bluuebunny/crossref_metadata_2025 huggingface dataset:
A Rapid Method for the Determination of Manganese Ethylenebisdithiocarbamate and its Residues on Grains
Authors: Rangaswamy Jois R , Vijayashankar Yadathore N
Published: February 2020

A method has been developed, based on the periodate oxidation of the manganese in the coordination product of zinc ion and manganese ethylene bisdithiocarbamate to permanganic acid, to determine DithaneM-45. The relationship between the intensity of color and the concentration of manganese obeys Beer’s law up to 100 μg at 540 nm. The method can be easily applied to the determination of the active ingredient in formulations and also for residue analysis. The method is sensitive to 0.6 μg and can be used to determine 6 /xg fungicide at the 20 g sample level.
Procedural Change in the Official Method for the Extraction of Light Filth from Cocoa, Chocolate, and Press Cake
Authors: Brickey Paris M , Gecan John S
Published: February 2020

The bleaching agent used for the extraction of light filth from cocoa, chocolate, and press cake has been changed from hydrogen peroxide to sodium hypochlorite. Although hydrogen peroxide has many advantages, it also bleaches light colored fragments of insect cuticles, thus making counting difficult. The change has been adopted as official and 44.006(d) will be revised.
Simple Method for Simultaneous Detection of Aflatoxin and Zearalenone in Corn
Authors: Seitz Larry M , Mohr Harold E
Published: February 2020

A method is described for the simultaneous detection of aflatoxin and zearalenone in corn at 5 and 200 ppb, respectively. No evaporation of solvent is required and the procedure is simple enough to be considered for use at marketing locations. The presence or absence of these mycotoxins can be determined in 10–20 min/sample. The procedure involves an initial blender extraction with methanol, partitioning of fat and pigments into 1,1,2-trichlorotrifluoroethane (Freon-113) from an aqueous ammonium sulfate layer, followed by extraction of aflatoxin from the aqueous layer with chlorobenzene. The chlorobenzene extract can be spotted directly onto a thin layer chromatographic plate which requires only 4 min development. Concentrations of aflatoxin and zearalenone can be estimated by visual comparison of sample spots with standards.
Screening Method for the Detection of Aflatoxin, Ochratoxin, Zearalenone, Penicillic Acid, and Citrinin
Authors: Wilson David M , Tabor William H , Trucksess Mary W
Published: February 2020

A modification of the official method for ochratoxins and a screening method for zearalenone, aflatoxin, and ochratoxin is described and expanded to include citrinin and penicillic acid. The method uses 0.5N phosphoric acid-chloroform (1+10) in the initial extraction; the extract is divided and eluted from 2 columns to provide a quantitative thin layer chromatographic (TLC) method for aflatoxin and ochratoxin in com and dried beans. Aflatoxin and zearalenone are eluted from one column and ochratoxin, penicillic acid, and citrinin from the other. Ochratoxin A recoveries are low (50%) in peanuts. Zearalenone, penicillic acid, and citrinin were qualitatively recovered from com and beans; zearalenone and penicillic acid were recovered from peanuts but citrinin was not. Several TLC solvents were used to separate interferences.
A Spectrophotometric Procedure, Using Carboxypeptidase A, for the Quantitative Measurement of Ochratoxin A
Authors: Hult Karl , Gatenbeck Sten
Published: February 2020

In the method described, ochratoxin A is cleaved into ochratoxin α (free isocoumarin chromophore) and phenylalanine, using carboxypeptidase. Detection is based on the difference in fluorescence excitation spectra of ochratoxin A (380 nm, maximum) and ochratoxin α (340 nm, maximum). The quantitation of ochratoxin A is based on the loss of fluorescence intensity at 380 nm. The method has been used for the quantitative determination of as little as 4 μg ochratoxin A/kg barley and barley meal but it could be extended to other products.
Analysis of Pesticide Residues by Chemical Derivatization. II. N-Methylcarbamates in Natural Water and Soils
Authors: Coburn John A , Ripley Brian D , Chau Alfred S Y
Published: February 2020

A method for the quantitative determination of several N-methylcarbamates in natural waters and the applicability of the derivative to soil samples using a previously published extraction procedure are described. After extraction of the carbamates from the substrate, the carbamates are hydrolyzed in a 10% methanol-potassium hydroxide solution to form the phenolic hydrolysis products, which are isolated and derivatized with pentafluorobenzyl (PFB) bromide to produce the PFB ether derivatives. The PFB derivatives are cleaned up and fractionated on a silica gel microcolumn and determined by electron capture gas-liquid chromatography (GLC). Eight organophosphate pesticides and 2 phthalate acid esters that hydrolyze to phenols or phthalic acid were evaluated as potential interferences and were found not to interfere with any of the carbamates tested. Quantitative determinations of 0.1 μg carbofuran and 3-ketocarbofuran and 0.5 μg carbaryl, metmercapturon, and Mobam in a 1 L water sample are possible. Propoxur was not determined at levels <1 μg/L due to the short GLC retention time of the derivative and interferences from the reagents at the lower levels.
Collaborative Study of the Determination of Endosulfan, Endosulfan Sulfate, Tetrasul, and Tetradifon Residues in Fresh Fruits and Vegetables
Authors: Mitchell Lawrence R
Published: February 2020

A method for the determination of endosulfan I, endosulfan II, endosulfan sulfate, tetrasul, and tetradifon residues in fresh fruits and vegetables was studied collaboratively. The method consists of extraction of the product with acetonitrile, extract cleanup by partition with petroleum ether and elution from a Florisil column with mixtures of hexane, methylene chloride, and acetonitrile, and determination of the residues by electron capture gas-liquid chromatography. This method was studied by 8 collaborators, using apples and cucumbers as the samples. Each sample was spiked with 2 levels of each pesticide. The average per cent recoveries for apples and cucumbers, respectively, were as follows: endosulfan I, 103.6 and 101.5; endosulfan II, 102.9 and 100.0; endosulfan sulfate, 100.9 and 92.9; tetrasul, 98.8 and 102.2; and tetradifon, 106.4 and 101.9. The method has been adopted as official first action.
Collaborative Study for the Comparison of Two Methods for the Determination of Total Cholesterol in Multicomponent Foods
Authors: Punwar Jalam K
Published: February 2020

The gas chromatographic method for determining total cholesterol in multicomponent foods, collaboratively studied by the AOAC in 1974 (Method 1), has been evaluated by 9 collaborating laboratories and compared with the Interim Methodology Instructions No. 2 modified method (Method 2). The 5 samples selected for collaboration were deviled ham sandwich spread, vegetable beef stew, frozen chicken pot pie, frozen fish sticks, and mayonnaise. The recovery data were obtained from a sample of wheat germ oil spiked with 0.297 % cholesterol as cholesteryl palmitate. Collaborators performed 2 replicate analyses on all samples by both methods. The statistical evaluation of the results showed that Method 1 is superior to Method 2. Average recoveries from the spiked wheat germ oil samples were 91.4% (9 laboratories) and 85.8% (7 laboratories) with coefficients of variation of 12.5 and 14.4%, respectively. Based on the collaborative results and statistical evaluation, Method 1 has been adopted as official first action.
Interlaboratory Study of Acid Orange 12 Dye Binding for Measuring Protein in Meat
Authors: Heller Steven N , Sherbon John W
Published: February 2020

Six samples of beef and pork were analyzed by 4 laboratories, using the dye binding method. Dye binding protein was calculated by using a dye binding capacity of meat of 0.410 mg dye bound/g protein. Correlations of 0.976, 0.987, 0.996, and 0.995 were found between dye binding and Kjeldahl protein values. An analysis of covariance showed that the slopes of regression between dye binding and Kjeldahl protein for 3 laboratories were not significantly different at the 5% level. The adjusted means of the regression lines for the same 3 laboratories were significantly different at the 1% level. The results show that 3 of the laboratories were finding the same relationship between dye binding and Kjeldahl protein but were not in calibration with one another.
Fluorometric Determination of Methyl Anthranilate in Concord Grape Juice
Authors: Casimir Donald J , Moyer James C , Mattick Leonard R
Published: February 2020

A method is described for the determination of methyl anthranilate in Concord grape products. A sample of juice, concentrate, pulp, or essence is steam distilled in a micro-Kjeldahl unit and the fluorescence of the distillate collected in pH 7 buffer is measured directly with a fluorometer. The method is rapid and sensitive to 0.1 ppm methyl anthranilate. A correlation coefficient of 0.988 was found between the AOAC colorimetric procedure and the fluorometric method.
Comparison of Analytical Methods for Metribuzin
Authors: Betker William R , Smead C Fred , Evans R Thomas
Published: February 2020

Determinations of the active ingredient in technical and formulated metribuzin were compared by gas-liquid chromatography (GLC) using various solvents, infrared (IR) spectrophotometry, and high-pressure liquid chromatography (HPLC). Ketones could not be used as a solvent for GLC analysis because of Schiff base formation. The GLC method using ethylene glycol monomethyl ether gave results about 1 % higher for technical metribuzin than the other methods. GLC using methylene chloride solvent agreed with IR and HPLC results to within 0.4%. GLC using methylene chloride is the preferred method.
Determination of Vitamin B12 in Dry Feeds by Atomic Absorption Spectrophotometry
Authors: Whitlock Larry L , Melton James R , Billings Toby J
Published: February 2020

Vitamin B12 was determined in dry feeds by atomic absorption spectrophotometry (AAS). Samples containing B12 were extracted with an assay solution, 5 g EDTA was added to the filtrate, the pH was adjusted to 7 with NH4OH, and 5 g charcoal was added. The charcoal was removed by filtering through ashless paper which was then placed in a beaker and ashed at 600°C. After dissolving the cobalt oxide from the ash in 5N HNO3, cobalt content was determined by using AAS. To determine mg B12/lb feed, ppm cobalt in the feed is multiplied by 10.43. The sensitivity of the proposed procedure is 1 mg vitamin B12/lb. The procedure is rapid and precise, and results compare favorably with AOAC method 43.109.
A Screening Method for Protein Characterization and Differentiation
Authors: Pinto Gerson F , Costa-Carvalho Vera L A , Souza Edna R , Araújo Neto Julio S
Published: February 2020

A circular paper chromatographic method was developed for the separation of the amino acids in proteins into 7 subgroups. Butanol-acetic acid-water (4+1+1) was used as the developing solvent. Eluted ninhydrin-stained aminograms gave rise to graphic profiles or numerical indexes based on absorbance percentages. The profiles can be used to compare protein-containing samples. Twenty different samples were studied through 190 comparisons of graphic profiles and coefficients of correlation, with only 4% misleading results. The method showed excellent reproducibility for the identification or differentiation of proteins and has the advantage of being performed with low-priced apparatus and reagents.
Lactic and Succinic Acid Levels and Refractive Indices in the Determination of the Age of Eggs
Authors: Daenens Paul , Laruelle Leander
Published: February 2020

The increase in the concentration of lactic and succinic acids during storage was measured in an attempt to determine the age of eggs. The increase in succinic acid alone is not sufficient to indicate egg age. Although lactic acid concentrations increase more rapidly, the levels are still very low, the increase is not linear, and concentrations in fresh eggs vary widely. On the other hand, refractive indices showed a nearly linear correlation with age and very little variation between eggs. These measurements are reproducible and easy to perform and, with further study, should provide an alternative to the AOAC method.
Analysis of Pesticides by Chemical Derivatization. III. Gas Chromatographic Characteristics and Conditions for the Formation of Pentafluorobenzyl Derivatives of Ten Herbicidal Acids
Authors: Chau Alfred S Y , Terry Ken
Published: February 2020

The reaction conditions to form pentafluorobenzyl derivatives of 10 herbicidal acids, at pesticide residue levels, were studied. The optimum conditions were reaction at room temperature for at least 5 hr (or overnight), using potassium carbonate solution as catalyst. The gas chromatographic characteristics of these derivatives were also studied. Nine of 10 of these derivatives can be separated on an OV-101/OV-210 gas chromatographic column.
Gas-Liquid Chromatographic Analysis and Chemical Confirmation of Azodrin (Monocrotophos) Residues in Strawberries
Authors: Lawrence James F , McLeod Harry A
Published: February 2020

A gas-liquid chromatographic (GLC) method is described for the analysis and confirmation of azodrin (monocrotophos, 3-(dimethoxyphosphinyl)-N-methyl-cis-crotonamide) residues in strawberries. The strawberries are extracted with acetone, and the filtrate is partitioned with a mixture of methylene chloride and petroleum ether followed by further extraction with methylene chloride. The organic phases are combined, dried with anhydrous sodium sulfate, and concentrated to a small volume for GLC analysis on a 3% OV-210 column with flame photometric detection. Identity of the compound is confirmed by chromatography on the same column after trifluoroacetylation of an aliquot of the strawberry extract. The detection limit is about 2 ppb. The types of strawberry samples analyzed were fresh, frozen, pureed, and jam.
Collaborative Study of the Determination of the Amount of Shrimp in Shrimp Cocktail
Authors: King Frederick J , Ryan John J
Published: February 2020

An acceptable method to determine shrimp in shrimp cocktail is needed to determine compliance with proposed labeling regulations. Our method employs a sieve and washing technique to separate shrimp from other ingredients. The percentage of shrimp is calculated from its weight and the declared weight of the total content. For the collaborative study, duplicate samples from 3 different formulations were selected randomly. Eighteen collaborators estimated the amount of shrimp in shrimp cocktail with a standard deviation of 2. A simplified version of the collaborative method has been adopted as official first action.
Clarity Evaluation of Distilled Alcoholic Products with a Particle Counter
Authors: Strunk Duane H , Timmel Bertha M , Andreasen Arthur A
Published: February 2020

An HIAC particle counter is used to measure clarity of distilled alcoholic products. The number of particles is measured in 5 size ranges from 2 to 90 μm. Average data are given for whiskies, brandy, rum, white gin, and vodka. The highest counts are obtained for aged products and most of the particles are 2–5 μm. The particle counts of different brands of blended whiskies varied from 62 to 5265 particles/ml in the 2–90 μm range. There is no apparent relationship between nephelometer values and particle counts.
Gas-Liquid Chromatographic Determination of β-Asarone in Wines and Flavors
Authors: Dyer Randolph H , Martin Glenn E , Buscemi Peter C
Published: February 2020

Wine samples containing β-asarone (cis-2,4,5-trimethoxy-1-propenylbenzene) are distilled; β-asarone is extracted by hexane and then quantitatively determined by gas-liquid chromatography (GLC), using ethyl palmitate as the internal standard. The GLC procedure is rapid and yields precise and accurate results. Mass spectrometery confirmed the identity of the GLC peak as β-asarone. The ultraviolet spectra of β-asarone and its isomer were also determined.
Collaborative Study of a Method for the Analysis of Chlorotoluron and Its Formulations
Authors: Heizler Werner , Meier Juerg , Nowak Klaus , Suter Rolf , Bosshardt Hans P
Published: February 2020

Chlorotoluron technical and its 80% wettable powder were analyzed by 19 participants in a collaborative study. The analytical method used involves acid extraction to remove interfering free amines, followed by alkaline hydrolysis of the extraction residue, distillation, and titration of the liberated dimethylamine. Related by-products which may interfere are determined by semiquantitative thin layer chromatography. Results obtained from 19 government and industrial collaborators showed good repeatability within laboratories. Good agreement was also achieved between laboratories. An overall coefficient of variation of about 0.8% was obtained. In 1974 the analytical method was accepted as a full CIPAC method. In 1975, the method was adopted as an official first action AOAC method.
Collaborative Study of the High-Pressure Liquid Chromatographic Analysis of Picloram-2,4-D Formulations
Authors: Skelly Norman E , Russell Robert J , Porter Deborah F
Published: February 2020

A high-pressure liquid chromatographic method for the analysis of picloram-2,4-D formulations has been studied by 11 collaborators. The method requires no sample preparation other than weighing and dilution. Salicylic acid is used as the internal standard. The compounds are separated on DuPont Zipax SAX (strong anion exchange resin) with 0.01M sodium tetraborate and 0.002M sodium perchlorate as the mobile phase, and measured by ultraviolet spectroscopy at 280 nm. Coefficients of variation for the 6 samples studied ranged from 1.35 to 3.54% for picloram (4-amino-3,5,6-trichloropicolinic acid) and 0.83 to 2.30% for 2,4-D (2,4-dichlorophenoxyacetic acid). Comments from the collaborators were generally favorable. The method has been adopted as official first action for the determination of both picloram and 2,4-D in picloram-2,4-D formulations.
Collaborative Study of the Spectrophotometric Determination of Procainamide Hydrochloride
Authors: Hamm Jeffrey C
Published: February 2020

The USP analysis for procainamide HCl is titrimetric and relatively nonspecific, capsule and tablet dyes may interfere, and the method is not applicable to coated tablets. In the spectrophotofluorometric method the sample deteriorates when exposed to a xenon source. In the ultraviolet spectrophotometric method reported here, the sample is dispersed in acid medium, possible interferences are extracted in chloroform, base is added, procainamide is extracted in chloroform, the residue is dissolved in sodium hydroxide, and the compound is measured by absorption at 272 nm and comparison with a standard. Recoveries of standards added to capsule, tablet, and injection composites ranged from 99.3 to 102%. Twelve collaborators reported duplicate assay results for all 3 dosage forms with per cent standard deviations for 5 samples ranging from 1.01 to 1.27%. The method has been adopted as official first action.
Collaborative Study of the Microanalytical Determination of Phosphorus in Organic Compounds
Authors: Lalancette Roger A , Steyermark Al , Cherapak Norbert C
Published: February 2020

Seven collaborators studied a specific method for the determination of phosphorus, using wet combustion followed by acidimetric titration of the hydronium ions produced by the precipitation of lanthanum phosphate. Statistical evaluation of the data for 29 determinations on triphenylphosphine gave: x̿ = 11.55%, x̿ — theory = −0.26%, s̄ = 0.33, and sm = 0.37. Omitting the results of one collaborator gave, for 21 determinations: x̿ = 11.66%, x̿ — theory = −0.15%, s̄ = 0.18, and sm = 0.30. Evaluation of the data for 33 determinations on diphenylphosphinic acid gave: x̿ = 14.11%, x̿ − theory = −0.09%, s̄ = 0.40, and sm = 0.45. Omitting the results of the same collaborator mentioned above, for 25 determinations, gave: x̿ = 14.28%, x̿ — theory = + 0.08%, s̄ = 0.27, and sm = 0.08. Since the number of collaborators was small, the study will be continued to collect more data.
Spectrophotometric Determination of Diphenylamine in Ext. D&C Yellow No. 1
Authors: Dantzman John G
Published: February 2020

A separatory funnel procedure is presented that separates diphenylamine (DPA) from Ext. D&C Yellow No. 1. The DPA is extracted from the color with isooctane and the amount of DPA is determined spectrophotometrically. Recoveries of 0.02–1 % added DPA ranged from 95.5 to 104%.
Screening and Confirmatory Methods for Determining Lincomycin Residues in Animal Tissues
Authors: Barbiers Arthur R , Neff A William
Published: February 2020

Methods for screening and for confirming residues of lincomycin in animal tissues, both sensitive to 0.1 ppm, are described. In the screening technique, residues are extracted, cleaned up by solvent partition, and detected by microbiological plate assay. In the confirmatory technique, residues are cleaned up on an unfunctionalized macroreticular-type resin column, concentrated, chromatographed on thin layer plates, and detected by bioautography. This system was effective in identifying lincomycin in the presence of 20 other antibiotics and chemicals used in the animal health industry.
Gas-Liquid Chromatographic Determination of C22 Fatty Acids for the Certification of Low Erucic Acid Varieties of Rapeseeds
Authors: Barrette Jean P
Published: February 2020

A rapid gas-liquid chromatographic (GLC) procedure was developed for the determination of C22 fatty acids (mostly erucic acid) in rapeseeds containing less than 5% erucic acid. The method involves an oil extraction from a representative sample of rapeseeds, a vigorous boron trifluoride-methanol transesterification of the oil to methyl esters, and analysis by GLC with the aid of an electronic integrator. Six laboratories participated in a monthly check sample program. By adjusting the GLC detector response with 2 synthetic reference standard mixtures containing 1.0 and 3.0% methyl behenate, interlaboratory agreement within 0.3% C22 was consistently obtained.
Gas-Liquid Chromatographic Determination of 3-Trifluoromethyl-4-nitrophenol in Natural Waters
Authors: Coburn John A , Chau Alfred S Y
Published: February 2020

A procedure for the analysis of 3-trifluoromethyl-4-nitrophenol (TFM) in natural waters is described. The lampricide is extracted from acidified water samples on the macroreticular resin XAD-7 and eluted from the column with ethyl ether. The ether extract is dried, concentrated, and partitioned with potassium carbonate. TFM is acetylated in the aqueous alkaline solution and the acetate derivative is extracted into benzene for analysis by electron capture gas-liquid chromatography. Recoveries of TFM from natural waters exceeded 90% and as little as 0.01 μg TFM can be quantitated in a 1 L sample.
Study of Speaker Identification by Aural and Visual Examination of Non-Contemporary Speech Samples
Authors: Smrkovski Lonnie
Published: February 2020

In this study, 10 pairs of unfamiliar voices were aurally and visually (with spectrograms) compared by 12 examiners to determine whether they belonged to the same speaker. Five decisions could be made: positive identification, positive elimination, probable identification, probable elimination, and unable to make a decision with the samples submitted. Each speaker recorded 9 cue words twice, spoken as a sentence, within a 15 month interval. The pair of speakers in each task was of the same sex. Match and no match constituted 50% each of the total, presented in a random fashion. For each group of examiners there were 40 possible positive correct decisions (20 identifications and 20 eliminations). Group I (professional examiners with >2 years experience) reported 90% correct positive identifications; the remaining 10% corresponded to probable identifications and no decision. Correct positive eliminations were 80%; the remaining 20% corresponded to probable eliminations and no decision. Group II (trainees with <2 years experience) reported 80% correct positive identifications; the remaining 20% corresponded to probable identifications. Correct positive eliminations were 75%; the remaining 25% corresponded to probable eliminations and no decision. No errors were produced by either Group I or II. Group III (novices) reported 40% correct positive identifications; probable identifications and no decision constituted 35%. Correct positive eliminations were 75%; probable eliminations were 20%. The percentages of error for false identifications and false eliminations were 5 and 25, respectively. The collaborative results suggest that professional examiners perform better than trainess and the performance of both groups is far superior to that of novices. Examiners with academic training in speech and hearing sciences and with over 2 years of experience perform better than those lacking academic and/or practical experience. The 15-month interval between the non-contemporary speech samples used in this study did not yield any errors for Groups I and II and no significant difference was found in examiners’ ability to identify or eliminate male or female voices. Group III had more difficulty with female speakers than with male speakers. The results also suggest that trained professional examiners can make very reliable decisions using no more than 9 cue words, regardless of speaker sex, and non-contemporary speech samples up to 15-month intervals. On the basis of this study, the official first action voiceprint method, 45.A01–45.A03, has been adopted as official final action.
Evaluation and Confirmation of an Alkylation-Gas-Liquid Chromatographic Method for the Determination of Carbamate and Urea Herbicides in Foods
Authors: Lawrence James F
Published: February 2020

An alkylation technique using methyl iodide and sodium hydride in dimethyl sulfoxide has been evaluated for 3 carbamate and 7 urea herbicides in 9 foods. Recoveries ranged from 56 to 113%, depending on herbicide, concentration, and food type. Reproducibility was about ±6% at 0.1 and 1.0 ppm. Identities of the herbicides were confirmed at these and lower levels by cleaving the aniline moiety from the alkylated herbicides with sodium methoxide in methanol, followed by gas-liquid chromatography on the same column as the parent compound. An electrolytic conductivity detector in the nitrogen mode was used for all analyses. Minimum detectable levels were in the range of 0.005–0.01 ppm in the foods studied.
Evaluation of Two Microbiological Methods for Detecting Residual Antibiotics in Milk
Authors: Ouderkirk Larry A
Published: February 2020

Two methods described in the AOAC Official Methods of Analysis for the detection of penicillin residues in whole milk were evaluated to determine the capability of each method to detect residues of 12 antibiotics used in the dairy industry. The first method, a cylinder-plate method that uses Sarcina lutea as the test organism, detected levels of 1 ppm of 8 of the 12 antibiotics tested. The second method, using paper disks with Bacillus subtilis as the test organism, detected approximately 1 ppm of only 4 antibiotics. This disk method was unable to detect <40 ppm of 5 of the antibiotics tested. The data indicate that the S. lutea cylinder-plate technique is more sensitive to more antibiotics than the B. subtilis disk method and is far superior for screening purposes.
Colorimetric Reagents for Determining Vitamin A in Feeds and Foods
Authors: Subramanyam Gurram B , Parrish Donald B
Published: February 2020

Selected blue-color developing reagents for determining vitamin A, effects of some carotenoids, tocopherol, and sterols commonly found in vitamin A extracts of feeds and foods, and effects of moisture and light on the colors developed under normal laboratory conditions were studied. Similar blue colors were obtained using SbCl3, CF3COOH, and CCl3COOH in solutions of CHCl3, CH2Cl2, and C2H4Cl2. In general, the reagents in CH2Cl2 solutions produced the most stable blue colors. The CCl3COOH-in-CH2Cl2 reagent developed slightly higher initial color, but CCl3COOH, especially in CHCl3 solution, was the least stable reagent. Small amounts of moisture affected only SbCl3 reagents, by forming cloudy solutions and precipitates. Carotene and monohydroxy and dihydroxy carotenoids reacted with all reagents tested to produce bluish colors, which, however, reached maximum development much later than the vitamin A blue colors. The presence of sterols slightly decreased color production of vitamin A solutions and frequently slightly increased rate of fading, especially for SbCl3 reagents. With proper precautions any of the reagents studied may be used to determine vitamin A. The preferred reagent for general use probably is CF3COOH-in-CH2Cl2, but it is not the most economical.
Identification of Cholesterol as a Possible Interference in the Analysis of Fish Tissue for Industrial Chemical Residues
Authors: Hollifield Henry C
Published: February 2020

The presence of cholesterol in cleaned up fish tissue extracts has been established by gas-liquid chromatography and confirmed by mass spectrometry. It was found both in extracts cleaned up by gel permeation chromatography and in those extracts prepared by the AOAC method for nonfatty foods. It is not normally observed in routine residue analyses because selective gas chromatographic detectors such as electron capture are commonly used.
Bis-Diazotized Benzidine as a Spray Reagent for Detecting Zearalenone on Thin Layer Chromatoplates
Authors: Malaiyandi Murugan , Barrette Jean P , Wavrock Paul L
Published: February 2020

Bis-diazotized benzidine is a highly sensitive spray reagent for detecting zearalenone (F-2) in corn samples. As little as 2.0 ng of this Fusarium toxin could be visualized on a thin layer plate after development. In addition, this spray reagent is more specific than the spray reagents currently used for zearalenone.
New Method for the Determination of Free Amino Groups in Intact Pure Proteins: Relationship to Available Lysine
Authors: Purcell James M , Quimby Daniel J , Cavanaugh James R
Published: February 2020

A new rapid method for the quantitative and routine determination of free amino groups in intact pure proteins has been developed. Primary amino groups are labeled with fluorescamine and the labeled groups are detected by absorption spectroscopy in the range 375–390 nm. The amino group concentration can be determined in a few minutes without hydrolyzing the labeled protein and extracting a lysine derivative. The method was tested with the following proteins: lysozyme, α-lactalbumin, β-lactoglobulin, bovine serum albumin, ribonuclease, ribonuclease-S-peptide, and αsl-rasciii B. Application of this method to the estimation of available lysine is discussed.
Thin Layer Chromatographic Estimation of Available Lysine in Dried Milk Powder
Authors: Datta Shompa , Datta Salil C
Published: February 2020

A rapid method for the estimation of available lysine in dried milk powder has been developed. Samples were treated with 2,4,6-trinitrobenzene sulfonic acid and then hydrolyzed with 6N HCl. The hydrolysate was purified and subjected to ascending thin layer chromatography to isolate ε-trinitrophenyl lysine in pure form. The color was read at 346 nm in a spectrophotometer.
Forms of Iron in Beer
Authors: Gorinstein Shela
Published: February 2020

Different forms of iron (total, ionic, and complexed) were investigated by colorimetry, emission spectroscopy, spectrophotometry, and electrophoresis on agar gel with the following results: The lowest concentration of complexed iron occurs in the sample of highest colloid-protein stability (limit of precipitation) ; the colloid protein stability is directly dependent on the content of complexed iron in hordein-globulin fractions ; a decrease in hydrogen ion concentration leads to an increase in the content of complexed iron; a low redox potential corresponds to high protein stability ; the change in fractional protein composition depends on the amount of complexed iron; the content of proteins in salt and in alcoholic fractions increases with added ferric ions, resulting in decreased colloid protein stability.
Loss of Chloride in the Official Method for the Determination of Sodium Chloride in Cereal Foods
Authors: Brammell Wallace S
Published: February 2020

The official final action method for sodium chloride in cereal foods, 14.129, was found to give erroneously low results because of loss of chloride during ashing. Comparison of the data with values obtained by the official first action potentiometric method, 32.A01–32.A06, which does not require ashing, showed that large and variable losses of chloride occurred. Official ashing methods for other foods specify addition of sodium carbonate to prevent conversion of chloride to volatile forms, but this was not specified in 14.129. In the present study it was found that sodium carbonate did not completely prevent loss of chloride. The official first action potentiometric method, 32.A01–32.A06, has been adopted as official first action for the determination of chloride in cereal foods to replace 14.129, which was repealed, official first action. A cross-reference to 32.A01–32.A06 has been added to 14.096.
Improved Thin Layer Chromatographic Method for the Isolation and Estimation of Sterigmatocystin in Grains
Authors: Athnasios Albert K , Kuhn Gustav O
Published: February 2020

A modified thin layer chromatographic (TLC) method has been developed in conjunction with the method of Stack and Rodricks which effectively separates sterigmatocystin from interfering materials and eliminates the time-consuming column chromatographic cleanup step. Initial extraction with acetonitrile-water (9+1) containing KCl is followed by partition of the extract first against hexane and then against CHCl3. The CHCl3 extract is evaporated and the residue is dissolved in benzene and applied directly to pre-coated high resolution TLC plates, which are developed in benzene-acetic acid (90+10). Visualization of the sterigmatocystin on TLC plates is enhanced by an AlCl3 spray reagent, and concentrations of sterigmatocystin as low as 50 μg/kg can be estimated by comparing fluorescence intensity against a pure sterigmatocystin standard. The method has been applied to barley, white and yellow corn, oats, and wheat. Recoveries of added toxin in the range of 50—400 μg/kg ranged from 86.3% for yellow corn and oats to >96% for barley, wheat, and white corn.
Semiautomated Fluorometric Analysis of Riboflavin in Nutrient Premixes Containing Reduced Iron
Authors: Roy Ram B , Buccafuri Anthony , Salpeter Jerry
Published: February 2020

A simple, rapid, and reproducible semiautomated method is described for routine analysis of riboflavin in premixes containing high levels of reduced iron. Reduced iron is separated from premixes by a magnet before digestion with sulfuric acid solution. The presence of ferrous sulfate, ferric pyrophosphate, and sodium ferric pyrophosphate in premixes did not affect the analytical results for riboflavin. Pretreating sample extracts with potassium permanganate and hydrogen peroxide gave variable results for riboflavin. Possible causes and mechanisms of iron interferences in fluorometric riboflavin analysis are briefly discussed. The procedure developed is capable of analyzing 40 samples/hr.
Collaborative Study of Assay Method for Erythromycin in Pelleted Feeds Containing Binding Agents
Authors: Winkler Victor W , Nyman Melvin A
Published: February 2020

A modified method for analysis of erythromycin in feeds containing the pelleting adjuvants bentonite and Masonex has been evaluated by collaborative study. Erythromycin is freed from the binding action of these adjuvants by an aqueous methanolic pH 8 buffer presoak before extraction with methylal. The recovery values for mash and pellets of 6 different sample types range from 86.6 to 103.0% of theory with a grand mean of 96.8%. This modification has been adopted as official first action.
Simple and Rapid Paper Chromatographic Method for the Simultaneous Determination of Histidine and Histamine in Fish Samples
Authors: Foo Lai Yeap
Published: February 2020

A simple and rapid method for the simultaneous determination of histamine and histidine in fish samples is described. The method entails paper chromatography and is sensitive from 0.5 μg to at least 30 μg. The method is reproducible to within ±5% and compares favorably with a biological method for histamine determination.
Determination of Dexamethasone in Milk by High Pressure Liquid Chromatography
Authors: DePaolis Anneli M , Schnabel Gabrielle , Katz S E , Rosen Joseph D
Published: February 2020

A rapid and sensitive high pressure liquid chromatographic method for the analysis of dexamethasone (9α-fluoro-11β,17α,21-trihydroxy-16α-methylpregna-1,4-diene-3,20-dione) in milk has been developed. The corticosteroid can be quantitated at 20 ppb, with the limit of detectability estimated at 5 ppb. Recoveries ranged from 72 to 94%. After dexamethasone was injected into 5 Holstein-Friesian cows, no residues were found in milk, even after the first milking.
Collaborative Study of a Semiautomated Method for the Analysis of Prednisolone and Prednisone Tablets
Authors: Brower James F
Published: February 2020

A semiautomated colorimetric method for the determination of prednisolone and prednisone was collaboratively studied by 6 collaborators. In the method, an alcoholic solution of the drug is extracted with chloroform and the extract is reacted with tetramethylammonium hydroxide and blue tetrazolium; the absorbance of the resulting color is read at 525 nm. Collaborators were supplied with 4 composites of tablets of different dosage levels, 2 containing prednisolone and 2 containing prednisone. Results agreed with those obtained by the author using the CSP total steroid assay method. The coefficients of variation of the individual collaborator’s results for prednisolone and prednisone ranged from 0.54 to 2.38 and from 0.34 to 2.19%, respectively. This method has been adopted as official first action.
Identification of 1-(1-Cyanocycloalkyl)amines, Intermediates in the Synthesis of Phencyclidine and Its Analogs
Authors: Gagné Denise R , Pike Richard K
Published: February 2020

Eight 1-(1-cyanocycloalkyl)amines are identified by spectroscopic techniques. Their ultraviolet and mass spectra are similar, but proton magnetic resonance and infrared spectra are distinctly different; reference spectra and data are provided. Gas-liquid and thin layer chromatographic systems for their qualitative analysis are discussed.
Simple and Rapid Gas-Liquid Chromatographic Determination of Diethylstilbestrol in Biological Specimens
Authors: Kohrman Karen A , MacGee Joseph
Published: February 2020

Diethylstilbestrol (DES) is readily extracted into toluene from biological fluids or tissue homogenates. Sodium carbonate is added to the initial mixture to eliminate potentially interfering substances. The toluene is extracted with a very small volume of aqueous trimethylphenylammonium hydroxide. This solution generates dimethyl DES in the vaporizer of a gas-liquid chromatograph. An internal standard, dienestrol (DI), is added at the beginning of the procedure and is partitioned and methylated in the same manner as DES. The DES and DI derivatives are well separated in less than 6 min on an OV-17 column. The entire analysis requires less than 15 min for a fluid specimen and less than 25 min for a solid tissue specimen. Seven samples can be analyzed each hour on a single column with a flame ionization detector. The relative standard deviations at levels from 2.5 to 100 ppm in bile are <5%. The lower limit of sensitivity is 8 ppb in a 1 ml bile sample.
Evaluation of Rapid Partitioning Cleanup Method for Pesticides
Authors: Friestad Håkon O
Published: February 2020

A partitioning cleanup method performed in test tubes with small solvent volumes, and using syringes instead of separatory funnels for phase separations, has been tested for potential as a general cleanup method for a variety of pesticidal compounds. More than 50% recoveries were obtained for most of the 60 compounds tested, even though minimal manipulation rather than maximum recovery was the aim. Since the recoveries usually are constant, procedural losses can be compensated for by correction factors.
Collaborative Study of a Method for the Detection of Clostridium botulinum and Its Toxins in Foods
Authors: Kautter Donald A , Solomon Haim M
Published: February 2020

The mouse toxicity and protection technique for the detection and identification of Clostridium botulinum and its toxins in foods was collaboratively studied by 11 laboratories. Each laboratory received 4 samples of cream of mushroom soup; 2 contained spores and toxin of C. botulinum type A, 1 contained spores and toxin of C. botulinum type E, and 1 contained spores of C. sporogenes. The media used were cooked meat medium (beef heart or chopped liver broth) and trypticase peptone glucose yeast extract broth with trypsin. The results indicate that this method has a high degree of repeatability and reproducibility. All 11 laboratories correctly identified the toxins and the nontoxic sample in the food and detected and identified the viable spores in the samples by means of the subsequent cultures. This method has been adopted as official first action.
Ball-Point Pen Ink Examination by High Pressure Liquid Chromatography
Authors: Colwell Lawrence F , Karger Barry L
Published: February 2020

High pressure liquid chromatography was applied to the analysis of ball-point pen inks. A written line was sampled by extracting 10 plugs punched with a syringe needle. All separations were performed on a 25 cm silica gel (10 μm) column with a mobile phase of 2% formamide in methanol. Differences in ball-point pen inks based on different dyes or relative dye amounts were easily established. Of special note was the ability to distinguish inks based on the ratio of vehicle (resins, viscosity adjusters, etc.) to dye or on the types of vehicles employed.
Analysis for Chloride Ion in High Purity Water and Heavy Water of Pressurized Reactors and Cooling Systems by Ion Selective Electrode
Authors: Sekerka Ivan , Lechner Josef F , Harrison Les
Published: February 2020

A rapid, simple, sensitive, and reliable determination of parts per billion (ppb) levels of chloride ion is described for high purity water or heavy water of pressurized and high temperature reactors, steam generators, and cooling systems by mercurous chloride-mercuric sulfide ion selective electrode. The method has been applied to heavy water samples of CANDU-type nuclear reactors as well as to the water of conventional steam generators. The manual method consists of treating 100 ml aliquots of standard solutions and water samples with 1 ml 2M HNO3. A calibration curve is constructed from the millivolt readings obtained in the standard solutions, and chloride ion concentration of the samples is determined by comparing the mv reading of the sample with the calibration graph. The automated and computerized version provides all operations automatically, together with a direct printout of the concentration and indexing. The electrode displays near-Nernstian response for the range 0.05–3.500 ppm chloride and can be used for concentrations as low as 0.02 ppm. Comparative tests and coefficients of variation are highly satisfactory.
Mass Spectral Coding Technique for Identification of Drugs and Related Compounds in Reference Compendia
Authors: Barron Robert P , Benson Walter R , Roach John A G
Published: February 2020

A modification of the spectral abbreviation technique originally described by Hites and Biemann is proposed for identifying compounds through a coding of mass spectral data. Data from 2 closely related compounds (trimethadione and paramethadione), acquired by using 3 instruments, are presented. The technique appears to overcome observed differences in low resolution spectra when the same compound is analyzed by electron impact on mass spectrometers differing in design, manufacturer, principle of ion separation, and operator. A list of spectra coded by this technique could constitute a rapid manual system of reproducing mass spectral data, using the significant high mass ions of low abundance as well as the frequently more abundant lower mass ions. This system is compared with existing systems.
Rapid Preparation of Micro Sample and Gas-Liquid Chromatographic Determination of Methoxychlor Residues in Animal Tissues and Water
Authors: Solomon John , Lockhart W Lyle
Published: February 2020

Methods are described for analyses of methoxychlor (2,2-bis(p-methoxyphenyl)-l,l,l-trichloroethane) in tissues of fish and invertebrate animals and in water samples. These micro methods offer economy in solvents and materials, and reduce health and fire hazards. Furthermore, the methods sufficiently reduce sample weights to allow analyses of small animals (mayflies) or animal organs. Samples are extracted in a ball-mill with n-hexane, and lipids are removed from fatty samples by freezeout. Small Florisil columns give final lipid cleanup and partial separation of methoxychlor from interfering materials. Methoxychlor is determined on a short gas-liquid chromatographic column (retention time 2.2 min). Animal tissue samples as small as 0.1 g and water samples of 5 ml can be analyzed at sensitivities of 10 and 1 ppb, respectively. Methoxychlor recoveries were 84–101% (fish and crab tissue), 92-100% (cod liver oil), and 98-107% (water) over a concentration range of 0–10 ppm. Results obtained for fish tissue by using micro procedures agreed to within 20% of results reported by an independent laboratory using an established method.
Quantitative Determination of Thiourea in Citrus Fruits
Authors: Mandrou Bernadette , Brun Suzanne , Kingkate Amara
Published: February 2020

A quantitative method for thiourea determination in orange peels is proposed, with direct reflectance spectrometric measurements on chromatoplates. Thiourea is separated on a silica gel plate with methanol-chloroform (10+90), and the spots are characterized with 2,6-dichloroquinone chloroimide; this colorimetric reaction is unstable, so thiourea is quantitated on the chromatogram by direct ultraviolet reflectance spectrometric measurements at 240 nm. Comparison between this method and the AOAC colorimetric method shows interferences and higher results in the colorimetric assay. By slightly modifying the extraction technique, such as purifying the extract on an alumina column, it is possible to decrease these interferences and to avoid erroneous results with the AOAC colorimetric method. For both methods, colorimetry in solution and reflectometry on chromatoplates, applied after the proposed extraction technique, the sensitivity is about 1 ppm and the reliabilities are similar.
Comparison of Igepal and Sodium Lauryl Sulfate as Defatting Agents in Extraneous Materials Analysis of Chocolate Liquor
Authors: Mastrorocco Donald A , Wagner Geraldine H
Published: February 2020

A detergent solution, 2% igepal CO 630, was compared with the AOAC-approved 2% sodium lauryl sulfate in the extraneous materials analysis of chocolate liquor. Thirty-two liquor samples were analyzed by one technician using both detergent solutions. No appreciable difference was noted between insect fragment and rodent hair counts obtained with the 2 detergent solutions. Igepal costs less and its use results in fewer filter papers to read. A wide range of insect fragment and rodent hair contamination should be studied with this reagent.