bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Gel Permeation Chromatography and Nonaqueous Reverse Phase Chromatography to High Pressure Liquid Chromatographic Determination of Retinyl Palmitate and β-Carotene in Oil and Margarine
Authors: Landen William O , Eitenmiller Ronald R 
Published: February 2020

Abstract
A high pressure liquid chromatographic method was developed using high pressure gel permeation chromatography (HP-GPC) and high pressure reverse phase chromatography (RP-HPLC) for quantitation of retinyl palmitate and β-carotene. HP-GPC was used for fractionation of vitamin A active compounds from oil preliminary to quantitation on nonaqueous RP-HPLC. HP-GPC fractionation was completed on oil and margarine dissolved in methylene chloride by 2 elution passes through 2 μStyragel (100Å) columns connected in series with methylene chloride as the mobile phase. RPHPLC separation of retinyl palmitate and β-carotene was achieved on μBondapak C18 (10 μm), using methylene chloride-acetonitrile ( 3 0 + 7 0 ) . Based on 10 repetitive analyses, recoveries of added β-carotene and retinyl palmitate from vegetable oils were 98.6±2.9 and 95.2±2.6%, respectively. The coefficients of variation were 2.9% for β-carotene and 2.7% for retinyl palmitate. The determination of vitamin A activity in 7 margarine brands with label claims of 10% U.S.RDA/serving revealed that all but one of the margarines contained at least 94% of the label claim. Vitamin A activity in the margarines ranged from 90.6 to 110.8% of the label declaration.
Determination of Crude Protein in Animal Feeds, Using Block Digestion Followed by Steam Distillation: Collaborative Study
Authors: Noel Rodney J 
Published: February 2020

Abstract
A method consisting of digesting animal feeds in a block digestor and determining ammonia by steam distillation followed by titration has been evaluated and compared with the official final action Kjeldahl method, 7.016. Fifteen laboratories analyzed 5 feed samples and lysine monohydrochloride. Statistical analysis showed that results from the 2 methods were comparable. The distillation technique has been adopted as official first action as an alternative technique for ammonia determination from the digest of the official final action block digestor method, 7.B11.
Laser Fluorometric Determination of Aflatoxin B1 in Corn
Authors: Diebold Gerald J , Karny Noga , Zare Richard N , Seitz Larry M 
Published: February 2020

Abstract
A 2-step chromatographic separation, using both thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC), in conjunction with the high sensitivity of laser fluorometry permits extension of the detection limits of aflatoxin contamination in corn to 0.1 ppb (μg/kg) with a 26% root mean square variation. Aflatoxin B1 is extracted from corn with water-methanol and cleaned up by TLC. The recovery of aflatoxin from the TLC plates was linear from 10 to 1000 pg. Aflatoxin B1 is converted to the more highly fluorescent B2A derivative by treatment with 1N HC1. Experiments with aflatoxin B1 standards establish a constant conversion to B2A over approximately 3 orders of magnitude in B1 concentration. An extract of the B2A aflatoxin derivative is injected onto a reverse phase HPLC column. A flowing droplet of eluant is irradiated by an amplitude-modulated 325 nm He-Cd ion laser beam, and fluorescence from the droplet is detected by a lock-in amplifier in phase with the laser modulation. Several chromatograms are presented that demonstrate the capability of this procedure for removing interfering components in the corn extract.
Colorimetric Determination of Boric Acid in Prawns, Shrimp, and Salted Jelly Fish by Chelate Extraction with 2-Ethyl-l,3-Hexanediol
Authors: Ogawa Shunjiro , Toyoda Masatake , Tonogai Yasuhide , Ito Yoshio , Iwaida Masahiro 
Published: February 2020

Abstract
Borate was directly chelate-extracted from foods with 5% 2-ethyl-l,3-hexanediol (EHD) in n-hexane–n-butyl acetate mixture (8+2), from which borate was selectively transferred into 1% NaOH, since EHD-chelated boron did not react with curcumin to develop color. Finally, an aliquot of the alkaline solution was acidified with HC1 and reacted with curcumin in a rotary evaporator. Color development was increased by heating for 8 min at 80°C under reduced pressure of 16 mm Hg. Frozen shrimp and prawns (peeled and with shells) and salted jelly fish were analyzed by the proposed method. Results were compared with the contemporary official method of Japan based on curcumin reaction on an incinerated sample. Over 90% of the boric acid was recovered by the proposed method when samples were fortified with 20 ppm boric acid. Recoveries were superior to those of the official method especially for shrimp and prawns with shells and salted jelly fish. Detection limit of boric acid is 1 ppm. Moreover, the method requires only about 1 hr for analysis of one sample, making it suitable for routine analysis.
Determination of Amprolium in Feeds: Collaborative Study
Authors: Davis E Jack 
Published: February 2020

Abstract
The official final action method, 42.028-42.032, for determining amprolium in feeds was modified by a change in the preparation of aluminum oxide for chromatography. A premix containing 0.5% amprolium was collaboratively studied by the modified and the official methods. Compared with the modified method, 87.7% of the drug was recovered from the premix by using the official method. The modification makes possible the assay of premixes as well as finished feeds. The official final action method has been modified to incorporate this change.
Identification of Species in Cooked Crabmeat by Thin Layer Isoelectric Focusing
Authors: Krzynowek Judith , Wiggin Kate 
Published: February 2020

Abstract
Thin layer polyacrylamide gel isoelectric focusing (TLIEF) is described for characterizing the species-specific, heat-denatured proteins of 8 species of crab: red (Geryon quinquedens), rock (Cancer irroratus), Jonah (Cancer borealis), blue (Callinectes sapidus), king (Paralithodes camtschatica), snow (Chionoectes spp.), European edible (Cancer pagurus), and dungeness (Cancer magister). Protein pattern differences are shown not only among species, but also between 2 modes of heat processing of the crabmeat. Individual variation within the species as to sex, size, and maturity, length of frozen storage, and body parts chosen for sampling do not alter the species banding pattern. The reproducible species-specific fingerprint obviates the need to analyze authenticated samples simultaneously with the unknown crabmeat.
Determination of Proof of Distilled Alcoholic Beverages, Using an Oscillating U-Tube Density Meter
Authors: Strunk Duane H , Hamman Jack W , Timmel Bertha M 
Published: February 2020

Abstract
A simple, rapid, and accurate method is described for determining the concentration of alcohol in ethanol solutions using a density meter. With this instrument, the U-tube is suctionfilled with 0.7 mL sample, and the results are displayed on a digital read-out in specific gravity units. These values are converted by tables to per cent ethanol or proof. For samples under 40° proof, the instrument is standardized on air and water. When testing samples between 40 and 193° proof, the instrument is standardized on air and an ethanol standard having a proof within ±30° of the sample tested. Thus, large corrections for the nonlinearity of the plot of the specific gravity of ethanol vs. proof are avoided. An equation is presented that corrects for this non-linearity, and the result is obtained in per cent ethanol rather than specific gravity. Proof results obtained with this instrument are in good agreement with the values obtained by a pycnometer and/or refractometer for 1–190° proof ethanol-water solutions, vodkas, whiskeys, brandies, and liqueurs.
Development of Culture Vessel for Sterility Testing of Bandages and Other Medical Devices
Authors: Quagliaro Daniel A , Spite George T , Guilfoyle Dennis E , Mestrandrea Leonard W , Stiesi Walter E 
Published: February 2020

Abstract
A cylindrical glass culture vessel equipped with a vented nylon closure was developed and evaluated for sterility testing. The sterility testing cylinder (STC), made in 2 sizes, accommodates 250 or 400 mL culture broth. A tightfitting, skirted nylon cap protects the upper part of the cylinder, and a membrane filter in a recessed opening allows venting during autoclaving and ensures sterility during removal and replacement of the cap. The configuration of the vessel in terms of the opening size and ratio of the horizontal to vertical cross section provides depths desirable for testing many shapes of medical devices, including elongated and narrow ones, without excessive waste of medium. They are easy to charge with medium, and to autoclave, store, inoculate, and observe for growth.
Spectrophotometric Determination of Caffeine in Coffee Products: Collaborative Study
Authors: Newton John M 
Published: February 2020

Abstract
An ultraviolet (UV) spectrophotometric method for determining caffeine in regular and decaffeinated coffee products has been studied collaboratively. Nine laboratories participated in this study which compares the proposed UV method with the official AOAC micro Bailey-Andrew method. Caffeine content was determined on as-is basis on 8 samples of green, roasted, and soluble coffees. The coefficients of variation for the proposed method ranged from 2.02 to 6.98% for the 8 samples studied. The results agreed well with those from the Bailey-Andrew method. The method was adopted as official first action.
IUPAC Gas Chromatographic Method for Determination of Fatty Acid Composition: Collaborative Study
Authors: Firestone David , Horwitz William 
Published: February 2020

Abstract
An international collaborative study of IUPAC methods II.D.19 and II.D.25 for preparation and GLC analysis of fatty acid methyl esters was begun in 1976. The IUPAC methodology, applicable to animal and vegetable oils and fats and fatty acids from all sources, contains special instructions for preparation and analysis of methyl esters of fatty acids containing 4 or more carbon atoms (analysis of milk fat). Twenty-three collaborators participated in the analysis of 5 known mixtures, 4 vegetable oils, 1 fish oil, and 2 butterfats. Several blind duplicate samples were included. The experimental data were subjected to statistical analysis to examine intra- and interlaboratory variation. Reproducibility and accuracy data for the higher fatty acid (14:0–22:1) mixtures and fish and vegetable oils were satisfactory and were in good agreement with results from an AOCS Smalley Committee check sample program involving analysis of the same samples. Typical coefficients of variation (%) at various concentrations were 15 (2% level), 8.5 (5% level), 7 (10% level), and 3 (50% level). Low recoveries and poor reproducibility were characteristic of results obtained for butyric acid in the butterfat and related known mixtures. A coefficient of variation of about 19% was found for analysis of butyric acid in butterfat, vs. coefficients of variation in the range of 4–13% for similar levels of other components in butterfat and other samples. The IUPAC methodology for GLC analysis .of fats and oils other than milk fats has been adopted by the AOAC as official first action to replace the current GLC method, 28.063-28.067.
Identification of Some Benzodiazepines of Forensic Interest
Authors: Noggle F Taylor , Clark C Randall 
Published: February 2020

Abstract
Ten benzodiazepines–clorazepate, nitrazepam, clonazepam, oxazepam, lorazepam, chlordiazepoxide, N-desmethyldiazepam, diazepam, prazepam, and flurazepam–in solid dosage form are identified by ultraviolet (UY) and infrared (IR) spectrophotometry and by high pressure liquid chromatography (HPLC). UV absorption data and IR spectra of the 10 benzodiazepines are provided and HPLC separation methods are described.
Charcoal Column/Thin Layer Chromatographic Method for High Fructose Corn Sirup and Spectrophotometric Method for Hydroxymethylfurfural in Honey: Collaborative Studies
Authors: White Jonathan W , Kushnir Irene , Doner Landis W 
Published: February 2020

Abstract
A new spectrophotometric method is described for determining hydroxymethylfurfural in honey in which interfering background absorption of honey is corrected for by use of a bisulfite-treated sample as blank. Two procedures for detecting high-fructose corn sirup (HFCS) in honey were also tested. In one, charcoal column pretreatment is used to concentrate trace oligosaccharides, followed by thin layer chromatography to differentiate those of HFCS from those of honey. The other method depends on measurement of the isomaltose/maltose ratio by gas-liquid chromatography. The charcoal/thin layer chromatographic method for HFCS has been adopted official first action. The bisulfite method for hydroxymethylfurfural has been adopted interim first action.
Some Principles of Microbiological Turbidimetric Assays of Antibiotics
Authors: Rippere Robert A 
Published: February 2020

Abstract
Turbidimetric methods for determining the potency of antibiotics are inherently more accurate and more precise than are comparable agar diffusion procedures, but assays conducted in liquid media are subject to degradation from less than ideal conditions to a much greater extent than are diffusion methods. The relationships between test organisms, antibiotics, and assay concentrations are discussed. A valid assay procedure must produce a linear response with an adequate slope (–0.4 to –1.2) by the test organism to increasing concentrations of drug; such linear response normally occurs over a limited range of concentrations. Criteria used to select photometers that offer the greatest advantages to analytical microbiologists are described, with guidelines for the most effective use of the chosen instrument.
Aflatoxigenic Potential of Dried Figs, Apricots, Pineapples, and Raisins
Authors: Morton S Glenn , Eadie Thomas , Llewellyn Gerald C 
Published: February 2020

Abstract
Spores from 3 aflatoxigenic strains were applied to the surface of dried figs, pineapple slices, apricots, and raisins. Half of the samples of each foodstuff was autoclaved (cooked) before inoculation. All 3 strains produced some toxin but not in all of the foodstuffs. No aflatoxins were found in any of the raisin cultures. The overall potential for toxin production in the dried fruit was apricot &lt; fig &lt; pineapple &lt; raisin. Among the cooked substrates, the order was apricot &lt; pineapple &lt; fig = raisin. For the raw dried fruits, the ranking was fig &lt; pineapple &lt; apricot &lt; raisin. Pineapple was considered the best broad spectrum substrate of the foodstuffs evaluated in the study.
Analysis of Foods for Iodine: Interlaboratory Study
Authors: Heckman Mary M 
Published: February 2020

Abstract
An accurate, reproducible method for ≤1 ppm iodine in foods is required for nutritional labeling. In order to ascertain the current status of iodine analysis in foods, 7 samples, representing different food classes, were analyzed by 8 laboratories. Six laboratories used their modifications of the Ce-As-I catalytic method preceded by alkaline dry ashing. Two laboratories used neutron activation analysis (NAA), with differing radiochemical separations. The study showed wide discrepancy in analytical results. Mean relative standard deviation for all laboratories was 77.9% between laboratories; 19.1% within-laboratories. Laboratories using NAA had only slightly better precision than did laboratories using the chemical method. The lowest level reported on the entire group of samples ranged among laboratories from 0.0089 to 0.65 ppm. Figures reported by a laboratory are, in general, consistently high or consistently low. The only differences in methodology which may possibly correlate with level of iodine obtained are the use of NAA technique and use of manual, rather than automated, colorimetry.
Reverse Phase Ion Pair High Pressure Liquid Chromatographic Determination of Ethylenediaminetetraacetic Acid in Crabmeat and Mayonnaise
Authors: Perfetti Gracia A , Warner Charles R 
Published: February 2020

Abstract
A method is described for the determination of ethylenediaminetetraacetic acid (EDTA) in crabmeat and mayonnaise. EDTA is extracted from the food sample with water and converted to its copper chelate, which is then quantitated by reverse phase ion pair high pressure liquid chromatography with ultraviolet detection. Maximum sensitivity is obtained with detection at about 254 nm; higher wavelengths may be used for enhanced specificity. Cleanup procedures for crabmeat and mayonnaise were improved by using a radiotracer method. Analyses of crabmeat and mayonnaise samples spiked at 3 different levels showed &gt;90% recovery of EDTA.
Identification of Analogs of the Hallucinogen Cyclohexamine
Authors: Bailey Keith , Legault Donald 
Published: February 2020

Abstract
The hallucinogenic drug 1-phenylcyclohexylamine and its N-methyl-, N-ethyl-, N-propyl-, Nisopropyl-, and N-(β-phenylethyl)-derivatives are identified by spectroscopic techniques. Reference mass and infrared spectra and gas-liquid and thin layer chromatographic data are provided and discussed.
Gas-Liquid Chromatographic Determination of Bayer 73 in Fish, Aquatic Invertebrates, Mud, and Water
Authors: Luhning Charles W , Harman Paul D , Sills Joe B , Dawson Verdel K , Allen John L 
Published: February 2020

Abstract
A gas-liquid chromatographic (GLC) method is described for determining residues of Bayer 73 (2-aminoethanol salt of 2’,5-dichloro-4’-nitrosalicylanilide) in fish muscle, aquatic invertebrates, mud, and water by analyzing for 2-chloro-4-nitroaniline (CNA), a hydrolysis product of Bayer 73. Bayer 73 residues are extracted from fish muscle tissue, invertebrates, and mud with acetone-formic acid (98+2), and partitioned from water samples with chloroform. After sample cleanup by solvent and acid-base partitioning, the concentrated extract is hydrolyzed with 2N NaOH and H2O2 for 10 min at 95°C. The CNA is then partitioned into hexane-ethyl ether (7+3) and determined by electron capture GLC. Average recoveries were 88% for fish, 82% for invertebrates, 82% for mud, and 98% for water at 3 or more fortification levels.
Gas-Liquid Chromatographic Determination of Thiourea in Citrus Peels
Authors: Toyoda Masatake , Ogawa Shunjiro , Ito Yoshio , Iwaida Masahiro 
Published: February 2020

Abstract
A gas-liquid chromatographic (GLC) method was developed for the detection and determination of thiourea in citrus peels. After the peel is extracted with ethyl ether, the ether extract is adsorbed on sodium sulfate together with water. Thiourea is recovered from both the sodium sulfate and the peel residue with ethyl acetateacetone( 2+l). The extracted mixture is cleaned on an alumina column, the eluate is concentrated under vacuum, and thiourea is extracted from the concentrate with sodium carbonate solution. GLC was carried out on the prepared benzoyl derivative of thiourea. The average recoveries of thiourea from lemon peel were 85.3, 93.1, and 97.6% at the fortification levels of 1, 10, and 100 ppm, respectively. The detection limit was as low as 0.08 ppm.
Colorimetric Determination of Caffeic Acid in Plant Materials
Authors: Bajaj Krishan L , Arora Yogesh K 
Published: February 2020

Abstract
A new colorimetric method is described for determining caffeic acid content in plant materials. Caffeic acid is separated by thin layer chromatography from the alcoholic extract, and color is developed using 0.5% aqueous thiosemicarbazide solution under alkaline conditions. The absorbance is read at 475 nm. Lambert-Beer's law is obeyed in the concentration range 0.37-17.5 μg caffeic acid/mL. The method is reproducible and has been applied to the estimation of caffeic acid in carrot roots.
Random Selection of Grid Squares for Scanning by Transmission Electron Microscopy
Authors: Chen Edwin H , Hallenbeck William H , Hesse Carolyn S 
Published: February 2020

Abstract
A practical method is presented for the random selection of grid squares to be scanned by transmission electron microscopy. The only prerequisite for applying the technique is that the electron microscope must have 2-dimensional stage controls which are calibrated in arbitrary units.
Single Step Extraction and Cleanup for Determination of Diuron in Soil
Authors: Kulshrestha Gita 
Published: February 2020

Abstract
A simplified method has been developed for the extraction and cleanup of diuron[3-(3,4-dichlorophenyl)- l,l-dimethyl urea, or Karmex] residues from soil. Soil mixed with Florisil and anhydrous sodium sulfate is eluted with acetone and determined spectrophotometrically. No further cleanup is necessary. Recoveries of diuron from alluvial, black, red, and calcareous soils were &gt;90%.
Identification of Nosiheptide in Feeds and Detection of Residues in Animal Tissues
Authors: Pascal Claude , Gaillard Claude , Moreau Marie-O 
Published: February 2020

Abstract
Nosiheptide is determined in fermentation broths of Streptomyces actuosus either by a microbiological method using Staphylococcus aureus or, more easily, by an automated colorimetric method. The results obtained with both methods correspond well for concentrations greater than 100 μg/mL with a standard deviation of 1-3%. For determination of nosiheptide as a feed additive, the microbiological assay is made more specific by pretreatment with petroleum ether and IN HCL Standard deviation is &lt;4%, and the assay is sensitive to 1 ppm. Nosiheptide is identified in feed containing other frequently used antibiotics by thin layer chromatography with bioautography; sensitivity is 1 ppm. The absence of traces of nosiheptide in tissues of treated swine and broiler is confirmed by microbiological diffusion, sensitive to 0.025 ppm.
Bacillus stearothermophilus Disk Assay for Detection of Residual Penicillins in Milk: Collaborative Study
Authors: Ouderkirk Larry A 
Published: February 2020

Abstract
A collaborative study was performed on a Bacillus stearothermophilus paper disk method designed to detect residual levels of 4 antibiotic drugs in whole market milk. This method is a modification of an earlier procedure developed for the International Dairy Federation. Whole milk samples spiked at low levels with ampicillin, cephapirin, cloxacillin, and penicillin G were sent frozen to 11 collaborating laboratories with instructions to assay them promptly according to the method provided. Five of the laboratories reported inconclusive results due to technical difficulties encountered with the method. The 6 remaining laboratories all detected levels of 0.005- 0.008 μg or unit/mL for penicillin G, ampicillin, and cephapirin and 0.05-0.08 μg/mL for cloxacillin. The most commonly used official methods, the Sarcina lutea (Micrococcus luteus) cylinder plate method and the Bacillus subtilis paper disk method, can detect levels of 0.01 and 0.05 unit penicillin G/mL, respectively. The B. stearothermophilus method is rapid, simple to perform, and more sensitive than present official methods. The method has been adopted as official first action for the detection of penicillins in milk.
Performance Specifications for Infrared Milk Analysis
Authors: Biggs Delmar A 
Published: February 2020

Abstract
Maximum limits of 0.02% are recommended for precision of IR analysis for fat, protein, and lactose, and 0.04% for total solids. Recommended maximum systematic errors are 0.06% for fat, protein, and lactose, and 0.12% for total solids, when instrument results are compared with results of specified AOAC methods. Recommended maximum mean differences between instrument and standard results are based on 95% confidence limits for the mean of 8 samples; precision and systematic errors are calculated as the standard deviation of difference between duplicates for 8 samples, and systematic errors are calculated as the standard deviation of difference between instrument and reference results for 8 samples. Automated sections for milk of Official Methods of Analysis were rewritten to eliminate references to individual instruments, to eliminate possible differences between calibration procedures for different instruments, and to stress important instrument operational characteristics which can have significant effects on instrument performance.