bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of GLC and Colorimetric Methods for Determination of Methanol in Alcoholic Beverages
Authors: Dyer R H
Published: February 2020

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.
Gas-Liquid Chromatographic Determination of N-Nitrosodimethylamine in Ham
Authors: Fiddler Walter , Doerr Robert C , Ertel John R , Wasserman Aaron E
Published: February 2020

A method is described for the gas chromatographic determination of N-nitrosodimethylamine in ham. The use of a commercial rubidium sulfate alkali flame ionization detector for nitrogen-containing compounds permits a simple cleanup procedure and a rapid analysis. This method consists of digesting the ham sample with methanolic KOH, distillation from aqueous alkali, washing the distillate with hexane, acidification and extraction of the aqueous layer with methylene chloride, and washing the extracts with base prior to concentration. The sensitivity of the method is 25 ppb; the average recoveries at this level range from 73 to 100%. Ten hams including 4 varieties were analyzed and found to contain less than 1 ppb apparent N-nitrosodimethylamine.
Identification of Amphetamines and Related Sympathomimetic Amines
Authors: Warren R J , Begosh P P , Zarembo J E
Published: February 2020

The IR, UV, and NMR spectral data as well as the pKa′ values of a series of 18 phenylpropyl amines are presented and discussed. The series includes the amphetamines and many of the commercially available phenylpropyl amines being used in the field of medicine as sympathomimetic agents. These data provide a basis for rapid identification of samples from biological, forensic, and medical research.
Identification and Determination of Sugars in Some Fruit Juices
Authors: Stepak Y , Lifshitz A
Published: February 2020

The sugars α-glucose, β-glucose, fructose, galactose, and sucrose were identified in the juice of Israel orange, grapefruit, and lemon by gas-liquid chromatographic methods. Rhamnose, xylose, and trehalose were also identified but only tentatively. The amounts of glucose and fructose before and after hydrolysis were measured in 88 samples of citrus juice by enzymatic methods. The concentration of glucose found was in all cases very near that of fructose. In other fruit juices (e.g., pear) the concentration of fructose was found to be higher than that of glucose. The ratio fructose:glucose cannot therefore be used as a criterion for purity in orange and grapefruit juices but may serve as a useful tool to detect addition of sucrose to other fruit juices.
Determination of Fill of Beer Containers
Authors: Schoeneman Robert L , Dyer Randolph H , Earl Elaine M , Greenfield Michael S
Published: February 2020

Since the tax on beer is based on volume, the Internal Revenue Service suggests that beer containers be filled as nearly as possible to the quantity shown on the label, with substantially as much underfill as overfill in each lot. However, the philosophy of weights and measures officials in protecting the consumer is that the beer container should always contain at least as much as the quantity shown on the label, with very little tolerance for underfills. These different attitudes illustrate the need for establishing reasonable and equitable fill tolerances. This paper compares and evaluates 2 methods (volumetric and gravimetric) for the determination of the fill of beer containers. These 2 methods were shown to give comparable results. Samples from 4 large and 4 small breweries were examined. The densities of the different samples and the contents in fluid ounces are tabulated. The effect of beer retention inside the container in the volumetric determination and the variations in container tare weights in the gravimetric method are examined. The effects of carbon dioxide on both methods are also discussed.
Colorimetric Method for Ester Content of Alcoholic Beverages
Authors: Coe G R , Baldwin S , Andreasen A A
Published: February 2020

A colorimetric method for determination of esters in alcoholic products was studied for the effect of procedural variables. It is based on the quantitative reaction of esters with hydroxylamine in alkaline solution to form a hydroxamic acid which, upon acidification, forms a colored complex in the presence of Fe(III) ions. Mathematical data are presented to demonstrate that the colorimetric method is superior to the AOAC saponification method, 9.051-9.052, for comparing samples which contain widely differing ester compositions. The colorimetric method is rapid and requires a small sample.
Gas Chromatographic Analysis of Kelthane Technical
Authors: Black R F , Kurtz C P , Baum H
Published: February 2020

A new gas chromatographic method for the analysis of Kelthane and minor impurities is under investigation. The separation is made on a 6′ glass column packed with 3% Oronite Polybutene 128 on Gas-Chrom Q, using temperature programming from 135 to 205°C. Retention time data for all known components in Kelthane Technical are reported. Work on a quantitative procedure for the determination of active ingredients and minor impurities, utilizing an internal standard (methyl myristate), is in progress.
Simultaneous Gas-Liquid Chromatographic Determination of Four Sulfonamides in Feeds
Authors: Daun Robert J
Published: February 2020

A procedure is described for the gas-liquid chromatographic determination of sulfathiazole, sulfamerazine, sulfamethazine, and sulfaquinoxaline in finished feeds at levels from 0.002 to 0.05%. The procedure utilizes a double derivatization technique to modify the sulfonamides so that they can be determined by gas-liquid chromatography with electron capture detection. The conditions for extraction, derivatization, and gas-liquid chromatography are given, along with recovery data.
Comparison of Two Infrared Methods for the Determination of Isolated Trans Unsaturation in Fats, Oils, and Methyl Ester Derivatives
Authors: Huang Anita , Firestone David
Published: February 2020

A study was made to compare the rapid method reported by Allen with the tentative method of the American Oil Chemists’ Society for the determination of isolated (unconjugated) trans isomers of unsaturated fatty acids. The rapid method was found to be less accurate. The accuracy of the rapid method can be improved by using an oil or methyl ester matrix with the same composition as the sample matrix for the determination of K-and f-values used for calculation of per cent trans isomers. Results obtained with both methods for methyl esters were more accurate than results for vegetable oils. An analysis of variance was performed to compare the methods.
Distribution of Chick Edema Factors in Chick Tissues
Authors: Firestone David , Flick D F , Ress J , Higginbotham G R
Published: February 2020

A study was made of hexa-, hepta-, and octachlorodibenzo-p-dioxin (higher chlorodioxins) absorption and tissue distribution in White Leghorn chicks fed a diet containing 3% toxic fat or the equivalent amount of the unsaponifiable fraction isolated from the toxic fat. Over 90% of the ingested higher chlorodioxins was excreted. Increasing chlorine content resulted in decreased absorption so that no octachlorodioxin could be detected in the tissues. Chlorodioxins were widely distributed in a number of tissues and it was estimated that 49% of the chlorodioxins detected in various tissues was present in the liver of the chicks fed the toxic unsaponifiable fraction.
Chromatography of Crude Aflatoxins on Adsorbosil-5
Authors: Chu Fun Sun
Published: February 2020

A method is described involving the use of Adsorbosil-5 silica gel as a stationary phase for aflatoxin purification. This method is especially advantageous for obtaining large quantities of aflatoxins B1 and G1 in a single chromatographic step. The distribution of individual aflatoxins in the different fractions obtained from chromatography on an Adsorbosil column is illustrated.
Improved Detection of Ochratoxin A on Thin Layer Plates
Authors: Trenk Hugh L , Chu Fun Sun
Published: February 2020

The fluorescent spectra of ochratoxins A, B, and C, one of the hydrolysis products of ochratoxin A, i.e., 5-chloro-3,4-dihydro-8-hydroxy-3-methylisocoumarin-7-carboxylic acid, and their respective ammoniated derivatives have been studied. The excitation maxima of these compounds shifted to a longer wavelength after exposure to ammonia fumes, whereas the emission maxima shifted to a shorter wavelength. The fluorescence intensity of ammoniated ochratoxin A was found to be almost twice that of ochratoxin A. It is suggested that TLC plates be exposed to ammonia fumes prior to densitometric analysis to increase the sensitivity of the assay for ochratoxin A.
Negative Ion Mass Spectra of Some Pesticidal Compounds
Authors: Rankin Peter C
Published: February 2020

A study of the negative ion mass spectra of a number of complex organic molecules (pesticides) was undertaken to determine what information this technique would yield for structural analysis. The simplicity of the negative ion mass spectra was a characteristic feature and the most abundant negative ions in the spectra were assumed to be similar to the stable carbanions postulated in classical organic chemistry. The simplicity of the mass spectra suggested a possible application of the technique to the identification of carbamate pesticides.
Determination of Residues of Carbofuran and Its Toxic Metabolites by Electron Capture Gas Chromatography after Derivative Formation
Authors: Butler Lillian I , Mcdonough Leslie M
Published: February 2020

Residues of carbofuran and its toxic metabolites (3-hydroxycarbofuran and 3-ketocarbofuran) were determined in cucumbers, lettuce, potatoes, tomatoes, tomato foliage, and soil. Samples were extracted with 0.25N HCl, partitioned into dichloromethane, and chromatographed on alumina. Liquid chromatography serves the dual purpose of cleaning up the sample and separating the phenols from the earbamates. The carbamate residues were then converted to trichloroacetates and determined by electron capture GLC. Recoveries ranged from 67.2 to 139.5% with most recoveries being 80-100%.
Air Sampling for Pesticides in the Human Environment
Authors: Tessari John D , Spencer David L
Published: February 2020

A simple and inexpensive method is described for the analysis of pesticides in air samples. The method involves quantitative extraction from a nylon chiffon cloth screen which has been exposed to the atmosphere for 5 days, followed by cleanup with aluminum oxide and Florisil column chromatography. Recovery studies were run on a cloth screen and results for the organochlorine pesticides ranged from 86 to 100% recovery. Evidence seems to indicate that an environment containing high residue levels has a direct relationship to pesticide body burden.
Mechanized Extraction and Cleanup of Atrazine Residues in Soil Prior to Gas Chromatographic Analysis
Authors: Ott D E , Formica G , Liebig G F , Eberle D O , Gunther F A
Published: February 2020

Complete mechanization of extraction and cleanup steps has been developed for atrazine residues in soils for analysis by nitrogen detector gas chromatography. Manually sieved and weighed soil samples are mechanically presented at a maximum rate of 6 per hour to this system, which delivers cleaned-up solvent extracts of the samples at the same rate to a fraction collector. Adjustment of final solvent volume in collection vessels and gas chromatography are performed manually in the present work. Atrazine residues in soils are thus rapidly determined down to a lower limit of 0.05 ppm.
Determination of Total Solids in Heterogeneous Heat-Sensitive Foods
Authors: Emmons D B , Larmond Elizabeth , Beckett D C
Published: February 2020

A study was conducted to determine the cause of poor precision in the determination of total solids in heterogeneous heat-sensitive foods. A larger, more representative sample and preliminary freeze-drying rather than air-drying of samples gave greater precision than a modified AOAC method. The standard deviation for creamed cottage cheese was ±0.060 for the modified AOAC method and ±0.016 for the method tested. Decreases in standard deviations were also obtained for fluid milk, uncreamed cottage cheese, and goose meat.
Screening Method for Aflatoxin in Corn and Various Corn Products
Authors: Dantzman John , Stoloff Leonard
Published: February 2020

An abbreviated AOAC method has been developed for detecting aflatoxin in corn. The residual oil from a water-chloroform extraction of the sample is used for spotting the thin layer chromatogram. The silica gel cleanup column is omitted, thereby realizing a substantial saving in time and materials. Sensitivity of the method is less than 5 μg aflatoxin Bi per kg corn sample. The method is applicable to shelled corn, corn meal, canned sweet corn, and corn breakfast cereal.
Collaborative Study of the Gas-Liquid Chromatographic Method for Determination of Stereochemical Composition of Amphetamine
Authors: Wells Clyde E
Published: February 2020

Eight laboratories collaboratively studied a method for the quantitative GLC determination of d- and l-amphetamine in tablets. The drugs are separated from tablet excipients by column chromatography and reacted with Ntrifluoroacetyl-( 0-prolyl chloride, and the resulting derivatives are analyzed by GLC. The samples consisted of commercial d-amphetamine sulfate tablets (with and without butabarbital), dl-amphetamine sulfate tablets, and a mixed d- and l-amphetamine sulfate standard. Recoveries were acceptable, and the standard deviations never exceeded 0.64%. The results demonstrate that the method gives good precision and accuracy, and the method is recommended for adoption as official first action.
Determination of Bismuth in Pharmaceutical Dosage Forms by Conventional DC Polarography
Authors: Plank William M
Published: February 2020

A method has been investigated for the determination of bismuth in pharmaceutical dosage forms by conventional dc polarography. The method is applicable to tablets, emulsions, suspensions, injectables, and bulk powders. A collaborative study has shown the method to be superior in accuracy and precision to the present official colorimetric method, 36.300- 36.304. The results from 16 determinations performed by 8 collaborators were: 100.0±1.5% recovery on a synthetic powder mix, a relative standard deviation of 1.9% on a commercial tablet sample, and a relative standard deviation of 2.1% on a magma sample. By comparison, the collaborative data reported for the present official method gave relative standard deviations of 3.4 and 3.2% on 2 samples of powder mixtures. It is recommended that the polarographic method be adopted as official first action.
Collaborative Study of the Determination of Dichlorophene in Veterinary Preparations by Ultraviolet Spectrophotometry
Authors: Gilvydis Dalia M
Published: February 2020

Dichlorophene is determined in veterinary preparations by a liquid-liquid extraction and UV quantitation. Eight collaborators each analyzed 4 commercial preparations and one synthetic mixture. The average recovery for dichlorophene in the synthetic mixture is 100.3% with a standard deviation of 2.13. The standard deviations obtained for the 5 samples range from 0.13 to 3.69 with coefficients of variation from 0.69 to 3.43. It is recommended that the method be adopted as official first action.
Assay of Strychnine in Nux Vomica Galenicals and in Formulations
Authors: Karawya M S , Ghourab M G
Published: February 2020

A colorimetric method is described for the estimation of strychnine in the presence of brucine. Strychnine is reduced with zinc amalgam and hydrochloric acid, and the color obtained by the action of nitroprussideacetaldehyde reagent on the reduced compound is measured. Brucine does not give this color reaction. The method was successfully used for the assay of strychnine in galenicals of nux vomica, as well as in various formulations.
Collaborative Study of a Colorimetric Determination of Nitroglycerin in Sublingual Tablets
Authors: Pfabe Yvonne H
Published: February 2020

The colorimetric determination of nitroglycerin in tablets (JAOAC 53, 579–581 (1970)) was collaboratively studied by 13 laboratories. The nitroglycerin is hydrolyzed to nitrite, which diazotizes p-chloroaniline; this diazotization product is coupled with N-(l-naphthyl)- ethylenediamine dihydrochloride and measured at 560 nm. Samples were analyzed at a composite level (1.2 mg) and at an individual tablet level (0.15–0.6 mg). Coefficients of variation ranged from 4 to 14%, with the highest variation in the individual assay of low dosage tablets. Samples analyzed by the Associate Referee 6 months after the first analysis showed lower assay results, indicating deterioration. It is recommended that this study be continued.
Analysis of Trisulfapyrimidine Preparations by Thin Layer Chromatography
Authors: Brunner Charlotte A
Published: February 2020

A method for the analysis of trisulfapyrimidine preparations is described. The total sulfonamide content is measured on the intact sample, and the ratio of the components is determined by colorimetric measurement of the individual compounds after separation by thin layer chromatography. A collaborative study will be performed.
Malonate Dulcitol Lysine Iron Agar—A New Differential Medium for the Identification of Salmonella Subgenera I—III
Authors: Stroup John R
Published: February 2020

A new differential medium, malonate dulcitol lysine iron agar, containing malonate, dulcitol, L-lysine, and an H2S indicating system has been developed for use at the triple sugar iron agar stage for the identification of Salmonella subgenera I–III. This medium differentiates the subgenera on the basis of the malonate and dulcitol reactions. L-Lysine is incorporated to confirm lysine decarboxylase activity for dulcitol-positive subgenus I cultures. Since it is a near minimal medium, it i? advantageous to inoculate triple sugar iron agar or lysine iron agar slants in parallel with the new medium to act as a source of cells for “O” group serology and to avoid missing aberrant biochemical types. Although a few atypical reactions were noted, all of the 35 typical Salmonella of subgenera I–III tested were typical on malonate dulcitol lysine iron agar medium. Triple sugar iron agar can be considered as giving a presumptive test for Salmonella. However, as it does not differentiate the subgenera, this distinction must be made when the results of in-depth biochemical tests are known. As the subgenera can be differentiated on the basis of malonate and dulcitol reactions, the new medium should allow for the presumptive identification of Salmonella subgenera at least 24 hr earlier than is now possible with conventional procedures.
Gas-Liquid Chromatographic Characterization of Sunscreens in Suntan Preparations
Authors: Paulus Geordie L
Published: February 2020

The spectrophotometric determination of isolated sunscreen compounds is often not specific enough to distinguish between closely related compounds. For this reason a procedure was developed for the identification of sunscreen compounds by gas-liquid chromatographic retention times. Partition chromatography is used to isolate the sunscreen from the cosmetic sample. Retention time data are listed for 16 sunscreens.
Rapid Spectrophotometry Method for the Determination of Sorbic Acid in Fresh Dairy Products
Authors: Maxstadt J J , Karasz A B
Published: February 2020

A rapid and accurate spectrophotometry method for sorbic acid in fresh dairy products has been developed. Sorbic acid is extracted from the dairy product with aqueous metaphosphoric acid and partitioned into an ethyl ether-petroleum ether mixture. The concentration of sorbic acid is determined from its absorbance at 250 nm and its presence is confirmed by the disappearance of this absorbance maximum after shaking the ether solution with aqueous permanganate. The procedure is very rapid; an analysis can be completed in 1 hr. Recoveries of added sorbic acid from various dairy products average 97.9%.
Collaborative Study of a Method for the Extraction of Light Filth from Dehydrated Potato Products
Authors: Gecan John S
Published: February 2020

In the method proposed for the extraction of light filth from dehydrated potato products, the sample is hydrolyzed with HC1, wet sieved, deaerated, and extracted with Ught mineral oil from hot 40% isopropanol. Collaborative studies resulted in good recoveries of light filth spike elements and easy-to-examine extraction papers. It is recommended that the method be adopted as official first action.
An Improved Urease-Bromothymol Blue Agar Medium for Detection of Wheat Grains Contaminated with Urine
Authors: Thrasher Joel J
Published: February 2020

Recommendations are made to delete sections 40.131–40.132, the urease-bromothymol blue paper test, and t o revise method 40.A09–40.A10 to reflect improvements in manipulations and reagent stability. The warm 1% agar is replaced by a 0.25% agar with a mold inhibitor and is useful up to 4 months.
International Aflatoxin Check Sample Program: 1971 Study
Authors: Coon F B , Baur F J , Symmes L R L
Published: February 2020

An International Aflatoxin Check Sample Committee was formed in 1971 to establish a check sample program of commodities or materials with aflatoxin contamination, which would be available to laboratories throughout the world. A set of 4 aflatoxin-contaminated peanut samples was prepared and mailed to 150 participating laboratories. Sufficient data were obtained from this study to permit a statistical comparison of 3 of the 4 AOAC methods for analysis of peanuts and peanut commodities. The analysis showed significantly higher means for the CB method tbun for the BF or Pons method for 2 of the samples examined.
Conversion of DDT and Its Metabolites to Dichlorobenzophenones for Analysis in the Presence of Polychlorinated Biphenyls
Authors: W Miles J R
Published: February 2020

The separation of DDT compounds from interfering polychlorinated biphenyls (PCB) has been effected by oxidation of DDE and DDMU (l-chloro-2,2-bis(p-chlorophenyl)ethylene) to the more polar dichlorobenzophenone. DDT and DDD (o,p’ - and p,p’-) are dehydrochlorinated by a convenient technique, utilizing l,5-diazobicyclo[5.4.0]undec-5-ene, and the resulting olefins are oxidized by chromic acid in acetic acid. In subsequent Florisil fractionation, the interfering PCB compounds, relatively unchanged by the dehydrochlorination and oxidation, are eluted in the hexane fraction, while the dichlorobenzophenones are eluted by benzene. Recoveries of p,p’-DDE and p,p’-DDT added to fish extracts at 5 ppm each were 82.5±2.1 and 86.0±2.2%, respectively.
Quantitative Dehydrochlorination of Perthane Residues and Effect of Alcoholic Potassium Hydroxide on Other Pesticides
Authors: Krause Richard T
Published: February 2020

An alkaline dehydrochlorination procedure is described for the quantitative analysis of Perthane residues in food products by electron capture gas chromatography. Perthane, as the olefin, is detected at a level as low as 0.02 ppm in vegetables and fruits and 0.2 ppm in fatty food products. Perthane is quantitatively recovered from fresh spinach, fresh pears, and butterfat by the appropriate official AOAC multiple residue method. The average recoveries obtained for these products are 102, 104, and 98%, respectively. Retention data are given for 46 pesticides before and after alkaline treatment for the 10% DC-200, 10% DC-200/15% QF-1, and 3% DECS columns. Only toxaphene and Strobane cannot be separated from Perthane before dehydrochlorination. After the alkaline treatment, only chlordane, toxaphene, and Strobane cannot be separated from the Perthane olefin.
The Use of a Solid Support for the Extraction of Chlorinated Pesticides from Large Quantities of Fats and Oils
Authors: Rogers W Michael
Published: February 2020

A solid support with a large surface area and a high affinity for oils has been used as a vehicle to suspend extracted fats and oils on its surface. Extraction of the fat-coated particles with an acetone-acetonitrile solvent mixture allows a quantitative isolation of chlorinated pesticide residues with a co-extraction of only about 1 g fat from a 30 g original sample. Recoveries of 5 chlorinated pesticides added to corn oil and butterfat samples at the 0.01 and 0.30 levels ranged from 83 to 100%. Satisfactory agreement between the proposed method and the official AOAC petroleum ether-acetonitrile partitioning method is obtained for various high fat products containing incurred chlorinated pesticide residues. The increased sensitivity and speed of the described method allow the rapid performance of qualitative, quantitative, and confirmatory analyses on a single sample.
Vertical Plate Gel Electrophoresis for the Differentiation of Fish and Shellfish Species
Authors: Coduri R J , Rand A G
Published: February 2020

The vertical plate polyacrylamide gel electrophoresis technique described for differentiation of meat was applied to fresh and frozen fish and shellfish species. A single 7% Cyanogum gel containing mercaptoethanol, in conjunction with a tris-chloride, tris-glycine discontinuous buffer system, produced satisfactory resolution of fish and shellfish species extracts. The electrophoretic patterns were obtained by direct analysis of the proteins extracted with a tris-chloride-10% glucose extraction buffer at pH 6.7. This technique can also be used to detect substitution of one fish or shellfish species for another.
Missouri Automated Nitrogen Method (MANM) for Fertilizers
Authors: Gehrke Charles W , Killingley John S , Wall Larry L
Published: February 2020

An automated spectrophotometric method, utilizing Technicon AutoAnalyzer modules, has been developed to determine total nitrogen in fertilizers containing only ammoniacal, nitrate , and urea nitrogen. This colorimetric system employs the Berthelot ammoniaphenate- hypochlorite reaction. A homogeneous chromous/titanous reduction system for the automatic reduction of nitrates was interfaced with the digestion unit and color development manifold, resulting in a total nitrogen system for fertilizers with an effective analysis r a t e of 20-25 samples/hr. A new sample retrieval system removes digested samples from the helix. The totally automated system was optimized to obtain t h e highest sensitivity for nitrogen. Data were compared for 458 samples analyzed by the automated method and the comprehensive nitrogen method (CNM), 2.053–2.054. The average difference between the 2 methods (MANM – CNM) was +0.04% nitrogen. The average relative difference was 1.12%. The average value for 140 samples of KNO3 primary standard analyzed by the MANM was 13.84% nitrogen (theoretical content 13.85%). The results of these standards ranged from 13.58 to 14.14% nitrogen and the standard deviation was 0.11%. The relative standard deviation was 0.80%. Of fertilizer samples received for analysis, less than 1% contained insoluble organic nitrogenous material which was unsuitable for analysis by the MANM. These few samples were not included in the statistical evaluation. The MANM is rapid, accurate, and precise and is a convenient and dependable automated method for the determination of total nitrogen in fertilizers containing only ammoniacal, nitrate , and urea nitrogen.
Modification of the Interpretation Section of Cryoscopic Methods for the Determination of the Freezing Point Value of Milk
Authors: Henningson K W
Published: February 2020

In 1969 the Interpretation of the freezing point value of milk was added as official first action to the official final action thermistor and Hortvel cryoscopic methods for the determination of the freezing point value of milk. During the ensuing year several State regulatory agencies indicated problems with 2 sections of the Interpretation, specifically, the 48 hr time limit for obtaining authentic , confirmatory samples of herd milk and/or the 0.010 difference permitted between the freezing point values of samples designated presumptive added water and authentic , confirmatory samples of herd milk. A survey of North American regulatory agencies was conducted to evaluate the extent of these problems. Twenty of the 41 regulatory agencies responding to the survey indicated that 48 hr was too short a time limit, 16 agencies indicated that the 48 hr was satisfactory, and 5 agencies declined to express an opinion. Six agencies indicated that the 0.010° difference permitted was too great, 29 agencies indicated the 0.010° difference permitted was satisfactory, 1 agency found the question inappropriate, and 5 agencies declined to express an opinion. No regulatory agency indicated other problems dealing with the Interpretation.
Collaborative Study of a New Method for the Extraction of Post-Milling Light Filth from High Bran Breads
Authors: Miller Mary T
Published: February 2020

A new method has been developed which utilizes the autoclave for an acid hydrolysis, followed by defatting with chloroform and alcohol or isopropanol and finally flotation of the filth elements in an HCl-ethanol or isopropanol medium. Collaborative study results give clean papers and good recoveries and the method has no critically timed steps. The method has been adopted as official first action to replace 40.037 and 40.038 for extraction of light filth from high bran breads.
Confirmation of Pesticide Residue Identity. I. Derivative Formation for the Confirmation of Photoproducts of Endrin: Hexachloro- and Pentachloro-ketone Pesticide Residues by Gas Chromatography
Authors: Chau Alfred S Y
Published: February 2020

Chemical conversions followed by GLC analysis are described for the confirmation of residues of 2 photoproducts of endrin, ketones I and II, in water and water-borne samples. These endrin degradation products were treated with potassium tert. -butoxide in tert.-butanol, followed by subsequent silylation or acetylation to the corresponding silyl ether or acetate. By this procedure, levels as low as 0.02- 0.03 ppm of these residues in 25 g fish sample extract or 0.01 ppb in 1 L water extract can be identified. The use of ehromous chloride to confirm these residues is also discussed. GLC data are given for some organochlorinated pesticides and their derivatives on a column of DC-ll/QF-1 and OV-101/OV-210.
Soil Moisture Influence on Treatment and Extraction of DDT from Soils
Authors: Nash R G , Harris W G
Published: February 2020

An investigation was conducted to determine techniques which prevented p,p’-DDT conversion to p,p’-DDE during (a) extraction of highly alkaline soils and (b) DDT treatment of highly alkaline soils. Moistening soils to near field capacity reduced DDT conversion to DDE during treatment and a new column extraction method was developed which prevented further conversion during extraction. Column extraction is more rapid than Soxhlet or shake extraction and requires less expensive equipment. However, column extraction was less efficient: about 4% DDT remained after extraction of incubated soils, whereas only about 1% remained in Soxhlet-extracted soils, except for clay soils in which both methods of extraction were low. Alkaline soils apparently can be extracted safely with either Soxhlet or column extraction without conversion of DDT to DDE, providing the soils have equilibrated in a moist condition.
Proposed Source of Chick Edema Factor
Authors: Metcalfe L D
Published: February 2020

Possible sources of contamination of fat by chlorophenols, precursors of chlorinated benzo- p-dioxins, are reviewed. Toxic fats (fleshings grease) from hides that had been treated with pentachlorophenol were tested in feeding studies and analyzed by electron capture GLC and GLC-mass spectrometric methods. Results of these analyses showed that several test samples contained extremely high amounts of chick edema factor.