bluuebunny/crossref_metadata_2025 huggingface dataset:
Threshold Radioactivity for Bulk Food Samples by Gamma Spectroscopy
Authors: Yakabe Harry M , Neilson Hiram
Published: February 2020

In the surveillance of bulk food produce by gamma ray spectroscopy for fission products, the activities of the commonly observed radionuclides are frequently in the magnitude of background inherent to the detection system. The problems of determining whether the sample is in fact contaminated, the lower limits of detecting the radionuclides, and the effect of compton smear on the lower limits are discussed. The discussions are based on the modified spectrum stripping method for quantitative analysis of gamma ray spectrum for the following radioisotopes: Cs-137, Zr-95/Nb-95, and K-40. A family of curves are shown for rapid determination of the minimum detectable true activity (AII) of Cs-137.
Evaluation of Four Stock Diets for Liver Lipid Research on Rats. I. Influence of Diet on Body Weight and Liver Composition
Authors: Sheppard A J
Published: February 2020

Four rations have been fed to weanling male albino rats for 14 and 21 days. The rations contained from 3.6 to 5.5% crude fat and ranged in fiber content from 0.1 to 6.0%. The rations were evaluated in terms of liver lipids, liver weight, feed efficiency, and average daily gains. The experiment was litter-mated across treatments. Significant ration effects on total lipids, phospholipids, free cholesterol, and average daily gain were observed after 21 days of feeding a low fiber, 19.1% crude protein, 5.1% crude fat, semisynthetic ration.
Microbiological Assay for Hygromycin B in Feed
Authors: Hilty W W
Published: February 2020

Two laboratories were evaluated with respect to hygromycin recovery in specially prepared rations. The inherent day-to-day variation was ± 14.9% of the mean value. The average per cent recovery in 30 determinations was 92.5%. Based upon the mass of data observed over the last 4 years and the confirmatory results of the limited collaborative study, it is recommended that a recovery factor of 1.1 be incorporated into method. 33.086.
Evaluation of the Assay of Penicillin in Animal Feed
Authors: Mayernik John J , Fiori Gloria Y
Published: February 2020

Four extraction procedures were evaluated for the assay of penicillin in seven mixed feeds containing 1.5–35 g penicillin/ton. The average recovery was 101.4% for single aqueous acetone extraction. With the two AOAC extraction procedures, multiple aqueous acetone and multiple pH 6 buffer, average recoveries were 95 and 80%, respectively. Feeds containing very low levels of penicillin should be assayed against penicillin standard prepared in feed extract. The 95% confidence limits of a single three-plate assay for feed mixtures, with concentrations of 35–1.5 g penicillin/ton, ranged from ±10 to ±36%, respectively. Assay precision can be improved by milling the feed sample and by increasing assay replication.
Gas Chromatographic Determination of 2,4-D and 2,4,5-T and Their Derivatives in Commercial Formulations
Authors: Pursley Patricia L , Schall E D
Published: February 2020

A solution of boron trichloride in methanol was employed for the complete transcsterification of 2,4-D and 2,4,5-T esters to the corresponding methyl esters. Gas chromatographic analysis of the methyl esters permitted mixtures of 2,4-D and 2,4,5-T esters in commercial formidations to be analyzed both qualitatively and quantitatively with no sample cleanup. The method is highly specific and detected the presence of other contaminating isomers of dichlorophenoxyacetic acid. Gas chromatography was also used to qualitatively analyze mixtures of various alkyl esters of 2,4-D.
Rapid Quantitative Vatside Check Test For Chlorinated Hydrocarbons in Aqueous Emulsions: Toxaphene and Lindane
Authors: Czech Fred P
Published: February 2020

A simple and rapid field test is described for the vatside determination of toxaphene and lindane in aqueous emulsions used for the eradication of ectoparasites in livestock. With appropriate modification, the test should also be useful for aqueous emulsions of other chlorinated hydrocarbons. The chlorinated hydrocarbon is “salted-out” of emulsion and extracted into an organic solvent, and the extract is reacted with sodium biphenyl, which strips the molecule of organic halogen. After solution of reaction products in a glycol-alcohol solvent and adjustment of pH, the resultant chloride is titrated with silver nitrate to a pink end point with 2″,7″-dichlorofluorescein. All procedures except extraction are carried out in one vessel and there is no need for special equipment. A field worker can perform an analysis in 15 minutes.
Extraction of Insecticides for Cleanup and Identification
Authors: Beroza Morton , Bowman Malcolm C
Published: February 2020

The extraction behavior of 25 insecticides in 19 binary solvent systems and the distribution of extractives from five representative foods in eleven of the solvent systems have been determined with a 5-pIate Craig countercurrent distribution apparatus. The insecticide p-value (fraction of total partitioning in upper phase) remains practically unchanged in the presence of food extractives and large amounts of pesticides. This value can be used to determine the amount of insecticide extracted in multiple extractions and in identifications of insecticides. Such identifications are possible at the nanogram level when electron affinity GLC is used for analysis. The data can be useful in the cleanup associated with insecticide analyses because the distribution of insecticides is predictable from the p-value. The 5-plate countercurrent apparatus may itself be useful in cleanup.
Evaluation of Four Stock Diets for Liver Lipid Research on Rats. II. Fatty Acid Patterns of Total Lipid Extracts
Authors: Sheppard A J
Published: February 2020

Fatty acid patterns of total liver lipid extracts were determined for groups of young rats fed ad libitum on four different diets. The diets were both of natural and semisynthetic composition in which fat content was 3.6–5.5%. Animals were supplied with diet at weaning and sacrificed after 3 weeks. The results indicate that the liver fatty acid patterns were independent of the dietary fatty acid patterns. However, significant differences in liver fatty acid patterns resulting from the feeding of the different diets were observed for hexadecanoate, 9-octadecenoate, 9,12-octadecadienoate, 9,12, 15-octadecatrienoate, eicosanoate, and decosanoate. No significant differences were observed for 5,8,11,14-eicosatetraenoate regardless of the diet fed.
A Chromatographic Method for Analysis of Strontium-90 in Foods
Authors: Ford Leonard A , Walton Mae S
Published: February 2020

The daughter, Y-90, can be separated from the parent nuclide, Sr-90, on a partition column with HDEHP as mobile phase on a Celite substrate. The ingrowth of yttrium and its subsequent removal and counting serves as a determination of strontium-90. The advantages and disadvantages of this system are contrasted with those of the shake-out method from which it was derived.
Activation Analysis of Physical Evidence Connected with Illicit Distilleries
Authors: Pro M , Schlesinger H , Cohan M
Published: February 2020

Neutron-activation analysis has been employed to compare “moonshine,” soil, and paint collected as physical evidence during the investigation of illicit distilleries. These materials were irradiated in a DASA-TRIGA nuclear reactor and the induced radionuclides were identified by nondestructive gamma-ray spectrometry. The results obtained indicate the technique can be employed to compare these materials. The findings have been accepted for use in court as evidence.
Qualitative Analysis of Propyl Gallate, Nordihydroguaiaretic Acid, Butylated Hydroxyanisole, and Butylated Hydroxytoluene in Fats and Oils
Authors: Schwien William G , Conroy Harry W
Published: February 2020

collaborative study was made of qualitative tests for added antioxidants in oils and fats. Samples of corn oil, edible tallow, and lard to which 5, 5, 10, and 15 ppm of propyl gallate, butylated hydroxyanisole, butylated hydroxytoluene, and nordihydroguaiaretic acid, respectively, had been added, plus blank samples of the oil and the fats were analyzed by 9 collaborators. The tests employed were previously described in This Journal, 45, 244 (1962). The present report includes an extraction procedure for separation of individual antioxidants, after which the qualitative tests are applied. All collaborators identified the added antioxidants correctly. (Four of the nine repeated the analyses of the samples, which were resubmitted to them in different sequence and with different identifications.) The procedure is considered suitable for routine screening, since oils and fats in commercial use contain a considerably higher level of antioxidants than were added to these collaborative samples.
Identification of Packaging Material by Infrared Reflectance Techniques
Authors: Morris Walter
Published: February 2020

The techniques of attenuated total reflectance and frustrated multiple internal reflectance have proved viseful in the analysis of wrappers for foods, such as polyethylene covers and laminated materials. Typical spectra are given.
Identification of Grape Varieties
Authors: Rice A C
Published: February 2020

The spectrophotometric characteristics of Concord grape juice have been found to vary greatly with season, growing area, and time of harvest. As a result, the spectral characteristics of the juice are not a suitable basis for a method to detect adulteration of the juice. The paper chromatographic separation of the anthocyanin pigments in Concord grape juice has been used successfully to obtain pure components, of which 10 have been identified. Quantitative data can now be obtained from the paper chromatograms by a Beckman Anatrol. A measure of the ratios of several of the anthocyanin pigments present in Concord juice is promising as a method of detecting adulteration.
Extraneous Materials in Ground Cocoa Bean Products
Authors: Brickey Paris M
Published: February 2020

Collaborative results are presented on a method for the extraction of extraneous materials from ground cocoa bean products. Insect fragment recovery among collaborators was very uniform. The method is rapid, results in clean filter papers, and gives uniformly high insect fragment recovery. It is recommended for adoption as official, first action.
Extraneous Materials in Egg Products
Authors: Thrasher Joel J
Published: February 2020

A pancreatin method has been developed to disperse and solubilize dried egg whites so that they may be filtered and examined for particles of extraneous materials. Collaborative results by the method were good, and the pancreatin method is recommended for adoption as official, first action.

The methods for extraneous materials in other egg products, 36.039(a), (b), and (c), have been written in a more concise form. It is recommended that these changes be incorporated in the official method.
Comparison of AACC and AOAC Methods for Extraneous Materials in Flour
Authors: Kurtz O’Dean L , McCormack Thomas H
Published: February 2020

Recovery of extraneous materials in flour by the AACC acid hydrolysis method is equal and perhaps superior to that obtained from the AOAC method (36.025(a)). There is no appreciable difference between the results obtained with the Wildman trap flask or a separatory funnel, although the latter requires less specialized technique. The.Kilborn funnel and the soil percolator have been found satisfactory. The AACC method is considerably less time-consuming and thus more suited to routine control procedure, is more easily standardized, and results in filter papers that are clean and easy to examine.
Analysis of Dithiocarbamates by CS2 Evolution
Authors: Bontoyan Warren R
Published: February 2020

A change in equipment and technique in the analysis of dithiocarbamates gave more consistent results and eliminated the problem of maintaining an equilibrium between the vacuum and the boiling mixture in the flask. The method was adopted as official, first action.
Pesticide Sampling
Authors: Poundstone Bruce
Published: February 2020

Changes in the sampling procedure for pesticides are described. The procedure was adopted by the Association.
Composition of Grain Fumigants
Authors: Loucks M F
Published: February 2020

Preliminary studies were made of the composition of grain fumigants. The most common constituents are carbon disulfide, carbon tetrachloride, ethylene dichloride, and ethylene dibromide. Gas chromatography seems to be a suitable technique for analysis.
Antihistamines Combined with Phenylephrine Hydrochloride and Codeine Phosphate or Dihydrocodeinone Bitartrate in Elixirs
Authors: Hyatt Rupert
Published: February 2020

The proposed method for combinations of antihistamines with phenylephrine.HCl uses three columns, HC1, NaOH, and H2SO4. Chlorpheniramine and codeine are removed from the columns with a chloroform solution of triethylamine. The chloroform eluates are evaporated and the residues taken up in dilute HCl. They are determined spectrophotometrically by comparison with the appropriate standard solutions. The phenylephrine is acetylated on the column with a chloroform solution of acetic anhydride. The acetylphenylephrine is then eluted with chloroform, and the solvent is evaporated and saponified with alcoholic-KOH. The reformed phenylephrine can then be determined spectrophotometrically in either an acid or alkaline aqueous solution and compared to the appropriate standard solution. The results of eight collaborators and the Associate Referee give the following average recoveries in the assay of an authentic elixir: codeine, 100.3%; phenylephrine.HCl, 97.4%; and chlorpheniramine maleate, 102.5%. The method was adopted as official, first action.
Spectra-Structure Correlations of Some Heterocyclic Pharmaceuticals
Authors: Hayden Alma L , Maienthal Millard
Published: February 2020

The results of a study of the relationship between spectra and structure of zoxazolamine, methimazole, and some related compounds are presented. Group frequency assignments of the infrared spectra were clarified or confirmed by comparisons with ultraviolet, near infrared, and nuclear magnetic resonance data.
The Determination of Methimazole by Infrared Spectrophotometry
Authors: Hayden Alma L , Brannon Wilson L
Published: February 2020

A method for the determination of methimazole by column chromatography and infrared spectrophotometry was subjected to collaborative study in four district laboratories. Although the results were favorable, they were not sufficiently precise nor accurate to recommend the method for adoption. Further study of the method is recommended.
The Role of Nuclear Magnetic Resonance in the Analysis of Pharmaceuticals
Authors: Alexander Thomas G , Koch Stanley A
Published: February 2020

The applications anticipated for nuclear magnetic resonance (NMR) in pharmaceutical analysis include the identification of compounds, elucidation of unknown structures, determination of sample purity, and quantitative analysis. “Fingerprint” identification of a sample is often readily possible with the aid of spectra catalogs. Examples are shown of how NMR aided in the structure elucidation of several compounds, particularly that of anthralin. Only in certain cases can NMR sensitively detect impurities; the necessary conditions and limitations for such detection are discussed. Comparisons are made of the ease with which impurities in selected phenothiazine drugs were detected by IR and NMR. Two different methods for quantitatively determining the relative amounts of components in a mixture are discussed. Future avenues of collaborative studies are indicated.
An Approach to the Separation, Identification, and Determination of at Least Ten Organophosphate Pesticide Residues in Raw Agricultural Products
Authors: McCaulley Donald F
Published: February 2020

This paper describes the preliminary development of a method that permits relatively rapid qualitative determination of residues of a number of common phosphate pesticide compounds. Extraction is followed by vacuum sublimation, gas-liquid chromatography, and infrared analysis. A wide variety of vegetables and fruits can be analyzed by the general procedure.
Potassium Permanganate and Potassium Dichrornate Standard Solutions
Authors: Ristich Radmilo
Published: February 2020

A review of Official Methods of Analysis revealed no revision necessary for the preparation and standardization of potassium dichromate solutions. Recommendations are made for the standardization of potassium permanganate solutions for three methods of analysis.
Screening Procedure for Organothiophosphate Pesticide Residues on Fruits and Vegetables Using Microcoulometric Gas Chromatography
Authors: Nelson Richard C
Published: February 2020

A screening procedure for the thiophosphates, previously adapted from the Mills- Onley-Gaither method for organic chloride pesticides, has been extended to include a total of 16 parent compounds and 25 crops. Two columns were studied: a 6 ft 15% DC-200 silicone oil column on 30/60 mesh Chromosorb P, which was used in all recovery work, and a fluorinated silicone column, 4 ft 10% QF-1 on HMDS-treated 60/80 mesh Chromosorb W. Sample sizes for injection were increased to 10 g and recoveries were run as low as 0.1 ppm. Over-all method recoveries on all thiophosphates tested, except dimethoate, Guthion, and Systox, were 70% or better; recoveries of these three were considerably improved by substituting benzene instead of petroleum ether in the shake-out step. Multilinear temperature programming was tried with the DC-200 column, and found to be promising. The QF-1 column was found to be useful in separating pesticide combinations not resolved by the DC-200 column.
Analysis of Lipids in Fish Meal
Authors: Parks Paul F , Hummel Mildred E
Published: February 2020

The lipid fraction of fish meal was extracted by four different solvent systems: diethyl ether, chloroform, the official AOAC method for fat in fish meal, 22.037, and a binary mixture of methanol-acetone. The lipid extracted by each solvent was partitioned into a triglyceride-fatty acid-sterol fraction (TFS) and a phospholipid fraction. The amount of material extracted by the different solvents was in the following descending order: methanol-acetone > official AOAC method 22.037 > chloroform > diethyl ether. The increased extraction of the binary mixture over the official AOAC method is partly due to a marked increase in the extraction of phospholipids from fish meal by the methanol-acetone mixture. The fatty acid composition of the TFS fraction from the methanol-acetone, chloroform, and diethyl ether extractions was similar. However, the TFS fraction extracted with acetone after acid hydrolysis (AOAC method 22.037) was higher in palmitic and stearic acids and lower in myristic and palmitoleic acids than the TFS fraction extracted by the other methods.
Infrared Determination of Sorbic Acid in Foods
Authors: Calloway George F , Schwartzman George
Published: February 2020

Preliminary study of an infrared method for determination of sorbic acid in foods gave promising results. The procedure consists of steam distillation of the food product, extraction of the distillate with chloroform, and measurement of the infrared absorbance of the chloroform extract at 10 μ. Recoveries from 92 to 110% were obtained from 14 food samples spiked with 0.05–0.15% sorbic acid. A collaborative study is recommended.
Gas Chromatographic Identification of Ethyl Esters of Fatty Acids in Domestic and Imported Rums
Authors: Stevens Robert K
Published: February 2020

Classical gas chromatographic techniques were used to identify the following ethyl esters in domestic and imported rum: ethyl caprylate, ethyl caprate, ethyl laurate, ethyl myristate, and ethyl palmitate. Quality of the rum may be related to the amounts of these esters present.
Collaborative Studies of Methods for Butterfat in Homogenized and Chocolate Milk
Authors: Mitchell D J
Published: February 2020

The AOAC Roese-Gottlieb, Babcock, and rapid detergent (TeSa) methods for the determination of butterfat were compared in a collaborative study on ten samples of homogenized milk by each of five laboratories. The Roese-Gottlieb and rapid detergent methods were also compared on ten samples of chocolate milk by the same collaborators. Each collaborator obtained the samples in his own area. The Babcock method gave low results for homogenized milk as expected. Comparing the TeSa method with the Roese-Gottlieb method, it appears that more developmental work on the rapid detergent method for homogenized milk and chocolate milk is necessary.
Evaluation of Protein Quality (Biological Method)
Authors: Derse Philip H
Published: February 2020

When casein, soy grits, white bread, or protein bread is tested individually for protein quality with sucrose or starch as the added carbohydrate, the over-all results obtained are in good agreement. Either carbohydrate gives good results and appears to contribute little effect on the 28 day assay period. Shorter assay periods may be possible, depending on the type of carbohydrate employed.
Polarographic Determination of Selenium in Biological Materials
Authors: Christian Gary D , Knoblock Edward C , Purdy William C
Published: February 2020

Polarography has been applied to the determination of selenium in biological materials. The direct determination described requires as little as 30 minutes for a single analysis. To increase the sensitivity, the selenium is isolated by one of two methods: The element is isolated by filtering through a Millipore filter, digesting the filter plus selenium, and obtaining a polarogram; or the selenium-diaminobenzidine complex is formed directly in the acid digest and then is extracted into a mixture of chloroform and ethylene chloride, the complex is backextracted into 2M perchloric acid, and a polarogram is obtained. Polarographic revalues are reported for the two selenium-DAB waves. As little as 0.2 µg selenium can be determined in a 1–2 g wet weight sample. Recoveries of organoselenium compounds from two different acid-digestion mixtures were comparable. A modification of the digestion mixture described by Cummins, et al. is given. Most procedures described require 2 hours or less analysis time for a single sample.
Fatty Acid Content of Vegetable Oils, Unusual Oils, Marine Oils, and Margarines
Authors: Iverson J L
Published: February 2020

Fatty acid compositions are tabulated for a number of vegetable oils, unusual oils, marine oils, and blended margarine oils.
Gas Chromatographic Determination of Thiouracils in Feeds
Authors: Fravolini Arnaldo , Begliomini Alfredo
Published: February 2020

A gas-liquid chromatographic method has been used to determine thiouracils added to feeds. The chromatographic separation is carried out on alkylated compounds. A column of SE-30 polymer methyl silicone was used. Recoveries averaged between 92 and 103%. The procedure is simple and brief.
Rapid Colorimetric Method for Determining Vanillin
Authors: Fitelson J
Published: February 2020

A simple and reliable colorimetric method for vanillin, based on the color produced with indole, has been developed for the use of laboratories that lack the equipment needed for the official method. Results average about 0.02% higher than those by the official method. Five laboratories obtained good agreement with the colorimetric method.
Preliminary Studies on Weathering of Chlordane Residues
Authors: Thruston Alfred D
Published: February 2020

The qualitative and quantitative determination of chlordane residues on raw agricultural products has been best achieved by gas chromatography techniques. While good recoveries (90–100% at the 0.1 ppm level) have been obtained from plant extracts with added standard chlordane, weathered chlordane residues show changes in number and size of gas chromatographic peaks. Chlordane at the 50 µg level, when exposed to the air at room temperature over a period of time, showed progressive decomposition and loss of the many components that make up chlordane.
Diphenylamine-Zinc Chloride as a Chromogenic Agent for the Detection of a Mixture of DDT, Chlordane, and Toxaphene on Thin Layer Chromatograms
Authors: Faucheux Lewis J
Published: February 2020

Diphenylamine-ZnCL2 has been evaluated as a chromogenic agent for detection of toxaphene, DDT, and chlordane on A12O3 thin layer plates. Characteristic colors were obtained for these pesticides; a lower level of about 5 µg was detectable. Color reactions of 34 pesticides at the 20 µg level are presented.
Various Components of Bourbon Whisky by Thin Layer and Gas-Liquid Chromatography
Authors: Martin Glenn E , Schmit John A , Schoeneman Robert L
Published: February 2020

By using various techniques such as thin layer chromatography and gas-liquid chromatography, with the assistance of silyl ether derivatives, the following seven compounds have been identified in bourbon whisky: vanillin, syringaldehyde, citric acid, alphaand beta-D-glucose, and alpha- and beta-D-fructose.
Chromatographic and Extraction Techniques for Vitamin C Assay
Authors: Ritter Elmer De
Published: February 2020

A review is presented of chromatographic procedures used in the assay of vitamin C. Paper, thin layer, and column chromatography have been used to advantage for separating interfering substances. Even the closely related erythorbic acid, which has no vitamin C activity, can be separated from ascorbic acid by various techniques on paper. Total vitamin C can be determined chromatographically after reduction of dehydroascorbic acid with H2S or after oxidation of the reduced form to dehydroascorbic acid. A combination of column and thin layer chromatography on silica gel of the dinitrosazone formed by reaction of dehydroascorbic acid with 2,4-dinitrophenylhydraiine is recommended as an effective method for achieving specificity in vitamin C assays of foods and feeds where the level of interference is high. Efficient extraction procedures are described for determining added ascorbic acid in feeds and mineral premixes.
A Critical Evaluation of the Ammonium Molybdophosphate Method for Phosphorus
Authors: Duncan R D , Srabson J A
Published: February 2020

The official ammonium molybdophosphate method for phosphorus is subject to both positive and negative errors. The solubility of the precipitate in the precipitation medium is negligible, but its solubility in water is high enough to introduce significant error if washing of the precipitate is excessive or prolonged. The precipitate contains only 97% of the stoichiometric amount of ammonia, a deficiency which results in a positive error of 3 parts per thousand in the conventional titration. High temperatures in the titration medium also result in positive errors from volatilization of ammonia. The errors resulting from deficiencies of ammonia are avoided in the formaldehyde modification of the method.
Determination of Minor Nutrients in Fertilizers by Atomic Absorption Spectrophotometry: Second Collaborative Study
Authors: Mcbride C H
Published: February 2020

The atomic absorption method studied last year was re-examined and extended to include calcium and sodium. The procedures were submitted to 16 collaborators for determination of Ca, Cu, Fe, Mg, Mn, Na, and Zn. Results for Ca and Na were discouraging; further study is recommended.
Rapid Quantitative Vatside Check Test for Chlorinated Hydrocarbons in Aqueous Emulsions: Methoxychlor, DDT, Dieldrin, and Chlordane
Authors: Czech Fred P
Published: February 2020

Field tests for certain chlorinated hydrocarbons in aqueous emulstions used for the eradication of ectoparasites in livestock were previously described. Pertinent parameters for the vatside determination of methoxychlor, DDT, dieldrin, and chlordane are given in this report in tabular form.
An Improved Method for Cleanup of Brassica for Parathion Analysis
Authors: Beckman Herman , Bevenue Arthur , Gauer W O , Erro Felix
Published: February 2020

An improved cleanup procedure has been developed for the recovery of parathion from crops, with special reference to cole crops. Parathion is separated from many chlorinated hydrocarbon pesticides that could cause interfering gas chromatographic responses. Electron capture techniques were used to detect the chlorinated hydrocarbon pesticides, and colorimetry and electron capture were used to determine parathion.
Gas Chromatographic Determination of Phenolic Pesticides and Residues
Authors: Gutenmann W H , Lisk D J
Published: February 2020

Polar phenolic pesticides often tail badly when direct gas chromatography is attempted. Rapid conversion of the phenolic group to the corresponding methyl ether eliminates tailing. Chromatography of DNOC, DNOSBP, ioxynil, and bromoxynil have been performed by this procedure. Determination of DNOC, DNOSBP, and ioxynil in agricultural samples is reported.
Criteria for Radiographic Examination of Internal Insect Infestation
Authors: Freeman C C
Published: February 2020

The insect tunnel is considered the common denominator for radiographic examination of internal insect infestation. General characteristics of insect tunneling are described to distinguish between natural appearance and infestation.
Determination of Total Choline in Feeds
Authors: Fritz James C
Published: February 2020

Five feed samples were analyzed for choline by a modified reineckate method following extraction with acid methanol. One sample was the basal diet for the chick vitamin D assay; the other four samples had known quantities of choline chloride added to this basal diet. The results obtained by 12 collaborating laboratories gave an average value of 863 ± 259 mg choline chloride/kg of the basal diet. The average recovery of added choline in the other samples ranged from 90.2 to 96.6%. The larger percentage variation in the lower potency samples suggested a need for further study of the extraction procedure.
Analysis of Organo-Metallic Fungicides and Related Compounds by Atomic Absorption Spectroscopy
Authors: Gudzinowicz B J , Luciano V J
Published: February 2020

A method is proposed for the analysis of organo-metallic fungicides (derivatives of thiocarbamic acids) and related compounds by atomic absorption spectroscopy. The effect of chloride and nitrate anions on absorption and sensitivity was investigated. The differences in the results by use of a single Zeiss or three Beckman burners with the spectrometer’s 5-pass optical system were negligible. Yellow wax bean and cucumber leaves were stripped with chloroform and with pyridine and analyzed for their external cation content. The standard recoveries of zinc added to the leaf extract were 95–100% with chloroform and 100–102% with pyridine. Calibration curves were established for the determination of the metal content of maneb (manganous ethylenebisdithiocarbamate), manganous acetylacetonate, ferbam (ferric dimethyldithiocarbamate), iron acetylacetonate, ziram (zinc dimethyldithiocarbamate), zineb (zinc ethylenebisdithiocarbamate), and zinc acetylacetonate. The most favorable concentration ranges for the analysis of zinc, iron, and manganese (10–50% absorption) are 0.07–0.50, 0.70–5.0, and 0.4–2.0 ppm, respectively.
Comparative Evaluation of a Direct Plating Procedure and an Enrichment Isolation Procedure for Detecting Coagulase-Positive Staphylococci in Foods
Authors: Gilden Mildred M , Baer Edward F , Franklin Marquitta K
Published: February 2020

Coagulase-positive staphylococci were detected in 160 of 663 frozen food samples examined. The organism was detected by both a direct plating procedure and an enrichment isolation procedure in 32 (20%) of the samples. Detection was made by the enrichment isolation procedure (but not by the direct plating procedure) in 118 samples (73.8%), and by the direct plating procedure (but not by the enrichment isolation procedure) in 10 (6.2%) of the samples found to contain coagulase-positive staphylococci.
Reliability of Several Diagnostic and Determinative Tests in the Identification of Coagulase-Positive Staphylococci
Authors: Franklin Marquitta K , Baer Edward F , Gilden Mildred M
Published: February 2020

Five diagnostic and fovir determinative tests applied to the identification of S. aureus were evaluated on the basis of their correlation with the tube coagulase test. The rate of correlation for the diagnostic tests was so low that these tests are unsuitable as substitutes for the tube coagulase test. The rate of correlation for the determinative tests exceeded 90%. These tests could be useful in augmenting the tube coagulase test to differentiate S. aureus from other coagulase-positive organisms.
Comparison of the Official Method for Total Phosphorus (Volumetric) and the Gravimetric Quinoline Molybdate Method for Total Phosphorus—1965 Collaborative Study
Authors: Whitley Voyce P
Published: February 2020

The official method for total phosphorus (volumetric), 2.026–2.028, and the gravimetric quinoline molybdate method for total phosphorus were collaboratively studied and compared. Analyses were made on alfalfa, wheat, cherries, raspberries, and eggs by seven collaborators. Differences between the methods were insignificant, and the quinoline molybdate method is recommended for adoption as official, first action.
Ion Exchange Resin Separation of Metals Occurring in Plant Material
Authors: Breault Eugene A
Published: February 2020

The study of the separation of metallic chlorides on Amberlite CG-120 (200–400 mesh) cation exchange resin was continvied. Na, K, Mo, Al, Ca, and Fe have been separated by hydrochloric acid solutions and determined by polarography or flame photometry. Semimicro quantities of these metals can be separated from each other with a minimum of eluting agent, small resin beds, and simple equipment. Mechanical grading of the air-dried resin was used to obtain more uniform particles. The ion exchange separation scheme offers advantages over present official procedures, and it should provide a unified method for the analysis of metals in mixtures. Further study is recommended.
Furazolidone and Nitrofurazone in Feeds
Authors: Stone Loyal R
Published: February 2020

Collaborative studies were continued on a rapid method for furazolidone in feeds where the drug is isolated by column chromatography and measured in aqueous solution. This procedure was extended to determine both furazolidone and nitrofurazone separately in feeds medicated with bifuran and was studied collaboratively. The activity of the aluminum oxide adsorbent in these procedures is critical. However, with a suitable lot of adsorbent, these proposed procedures are more rapid and specific than the official methods.
Determination of Temik Residues in Raw Fruits and Vegetables
Authors: Johnson D P , Stansbury H A
Published: February 2020

Temik, 2-methyl-2-(methylthio) propionaldehyde O-(methylcarbamoyl)oxime, is a systemic pesticide effective both by topical application to the plant and by systemic translocation from treated soil. The method developed for residues of Temik in crops is based on extraction of the crops with chloroform, followed by cleanup involving both coagulation and liquid partitioning techniques. The analysis involves both base- and acid-catalyzed hydrolysis to liberate hydroxylamine, which is then oxidized by iodine to nitrous acid; the latter is determined by diazotization (a modification of the Griess test for nitrites). The method is sensitive to about 0.03 ppm; average recovery from 8 crops is 96.3 ± 3.2%. Other current commercial pesticides do not interfere in the analysis.
Characteristic Infrared Absorption Spectra and Frequencies of Carbamate Pesticides
Authors: Chen Jo-Yun T , Benson Walter R
Published: February 2020

The infrared spectra of 32 carbamate pesticides and model compounds in liquid (CS2) and solid (KBr) phases are presented. The characteristic infrared absorption frequencies and associated structures are tabulated in a summary and presented in a correlation chart. The carbonyl absorption frequencies of carbamates containing the N—H group are shifted to higher frequencies by approximately 35 cm-1 in going from the solid to the liquid phase. This shift is attributed to a loss of hydrogen bonding. In general the N,N-disubstituted carbamates show no such shift.
Collaborative Study of a Method for Multiple Chlorinated Pesticide Residues in Leafy and Cole-Type Vegetables
Authors: Gaul Jean
Published: February 2020

Sixteen collaborators representing eight laboratories studied an electron capture gas chromatography method for lindane, heptachlor, and TDE residues in leafy (endive) and cole-type (cauliflower) vegetables. Average recoveries for lindane at the 10 ppm level were 91.7% from endive and 95.7% from cauliflower; at the 1 ppm level, 93.6% from endive and 88.3% from cauliflower. Average recoveries for heptachlor at the 0.1 ppm level were 82% on endive and 94% on cauliflower; at the 0.05 ppm level, 88% on endive and 82% on cauliflower. Average recoveries for TDE at the 7 ppm level were 78.6% on endive and 85.4% on cauliflower; at the 1 ppm level, 86.1% on endive and 86.4% on cauliflower.
Collaborative Study of a Rapid Method for Multiple Chlorinated Pesticide Residues in Small Fruits
Authors: Davidson Arthur W
Published: February 2020

Twelve collaborators from six laboratories used gas-liquid and thin layer chromatography to measure BHC, p,p′-DDT, and endrin residues on apricots and strawberries. Recoveries for both crops by gas chromatography averaged: BHC, 104 ± 23 %; p,p′-DDT, 102 ± 10%; endrin, 96 ±14%. Recoveries for both crops by thin layer chromatography averaged: BHC, 98 ± 29%; p,p′-DDT, 97 ± 18%; and endrin, 96 ± 16%.
Potentiometric Determination of Chlorides in Wine, Distilled Spirits, and Wine Vinegar
Authors: Hubach Clifford E
Published: February 2020

Collaborative study of the Pro method for determining chlorides in wines and distilled spirits by direct titration with silver nitrate followed by potentiometric reading of the end point gave accurate and reproducible results. The procedure is suitable for repetitious analyses in control laboratories, and it is also adaptable to determinations requiring a high degree of precision. Recoveries of chloride added to samples averaged 99.7%. The method is recommended for adoption as official, first action.
Determination of Potassium and Calcium in Tobacco
Authors: Cundiff Robert H , Dobbins J T
Published: February 2020

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

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

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

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.
Fumaric Acid in Foods
Authors: Smith Howard R
Published: February 2020

A polarographic method for determining fumaric acid in foods, investigated in 1964, was submitted to collaborative study. Results of analysis of gelatin products and grapefrviit drink indicate that the method may be suitable with further refinement. Studies will be continued.
Screening Procedure for Organothiophosphate Pesticide Residues on Fruits and Vegetables by Microeoulometric Gas Chromatography
Authors: Nelson Richard C
Published: February 2020

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

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

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

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

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 < 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

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

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

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.