bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Potassium and Calcium in Tobacco
Authors: Cundiff Robert H , Dobbins J T 
Published: February 2020

Abstract
The methods for potassium and calcium in tobacco, based on column elution with dilute HC1 followed by flame photometry of the extract, were studied collaboratively by 12 laboratories. Potassium results were sufficiently precise to recommend that the potassium procedure be adopted as an official, first action method. Results for calcium indicate that additional study is necessary. Atomic absorption spectrophotometry offers considerable promise in overcoming many of the hindrances experienced with flame photometry, particularly the calcium measurement.
Determination of Aflatoxins in Agricultural Products: Use of Aqueous Acetone for Extraction
Authors: Pons W A , Cucullu A F , Lee L S , Robertson J A , Franz A O , Goldblatt L A 
Published: February 2020

Abstract
An analytical procedure originally developed for the determination of aflatoxins in cottonseed products has been modified for application to many agricultural materials. Aflatoxins are rapidly extracted free of lipid contamination with 70% acetone. Many interfering pigments are removed from the crude extract by precipitation as insoluble lead derivatives, transfer of aflatoxins into chloroform, and further purification of the chloroform extract with silica gel.
The procedure was compared with four recently proposed methods for the analysis of peanut products. This technique is capable of detecting as little as 0.3 ppb of aflatoxin Bi in peanuts and peanut butters. Adequate recovery of added aflatoxins was obtained when this method was applied to numerous different agricultural products.
Extraction and Estimation of Polycyclic Aromatic Hydrocarbons in Smoked Foods. I. General Method
Authors: Howard John W , Teague Robert T , White Richard H , Fry Bert E 
Published: February 2020

Abstract
A method for the isolation and determination of polycyclic aromatic hydrocarbons in smoked foods has been developed. The compounds are extracted with ethanol, saponified with potassium hydroxide in a Soxhlet apparatus, concentrated, diluted with water, and extracted with a hydrocarbon solvent. The polycyclic hydrocarbons are isolated by partition, paper, and thin layer chromatography and measured by ultraviolet and spectrophotofiuorometric procedures. Average recoveries of benzo(a)- pyrene, dibenz(a,h) anthracene, benz(a)- anthracene, and benzo(g,h,i)perylene, added to 500 g samples of frankfurters, cheese, and fish at levels of 2 ppb, ranged from 70 to 88%. The carcinogen, benzo(a)- pyrene, was isolated from smoked fish and ham samples at levels varying from 0.8 to 3.2 ppb.
Paper Chromatography in Pesticide Residue Analysis
Authors: Coffin D E 
Published: February 2020

Abstract
Some of the paper chromatographic techniques and detection methods used for pesticide residue analysis are reviewed. Procedures utilized for quantitative estimation pesticide residues separated by paper chromatography, such as measurement of spot size, combusion prior to analysis, and elution before chemical analysis, are also discussed. The advantages and disadvantages of paper chromatographic techniques and the problems inherent in the paper chromatographic separation and detection of minute amounts of pesticide residues are outlined. Additional applications and modifications of paper chromatography to extend its usefulness in pesticide residue analysis are suggested.
Screening Procedure for Organothiophosphate Pesticide Residues on Fruits and Vegetables by Microeoulometric Gas Chromatography
Authors: Nelson Richard C 
Published: February 2020

Abstract
Microeoulometric gas chromatography (sulfur detector) has been extended to include additional cleanup of the petroleum ether extract, using Florisil columns of varying lengths with eluting mixtures of ethyl ether/dioxane in petroleum ether. Preliminary results show fair-to-good recoveries of most compounds and generally satisfactory cleanup of six crops. A procedure is presented for the extraction and determination of the thiophosphates remaining in the acetonitrile-water layer after petroleum ether partitioning. Recoveries of dimethoate (0.2–2.0 ppm level) and Guthion (2.0–10.0 ppm level) were 70% or better. Studies of the method will be continued, with emphasis on cleanup procedvires.
Determination of Nicotine Residues on Foods
Authors: Martin Robert J , Schwartzman George 
Published: February 2020

Abstract
Mustard green samples were analyzed by the official method for nicotine content. The high crop blank exhibited by these samples was shown by a new qualitative TLC technique to be due to crop extractives rather than to the presence of nicotine. Nicotine is determined qualitatively on a TLC plate coated with silica gel G, 0.25 μ thick and activated at 80°C lor 2 hours, and developed with a chlo rof orm-ethanol solvent. After the developed plate is sprayed with the Dragendorff reagent, nicotine, at an Rf of 0.45, appears as an orange spot on a light yellow background. Amounts as low as 2–3 μg nicotine have been detected with this method.
Determination of Submicrogram Quantities of Mercury by Cold Vapor Atomic Absorption Photometry
Authors: Pappas Ernest G , Rosenberg Lynn A 
Published: February 2020

Abstract
One gram samples are burned in oxygen in a modified Schöniger flask, and the combustion products are absorbed into 1.2N HCl. After neutralization of this solution to pH 6–7, the mercury is collected as HgS on CdS-impregnated asbestos pads. The pads are pyrolyzed at 650°C, and the vapors are swept by nitrogen gas into a cold vapor atomic absorption cell where the absorption by mercury is measured. Interferences that may absorb are removed by a series of traps before they reach the absorption cell. Mercury recoveries from wheat at levels between 0.01 and 2.00 ppm averaged 86%. Wheat samples treated with organic mercurials as well as untreated samples were analyzed.
Colorimetric Determination of Mercury Residues on Rice
Authors: Epps Ernest A 
Published: February 2020

Abstract
Mercury residues at the microgram level are determined in rice by digestion with nitric and perchloric acids; mercury loss by volatilization is prevented by using a packed air condenser. Final determination is made colorimetrically with dithizone. The method is simple; it requires no complex glassware and a only minimum of manipulation. It is adaptable for use on other plant and animal tissues.
Detection of PG, NDGA, BHT, and BHA in Fats and Oils by Thin Layer Chromatography
Authors: Scheidt Shirley A , Conroy Harry W 
Published: February 2020

Abstract
PG, NDGA, BHT, and BHA were extracted with acetonitrile from fat or oil, followed by thin layer chromatographic separation and identification. The four antioxidants were distinctly separated from one another by one-dimensional solvent development of the silica gel adsorbent layer. The chromatography required &lt; 1 hour from spotting to visualization with 2,6-dichloroquinone chlorimide. As little as 1 μg of BHT and 0.5 μg of PG, NDGA, and BHA were detected by this method.
Mineral Oil in Foods
Authors: Silverberg Hymen D , Marchin John , Morgenstern Walter W 
Published: February 2020

Abstract
A collaborative study was conducted of the method for mineral oil in foods published in This Journal, 45, 241 (1962). Suggestions and recommendations by the collaborators were evaluated, and necessary reagent and procedural changes were incorporated into the method prior to the current collaborative study. The method now includes the preparation of sample, extraction of the total oils from the dried bakery product, separation of the mineral-type oil from the total by an alkaline aluminum oxide column using petroleum ether, and identification of the dried, weighed, mineraltype oil by infrared and refractive index. The method is considered suitable for detecting small amounts of mineral-type oil in bakery products and is recommended for adoption as official, first action.
Determination of Benzoates and Hydroxybenzoates in Foods
Authors: Pinella Salvatore J , Falco Anthony D , Schwartzman George 
Published: February 2020

Abstract
A method has been devised for the qualitative and quantitative determination of benzoates and hydroxybenzoates in foods. The qualitative procedure is based on the TLC separation of benzoic acid, the hydroxybenzoates, and sorbic acid, using kieselguhr G-silica gel GF 254 as the absorbent and hexane:acetic acid as the mobile solvent. The separated preserving acids are identified under UV radiation and by specific chromogenic reagents. Benzoic acid in foods was determined quantitatively by steam distillation, extraction, and TLC separation. The benzoic acid was removed from the chromatographic plate, extracted with ethanol, and determined in the UV region with a recording spectrophotometer and 5 cm micro cells. These procedures should be subjected to collaborative study.
Fluorometric and Thin Layer Chromatographic Determination of Aminacrine and Its Salts in Drug Preparations
Authors: Roberts Laura A 
Published: February 2020

Abstract
A fluorometric method has been developed for the quantitative determination of aminacrine (USAN name for 9-aminoacridine) and its salts in a wide variety of drug preparations. Aminacrine is extracted with chloroform from basic solution, the chloroform is evaporated, and the residue is dissolved in acidic ethanol. Aminacrine is identified by thin layer chromatography; travel of sample and standard spots is compared under ultraviolet light. Aminacrine is confirmed by spraying the plate with a solution of antimony pentachloride in carbon tetrachloride to produce a yellow spot.
Rapid Colorimetric Method for the Determination of Methyl Salicylate in Medicated Oils
Authors: Dutt M C 
Published: February 2020

Abstract
The well-known reaction between methyl salicylate and ferric chloride has been successfully applied to the quantitative estimation of methyl salicylate in medicated oils. An aqueous solution of ferric chloride is added to an ether solution of medicated oil dissolved in excess water. After filtering, the absorbance of the filtrate is measured at 530 m/j, and the content of methyl salicylate is determined from a calibration curve. Methyl salicylate recoveries range from 92 to 97% for concentrations between 10 and 60% in a synthetic mixture. The method is simple and rapid, and compares favorably with Wilson’s method.
Effects of Calcination Temperature and Time on the Retentive Properties of Florisil Used for Pesticide Residue Analysis
Authors: Burke Jerry A , Malone Bernadette 
Published: February 2020

Abstract
Nineteen samples of Florisil, calcined at times ranging from 2 to 16 hours and temperatures ranging from 1000 to 1400°F, were evaluated by checking the elution of certain chlorinated pesticides and the retention of butterfat extractives by the column. Results indicated the choice of 1250°F/ three-hour calcination as the desired “activation.” Subsequent evaluations of 22 lots calcined at these conditions over a 5-month period showed consistency in the product as obtained from the manufacturer. This material, designated 60/100 PR (Pesticide Residue) Grade, is suggested for use in certain pesticide residue methodology.
Channel Layer Chromatography (CLC) : A Cleanup Procedure For Pesticide Residue Analysis
Authors: Matherne Mederic J , Bathalter William H 
Published: February 2020

Abstract
The chromatographic properties of aluminum oxide G are utilized to separate pesticide residues from plant extractives. A square glass plate is prepared with recessed, discrete parallel channels; the channels are filled with aluminum oxide G, creating flat rectangular columns or strips. Plant extractives are applied to the channel layer strip and the strip is chromatographed, first with acetonitrile and tetrahydrofuran (1 + 1) and then with acetonitrile alone. As the solvent rises, plant extractives remain in place or move only part way up the column, while pesticide residues move more rapidly and stay with the solvent front. The portion of the channel layer strip containing the solvent front (and any pesticides present in the product) is mechanically removed from the plate, and the pesticides are eluted from the adsorbent. This solution is injected directly into the gas chromatograph for identification and quantitative measurement. Addition of aldrin and endrin (0.050 and 0.030 ppm each) and dieldrin and thiodan (0.050 and 0.020 ppm each) to a composite of peanuts, onions, carrots, and cabbage resulted in recoveries from 74 to 98%. Recoveries of various chlorinated pesticides from different crops were good, ranging from 78 to 118%. Recoveries of pesticides from various food crops after cleanup with the Florisil column and with CLC were comparable.
Response Characteristics of a New “Stacked” Flame Ionization Detector
Authors: Abel Kenneth , Lanneau Keith , Stevens Robert K 
Published: February 2020

Abstract
A modified Karmen “stacked” flame detector has been designed which has controlled specificity for phosphates and halides in the order of 100,000–200,000 to 1 over other organic species. The background current of the upper flame is controlled by electrically heating a coil coated with an alkali salt, thus enabling the investigator to optimize the parameter for his burner gas mixture without consideration of the background current. From this study, it has been observed that a burner gas mixtvire of oxygen and hydrogen reduced the response for phosphates and preferentially favored organohalides. The detector can be applied to analysis of biological tissue extracts.
Response Characteristics of a New High Temperature Electron Capture Detector
Authors: Yauger W L , Addison L M , Stevens R K 
Published: February 2020

Abstract
An electron capture detector, which uses Ni63 as its radioactive source and whose design features permit operation up to 300°C, has been developed and tested. This detector exhibits essentially the same electron capture characteristics as a parallel plate detector using tritium, but it does not lose its activity when operated above 200°C. Continuous operation of this detector for 6 months at 300°C did not change its response pattern to a variety of organohalide and phosphate pesticides. Maintenance of this response integrity over a 6-month span shows that this detector is a considerable improvement over existing systems for routine quantitative gas chromatography of pesticide residvies.
An Improved Enzymatic-Ultraviolet Method for Determination of Uric Acid in Flours
Authors: Sen N P , Smith D Morison 
Published: February 2020

Abstract
Main improvements in the enzymaticultraviolet method for uric acid in flours include elimination of the uricase precipitation by trichloroacetic acid, which was not reproducible, and destruction of uricaselike material in flour before extraction. The method is capable of measuring as low as 3.2 mg uric acid per 100 g flour and is applicable to a variety of cereal products such as rice, rye, corn and soya flours, as well as barley, oats, etc.
Radioactivity in Phosphate Animal Feed and Fertilizers
Authors: Habashi Fathi 
Published: February 2020

Abstract
Commercially available defluorinated phosphate and dicalcium phosphates marketed as animal feed contain 0.01-0.02% uranium. If an animal is fed 1 lb of this material, a dose of about 0.17 microcurie will be given, which is about 20 times the maximum permissible limit.
Spectrophotometric Determination of Hexachlorophene and Zinc Phenolsulfonate in Aerosol Deodorants
Authors: Will Fritz , Varsel Charles 
Published: February 2020

Abstract
A spectrophotometric method has been developed for the determination of hexachlorophene (HCP) and zinc phenolsulfonate (ZPS) in aerosol deodorants. An ethanolie solution containing hexachlorophene and zinc phenolsulfonate was partitioned between water and chloroform, and the zinc phenolsulfonate was determined in the water phase at 270 mμ. The chloroform phase, containing hexachlorophene, was extracted with 0.1N KOH, and the hexachlorophene was determined in the KOH phase at 320 mμ. The method has been applied successfully to commercial samples of aerosol deodorants. The relative standard deviation at the 2 sigma level is ± 3.5% for hexachlorophene and ± 2.6% for zinc phenolsulfonate.
Determination of Methylcarbamate Pesticides in the Presence of Methyl Anthranilate in Concord Grapes
Authors: Broderick E J , Bourke J B , Mattick L R , Taschenberg E F , Avens A W 
Published: February 2020

Abstract
For a valid infrared analysis of carbamate pesticides in ripe Concord grapes, interference from methyl anthranilate should be eliminated without altering the carbamate concentration. This is possible by extracting the samples with acetone, filtering, and partitioning into chloroform. The sample is then cleaned up by precipitation with an aqueous ammonium chloride solution, methyl anthranilate is removed with a 25% hydrochloric acid wash, and the carbamate is determined by infrared spectroscopy. This method removes 93% of the interfering methyl anthranilate, thus permitting detection of as little as 50 μg of carbamate.
Micro-Infrared Analysis of Dieldrin, Endrin, and Other Chlorinated Pesticide Residues in Complex Substrates
Authors: Payne W R , Cox William S 
Published: February 2020

Abstract
The combination of column and thin layer chromatography provides an effective technique for the isolation of “trace” amounts of chlorinated hydrocarbon insecticides in complex substrates. These insecticides can then be identified by micro-infrared spectroscopy. The extraction procedures, column techniques, and KBr pellet preparation for analyses of chlorinated pesticides in industrial wastes are described.
Experiments with Evaporation of Solutions of Chlorinated Pesticides
Authors: Burke Jerry A , Mills Paul A , Bostwick David C 
Published: February 2020

Abstract
Various experiments with evaporation techniques and equipment have shown that severe losses of pesticides may occur when solutions are concentrated to volumes of 0.5 ml or less. About 10 ml of solution can be rapidly concentrated to 0.1–0.3 ml without loss of pesticide by attaching a micro Snyder column to a K-D collection tube and evaporating on a steam bath.
Separation and Identification of Substituted Urea Herbicides by Paper Chromatography
Authors: Mitchel Lloyd C 
Published: February 2020

Abstract
Nine substituted urea herbicides and/or their TCA salts and TCA can be separated from one another by the use of two solvent systems, one aqueous and the other nonaqueous, with the exception of monuron and 3-(2-chlorophenyI)-l-methylurea; the latter, however, is not a commercial pesticide. The compounds are detected in the chromatogram by screening under ultraviolet light, except TCA, or by spraying with the silver nitrate-2-phenoxyethanol chromogenic agent followed by exposure to germicidal ultraviolet light, except fenuron and the fenuron moiety in fenuron TCA.
Determination of Sorbitol in Bakery Products
Authors: Hundley Harvey K , Hughes Duane D 
Published: February 2020

Abstract
Sorbitol is extracted from bakery products with water, and nonreducing sugars are inverted by acid hydrolysis. Carbohydrates other than the sugar alcohols are degraded in alkaline solution and reaction products are removed by ion exchange resins. Sorbitol is determined by the amount of periodate consumed in oxidation and identified by thin layer chromatography.
Quantitative Determination of Sugar Alcohols in Dietetic Foods by Gas-Liquid Partition Chromatography (GLC). I. Analysis of Dietetic Biscuits
Authors: Jones H G , Smith D M , Sahasrabudhe M 
Published: February 2020

Abstract
GLC has been used to quantitatively measure the amount of sugar alcohols in dietetic biscuits. The total hexitol content is estimated by analysis of the trimethylsilyl ethers (TMS) and the individual hexitols are estimated as the acetate esters. An internal standard (1,4-sorbitan) was added to the biscuit during the extraction procedure. The TMS ethers were chromatographed on an SE-30 GLC column and the acetate esters were detected on a QF-l/BDS column. Recoveries of total hexitols from biscuits baked in the laboratory were 97–100%. Analyses of various commercial biscuits were also reported.
Gas-Liquid Chromatography of Some Fatty Acid Esters and Alcohols in Lipsticks
Authors: Gross Frederick C 
Published: February 2020

Abstract
Gas-liquid chromatography (GLC) is used to separate and determine the lipstick ingredients: butyl stearate, oleyl alcohol, cetyl alcohol, isopropyl myristate, and isopropyl palmitate. The interfering hydrocarbons normally found in lipsticks are removed by column chromatography prior to the GLC analysis. Two columns, Triton X-405 on Fluoroport T and Carbowax 20M on Fluoroport T, are used in the procedure. Those ingredients which are not well separated on one of these columns will separate on the other. An internal standard technique is used for quantitative determination of the ingredients. Recoveries of 93–107% were obtained when known amounts of these compounds were carried through the procedure. Recoveries in the same range were obtained when the compounds were added to commercial lipsticks. The method should be applicable to the determination of these compounds in other types of cosmetics. It is recommended that study be continued.
Determination of Dienestrol Diacetate in Mixed Feeds
Authors: Hill V B , Schneider E L , Martin E E 
Published: February 2020

Abstract
Dienestrol diacetate in broiler feeds is isolated by extraction followed by alkaline hydrolysis to yield the parent phenolic compound. Interferences are removed by partition between NaOH and chloroform, in a manner similar to the AOAC procedure for diethylstilbestrol. The dienestrol is acidified, extracted with chloroform, and measured spectrophotometrically at 610 mμ after reaction with anisaldehyde. Recovery of dienestrol diacetate from 4 feeds known to contain 23–92 ppm ranged from 93 to 107% with coefficients of variation of 7.0–16.4%. Values for blank feeds were low enough to exclude a feed blank from the analytical procedure. Amounts of colorimetric reagents, reaction time, and linearity of response were studied. Of 24 common medicaments and 6 solvents tested, only acetone interferes.
Identification of Fish Species by Agar Gel Electrophoresis
Authors: Hill Wilma S , Learson Robert J , Laxe J Perry 
Published: February 2020

Abstract
An electrophoretic method for the identification of fish species is described in which agar gel is used as the supporting medium. Electrophoresis takes place under constant temperature and voltage, and protein is detected by staining. The gels are fixed to glass histological slides that may be preserved indefinitely. Six determinations may be done together in less than three hours. This method has been used for species identification of fish in the fresh, frozen, freeze-dried, and precooked states.
Detection of Chick Edema Factor and Other Chlorinated Hydrocarbons in Fats and Oils by Electron Capture Gas Chromatography: Use of TLC as a Preliminary Cleanup Procedure
Authors: Huang Anita , Firestone David , Campbell A D 
Published: February 2020

Abstract
A thin layer chromatographic (TLC) procedure is described for detecting chick edema factor in fats and oils. A specific fraction containing chick edema factor compounds is isolated by TLC from extracted unsaponifiables and cleaned up by sulfuric acid treatment. The residue is analyzed by electron capture gas chromatography. Results on several toxic samples of fats or fatty acids were comparable to the alumina adsorption column-electron capture gas chromatographic procedure. A 1.56% reference toxic fat sample can be detected under the conditions described. Toxicity of the specific TLC fraction was verified by tissue culture and chick embryo assay. Highly chlorinated biphenyls and naphthalenes which produce characteristic symptoms of chick edema disease at higher levels than the chick edema factor were also detected.