bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collaborative Study of Gas Chromatographic Method for Determining Captan in Formulations
Authors: Carlstrom A A 
Published: February 2020

Abstract
Captan is extracted from inert substances with a solution containing dieldrin in dioxane. The GLC procedure is stated in performance requirements except to specify XE-60 packing in a glass column. The ratio of captan to HEOD peak heights is measured for the sample and compared to the same ratio calculated for standard captan. Effects of extraction, peak measuring technique, sample size variation, and captan degradation on column and in solution were investigated. Twenty chemists from 18 laboratories quantitatively measured captan content of 6 samples. The coefficient of variation for the 2 technicals was 3.67%, for the two 50% wettable powders, 2.07%, and for the 10% dusts, 5.78%. A significant amount of systematic error was detected. Submitted chromatograms of a standard injection revealed that if captan degraded, as detected by formation of tetrahydrophthalimide, answers were often outliers rejected by the Dixon test. The method has been adopted as official first action and it is recommended that the problem of captan degradation be studied further.
Comparative Efficiency of Two Methods and Two Plating Media for Isolation of Staphylococcus aureus from Foods
Authors: Tardio Joseph L , Baer Edward F 
Published: February 2020

Abstract
Modifications of 2 methods were compared for determination of staphylococci in foods as recommended by the International Committee on Microbiological Specifications for Foods. One method was a direct plating procedure using Baird-Parker (BP) medium. The second method was the current AOAC official first action method for isolation of Staphylococcus aureus from foods (41.018). The efficiency of Vogel and Johnson (VJ) agar and BP as plating media for the AOAC method was also compared. The presence of S. aureus (positive samples) was detected more often by the AOAC method than by the direct plating method. The use of BP as a plating medium in the AOAC method resulted in detection of 25% more positive samples than were detected with VJ agar.
Isolation and Enumeration of Staphylococcus aureus: Review and Recommendations for Revision of AOAC Method
Authors: Baer E F 
Published: February 2020

Abstract
The genesis of the present AOAC official first action method for isolation and enumeration of Staphylococcus is reviewed and information is supplied to support recommendations for revision of the method. It is recommended that the present method be revised by deleting instructions for preparation and use of Vogel and Johnson agar and substituting instructions for preparation and use of Baird-Parker medium. It is also recommended that a direct plating method be provided as an alternative method and that the required collaborative study of the alternative method be conducted. The recommendations have been accepted by the Association.
Comparative Efficiency of Two Enrichment and Four Plating Media for Isolation of Staphylococcus aureus
Authors: Baer E F , Gilden M M , Wienke C L , Mellitz M B 
Published: February 2020

Abstract
The efficiency of 2 enrichment broths and 4 plating media for detecting the presence of Staphylococcus aureus was compared in 109 food samples. Media tested were Trypticase Soy broth containing 10% NaCl (TSBS), the tellurite enrichment broth (TEB) of Giolitti and Cantoni, Vogel and Johnson agar, egg yolk 110 agar, tellurite polymyxin egg yolk agar, and Baird-Parker medium. S. aureus was detected more frequently with combinations of TSBS and the 4 plating media than with TEB combinations. We also found TEB more inconvenient to use than TSBS. The superiority of a single plating medium was not clearly demonstrated. In only 10 of 108 positive samples did one plating medium fail when all others successfully detected S. aureus, and in over 50% of these samples the organism was detected by all plating media tested.
Evaluation of a Rapid Procedure for Determining Organochlorine Insecticides in Raw and Canned Beef and Cheese Fat by Microcoulometric GLC
Authors: Iwata Y , Westlake W E , Gunther F A 
Published: February 2020

Abstract
The ingenious, completely column chromatographic cleanup procedure described by Wood for organochlorine pesticide residues in fats was found to be excellent for sample preparation for GLC analysis by chloride determination using a microcoulometric detector. Fortification studies on corned beef and ground beef fats (0.07–3.90 ppm) and cheese fat (0.02–0.50 ppm) with lindane, dieldrin, p,p′-DDT, and p,p′-DDE indicated recoveries no lower than 60% but generally greater than 80%. Only noninterfering trace amounts of fatty materials remained after the cleanup of 2 g fat samples.
Collaborative CIPAC Study of Titrimetric Methods for the Assay of Methylthio- and Chlorotriazines
Authors: Bosshardt H P , Nowak K , Eberle D O 
Published: February 2020

Abstract
Methylthiotriazines are analyzed by titration with perchloric acid, and chlorotriazines by titration with silver nitrate after condensation with morpholine. Two methylthiotriazines and 3 chlorotriazines—both technical active ingredients and wettable powder formulations—were analyzed by these methods in a CIPAC collaborative study in which 7 laboratories participated. Statistical evaluation of the results shows good reproducibility of assay values within laboratories and satisfactory agreement between laboratories. The titrimetric methods for the assay of triazines have been adopted as provisional CIPAC methods.
Determination of Iodide in Feeds and Plants by Ion-Selective Electrode Analysis
Authors: Hoover William L , Melton James R , Howard Peggy A 
Published: February 2020

Abstract
A method for determining low levels of iodide in feeds and plants is proposed. The samples are mixed with a 10% phosphate solution to maintain relatively constant ionic strength and pH and analyzed with a solid-state iodide electrode. Ashing is not required and there are no significant interferences by ions commonly found in feeds. The method is accurate in determining iodide content ranging from 10.0 ppm to high concentrations. Necessary conditions for storing and cleaning the electrodes are described. The proposed method is rapid and results compare favorably with AOAC method 7.091.
Determination of Carotene and Xanthophyll in Alfalfa Protein Concentrates
Authors: Knuckles B E , Witt S C , Miller R E , Bickoff E M 
Published: February 2020

Abstract
Methods for the determination of carotene and xanthophyll in dried protein concentrates prepared during the wet fractionation of alfalfa have been studied. The AOAC method for carotene and xanthophyll in dried forages, 39.018–39.023 (11th Ed.), proved most satisfactory for analysis of the dried whole juice. The modification of a method developed earlier in this laboratory for dried forages proved most effective for analysis of a protein concentrate, high in xanthophyll and carotene, prepared from the whole juice. The modified procedure gave significantly higher values for carotene and xanthophyll in this protein-xanthophyll concentrate than the AOAC method.
Comparison of GLC and Colorimetric Methods for Determination of Methanol in Alcoholic Beverages
Authors: Dyer R H 
Published: February 2020

Abstract
A comparison of results by a proposed GLC method and the present AOAC colorimetric method (9.071-9.074) for methanol in alcoholic beverages is presented. The GLC method utilizes a Carbowax 1500 on Chromosorb W column (similar to 9.063) for determination of methanol content at concentrations as low as 0.003% methanol. In the lower methanol concentrations the GLC results were higher, possibly due to a loss of methanol during the distillation required for the colorimetric method. A total of 20 samples of various alcoholic beverages were analyzed for methanol and the concentration of methanol ranged from 0.004 to 0.37%.
Atomic Absorption Spectrophotometric Determination of Molybdenum in Fertilizers
Authors: Koirtyohann SR , Hamilton Maureen 
Published: February 2020

Abstract
Molybdenum is extracted into chloroform from fertilizer sample solutions at pH 1.6 as the 8-hydroxyquinolate. Atomic absorption in the premixed nitrous oxide-acetylene flame is used for determination. Methyl isoamyl ketone is added to the chloroform extract to improve the burning qualities. The method is sensitive and precise but appears to have a positive bias of about 5%.
Determination of Boron in Fertilizers by Emission Flame Photometry in the Air-Hydrogen Flame
Authors: Pickett E E , Pau J C-M , Koirtyohann S R 
Published: February 2020

Abstract
The highly selective extraction of boron from acid solutions by 2-ethyl-l,3-hexanediol, recently applied to determination of boron in boronated fertilizers by atomic absorption, can be used also in the flame emission mode in the air-hydrogen flame with distinct advantage. This convenient and inexpensive flame, although relatively cool, excites boron oxide emission intensely and provides superior detection limits, about 0.1 ppm in the extract (time constant 2 sec). The freedom from interference provided by the extraction permits the background and boron oxide emission measurements to be made easily and reliably. Certain older flame photometers can be used satisfactorily, although modern flame emission photometers, including some atomic absorption instruments, equipped with recorders, are preferred. Interferences and extraction conditions were studied further and the method was tried on several fertilizers.
Collaborative Study of Simultaneous Carbon, Hydrogen, Nitrogen Determination by Two Automatic Analyzers
Authors: Scroggins Laverne H 
Published: February 2020

Abstract
A collaborative study was conducted, using 2 types of automatic carbon-hydrogen-nitrogen analyzers. Thirty collaborators performed duplicate analyses on 6 samples with the duplicates being run on different days. Two collaborators sent a set of results for both types of apparatus. The samples studied were sulfadiazine, sulfanilamide, benzyl isothiourea hydrochloride, nicotinic acid, stearic acid, and ethyl laurate. A critical factor was the choice of parameters or parameter combinations such as the catalyst used, combustion time, combustion temperature, reduction temperature, temperature differential between main and sub-ovens of the gas chromatographic column and detector unit, and use of on-line computer or electronic integrator. Evaluation of the data and overall consideration indicate that satisfactory results for carbon, hydrogen, and nitrogen may be obtained with either instrument. It is further indicated that certain conclusions will make possible an improvement in the results obtained by these apparatus. High combination temperature, low temperature differential between ovens, and the use of electronic integration of the detector response seem to be required for good accuracy and precision with the one apparatus. High temperature, longer combustion time, additional catalyst, and electronic integration led to better results with the other. It is, therefore, recommended that, before adoption as official first action, a second collaborative study be made, using the parameters indicated by this study.
Determination of Trace Amounts of Mercury in Foods by Flameless Atomic Absorption
Authors: Hoover William L , Vielton James R , Howard Peggy A 
Published: February 2020

Abstract
A method is proposed whereby levels as low as 0.01 μg He can be determined by flameless atomic absorption. A simple HNO3 digestion procedure is employed, and an easily constructed vapor aeration system is described. Maximum accuracy is obtained by multiple cycling and expulsion of mercury vapor. The method is rapid and accurate, and recoveries of organic and inorganic mercury in samples range from 95 to 102%.
Ion Exchange Method for Benztropine Mesylate in Tablets
Authors: Stricklin Marshall C , Smith Donald J 
Published: February 2020

Abstract
Benztropine is retained on a column of sulfonated polystyrene cation resin, then eluted with 250 ml l.00N alcoholic KC1 and determined by UV absorption. The recoveries of benztropine from a simulated drug preparation ranged from 99 to 106%. The analysis of 0.5 and 2 mg benztropine mesylate tablets both gave 101% of label declaration, respectively. It is recommended that the method be studied further before collaboration.
Collaborative Study of a Rapid Method for Extraction of Light Filth from Corn Meal, Rye, Pumpernickel, and Buckwheat Flour
Authors: Miller Mary T 
Published: February 2020

Abstract
A rapid method based on product defatting in a Soxhlet extractor, hydrolysis in acid-alcohol, water washing, and, finally, separation of light filth in mineral oil has been developed for the separation of light filth from white and yellow corn meal, cracked wheat, rye, pumpernickel, and buckwheat flour. Collaborative results are satisfactory for all products tested; the method has been adopted as official first action.
Use of the Microscope in Criminalistics
Authors: McCrone Walter C 
Published: February 2020

Abstract
The identification of particulate evidence can be divided into 3 groups: individualization (identification as from the same source) virtually impossible, individualization often impossible, and individualization usually possible. The use of comparison microscopes for the study of the wide range of physical evidence available (paper, blood, hair, glass, paint, etc.) should be expanded, considering the wide range of tools and techniques of microscopy available. Specific analytical tests for individualization of typical particulate evidence, paint chips and synthetic fiber, are listed.
Gas and Thin Layer Chromatographic Determination of Sugars in Cocoa Products
Authors: Luke Milton A 
Published: February 2020

Abstract
A GLC method is presented in which trifluoroacetate derivatives are used for the determination of sucrose and lactose in cocoa products. The samples are extracted with ether-petroleum ether to remove fats and oils, and the sugars are then extracted with water. An aliquot of the water solution is evaporated to dryness; the derivative is formed with trifluoroacetic anhydride and is quantitatively measured and identified by GLC. Recoveries ranged from 90 to 105%. The method is also applicable to glucose and fructose. A TLC method is also described which can be used as an additional identification test and for the semiquantitative measurement of glucose, fructose, sucrose, lactose, and maltose. It is recommended that the GLC and TLC methods for analysis of sugars in cocoa products be studied collaboratively.
Extraction and Microbiological Assay of Erythromycin in Feeds. I. Development of the Method
Authors: Winkler Victor W , Nyman Melvin A , Benjamin Floyd 
Published: February 2020

Abstract
The mixed solvent, methylal-methanol, serves as an excellent extractant of erythromycin from feeds. The microbiological assay solution may be prepared from the extract by simple dilution with phosphate buffer. Methylal-methanol is miscible with water and does not interfere with the Sarcina lutea assay, even when present in 20% concentration. The procedure was checked successfully on feeds blended under commercial conditions with the variables: rations—poultry and swine; drug forms—Methocel-coated and tallow matrix; pelleting adjuvants—control, 2% bentonite and 1% Masonex; drug levels—5, 10, and 100 g/ton. Release of erythromycin from pellets containing bentonite was accomplished by wetting the pellets with basic phosphate buffer prior to extraction.
Determination of Copper in Alfalfa
Authors: Baker A Donald 
Published: February 2020

Abstract
Copper in alfalfa is determined by atomic absorption spectrophotometry after dry-ashing or wet-ashing of the sample. The method is as precise as and considerably more rapid than the present AOAC method. The standard deviations of the method for wet- and dry-ashing sample preparation were 0.56 and 0.97%, respectively. Recovery of copper from spiked samples was 96—100%. Removal of silica by hydrofluoric acid fuming was not necessary.
TLC Method for Determination of o-Phenylphenol Residues in the Acetonitrile Extracts of Fruits and Vegetables
Authors: Davenport Joan E 
Published: February 2020

Abstract
A semiquantitative TLC method is described for the determination of o-phenylphenol (OPP) residue from the fungicide sodium o-phenylphenate applied to fruits and vegetables, o-Phenylphenol is extracted from crops with acetonitrile and cleaned up on a Florisil column. Residues separated by silica gel TLC are detected with p-nitrobenzenediazonium fl uoborate spray. Recoveries of 80-100% were obtained for OPP added at 0.1 to 200 ppm on 8 crops. Satisfactory intralaboratory recoveries of 68-115% were obtained for OPP at levels between 0.5 and 10.0 ppm.
A Review of Collaborative Studies of the Microslide Gel Diffusion Test for the Detection of Serologically Identifiable Staphylococcal Enterotoxins
Authors: Bennett R W 
Published: February 2020

Abstract
The high specificity of the microslide gel diffusion test far outweighs the more sensitive, but less specific, agglutination procedures for the detection of the serologically identifiable staphylococcal enterotoxins. The results of collaborative and interlaboratory studies during the past 2 years on the detection and identification of staphylococcal enterotoxins indicate that a high degree of sophistication and serological expertise is needed for proper test performance. These results showed that the test has a high degree of utility for those persons who have extensive training in the manipulation of this technique or a strong background in serological procedures. Since the microslide gel diffusion test, as well as any other serological procedure, is so dependent on the training and experience of the individuals who perform the analyses, there is no justification for continued collaborative studies on this procedure. Therefore, this project is being held in abeyance until other tests are available for comparative collaboration in the detection of this microbial toxin.
Colorimetric Determination of Carbaryl in Apple, Lettuce, Chard, and Tomato
Authors: De Riveros Maria H C K , Vonesch Eugenio E 
Published: February 2020

Abstract
A direct Spectrophotometric technique for determination of carbaryl in apple, lettuce, chard, and tomato has been developed, based on formation of a specific color complex with diazotized 2,5-dichloroaniline sulfate. Carbaryl is extracted with methylene chloride, concentrated, and cleaned up with zinc hydroxide. The color produced with diazotized 2,5-dichloroaniline is measured at 510 nm. Recoveries of added carbaryl from the 4 crops tested ranged from 89.6 to 105%.
Use of Dexsil 300 on a Specially Washed Chromosorb W for Multicomponent Residue Determinations of Phosphorus- and Sulfur-Containing Pesticides by Flame Photometric GLC
Authors: Bowman M C , Beroza Morton 
Published: February 2020

Abstract
A column containing the thermally stable liquid phase Dexsil® 300 on Chromosorb W specially washed with HC1 was found well suited for the multicomponent residue analysis of foods for phosphorus- and sulfur-containing pesticides by GLC with flame photometric detection and temperature programming. Interference accumulating on the column from analyses of large samples subjected to minimum cleanup was removed by replacing a short plug of glass wool and packing at the head of the column and purging the remaining packing with carrier gas at 400°C for 1 hr. Silicone O-rings for sealing the glass columns were replaced by asbestos-Dexsil 300 gaskets to permit operation at 400°C. Retention times relative to parathion of 146 pesticides containing phosphorus and/or sulfur are reported; they are similar to those obtained on a column of OV-101 on Gas-Chrom Q. Performance of the new column packing was illustrated by an analysis of milk for 10 organophosphorus pesticides. Recoveries of the pesticides at levels of 0.25-0.01 ppm were 73-98%. The specially washed support was superior to 2 others tried with Dexsil 300 because less conditioning of the packing was required, the resolution and response were improved, and decomposition of Dyfonate was avoided.
Determination of Chlorohydrins in Hydroxypropyl Starch Ethers
Authors: Brobst K M , Tai Han 
Published: February 2020

Abstract
An acid hydrolysis procedure is described to liberate chlorohydrins from the starch matrix in the determination of chlorohydrins in hydroxypropyl starch. An ether extraction method is then used to isolate the chlorohydrins which are separated and determined by gas chromatography. The sensitivity level was 1 ppm and recovery was 90% at 5 ppm.
Electron-Donor-Acceptor Complexing Reagents for the Analysis of Pesticides. I. Survey of Reagents and Instrumental Techniques
Authors: Hutzinger O , Jamieson W D , Macneil J D , Frei R W 
Published: February 2020

Abstract
The formation of electron-donor-acceptor complexes for the detection of pesticides and their metabolites in conjunction with thin layer chromatography is discussed. The method is nondestructive, as the π-complex formation is reversible. Thus, the pesticide (or metabolite) may be recovered after separation from the complexing agent. The complexes studied may be transferred into a mass spectrometer sample tube and individual spectra of the pesticide and complexing agent may be obtained at different temperatures. The complexes are generally highly colored and this is an additional aid in distinguishing between closely related pesticides and metabolites. The absorption spectra of the chromatographed species on thin layer plates may be determined by in situ reflectance spectroscopy. The techniques discussed lack the sensitivity of methods such as esterase inhibition or fluorescence, but provide a high degree of selectivity for samples which may be separated at the microgram level or higher. The method of complexation and the instrumental techniques discussed could be useful to researchers involved in metabolic or structural studies.
Atomic Absorption Determination of Boron in Foods
Authors: Holak Walter 
Published: February 2020

Abstract
A rapid and specific atomic absorption method is presented for the determination of boron as boric acid, which is usually added to foods at the 0.5% level. The sample is digested with sulfuric acid, nitric acid, and 30% hydrogen peroxide. Boron is then chelated with 2-ethyl-l,3-hexanediol and extracted into methyl isobutyl ketone. Absorption due to boron is measured in the organic layer and compared to standards similarly extracted and measured. Recovery studies with food samples indicate that the method may be applicable to a wide variety of foods.
Immunodiffusion Technique for the Identification of Animal Species
Authors: Fugate H Guy , Penn Shelton R 
Published: February 2020

Abstract
An agar-gel immunodiffusion technique was developed for the identification of meat animal species. A pattern of wells and troughs was cut from agar plates. The wells and troughs contained antigens and antisera, respectively. The diffusion of the antigens and antisera through the agar results in the formation of precipitin lines when optimum antigen-antibody conditions exist. The interpretation of the reactions depends upon the position of the formed precipitin lines in relation to each other. Eleven of 12 mixed tissue samples submitted to the authors’ laboratory for species determination were identified correctly by the agar-gel immunodiffusion test. The test is a relatively rapid and simple method of confirming the results of the tube precipitin ring test for animal species identification.