bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Procedure for Quantitative Determination of Aflatoxins in Corn and Wet Milled Corn Products
Authors: Barabolak Roman 
Published: February 2020

Abstract
Aflatoxins are extracted from the sample by high-speed blending with aqueous acetone, purified with ammonium sulfate, and partitioned into benzene. The benzene extract is purified on a silica gel-alumina column by washing with benzene-acetic acid and ether-hexane, and eluted with methylene chloride-acetone. The eluate is evaporated, redissolved in benzeneacetonitrile, and spotted on a thin layer chromatographic plate for resolution and quantitative determination against standards.
Determination of Urethane in Wines by Gas-Liquid Chromatography and Its Confirmation by Mass Spectrometry
Authors: Joe Frank L , Kline David A , Miletta Elaine M , Roach John A G , Roseboro Emma L , Fazio Thomas 
Published: February 2020

Abstract
A gas-liquid chromatographic (GLC)-mass spectral (MS) method for the determination and confirmation of urethane in wines has been developed. Analyses of domestic and imported wines indicated urethane to be present at levels ranging from 1 to 20 μg/L. Recoveries of urethane from wines fortified at 10 ppb (μg/L) ranged from 50 to 100% with an average value of 71%. GLC-MS was used to confirm the identity of urethane in wine extracts in which GLC indicated the presence of urethane.
Collaborative Study of the Colorimetric Determination of Zirconium in Antiperspirant Aerosols
Authors: Beavin Paul 
Published: February 2020

Abstract
A previously published method for determining zirconium in antiperspirant aerosols was collaboratively studied by 7 laboratories. The method consists of 2 procedures: a rapid dilution procedure for soluble zirconium compounds or a lengthier fusion procedure for total zirconium (soluble and insoluble compounds), followed by colorimetric determination. The collaborators were asked to perform the following: Spiking materials representing 4 levels of soluble zirconium were added to weighed portions of a zirconium-free cream base concentrate and the portions were assayed by the dilution procedure. Spiking materials representing 4 levels of zirconium in either the soluble or the insoluble form (or as a mixture) were also added to portions of the same concentrate and these portions were assayed by the fusion procedure. They were also asked to concentrate and assay, by both procedures, 2 cans each of 2 commercial aerosol antiperspirants containing zirconyl hydroxychloride. The average per cent recoveries and standard deviations for spiked samples were 99.8–100.2 and 1.69–2.71, respectively, for soluble compounds determined by the dilution procedure, and 93.8–97.4 and 3.09–4.78, respectively, for soluble and/or insoluble compounds determined by the fusion procedure. The average per cent zirconium found by the dilution procedure in the 2 commercial aerosol products was 0.751 and 0.792, respectively, with coefficients of variation of 2.94 and 2.53%, respectively. Insufficient collaborative results were received for the fusion procedure for statistical evaluation. The dilution procedure has been adopted as official first action.
Gas-Liquid Chromatographic Determination of Captan and Two Metabolites in Milk and Meat
Authors: Onley John H 
Published: February 2020

Abstract
A gas-liquid chromatographic (GLC) method has been developed for the determination of captan (N-trichloromethylthio-4-cyclohexene-1, 2-dicarboximide) and 2 metabolites, tetrahydrophthalimide (THPI) and tetrahydrophthalamic acid (THPMA), in milk and meat. The sample is extracted with ethyl acetate and is cleaned up by acetonitrile partition and silica gel chromatography where captan, THPI, and THPMA are separated. Captan is directly determined by GLC. THPI and THPMA are separately derivatized in an acetone solution of penta fluorobenzyl bromide. The resultant derivatives are purified separately on an Al2O3, column and quantitated by GLC, using an electron capture detector. Recoveries from milk samples fortified at 0.02–10 ppm ranged from 71 to 102%; recoveries from meat samples fortified at 0.04–10 ppm ranged from 75 to 99%.
Aluminum Oxide Cleanup of Feed Grade Fats for Residues of Dieldrin
Authors: Lane Larry G , Gray Terri C , Minyard James P 
Published: February 2020

Abstract
A method is described for the analysis of dieldrin in feed grade fats. Fat samples in petroleum ether are cleaned up by column chromatography on 10% deactivated aluminum oxide followed by Florisil and analyzed by electron capture gas chromatography. Fourteen laboratories tested the method for determining dieldrin in naturally contaminated feed grade fats. Recoveries averaged &gt;90% with a coefficient of variation of 13% (0.54 ppm ± 0.07), indicating that the method is sufficiently reproducible to be used by different laboratories for detecting dieldrin in feed grade fats.
Collaborative Study of Gas-Liquid Chromatographic Method for Determining Methyl Parathion
Authors: Jackson Edwin R 
Published: February 2020

Abstract
Methyl parathion in technical material, 4 lb/gal. emulsifiable concentrate, and 25% wettable powder was chromatographed on a 1.5% SE-30 + 1.5% OV-210 column with p,p′-DDE as internal standard and flame ionization detection. Three matched sample pairs were analyzed by 15 collaborators using peak height measurements. Liquids were diluted to volume with p,p′-DDE internal standard solution; wettable powders were extracted with chloroform-acetone (9+1), solvent was removed, and extracts were dissolved in internal standard solution. The mean of the coefficients of variation for the 6 samples was 1.65%. The method has been adopted as official first action.
Direct Plating Versus Dilution Plating in Qualitatively Determining the Mold Flora of Dried Beans and Soybeans
Authors: Mislivec Philip B , Bruce Verneal R 
Published: February 2020

Abstract
Two methods presently used for examining whole foods and feeds for viable molds were evaluated for their relative effectiveness in the qualitative determination of the total number of mold species present in soybeans and dried beans: the direct plating method and the serial dilution method. Sixty-nine soybean samples and 40 dried bean samples were examined. Although the quantitative results of this study were inconclusive, the qualitative results show that the direct plating method was substantially more effective in detecting individual mold species. An average of 12.9 and 10.9 species was detected by the direct plating method in whole soybean and dried bean samples, respectively. An average of 4.4 and 2.8 species was detected by the dilution method in ground soybean and dried bean samples, respectively. A total of at least 37 mold species were found in the study, including 10 toxicogenic species. With few exceptions, detection rates of the 37 individual species were substantially greater among the samples examined by direct plating than those examined by serial dilution.
Effect of Storage in Flour and of Particle Size on the Bioavailability of Elemental Iron Powders for Rats and Humans
Authors: Verma Ramesh S , Motzok Ilary , Chen Shy-Show , Rasper Jaroslava , Ross Henry U 
Published: February 2020

Abstract
Elemental iron powders produced by different processes were separated by nitrogen elutriation into fractions based on particle size. The fractions containing fine particles (7–10 μm) of electrolytic iron, hydrogen (H2)- and carbon monoxide (CO)-reduced iron, and the whole sample of carbonyl iron (92% &lt;11 μm) were blended into freshly milled wheat flour and stored at about 21°C. Storing the enriched flour up to 9 months had no effect on the relative biological value (RBV) of iron for rats from each type of iron supplement. Baking bread with flour containing electrolytic, H2-reduced, and carbonyl iron after storage for 10 months also had no effect on the RBV of the iron powders. There was no change in the RBV of iron for rats from flour enriched with electrolytic iron (200 mg/kg) and ascorbic acid (200 and 1665 mg/kg flour) after storage for 1 week and 3 months. The decreases in RBV due to increase in size of particles (7–10 vs. 20–26 μm) were significant for H2-reduced iron and CO-reduced iron but not for electrolytic iron and carbonyl iron. The RBVs of elemental iron powders for rats were similar to the values obtained with humans, based on iron absorption after an overnight fast.
Reverse Phase Analytical and Preparative High Pressure Liquid Chromatography of Aflatoxins
Authors: Stubblefield Robert D , Shotwell Odette L 
Published: February 2020

Abstract
Reverse phase high pressure liquid chromatography (HPLC) was investigated and found applicable for determining 6 aflatoxins. Aflatoxins M2, M1, G2, G1, and B1 were completely resolved and B2 was satisfactorily separated on a C18 (10 μm, 4 mm id × 30 cm) column with an eluting solvent of acetonitrile-water (35 + 65) and flow rate of 1.5 ml/min. Compounds were detected by ultraviolet absorbance at 350 nm. Peak height and retention time reproducibility of multiple injections was excellent with coefficients of variation of 1.0% (M1) and 1.9% (B1) when laboratory temperatures were relatively constant throughout a day ; however, coefficients of variation increased significantly when temperatures varied by 10°F. HPLC determinations of aflatoxin B1 added to uncontaminated corn extracts at 20 and 50 ppb levels were 83±14 and 92.5±8%, respectively, of those expected. Comparison of com extract assays (6–98 ppb B1) by thin layer chromatography (TLC) and HPLC revealed that HPLC values averaged 25% less than TLC values. Numerous peaks and background interferences were present in corn extracts which made interpreting chromatograms difficult. None of the cleanup procedures tried was successful in removing these interferences. Preparative HPLC was used to isolate and purify quantities of aflatoxins M1, B1, and G1 from silicic acid column mixtures of M1-M2, B1-B2, and G1-G2. Separations were achieved on C18/Porasil B (35–75 μm) columns (⅜″ od × 8′) developed with acetonitrile-water mixtures (M1, 20+80; B1, 35+65; G1, 25+75) at 9.0 ml/min. These columns permitted isolation of 40 mg aflatoxin B1 or G1 in less than 3 hr. Aflatoxin M1 required 2 HPLC steps.
High Pressure Liquid Chromatographic Determination of Aflatoxins in Wines and Other Liquid Products
Authors: Takahashi David M 
Published: February 2020

Abstract
A previously developed high pressure liquid chromatographic (HPLC) method was evaluated by an extensive recovery study of aflatoxins from wines and other liquid products. The HPLC column and the preliminary cleanup procedures were both modified for this study. Four aflatoxins (B1, B2, G1, and G2) were recovered at 80–116% from 28 samples of various liquid commodities spiked at the 1 μg/L (1 ppb) level. The detection limit of the proposed method for wines and fruit juices was about 0.02 ppb. A total of 53 samples were analyzed for aflatoxins during this study.
High Pressure Liquid Chromatographic Determination of Sucrose in Honey
Authors: Thean James E , Funderburk Walter C 
Published: February 2020

Abstract
A normal phase high pressure liquid chromatographic (HPLC) method is presented for separating and determining sucrose in honeys. This method has been successfully applied to the analysis of field samples containing sucrose (0.63–8.44 wt %). Diluted honeys are filtered through a 0.45 μm membrane filter, and injected directly into the chromatograph. Samples are eluted from a μBondapak/carbohydrate column with acetonitrile-water (83+17) and quantitated with a refractive index detector. Average recovery of sucrose is 97%.
Ultraviolet Spectrophotometric Determination of Gibberellic Acid in Product Formulations
Authors: Ealy Daniel B , Gorman Robert R , Koester Jerome L 
Published: February 2020

Abstract
A new procedure is described for quantitating gibberellic acid in finished product formulations. The parent compound, which shows no significant ultraviolet absorbance, is chemically converted to the methyl ether of gibberellenic acid. The reaction product absorbs strongly in the ultraviolet region and thus provides the basis for Spectrophotometric quantitation. Results obtained by the new procedure are compared with results obtained by the commonly employed fluorometric procedure.
Isomer-Specific Assay of Ester and Salt Formulations of 2,4-Dichlorophenoxyacetic Acid by Automated High Pressure Liquid Chromatography
Authors: Skelly Norman E , Stevens Timothy S , Mapes David A 
Published: February 2020

Abstract
An automated high pressure liquid chromatographic method is described for the assay of 2,4-dichlorophenoxyacetic acid (2,4-D) in either salt or ester herbicide formulations. The method is specific for the 2,4-D isomer, and resolves all known impurities from 2,4-D and the internal standard. Ester products are assayed similarly to salt formulations, following room temperature in situ saponification. Results are thus obtained for all products as a per cent 2,4-D acid equivalent. Compounds are separated on a reverse phase microparticulate column with acetonitrile-water (20+80), buffered at pH 3. Precision data indicate a relative standard deviation of better than 1%. The method was developed to replace the nonspecific total chlorine, titration, and saponification assay procedures.
Evaluation of Rapid Polarographic Method for Determining Tocopherols in Vegetable Oils and Oil-Based Products
Authors: Waltking Arthur E , Kiernan Mary , Bleffert George W 
Published: February 2020

Abstract
A polarographic procedure for the determination of the tocopherols in vegetable oils was compared to a conventional gas-liquid chromatographic procedure. The polarographic method is 2–3 times more precise and more rapid, which is an important advantage for monitoring the nutritional value of processing conditions of vegetable oil-based products. Attempts to establish the validity of apparently slightly higher values for α and γ-tocopherols obtained by polarography has implicated the gas chromatograph or derivative formation rather than the extensive prior manipulation of the sample for chromatography as the source of error. Essentially the same results were obtained for α-tocopherol, regardless of the technique used. However, more variable results which were product dependent were obtained for γ- and Δ-tocopherols when gas-liquid chromatography was used.
Modification of Canadian Food and Drug Directorate Lipoxidase Method for Polyunsaturated Fatty Acid Determination
Authors: Prosser Allan R , Sheppard Alan J , Hubbard Willard D 
Published: February 2020

Abstract
The Canadian FA-59 enzymatic method for determining cis,cis-methylene interrupted polyunsaturated fatty acids has been modified to meet the needs of the cholesterol and fatty acid regulations of the U.S. Food and Drug Administration. A centrifugation step has been introduced to remove palmitate and stearate interference with absorbance readings for samples containing low amounts of cis,cis-methylene interrupted polyunsaturated fatty acids. The data are calculated by using a standard curve and an equation which yields g trilinolein/100 g product rather than % linoleic acid in a given weight of sample. The standard curve was linear for 1–12 μg trilinolein. Recovery of added trilinolein was 99.5%, with 4% coefficient of variation. The modified procedure was successfully applied to a wide variety of foodstuffs.
Flame Photometric and Atomic Absorption Determination of Calcium, Potassium, and Sodium in Ringer’s Solution and Injection and in Lactated Ringer’s Solution
Authors: Weeks John F 
Published: February 2020

Abstract
Authentic and commercial counterparts of Ringer’s solution and lactated Ringer’s solution were analyzed by 14 collaborators. Calcium, potassium, and sodium were to be determined by any flame emission or atomic absorption instrument operated at prescribed performance levels, and basic procedures for comparing samples and standards were also given. Recoveries of the cations from authentic and commercial solutions were as follows: calcium 95.6–102.1 and 95.6–103.6%, respectively; potassium 97.9– 101.7 and 98.4-102.4%; sodium 98.2-103.1 and 97.3–103.7%. The results indicate that the method yields acceptable precision for the determination of the 3 cations in fluid and electrolyte replenishers. The method has been adopted as official first action.
Glucosinolates and Derived Products in Cruciferous Vegetables: Total Glucosinolates by Retention on Anion Exchange Resin and Enzymatic Hydrolysis to Measure Released Glucose
Authors: VanEtten Cecil H , Daxenbichler Melvin E 
Published: February 2020

Abstract
Details are given for determining total glucoginolates in Cruciferae plants by a procedure measuring released glucose. The glucosinolates are separated from about 90% of other material in the plant extract by adsorption on an anion exchange resin. Then, by a selective thioglucosidase hydrolysis of the glucosinolates retained on the exchange resin, the glucose and aglucons are separated from other substances retained by the resin. Glucose is released into an aqueous medium and is equivalent to the total glucosinolates. The aglucons formed by the hydrolysis are extracted into methylene chloride and determined by gas-liquid chromatography. Based on 29 determinations of the glucose from sinigrin, analyzed under different conditions, accuracy of the total glucosinolate determination was 94.8 ± 7.3%. The coefficient of variation, determined by duplicate analyses on extracts from 58 cabbage samples, was 4.6%.
Colorimetric Determination of Cyanide Liberated from Apricot Kernels
Authors: Egli Keith L 
Published: February 2020

Abstract
A simple colorimetric method is described for determining the quantity of hydrogen cyanide produced by the spontaneous decomposition of amygdalin in apricot kernels. The evolved cyanide is collected in sodium hydroxide solution and assayed colorimetrically by reaction with picric acid. Results for duplicate assays, 3.02 and 3.06 mg CN-/g, compare well with those obtained by AOAC method 26.115 which specifies steam distillation and silver nitrate titration; results for triplicate assays were 3.02, 3.03, and 3.08 mg CN-/g by the latter. Recovery of cyanide from potassium cyanide at a level equivalent to 243 μg CN-/g was 101.0%.
Analysis of Fat-Soluble Vitamins. XVI. Antirachitic Activity of 5,6-trans-Vitamin D3 Alone and in the Presence of 5,6-cis-Vitamin D3 Resin, Using Chick Bioassays
Authors: Borsje Ben , Heyting Arend , Roborgh Jan R , Ross David B , Shillam Kenneth W G 
Published: February 2020

Abstract
Two biological assays were conducted in which the antirachitic activity in chicks of 5,6-trans-vitamin D3 added to feed is compared with that of 5,6-cis-vitamin D3. On the basis of the results obtained it is concluded that the relative potency of the trans isomer is, at the most, 5% and that the antirachitic activity of the trans isomer is not markedly enhanced (an increase to a relative potency of 16%, at the most) if the cis isomer is also included in the diet. The results are not conclusive on the inhibition or lack of inhibition of the antirachitic activity of 5,6-cis-vitamin D3 by the presence of 5,6-trans-vitamin D3 in the feed.
Flameless Atomic Absorption Spectrophotometry of Selenium in Fish and Food Products
Authors: Shum Gerald T C , Freeman Harry C , Uthe John F 
Published: February 2020

Abstract
A method is described for determining selenium in fish tissues, meat, cereals, milk powder, and other materials by flameless atomic absorption spectrophotometry. Samples are solubilized in HNO3 and atomized in a graphite furnace in the presence of nickel nitrate. Recoveries of 0.500 and 1.000 μg selenium added to several fish samples averaged 99.0 and 98.3%, respectively, with standard deviations of 5.3 and 4.0. Results agreed with those obtained for samples previously analyzed by fluorometry, and with results for NBS Standard Reference Material. The detection limit was 3 ng/ml solution and 50 ng/g sample.
Collaborative Study of a Spectrofluorometric Assay for Rauwolfia serpentina Tablets and Powdered Root, Using a Vanadium Pentoxide-Phosphoric Acid Determinative Step
Authors: Smith William M 
Published: February 2020

Abstract
Reserpine-rescinnamine group alkaloids are extracted from Rauwolfia serpentina preparations into dimethylsulfoxide (DMSO)-methanol and diluted with 0.5N H2SO4. The chloroform extract of this solution is passed through a 0.1N NaOH-Celite column and then through a silica gel column. The weakly basic alkaloids trapped on the latter column are eluted with chloroform-methanol; a portion of the eluate is treated with a vanadium pentoxide-phosphoric acid solution, and the reserpine-rescinnamine content is determined by measuring the intensity of the resulting fluorescence. The following means and standard deviations (11 collaborators) were obtained for the determination of reserpine-rescinnamine group alkaloids in 4 samples of Rauwolfia serpentina (NF reference powder, 100 and 50 mg commercial tablets, and 45 mg synthetic tablet formulation) : 0.173%, 0.0050; 0.128%, 0.0030; 0.150%, 0.0069; and 0.142%, 0.0032; respectively. The method has been adopted as official first action.
Ruggedness of Official Colorimetric Method for Sorbic Acid in Wine
Authors: Caputi Arthur , Stafford Paul A 
Published: February 2020

Abstract
Two methods for determining sorbic acid in wine were studied collaboratively in 1974 and both methods were adopted as official first action. The ultraviolet absorption method gave excellent results, but the method using colorimetric measurement of a thiobarbituric acid complex yielded some erratic results. To isolate the source of this problem, the effects of various parameters in the analysis were investigated further. The method of cooling the sample after heating to develop the color complex was the most important variable found, and a slight modification in the wording of the method is proposed. With this change in the thiobarbituric acid procedure, both methods were adopted as official final action.
Colorimetric Method for Carbadox in Feeds: Collaborative Study
Authors: Goras John T 
Published: February 2020

Abstract
A colorimetric method for determining carbadox in complete swine feeds and feed supplements was collaboratively studied. Carbadox is separated from feed with CHCl3-methanol (3+1) and then separated from interfering materials by a series of solvent-solvent extractions. The drug is isolated as a dry residue, reconstituted, and reacted with stannous chloride to form a colored complex that is measured at 520 nm. The method of standard additions is used to compensate for a feed or feed supplement matrix effect. Twenty-seven laboratories assayed feeds containing 0.0013, 0.0053, and 0.0242% carbadox. The repeatability standard deviation (σ0) and reproducibility standard deviation (σx) were σ0 = 0.00014%, σx = 0.00035% (29% of grand mean) for 0.0013% carbadox in feed; σ0 = 0.00025%, σx = 0.00037% (6.7% of grand mean) for 0.0053% carbadox in feed; and σ0 = 0.0019%, σx = 0.0024% (9.6% of grand mean) for 0.0242% carbadox in feed. The between-laboratory variance ratio was not significant for feeds containing 0.0013 and 0.0053% carbadox, but was significant for feeds containing 0.0242% carbadox. The mean recovery values for feeds containing 0.0013, 0.0053, and 0.0242% carbadox were 92, 104, and 103%, respectively. The method was adopted as official first action for feeds having a guaranteed potency of 0.0055% carbadox or higher.