 6 domestic manufacturers of certified food colors were represented as well as the Division of Color Certification and Evaluation, FDA, Washington, D.C. Eight collaborators analyzed 3 samples each. Intermediates were separated by column chromatography and their concentrations were estimated from ultraviolet absorption measurements. N-Ethyl-iV-(3-sulfobenzyl) sulfanilic acid (ESBSA) and mixed isomers of sulfobenzaldehyde (SB) were recovered at an average level of 98% of the amounts added. Between-laboratory standard deviations ranged from 0.014 to 0.18% when the intermediates were present at levels of 0.07-1.46%. The method is recommended for adoption as official, first action
Gas Chromatographic Determination of Residues of
Organophosphorus Pesticides with a Modified
Flame Ionization Detector
Authors: Ford Joseph H , Beroza Morton 
Published: February 2020

Abstract
The effect of various salt coatings, metals, and carrier gases was investigated in an attempt to improve the Giuffrida thermionic detector for residues of phosphorus-containing pesticides. As reported recently hy Giuffrida et al., the highest sensitivity to phosphorus (with insignificant response to halogen) was obtained with a potassium chloride coating. The use of helium as the carrier gas produced an 8-fold enhancement in response to phosphorus over that obtained with nitrogen, and the response to halogen remained nil. Substrate interference was very low with the KCI detector and helium carrier gas, and analyses were possible at the subnanogram level
Determination of Methimazole by Infrared Spectrophotometry
Authors: Hayden Alma L , Brannon Wilson L 
Published: February 2020

Abstract
A method is described in which melhimazole is separated from tablet excipients by column chromatography on Celite 545 with chloroform as the eluant and then quantitatively measured and identified by infrared spectrophotometry. This method was studied collaboratively by 10 analysts; average recoveries from two simulated and two tablet mixtures ranged from 96.6% ± 1.0 to 101.1% ± 0.9. This method is recommended for adoption as official, first action.
Stoichiometry of the Volumetric Ammonium Phosphomolybdate Method for P2O5
Authors: Barker J E 
Published: February 2020

Abstract
A study was made to determine the stoichiometry of this method with particular reference to solubility losses and ammonia content of the precipitate. Studies show that the recovery of ammonia by distillation from a caustic solution is depressed by the presence of molybdic acid. Recovery was reduced to as little as 99% at the stoichiometric ratio of MoO3 to IN. The mechanism of this phenomenon is unknown. However, after standardizing the method for ammonia in the presence of molybdic acid, the yellow precipitate was found to contain 99.5% of the theoretical ammonia according to the formula (NH4)3PO4:12MoO3
Cobalt Loss by Dry Ashing in Porcelain Crucibles
Authors: Mays David L , Kessler Wayne V , Chilko John A , Schall Elwyn D 
Published: February 2020

Abstract
The adsorption of cobalt on porcelain crucibles during dry ashing was studied. The results showed that adsorption was slight if a residue was formed in the ashing procedure and heavy when no residue was formed.
Determination of Menthol in Cigarette Tobacco Filler
Authors: Tucker Charles L , Ogg C L 
Published: February 2020

Abstract
A gas chromatographic and a colorimetric method for determining menthol in cigarette tobacco filler were studied collaboratively by 15 laboratories. No statistically significant differences were found in the precisions within or between laboratories. There were no significant differences between mean values for the two methods for any of the samples. Trends toward higher mean values for the colorimetric method and lower within-laboratory standard deviations for the gas chromatographic method were noted. Remarks by collaborators suggest that the accuracy and precision of the colorimetric method may be improved, and further studies are recommended.
EDTA Titration of Calcium and Magnesium
Authors: Steagall Edward F 
Published: February 2020

Abstract
The revised method for the EDTA titration of calcium and/or magnesium in pharmaceutical preparations and canned whole tomatoes, adopted as official, first action last year, was studied collaboratively again this year. Two simulated pharmaceutical mixtures and two samples of tomato juice were analyzed by 13 analysts in 12 laboratories. The results were easily reproducible, and the agreement between laboratories was good. The required use of a pH meter in all pH adjustments has eliminated most of the turbidity and fading end points; occasional turbidity or fading end points are due to faulty or improperly prepared resin that does not completely remove phosphates. Because the revised method gives continuing precision and low standard deviations, it is recommended for adoption as official, final action.
lAscorbic and d-Isoascorbic Acids: Quantitative Separation and Assay
Authors: Weeks Cora E , Deutsch Mike J 
Published: February 2020

Abstract
d-Isoascorbic (erythorbic) acid is a permissible food additive. Chemical assays do not differentiate between the additive and the vitamin, l-ascorbic acid. Chromatography on silicic acid-impregnated glass fiber paper separates the two acids in 25 minutes. They are extracted from the chromatogram and assayed by the microfluorometric method (Deutsch and Weeks, This Journal, 48, 1248-1256 (1965)). Modifications have been developed for assaying small volumes of solution. Concentrations as low as 1.8 /μg/20 μl can be successfully separated and assayed.
Gas-Liquid Chromatographic Method for the Determination of Fat-Soluble Vitamins. V. Application to Pharmaceuticals Containing Vitamin E
Authors: Pillsbury H C , Sheppard Alan J , Libby David A 
Published: February 2020

Abstract
Gas-liquid chromatography, using a 5% SE-30 column and a hydrogen flame detector, has been used to quantitate vitamin E in pharmaceuticals. The gas chromatographic measurements were compared with the Emmerie-Engel results obtained on the same samples. Because of total recovery, smaller standard deviation, and simplicity, the GLC method was more desirable than the Emmerie-Engle method which includes a saponification preparatory step. The GLC method is also specific for each of the tocopherol analogs measured.
Studies on the Stability of Chlortetracycline in Mixed Feeds: Epimerization of Chlortetracycline
Authors: Katz Stanley E , Fassbender Carol A 
Published: February 2020

Abstract
Chlortetracycline is known to degrade in aqueous solution by four pathways: anhydrochlortetracycline formation under strong acid conditions, epimerization under weakly acid conditions, isochlortetracycline formation under strongly basic conditions (usually anaerobic), and formation of a desdimethylamino chlortetracycline compound under aerobic conditions at pH values greater than 5. Studies on feeds decomposed to 50% of activity indicated that isochlortetracycline and anbydrochlortetracycline were not formed in the decomposition, while epichlortetracycline and a highly fluorescent unknown compound were formed. Epimerization occurs rapidly in feeds, reaching an equilibrium in a few hours. In several types of feed, protein, fat, fiber, moisture contents, and pH did not affect the degree of epimerization. Temperature of storage appears to be significant. Data suggest that an equilibrium is established between the chlortetracycline and epichlortetracycline followed by breakdown of either chlortetracycline or its epimer or both to as yet unidentified products.
Collaborative Study of the Determination of Ethoxyquin In Chick Tissue and Eggs
Authors: Vanderen J M , Jaworski E G 
Published: February 2020

Abstract
The method for determining ethoxyquin (Santoquin) in chicken muscle, liver, and egg and a procedure for fat have been studied collaboratively. Results were reproducible for individual collaborators but not between collaborators. A sensitive standard curve, i.e., one which has an instrument reading of &gt; 50% full scale for the most concentrated ethoxyquin standard, was prepared to compare between-collaborator precision. With sensitive standard curves, the standard deviation was &lt; 10% of the average value for sample analyses. Determinations must be made on an instrument with sufficient sensitivity. For analyses with low standard deviations, average ethoxyquin recoveries of 75% were obtained for egg yolks and chicken liver and muscle and 85% recovery for chicken fat.
Sodium Lauryl Sulfate in Egg Whites
Authors: Wiskerchen John 
Published: February 2020

Abstract
A method is given for the quantitative determination of sodium lauryl sulfate in liquid, frozen, powdered, or flake-dried egg white. The egg white is dissolved in water and the protein is precipitated with ethanol and filtered off. The filtrate is evaporated, the residue is dissolved in water, and the pH is adjusted to 5.0. Total alkyl sulfates are titrated with standard benzethonium chloride solution in the presence of chloroform with bromphenol blue indicator. Results are calculated as sodium lauryl sulfate. The formation of the bromphenol bluebenzethonium chloride complex, when excess benzethonium chloride is present, is taken as the end point. The blue-green complex is soluble in the chloroform. Overall recoveries of sodium lauryl sulfate from egg whites ranged from 94 to 100%. Collaborative study of the method is recommended.
Further Collaborative Studies on Methods for Vanillin and Ethyl Vanillin in Flavoring Material
Authors: Fitelson J 
Published: February 2020

Abstract
A second collaborative study was conducted on two ultraviolet absorption methods for vanillin (the official, final action screening method and the official, first action modified method) and on a paper chromatographic method for the detection of vanillin and ethyl vanillin when present together. All three methods gave adequate and reproducible results. Both the modified ultraviolet method and the paper chromatographic procedure are .recommended for adoption as official, final action.
Determination of Nicotine Residues on Foods
Authors: Martin Robert J 
Published: February 2020

Abstract
Mustard green samples were analyzed by the official method for nicotine content. The final determinative step was made on a gas chromatograph equipped with a thermionic detector (coated with KC1). The final extract was chromatographed on a 6' X 4 mm i.d. glass column containing Gas Chrom Q coated with 10% DC-200 and maintained at 125°C. Flow rate (nitrogen) was 135 ml/niin. Amounts as low as 0.3 μg nicotine were detected. Response was linear from 0.1 to 1.0 μg. For identification, a portion of the effluent was split and 2 or 3 combined injections were trapped in petroleum ether and spotted on a TLC plate as described in This Journal, 49, 175— 179 (1966).
System for the Determination of the Potential Degradability of Urea-Aldehyde Condensates Used as Fertilizers
Authors: Katz Stanley E , Fassbender Carol A 
Published: February 2020

Abstract
A solution biodegradability system, based upon the biochemical oxygen demand principle, narrower fractionation of materials, and use of microbial cultures adapted to these individual fractions, was developed to determine potential availability. Urea-formaldehyde condensates were fractionated into five fractions: the 25°C water-soluble fraction, the fraction insoluble at 25°C but soluble at 50°C, the fraction insoluble at 50 °C but soluble at 75 °C, the fraction insoluble at 75°C but soluble at 100°C, and the fraction insoluble at 100°C. Mixed microbial cultures were developed to utilize the nitrogen in these fractions as a source of nitrogen. Degradation studies of these fractions showed that each fraction used 90—100% of the theoretical amount of nitrogen. Sample sizes as large as 0.2 g of ureaform can be used. When this system was applied to the urea-crotonaldehyde condensate used as a fertilizer, results showed that 90—105% of the nitrogen was utilizable. These biodegradability principles are useful in determining the potential degradability of any urea-aldehyde condensate showing agronomic potential.
Comparison of Various Carbon Adsorbents and Quantitative Elution and Separation of Forty-two Pesticides from a Carbon-Solka Floe Cleanup Column
Authors: Mcleod H A , Mendoza C , Wales P , Mckinley W P 
Published: February 2020

Abstract
Ten different carbons were investigated as adsorbents in a column cleanup procedure for extracts of lettuce and carrots. Organochlorine pesticides were eluted with 175 nil of 1.5% acetonitrile in hexane. The quantitative elution of 13 pesticides as a mixture with and without the presence of carrot or lettuce extract was determined by gas-liquid chromatography (GLC) with electron capture detection (ECD). The mean recovery values for each pesticide from all carbons, excluding Norit A neutral, ranged from 87 to 106% with a coefficient of variation (C) of 3 to 11. In the presence of plant extracts the individual pesticide recoveries for 6 carbons ranged from 75 lo 99% with a C of 6 to 16. All pesticides from 9 individual carbons had mean recovery values ranging from 93 to 108% with a C of 5 to 10. In the presence of plant extracts these values were 81 to 100% with a C of 8 to 12. Four carbons (Darco G60, Darco S51, Nuchar C-190N, Norit FQP) were considered satisfactory in the cleanup procedure. The procedure was applied to quantitative elution of 42 pesticides representing insecticides, fungicides, and herbicides from a Darco G60-Solka Floe cleanup column. The mean per cent recoveries (3 determinations) ranged from 82 to 112 with C from 2 to 10 for 38 compounds. The mean per cent recovery of EPN was 108 with a C of 13. The per cent recoveries of three compounds were considered low: Thimet 72, Daconil 73, and Guthion 77. Twenty of the pesticides as three mixtures containing 2, 4, and 14 compounds were added to plant extracts of carrots, potatoes, wheat, and pineapples. The mean per cent recovery values ranged from 81 to 108 with a C range of 2 to 10 for 17 compounds
A Rapid Specific Method for the Gas Chromatographic Determination of Organophosphate Pesticides in Cold Pressed Citrus Oils
Authors: Stevens Robert K 
Published: February 2020

Abstract
Organophosphate pesticides in cold pressed citrus oils can be determined rapidly by a method using gas chromatographic procedures and the flame photometric detector developed by Brody and Chaney. This study revealed that cold pressed citrus oils obtained from the 1965— 1966 citrus crops from Florida and California contained from 1.5 to 20 ppm thiophosphate pesticides. The analytical procedure required approximately 40 min per analysis and eliminated the need for extensive preparation of the sample prior to introduction into the gas chromatograph. The procedure is more specific and less time consuming than methods previously described
Sesquiterpene Hydrocarbons of Commercial Copaiba Balsam and American Cedarwood Oils
Authors: Wenninger John A , Yates Ronald L , Dolinsky Meyer 
Published: February 2020

Abstract
The sesquiterpene hydrocarbons of commercial samples of copaiba balsam and American cedarwood oils were separated by a combination of techniques including silver nitrate adduction, column chromatography on alumina, distillation, and gas chromatography. Components were identified by their infrared spectra. Of the 24 sesquiterpene hydrocarbons detected in copaiba balsam oil, 18 were identified as follows: δ-elemcne, copaene, β-cubebene, cyperene, α-bergamotene, β-elemene, caryophyllene,γ -elemene, β-farnesene, allo-aromadendrene, α-, β-humuIene, β-bisabolene, α-selinene, β-selinene, δ-cadinene, ar-curcumene, γ -cadinene, calamenene, and a-cubebene (tentatively identified). The following sesquiterpene hydrocarbons were identified in American cedarwood oil: β-eIemene, acedrene, caryophyllene, thujopsene, α-,βhumulene, "acorene," valencene, cuparene, a cuprenene, and two additional hydrocarbons (tentatively identified). Gas chromatographic retention data are reported for 27 of the sesquiterpene hydrocarbons isolated
Gas-Liquid Chromatography of Vitamin B6 (Pyridoxal, Pyridoxol, and Pyridoxamine) and Its Application to Pharmaceuticals Containing Pyridoxol
Authors: Prosser A R , Sheppard A J , Libby D A 
Published: February 2020

Abstract
A gas chromatographic procedure has been developed for the determination of pyridoxal, pyridoxol, and pyridoxamine. These compounds are first converted to their acetyl derivatives and then injected into the gas chromatograph. The acetyl derivatives are formed by the interaction of the vitamin B6 analogs with acetic anhydride in the presence of a catalyst, extracted with a suitable organic solvent, and separated by gas chromatographic techniques. Results were confirmed by infrared, ultraviolet, nuclear magnetic resonance, and mass spectrometry. This technique has been successfully used to quantitatively measure the pyridoxol content of pharmaceutical products
A Sensitive Method for the Detection and Determination of Reducing Substances, as Hydroquinone, in Ergocalciferol
Authors: Guttman David E 
Published: February 2020

Abstract
A rapid and simple method for the detection and determination of reducing substances, as hydroquinone, in ergocalciferol is based on the large difference between hydroquinone and ergocalciferol in rate of reaction with blue tetrazolium. The tetrazolium salt was found to be effectively and rapidly reduced by hydroquinone; only slight reaction occurred with ergocalciferol. The method will detect levels of hydroquinone in the vitamin as low as 0.001% (w/w) and can give a quantitative estimation of hydroquinone content. Some commercial samples of erogocalciferol were found by the proposed method to contain appreciable amounts of hydroquinone that could not be detected by the spectrophotometric method of USP XVII
Spectrographs Determination of Lead in Agricultural and Related Materials
Authors: Maclean K S , Byers D L , Brown M H 
Published: February 2020

Abstract
A quantitative spectrograph^ method has been developed for the determination of lead in plant tissue, soils, and biological material. Organic matter is removed by ashing, and a mixture of 20 mg sample plus 40 mg of a lithium carbonate-graphite buffer is arced in a d-c arc under atmospheric conditions. Lead standards are prepared in a silica dioxide-aluminum oxidesodium carbonate base matrix to cover the range 5—1000 ppm, with bismuth as an internal standard. Other elements do not cause serious interferences. A minimum of 0.2 ppm lead can be determined in plant tissue, 2.5 ppm in soil, and 0.05 ppm in animal livers (dry weight basis). By dilution with base material, lead concentrations of up to 16% can be determined accurately, as indicated by analysis of high grade lead ores. Results for several samples have an average relative error of 5.2%.
Survey of Polycyclic Aromatic Hydrocarbons in
Smoked Foods
Authors: Malanoski A J , Greenfield E L , Barnes C J , Worthington J M , Joe F L 
Published: February 2020

Abstract
A survey was conducted jointly by the Food and Drug Administration and the Department of Agriculture to ascertain the types and amounts of polycyclic aromatic hydrocarbons present in smoked foods. The samples include many varieties of meat products, poultry, fish, and other miscellaneous items. All samples were analyzed by the published methods of Howard et al. Results indicate that many smoked foods contain small amounts (0.5—7.0 ppb) of polycyclic aromatic hydrocarbons
Determination of DLTDP and Other Antioxidants by a
Modified Sublimation Technique
Authors: Fazio Thomas , Howard John W , Sandoval Armando 
Published: February 2020

Abstract
A method has been developed for the determination of dilaurylthiodipropionate (DLTDP) and other antioxidants in lard, using a simplified and less complex vacuum procedure than previously reported. Recoveries ranged from 93-100% for DLTDP, 91-96% for BHT, 85-105% for Ionox- 100, 90-100% for PG, and 9 1% for BHA
TLC Spotting Solvent for Aflatoxins
Authors: Stoloff L , Beckwith A C , Cushmac Mary E 
Published: February 2020

Abstract
Benzene is recommended as a spotting solvent for aflatoxins on silica gel thin layer plates in preference to chloroform. Based on a 12-month study of stability and practical application, aflatoxin in benzene was as stable as in chloroform; benzene was less volatile, helping insure volume integrity, and easier to manipulate than chloroform. Spots on thin layer chromatograms were more compact and uniform when dispensed from benzene than from chloroform.