bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collaborative Study of a Method for the Analysis of Cocoa Beans for Aflatoxins
Authors: Scott P M , Przybylski W 
Published: February 2020

Abstract
Results from 10 collaborating laboratories were used to evaluate a method for the determination of aflatoxins in cocoa beans. Two types of raw cocoa beans, one from Trinidad and one from Ghana, were intentionally contaminated with aflatoxins at levels of 8 to 35 μg/kg. Mean recoveries of all aflatoxins from all samples ranged from 57 to 104%; mean recoveries of aflatoxin B1 from Ghana cocoa beans were 83 to 97%. The method has been adopted as official first action.
Polarographic Determination of Piperazine in Animal Feeds
Authors: McLean J D , Daniels O L 
Published: February 2020

Abstract
A simple and rapid polarographic method has been developed for the analysis of piperazine in animal feeds. A polarographically reducible condensation product of piperazine dihydrochloride is formed in the presence of excess formaldehyde in pH 5 buffer solution; the diffusion current of the product is measured at —0.98 v vs. a saturated calomel reference electrode.
Collaborative Study of the Determination of Propylene Glycol, Glycerol, and Triethylene Glycol in Tobacco
Authors: Williams John F 
Published: February 2020

Abstract
Collaborative study was carried out on a method for determination of propylene glycol, glycerol, and triethylene glycol in tobacco. The method involves gas chromatography of the methanolic extract of tobacco on a 42 × 3/16″ column packed with 5% Carbo wax 20M-terephthalic acid on 60-80 mesh 1:1 Diatoport S-Chromosorb 101 mixed support. 1,3-Butylene glycol is used as an internal standard. The oven temperature is programmed from 90 to 240°C at 15°/min. Results for propylene glycol and glycerol gave coefficients of variation &lt;10%. Results for triethylene glycol in cut tobacco at mean concentration levels of 0.95 and 1.30% gave coefficients of variation of 9.24 and 6.93%, respectively. At a mean concentration level of 0.54% triethylene glycol, the coefficient of variation was 20.8%. The method has been adopted as official first action.
Volume Determinations of Oil- and Dry-Roasted Nut Products
Authors: Werren John C , Allhands Frank H , Blomquist V H 
Published: February 2020

Abstract
Six laboratories studied a method for determining the volume of oil- and dry-roasted nut products. Five different samples consisting of 10 units each were examined and the mean volumes were determined. Satisfactory precision was obtained. The method has been adopted as official first action.
Collaborative Study of the Analysis of Mestranol in Combination with Norethindrone or Norethynodrel
Authors: Brunner Charlotte A 
Published: February 2020

Abstract
A collaborative study was conducted on the analysis of mestranol in combination with norethindrone or norethynodrel by partition chromatography and UV measurement. The test preparations consisted of 4 samples: a composite of norethindrone commercial tablets and the corresponding synthetic mixture, and a composite of norethynodrel commercial tablets and the corresponding synthetic mixture. Single analyses were performed on each of the samples by 13 collaborators. The average per cent recovery was 100.4, 99.9, 98.7, and 101.2%, respectively. The method has been adopted as official first action.
Collaborative Study of the Colorimetric Determination of Progestational Steroids in Contraceptive Tablets
Authors: Wu John Y P 
Published: February 2020

Abstract
A collaborative study of the proposed method for progestational steroids in oral contraceptive tablets has been conducted. Both the tablets of commercial brands and simulated tablet mixtures of norethynodrel, norethindrone, and medroxyprogesterone acetate were assayed by the proposed method. Average recoveries of the steroids ranged from 95.30 to 101.91% of the declared amounts of commercial tablets, and 97.77 to 99.20% of the added quantities in simulated samples. The method has been adopted as official first action.
Collaborative Study of a Method for Determining the Fish Flesh Content of Frozen Breaded Fish Products
Authors: Werren John C , Allhands Frank H 
Published: February 2020

Abstract
Eight laboratories studied the modified USDI method for determining the fish flesh content of frozen breaded fish products. Four different samples of 10 units each were analyzed for per cent fish flesh. Some recovery difficulty was encountered with the precooked fish stick sample. Statistical analysis indicated that the problem was related to a prolonged high temperature (120°F) dip and this has been corrected. Satisfactory reproducible precision was obtained. The method has been adopted as official first action.
Collaborative Study of the Colorimetric Determination of Sorbic Acid in Cheese
Authors: Wilamowski George 
Published: February 2020

Abstract
After isolation of sorbic acid from cheese by steam distillation, the acid recovered is cleaved with potassium dichromate in acidic medium to form an intermediate malonaldehyde, which, in turn, reacts with 2-thiobarbituric acid to produce a red dye. The absorbance of the red color, measured at 532 nm, is proportional to the concentration of sorbic acid in the sample. Seven collaborators reported recoveries of 96.7–102.4% from cheese samples spiked with 0.05% sorbic acid. This method has been adopted as official first action.
Pepsin-Digestibility Method for Animal Proteins
Authors: Gehrt Albert J 
Published: February 2020

Abstract
The official method for pepsin digestibility of animal proteins, 7.040-7.046, has been improved by replacing the centrifuge isolation of the indigestible residue with filtration through glass fiber paper. The modified method was studied by 25 collaborators. The study included meat meals, digester tankage, fish meal, blood meal, poultry by-product meal, and hydrolyzed feathers. The filtration method is more rapid, less laborious, and free from decantation losses. Basic digestion conditions of the official method, pepsin concentration, acidity, digestion time and temperature, and continuous agitation, are unchanged. The study also included grinding the portion of the samples that was larger than 20 mesh. Agreement between replicates in individual laboratories was excellent. Agreement between laboratories on all samples except poultry byproduct meal and hydrolyzed feathers was satisfactory; standard deviations ranged from 0.43 to 1.07. Data indicate that part of the variation was due to slight differences in the samples. The modified method has been adopted as official first action for all animal proteins except poultry by-products and hydrolyzed feathers.
Collaborative Check for Paraquat in Formulations
Authors: Carlstrom A A 
Published: February 2020

Abstract
A collaborative test was conducted by the Association of American Pesticide Control Officials, Inc. on the official first action colorimetric method for paraquat in formulations, 6.160–6.163. The standard deviation for a 2 lb/gal. formulation (20% cation) was 0.32, based on results from 27 analysts. The method has been adopted as official final action.
Modifications of the Official GLC Method for Volatile Acids in Eggs
Authors: Starling Michael K , Staruszkiewicz Walter F , Salwin Harold 
Published: February 2020

Abstract
During the past year, this laboratory has made extensive use of the AOAC gas chromatographic method for the determination of volatile acids in application to eggs. Our experience has led to the development of several modifications that provide greater flexibility, speed, and economy without altering the chemical approach of the method. The hasis for some of these modifications was established in the more recently developed gas chromatographic method for lactic and succinic acids. This report describes these alternatives and several observations that were made. Specific details of the modifications are presented. The method as modified has been adopted as official first action as an alternative to 17.040, 17.041, and 18.035–18.038.
Collaborative Study of the GLC Determination of β-Hydroxybutyric Acid in Eggs
Authors: Staruszkiewicz Walter F , Starling Michael K 
Published: February 2020

Abstract
The GLC method for the determination of β-hydroxybutyric acid in eggs was submitted to collaborative study. The collaborators analyzed passable and incubator-reject eggs as well as mixtures of the 2 types. The organic acids were extracted into ether, their propyl esters were formed by reaction with BF3-l-propanol, and the esters were quantitatively measured by gas-liquid chromatography. Lactic and succinic acids were determined simultaneously along with β-hydroxybutyric acid. All collaborators were able to distinguish between passable eggs and samples containing incubator-reject eggs. The method has been adopted as official first action.
Determination of Carbon Dioxide in Wine
Authors: Caputi Arthur 
Published: February 2020

Abstract
A study of the various official methods available for the determination of carbon dioxide in wine was conducted. The enzymatic method, which is the fastest of the 3 available, is still relatively slow for use as a control analysis when large quantities of wines are being bottled at high speeds. A new method was devised which involves the neutralization of a wine sample with 50% NaOH to pH 10–11 and titration with a standard acid solution in the presence of carbonic anhydrase. The titer is recorded between pH 8.6 and 4.0. A degassed sample of the same wine is neutralized and titrated in the same range and its titer is subtracted from the sample titer. The difference is used to calculate the carbon dioxide concentration in the sample. Comparison to the volumetric, manometric, and enzymatic methods showed that this new titrimetric method is comparable in terms of accuracy and reproducibility and that it offers the advantage of rapidity of analysis. It is recommended that the method be studied collaboratively.
Collaborative Study of a Zincon Ion Exchange Method for the Quantitative Determination of Zinc in Fertilizers
Authors: Jones C E , Pracht L E 
Published: February 2020

Abstract
This collaborative study represents an attempt to validate the ion exchange zincon method for the quantitative determination of zinc in fertilizers. The values of the standard deviations Sd, Sr, and Sb and the results of the F- and t-tests are presented as an estimate of the precision, accuracy, and dependability. Atomic absorption measurements were also made and provided reference data for evaluation purposes. In its present form, the method falls short of expectations as an alternative wet approach to the dithizone method. It is recommended that the methods for determining zinc in fertilizers be studied further.
Refinement of a Quantitative Technique for Estimating Alkaline Phosphatase Activity in Milk
Authors: Huaxg C L , Kleyn D H 
Published: February 2020

Abstract
A procedure for determining alkaline phosphatase activity in milk and chocolate milk, based upon the dialysis of phenolphthalein monophosphate and subsequent measurement of absorbance of the dialysate at 550 nm, has been refined. The modified procedure specifies 3 ml milk, 3 drops (0.04 ml/drop) of substrate, and a 3 hr incubation period. These changes have resulted in a decrease in the cost of reagents and higher, more suitable absorbance values. The Scharer modified Spectrophotometric method was used as a reference. The modified method showed an apparent linear relationship which was verified by calculating correlation coefficients, 0.996 for milk and 0.992 for chocolate milk; both of these values are significant at the 1% level.
Evaluation of Reflectance Fluorodensitometry for Measuring Aflatoxins on Thin Layer Plates
Authors: Pons Walter A 
Published: February 2020

Abstract
A reflectance fluorodensitometer employing illumination of chromatograms with longwave UV light at 45° angles to the plate surface and measurement of reflected fluorescence at 90° was found to be suitable for measuring aflatoxins on silica gel-coated thin layer plates. The relationship of peak area vs. concentration was linear for 1–20 ng aflatoxins B1 and G1/ spot. Degradation of aflatoxins was slight. Five repetitive scans of the same chromatogram containing 5 ng each of B1 and G1 reduced the recorded areas an average of 1% per scan. Consecutive scans of 8 identical standard chromatograms containing 5 ng each of B1 and G1 and 1.5 ng each of B2 and G2 showed a reproducibility, as measured by coefficients of variation, of ±4–5% (B1 and G1) and ±5–9% (B2 and G2), representing the combined errors of standard application, TLC development, and scanning. Analysis of aflatoxins in purified sample extracts from 6 contaminated oilseed meals, 3–500 μg afla toxins/kg, in which the same TLC plates were scanned by a transmission densitometer and the reflectance densitometer yielded essentially equivalent values.
Gas Chromatographic Determination of Safrole and Related Compounds in Nonalcoholic Beverages: Collaborative Study
Authors: Larry Damon 
Published: February 2020

Abstract
A method for the GLC determination of methyl salicylate, safrole, and related compounds in nonalcoholic beverages was studied collaboratively and reported previously. Only the methyl salicylate analysis gave acceptable precision and accuracy at all spiking levels. The study was continued and the optimum conditions for the analysis of safrole were selected. The present collaborative results show that average recoveries for safrole ranged from 77 to 98% with more variable recoveries obtained for isosafrole, dihydrosafrole, and dihydroanethole. The method has been adopted as official first action for the quantitative determination of safrole and for the semiquantitative determination of the 3 related components in nonalcoholic beverages.
Forensic Applications of Spark Source Mass Spectrometry
Authors: Harrison W W , Clemena G G , Magee C W 
Published: February 2020

Abstract
Spark source mass spectrometry provides unique capabilities in trace elemental analyses which have been useful in the examination of materials of forensic interest. Response of this technique to all inorganic elements, sensitivities to the ppb range, and qualitative-quantitative data display allow acquisition of trace element “profiles” for comparison and identification purposes. Sample preparation and pretreatment is quite important. Instrumental parameters must also be carefully controlled, including spark conditions, electrode position, and ion flux. Materials studied in our laboratories include metallurgicals, synthetic fibers, and graphites as well as human hair, blood, nails, and tissues.
Simplified Fluorometric Determination of Chlortetracycline in Mixed Feeds
Authors: Katz Stanley E , Fassbender Carol A , Dorfman Donald 
Published: February 2020

Abstract
The procedure described is based upon the alkaline conversion of Chlortetracycline to the corresponding isochlortetracyclines. The isochlortetracyclines fluoresce with equivalent intensity at the same activation and emission wavelength. Direct dilution of feed with ammonium hydroxide to levels similar to microbiological assay concentrations, the use of a feed matrix to eliminate problems of fluorescence interference from feeds, and a sensitive optical system permit the simplified assay of feeds at levels as low as 25 g/ton. Agreement with the microbiological assay is good.
Extraction Efficiency Study—Examination of Three Procedures for Extracting 14C-Labeled and Unlabeled Residues of Organophosphorus Pesticides and Carbaryl from Bean Leaves and Kale
Authors: Watts Randall R 
Published: February 2020

Abstract
Two rapid extraction procedures which consist of sample blending with ethyl acetate or acetonitrile and an exhaustive Soxhlet extraction procedure using 10% methanol in chloroform were tested for efficiency of extraction of 14C-labeled residues of carbaryl, malathion, and phosphamidon on laboratory-grown and treated bean plants. The extraction procedures were also tested on field-treated kale containing 7–11 day old residues of azinphosmethyl, parathion, and malathion. The extraction efficiencies of the 3 procedures were in very close agreement for all residues in both studies. More than 90% of the 14C-containing residues were extracted from treated bean leaves. The extraction efficiencies for field-weathered residues on kale were judged to be essentially 100%, since several hours of additional Soxhlet extraction did not remove any more residue.
Extraction and Identification of Endrin and Heptachlor Degradation Products
Authors: Nash R G , Beall M L 
Published: February 2020

Abstract
Two endrin degradation products and a heptachlor degradation product, in addition to heptachlor epoxide, were extracted from soybean plants grown in soil treated with 14C-endrin or 14C-heptachlor. One endrin product was identified as 1,8,9,9,10,11-hexachloropentacyclo[6.3.0.12,5.03′7.06,10]dodecan-12-one (endrin delta ketone); the second endrin product was identified as 1,8,9,9,10,11-hexachlorohexacyclo-[6.3.0.12′5.03,7.06,10.011,12]dodecan-12-ol (endrin alcohol); and the heptachlor product was identified as l,7,8,9,10,10-hexachloro-2,3-6,5-endo-tricyclo[5.2.1.02′6]deca-4,8-diene-exo-3-ol (hydroxychlordene). Identifications were by multiple GLC and TLC techniques.
Analysis of Commercially Fumigated Grains for Residues of Organic Fumigants
Authors: McMahon Bernadette Malone 
Published: February 2020

Abstract
Seven lots of commercially fumigated grains were sampled from storage bins and analyzed for residues of the organic fumigants. Residues were isolated by the acid reflux procedure and determined by gas-liquid chromatography. Residue levels ranged from 0.84 to 2.16 ppm carbon disulfide, 2.92 to 20.4 ppm carbon tetrachloride, and &lt;0.01 to 6.10 ppm ethylene dibromide. In general, residue levels found on grains fumigated at different times indicated the tendency for the volatile fumigants to dissipate with time. The lower volatility of ethylene dibromide results in disproportionately high residues compared to carbon disulfide and carbon tetrachloride, which were applied at higher rates.
Proteolytic Activity of Papain
Authors: Cayle Theodore 
Published: February 2020

Abstract
A method based on the ultraviolet absorption of the hydrolytic products of casein digestion and expression of the results as tyrosine equivalents was adopted in 1966 by the Pharmaceutical Manufacturers Association and the Food Chemicals Codex. Based on the collaborative data obtained in 2 studies the method has been adopted by the AOAC as an alternative to 20.114–20.117.
Determination of Carotene and Xanthophyll in Alfalfa Products
Authors: Livingston A L , Knowles R E , Kohler G O 
Published: February 2020

Abstract
The addition of an increment of water to the extracting solvent increased the extraction of xanthophyll from dehydrated alfalfa meals but not from lyophilized meals. Results of the analysis for carotene and xanthophyll compared favorably with analysis by AOAC method 39.018–39.023.
Free and Total Water in Fertilizers
Authors: Duncan R D 
Published: February 2020

Abstract
Methods for the determination of free and total water in fertilizers are based on the Karl Fischer titration. Free water is extracted with 1,4-dioxane, and total water is separated by azeotropic distillation with n-amyl alcohol. Results of a preliminary collaborative study were in wide disagreement. It is recommended that the method be written in more explicit detail before further collaborative study.
Collaborative Study of the Determination of Tar and Nicotine in Cigarette Smoke: 1970 Study
Authors: Ogg C L , Schultz E Fred 
Published: February 2020

Abstract
A collaborative study was made to evaluate the effects of (1) reducing the number of cigarettes per port, (2) using sleeves vs. dams for sealing the cigarette in the holders, and (3) pooling filter pads before water and nicotine analyses. None of these variables had a significant effect on the precision of the method. The statistical data obtained from this study agreed closely with those reported last year.
Lipid Changes Associated with the Degradation of Fish Tissue
Authors: Wood Garnett , Hintz Lane 
Published: February 2020

Abstract
The stability of fish lipids during storage of fish tissue at ice temperature was investigated. Homogenized tissue from rockfish (striped bass, Roccus species) was stored 16 days at melting ice temperature. Lipids were extracted at intervals and separated into various components by silicic acid column chromatography. Changes in the weights of individual lipid components were correlated with gas chromatographic data on changes in individual acids of these components. In the fresh tissue, the phospholipid fraction contained the highest proportion of polyunsaturated acids and the neutral lipid fraction contained the highest proportion of monounsaturated acids. During storage of the tissue, there were decreases in the weights of total phospholipids and neutral lipids and an almost equivalent increase in the amount of free fatty acids. Although there were changes in all acids during storage, the polyunsaturated acids, eicosapentaenoic (C20:5) and docosahexaenoic (C22:6), were affected most and were lost at a faster rate from phospholipids than from neutral lipids. The loss of polyunsaturated acids was apparently by a selective process because most of the loss was from the cephalin fraction, even though it contained only about ¼ of the total polyunsaturated acids. Relatively small amounts of these acids were lost from the neutral lipids and virtually none from the lecithin.
Preparation of 14C- and 3H-Labeled Aflatoxins
Authors: Ayres J L , Lee D J , Sinnhuber R O 
Published: February 2020

Abstract
A new method for the preparation of 14C- and 3H-labeled aflatoxins was devised, using rice as a supporting mold media. Labeled precursors were added to sterile rice and the mixture was inoculated with Aspergillus flavus spores. After a 7 day incubation at 25°C, the toxins were extracted with chloroform and purified by column chromatography and subsequent recrystallization. Aflatoxins B1 and G1 were recovered with 70% efficiency from the culture. Incorporation of radioactivity was examined with glucose-U-14C, sodium acetate-1-14C, and sodium acetate-2-14C. The latter gave the most efficient incorporation of 14C at 0.1% for aflatoxin B1 and 0.05% for aflatoxin G1. Conversion of 3H from tritiated water was 0.006% for aflatoxin B1 and 0.003% for aflatoxin G1. Extensive tests of radiopurity were performed on the labeled toxin which included: recrystallization to constant specific activity, thin layer and column chromatography, and hydrogenation of aflatoxin B1 to tetrahydrodeoxoaflatoxin B1. The rice-culturing technique gave good toxin yields of 1 mg aflatoxin B1/g rice. The purification was simplified by the absence of highly radioactive impurities and no appreciable degradation of labeled toxins was noted throughout extraction and purification.
Detection of Clostridium botulinum Type E in Smoked Fish
Authors: Kautter Donald A , Lilly Timothy 
Published: February 2020

Abstract
Smoked whitefish chubs artificially contaminated with small numbers of Clostridium botulinum type E spores gave as many positives with no apparent loss of toxicity in 5 days at 30°C as at 26°C in an enrichment medium containing 1 mg trypsin/ml. However, failure to increase the detection of proteolytic type B spores under the same conditions was not corrected by incubation at 30°C. Therefore, no alteration of the conditions most suitable for type E was made. Collaborative study is recommended.