bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collaborative Study of the Determination of Iron and Aluminum in Baking Powder by Atomic Absorption Spectrophotometry
Authors: Holak Walter 
Published: February 2020

Abstract
Commercial halting powder and samples containing added iron and aluminum were subjected to an interlaboratory study. The iron and aluminum were determined by an atomic absorption method reported earlier. The results for aluminum were satisfactory (average recoveries of 98, 99, and 107% for 3 levels) and the method has been adopted as official first action for aluminum. The iron results are somewhat erratic and study will be continued.
Amino Acid Analysis of Soybean Meal: Interlaboratory Study
Authors: Cavins J F , Kwolek W F , Inglett G E , Cowan J C 
Published: February 2020

Abstract
Amino acid analysis of soybean meal was studied by 5 laboratories. Between- and within-laboratory variations were significant for most amino acids, whereas variations due to hydrolysis procedure and sample mesh size in the under 30 to under 270 mesh range were significant at the 0.05 level for only 2 amino acids. The relative standard deviation was different for each amino acid with cystine, methionine, and ammonia having the highest values. Normalization of results to 95% nitrogen recovery had only a small effect on statistical analysis of the data. Values from special analytical procedures for cystine did not agree, whereas those for tryptophan agreed very well.
Collaborative Study of Methods for Free and Total Water in Fertilizer
Authors: Duncan Russell D 
Published: February 2020

Abstract
A collaborative study was made of the 1,4-dioxane extraction method for free water and the distillation method for total water i n fertilizer. Six laboratories participated in the analysis of 5 samples, and the results of t he extraction method were evaluated by the technique of matched pairs. The extraction method compared favorably with the official vacuum desiccation method and was adopted as official first action. While the study was in progress, the Associate Referee found that nitrate interfered with the proposed method for total water. Study of this method has been discontinued.
Methods for Determining Ronnel in Feeds and Mineral Mixtures
Authors: Gehrt Albert J 
Published: February 2020

Abstract
The official first action GLC method (electron capture detector) for ronnel in feeds, 38.126–38.129, is rapid and dependable but has been found to give low ronnel recoveries with stored samples. A major study was made to determine whether the low results are due to decomposition or binding of the ronnel. Ronnel and trichlorophenol (TCP) analyses were made by GLC on a feed sample stored for 9 months; results showed that 29–33% of the added ronnel and 29–54% TCP (reported as ronnel) were recovered under various conditions, accounting for 58–87% of the original ronnel. Analyses for TCP made by hydrolysis gave similar results. The ronnel not accounted for was probably lost through degradation, followed by volatilization and/or sublimation on the container walls. This study indicates conclusively that degradation of the ronnel is a major cause for the low recoveries in stored feeds. A biological (housefly killing) assay was made on another sample of the stored feed and showed 41% of the ronnel remaining. Agreement between the GLC analyses and the biological assay, plus proof of ronnel decomposition in stored samples, are convincing evidence that the first action method determines the true ronnel content of the feed. The official first action GLC method for ronnel in feeds has been adopted as official final action.
Uncombined Intermediates in FD&C Yellow No. 6
Authors: Marmion Daniel M 
Published: February 2020

Abstract
Ten collaborators participated in a study of the analysis of uncombined intermediates in FD&C Yellow No. 6; each collaborator analyzed 4 samples. The intermediates were separated by column chromatography and quanti-tated by ultraviolet spectrometry. Sulfanilic acid, Schaeffer’s salt, and 6,6‚-oxybis(2-naphthalenesulfonic acid) were recovered at an average level of 95% of the amounts added. Between- laboratory standard deviations ranged from 0.01 to 0.20% when the intermediates were present at levels of 0.02 to 1.47%. The method has been adopted as official first action.
Rapid Quantitative TLC Method for Determining Aflatoxins in Cottonseed Products
Authors: Pons Walter A , Cucullu Alva F , Franz Anthony O 
Published: February 2020

Abstract
The official AOAC method for aflatoxins in cottonseed products was modified to provide a rapid quantitative method whereby an analysis can be completed in as little as 1 hr. The method incorporates a choice of either 5 min blender or 30 min shaker extraction and either half-plate (20 min) or full-plate (50 min) TLC development to provide a flexible method to meet different analytical requirements. The rapid method was compared with the official AOAC method and the ferric gel method of Velasco for determining aflatoxins in 10 samples of cottonseed kernels and 14 samples of meals. With kernels, all 3 methods were essentially equivalent up to a contamination level of 3800 μg/kg. For quantities above this level, results by the official method were 77% of those obtained by the other 2 methods. With meals, both the rapid and official methods were equivalent for aflatoxin B1, but interferences were encountered at the Rf value of B2 on TLC plates in 3 of the 14 samples analyzed by the rapid method. With the ferric gel method, interferences at the Rf values of aflatoxin B1 or B2 were encountered in 9 of the 14 samples, and the B1 estimates by this method averaged 87% of that found for the rapid or official methods.
Quantitative Fluorodensitometric Measurements of Aflatoxin B1 with a Flying-Spot Densitometer. I. Fluorodensitometric Study of the Behavior of Aflatoxin B1 Standard Spots on Different Types of Silica Gel
Authors: Beljaars P R , Fabry F H M 
Published: February 2020

Abstract
TLC plates were scanned after development with a reflectance flying-spot densitometer. The procedure for routine measurements of standard B1 spots is described herein. Three different types of silica gel layers were spotted with standard aliquots of aflatoxin B1 covering a range of 0.4–20 ng. Silica gel H plates were developed with a mixture of chloroform– trichloroethylene–n-amyl alcohol–formic acid (80 + 15 + 4 + 1), while silica gel G and MNG- HR plates were developed with a mixture of chloroform-acetone (90 + 10). Sharp and defined separation patterns for anatoxins B1, B2, G1, and G2 were recorded on H and MN-G-HR plates, while unsatisfactory separation was found on G plates. The relationship between peak area and concentration was linear for II and MN-G-IIR plates, but not for G plates. Variations of ±15–20% were calculated among the fluorescence of standard B1 spots between plates with same sorbent layers. Coefficients of variation of ±5–7% for single densitometric measurements on one plate under normal routine conditions were calculated for a series of 3 or 4 standard aflatoxin B1 spots ranging from 1 to 4 ng on H and MN-GHR plates. Coefficients of variation of ±11–12% were calculated for G plates. Results obtained in this investigation are compared with those found by previous investigators.
Collaborative Study of the Determination of Aflatoxin in Corn and Soybeans
Authors: Shotwell O L , Stubblefield R D 
Published: February 2020

Abstract
A study was made to determine whether the procedure commonly designated as the CB method, previously recommended for determining anatoxin in peanuts and peanut products, could be applied to corn and soybeans. Both naturally contaminated and spiked corn and soybeans were extracted and analyzed by TLC. Of the 15 collaborating laboratories, 9 were equipped to measure anatoxins on TLC plates densitometrically, as well as visually. Seven collaborators used molar absorptivities to determine the concentration of anatoxins in solutions to be used for TLC standards. The official CB method has been extended to include corn and soybeans, and the rapid TLC screening technique for aflatoxin in corn has been adopted as official first action.
Infrared Studies of Dicyclohexylamine
Authors: Chen Jo-Yun T 
Published: February 2020

Abstract
Some physical and chemical properties of dicyclohexylamine were investigated by IR spectroscopy. The spectra of dicyclohexylamine are presented, not only of the pure liquid, but also of the solid which results from high pressures and low temperatures. The IR spectral data indicate that dicyclohexylamine exists under standard conditions as 3 rotational isomers in dynamic equilibrium. Below – 24°C, dicyclohexylamine in the crystalline state exists entirely in the axial-equatorial form. This work reveals that solid dicyclohexylamine goes through several phase transitions, depending on the temperature and/or pressure. Dicyclohexylamine has marked chemical activities, i.e., the amine group will add to double bonds such as with CS2 and CO2 and forms salts with HC1, acetic acid, and moist NaCl powder. The IR spectra of these derivatives are also presented.
Gas Chromatographic Determination of Propionic, Sorbic, and Benzoic Acids in Rye Bread and Margarine
Authors: Graveland A 
Published: February 2020

Abstract
A rapid and accurate method is presented for the GLC determination of propionic and sorbic acids in bakery products and benzoic acid in margarine. The acids are extracted with ether containing orthophosphoric acid, to which valeric acid is added as internal standard. The extract is injected directly into the gas chromatograph. Glass columns (2 m × 2.0 mm id) containing 5% Carbowax 20M-terephthalic acid coated on Chromosorb W (AW-DMCS) are used for analysis. The simplicity and convenience of the method make it suitable for routine determinations.
Chemical Composition of Canadian Apple Juice
Authors: Ryan J J 
Published: February 2020

Abstract
Twenty-one samples of authentic apple juice have been studied. Analytical values are presented for amino acids, pH, density, soluble solids, potassium, ash, individual organic acids, and individual sugars. These values are compared to those obtained from 11 samples of apple juice from local markets. It has been found that the potassium, ash, and organic acid patterns are the most useful components to characterize this juice. A facile method is also described for measuring inorganic phosphate content of fruit juice.
Analysis of Botanical Standard Reference Materials by Cathode Ray Polarography
Authors: Maienthal E June 
Published: February 2020

Abstract
The need for certified botanical and biological standards both in research and in industrial and field applications is leading to the development and production of a number of new Standard Reference Materials by the National Bureau of Standards. The first of these to be produced and certified is an orchard leaf standard. The determination of a number of important trace elements by cathode ray polarography was investigated and found to offer considerable advantages in sensitivity and accuracy over many other techniques. In addition, several elements may be determined simultaneously in the same solution. The methods were developed and applied to the analysis and certification of nickel, lead, bismuth, and iron in the orchard leaves. Results were also obtained for aluminum which has not yet been certified. Nickel was determined on 1 g samples after extraction with dimethylglyoxime and CHCI3. Lead and bismuth were determined concurrently on 1 g samples after a sodium diethyldithiocarbamate separation. Iron and aluminum were determined on 0.25 g samples after cupferron separations. Details of the methods are given and the results are compared with those obtained by other techniques.
Application of the Animal Hemoglobin Repletion Test to Measurement of Iron Availability in Foods
Authors: Fritz James C , Pla Gwendolyn W 
Published: February 2020

Abstract
The animal hemoglobin repletion test, adopted as official first action last year, was successfully applied to a number of food products. The method is applicable to foods if the concentration of iron in the sample is adequate to permit a reasonable addition of iron to the basal diet. The addition of the test food must be done in a manner to maintain protein and energy levels as nearly constant as possible. Similar bioavailability was found when the iron source was added directly (alone) to the test diet and when it was a component of a food which was then added to the test diet. The source of supplemental iron was more important for bioavailability than other diet components present. Cooking farina or baking biscuits from enriched cereal had little or no effect on bioavailability of the iron.
Argentimetric Method for Determination of Malathion in Formulations
Authors: Miles James W , Goette Mary B , Guerrant Gordon O , Churchill Frederick C 
Published: February 2020

Abstract
A method has been developed for the determination of malathion in technical grade products by argentimetric titration of the dimethylphosphorodithioate ion formed by alkaline cleavage of the molecule. Free dimethylphosphorodithioic acid and other polar impurities are removed by a column of cellulose powder containing 30% moisture. Malaoxon, isomalathion, and diethylmercaptosuccinate do not interfere. However, the methyl ethyl ester of malathion, if present, will titrateasmalathion . The method has been adapted to the analysis of formulations of emulsifiable concentrates, water-dispersible powders, and dusting powders. The analyses can be performed potentiometrically by titration to a fixed millivoltage, using a pH meter, or with anautomatic titrator operated in the derivative mode. When the method was applied to samples of technical grade malathion, the standard deviation varied from 0.21 to 0.42%.
GLC Determination of β-Hydroxybutyric Acid in Decomposed Eggs: Separation from a Complex Mixture Containing an Unknown Interference
Authors: Staruszkiewicz Walter F , Bond John F 
Published: February 2020

Abstract
A sample of frozen decomposed egg, which was analyzed by using official first action method 17.034–17.038, was found to exhibit several extraneous peaks. One of the peaks had the same retention time as β-hydroxybutyric acid, which has been previously associated with incubator-reject eggs. Since the samples were known to contain no incubator-reject eggs, gas-liquid chromatography on several columns was performed to determine whether or not the peak represented β-hydroxybutyric acid. Separations performed on 5 different columns demonstrated that the principal component of the questionable peak was not β-hydroxybutyric acid. The presence of the compound may have been the result of contamination by processing equipment or sample containers.
Quantitative Determination of Chlorobutanol in Milk by Gas-Liquid Chromatography
Authors: Wiskerchen John E , Weishaar Joseph 
Published: February 2020

Abstract
A method is described for the quantitative determination of chlorobutanol in milk by gas-liquid chromatography. The cleanup includes isolation of chlorobutanol from milk by steam distillation and extraction with ether. The chlorobutanol is quantitatively determined on a column of 5% Igepal 880 on Gas-Chrom Q with electron capture detection. Recoveries were 87–101% for milk fortified at 0.01–10 ppm levels. Collaborative study is recommended after an intralaboratory study is completed.
Collaborative Study of an Automated Method for Phosphorus in Fertilizers
Authors: Johnson Frank J 
Published: February 2020

Abstract
A collaborative study was made of an automated method for total and direct available phosphorus (P2O5) in comparison with the official gravimetric quimociac method, 2.023–2.025. Eight laboratories participated in the analysis of the 13 sample solutions, and the results were evaluated by the technique of closely matched pairs. The fc-test showed no difference in the means of the results of the 2 methods. The estimates of the random, systematic, and total errors of the automated method all differed significantly from those of the official method when evaluated by the F-test. Further study of the automated method for P2O5 in fertilizers is recommended.
Revised Kjeldahl Total Nitrogen Method for Feeds and Premixes
Authors: Odland Robert 
Published: February 2020

Abstract
A Kjeldahl method for equivalent crude protein in feeds was modified by using a smaller sample (0.25 g) and smaller amounts of reagents in order to reduce analysis time and cut costs. A 6% CuSO4 catalyst was used for the complete digestion of refractory material. Winkler’s boric acid method was modified by including a 90% pretitration to insure complete retention of ammonia so that only one standardized reagent is needed.
Rapid Gas-Liquid Chromatographic Determination of Phenethyl Alcohol in Alcoholic Distillates Division, National Distillers
Authors: Kahn J H , Conner H A 
Published: February 2020

Abstract
A rapid gas-liquid chromatographic method is described for the quantitative determination of phenethyl alcohol in alcoholic distillates. No prior sample preparation is required. Values are presented for 47 samples of bourbon, blended, light, Canadian, and Scotch whiskies as well as for rum, brandy, and tequila. The phenethyl alcohol concentration in these samples varies from zero to 131 g/100 L at 100° proof. The accuracy and precision of the method are demonstrated.
Analysis of Drug Residues in Guinea Pigs Treated with Dimetridazole
Authors: Allen Patricia C , Mcloughlin D K 
Published: February 2020

Abstract
Guinea pigs were given single oral doses of 250 mg dimetridazole/kg. At intervals after dosing, urine and plasma samples were directly subjected to polarographic analysis in which the original drug plus nitroimidazole metabolites were assayed. Kidney, liver, muscle, fat, and feces samples were extracted to recover the original drug and the extracts were assayed polarographically. The highest concentrations of dimetridazole were found in urine, plasma, muscle, and fat samples 2 hr after dosing. No drug was detected in any kidney, liver, or feces samples. A small quantity of drug was still detectable in urine 24 hr after dosing. No residues could be detected at 48 hr.
X-Ray Powder Diffraction Data for Seventeen Local Anesthetics
Authors: Owen J T R , Sithiraks Rewadee , Underwood F A 
Published: February 2020

Abstract
X-ray powder diffraction data for some local anesthetics have been obtained by the Debye-Scherrer technique. The data for individual local anesthetics are tabulated in terms of lattice spacings (d in Å) and the relative intensities of lines. In addition, a classification is provided of the 3 most intense lines for each of the local anesthetics, with their relative intensities arranged in descending numerical order with regard to d spacing of the most intense line from each pattern.
Direct Gas-Liquid Chromatographic Determination of Water-Soluble Vitamin K3 in Feed Premixes
Authors: Winkler Victor W , Yoder John M 
Published: February 2020

Abstract
A method for the quantitative determination of menadione bisulfite addition products in feed premixes is presented. The menadione bisulfite compound is extracted with methanol from the premix and is determined by gas chromatography directly without pretreatment with alkali. The principle of the method is on-column pyrolysis of menadione bisulfite and subsequent gas chromatographic analysis of the pyrolytic product, menadione.
Thin Layer Chromatographic Identification of Preservatives in Food
Authors: Tjan Gwan H , Konter Theodorus 
Published: February 2020

Abstract
A thin layer chromatographic method is described for the identification of benzoic, phydroxybenzoic, salicylic, and sorbic acids in foods. The preservatives are extracted from food with petroleum ether-ethyl ether (1+1); the acid preservatives are converted to their sodium salts by addition of sodium bicarbonate and the esters of p-hydrobenzoic acid remain in the organic layer. The acid preservatives are spotted on activated silica gel G plates and the plates are developed in a mobile solvent containing ammonia. The preservatives are detected by spraying with bromocresol purple. The ester preservatives are spotted on silica gel G plates with and without a fluorescent indicator; the plates are developed with benzeneethyl acetate (4+1) and then viewed under shortwave ultraviolet light or sprayed with bromocresol purple.
Confirmation of Pesticide Residue Identity. V. Alternative Procedure for Derivative Formation in Solid Matrix for the Confirmation of α- and β-Endosulfan by Gas Chromatography
Authors: Chau Alfred S Y 
Published: February 2020

Abstract
A quick and sensitive new method has been developed for the confirmation of α- and β- endosulfan by conversion to the same ether in a solid matrix. It seems by far to be the most sensitive method reported to date for positive identification of α- and β-endosulfan. As little as 0.005 ppm of the parent compounds in a 10 g fish or sediment extract and 0.003 ppb in a 2 L water extract can be routinely confirmed.
Determination of Matacil and Zectran by Fluorigenic Labeling, Thin Layer Chromatography, and In Situ Fluorimetry
Authors: Frei R W , Lawrence J F 
Published: February 2020

Abstract
The fluorigenic labeling of Matacil (4-dimethylamino- m-tolyl N-methylcarbamate) and Zectran (4-dimethylamino-3,5-xylyl Wmethylcarbamate) with dansyl chloride (1-dimethylamino- naphthalene-5-sulfonyl chloride) results in 3 fluorescent derivatives, and labeling with NBD-Cl (4-chloro-7-nitrobenzo- 2,1,3-oxadiazole) produces 2 fluorescent derivatives for each carbamate, all of which can be separated by thin layer chromatography (TLC). These derivatives are identified by nuclear magnetic resonance, infrared, and fluorescence spectroscopy, aided by TLC data. The carbamates are hydrolyzed in dilute base and the resulting amine or phenol hydrolysis products react with the labeling reagents. The derivatives are analyzed by TLC and in situ fluorimetry with a spectrophotometer in the fluorescence mode and a spectrophotofluorometer with the thin layer scanning accessory. Reactions, fluorescence phenomena, and chromatographic properties of the derivatives are investigated for evaluation of the method as a quantitative technique. A reproducibility of 3–5% relative standard deviation can be expected in the concentration range from 15 to 300 ng/spot for derivatives of the 2 labeling procedures. The dansyl derivatives are instrumentally detectable as low as 1 ng/spot while the NBD derivatives may be detected at concentrations of less than 0.5 mg/spot.
Gas-Liquid Chromatographic Method for the Determination of Dimethoate and Dimethoxon Residues in Plant and Animal Tissues, Milk, and Eggs
Authors: Steller W A , Pasarela N R 
Published: February 2020

Abstract
Residues of both dimethoate and dimethoxon are extracted from finely chopped plant or animal tissues with methylene chloride. The resulting extract is concentrated and cleaned up by silica gel chromatography, if necessary. The concentrate is injected into a gas chromatograph equipped with either a flame photometric or an alkali flame ionization detector and a column containing 11% DC-200 on 60–80 mesh Gas-Chrom Q/0.01% Versamid 900. Recovery values for dimethoate and dimethoxon added a t 0.002–1.0 p pm ranged from 56 to 112% with an overall average of 89.2% for dimethoate and from 60 to 127% with an overall average of 81.9% for dimethoxon. The lower limit at which recovery values were obtained for both compounds was 0.05 p pm for plant tissues, 0.02 for animal tissues and eggs, and 0.002 for milk. Residue values obtained for animal tissues involving both exposure and feeding studies a n d for field-treated plant samples are also presented.