bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitation of Polychlorinated Biphenyl Residues by Electron Capture Gas-Liquid Chromatography: Collaborative Study
Authors: Sawyer Leon D 
Published: February 2020

Abstract
Ten collaborators quantitated 2 synthetically prepared polychlorinated biphenyl (PCB) mixtures, 2 PCB-fortified milk samples, and an incurred PCB residue in milk and chicken fat. Three electron capture gas-liquid chromatographic (GLC) methods were used for quantitating each unknown PCB against Aroclor reference materials. Two of the methods were existing AOAC total response comparisons and the third was a proposed individual peak comparison. In addition, existing AOAC multiresidue pesticide methodology was employed for determining PCB recovery from whole milk. The average combined recovery of Aroclor 1254 from milk fortified at 1.4 and 2.7 ppm (fat) was approximately 85% (coefficient of variation, 15%) with no significant difference by the methods of quantitation. The incurred PCB residue in milk (as 1254) was determined to be 1.3 (30%), 1.7 (31%), and 1.2 ppm (18%) by total peak height, total area, and individual peak quantitation methods, respectively. In the same order, incurred PCB in chicken fat was determined to be 6.8 (13%), 7.5 (16%), and 5.6 ppm (8%) as 1242, or 6.9 (6%), 5.9 (8%), and 6.3 ppm (8%) as 1248. Total PCB quantitated individually in a 3- and a 4-component chlorobiphenyl mixture, using 1248 as the reference standard, resulted in the following averages of actual amounts present: 3-component—109% (23%), 95% (18%), and 95% (6%); 4-component— 116% (16%), 112% (29%), and 104% (7%), respectively, for total peak height, total area, and individual peak quantitation methods. Both the individual peak quantitation method and the AOAC multi-pesticide methodology have been adopted as official first action methods for PCB.
Spectrophotometric Determination of Pyrantel Tartrate in Swine Feeds by Method of Standard Additions: Collaborative Study
Authors: Litchman Mark A 
Published: February 2020

Abstract
The spectrophotometric method for pyrantel tartrate in swine feeds was collaboratively studied. Twenty-seven laboratories assayed feeds containing 0.0103, 0.0965, and 0.7902% pyrantel tartrate. Repeatability (σo) and reproducibility (ax) standard deviations were: σo = 0.00068%, σx = 0.00105% (10% of grand mean) for 0.0103% pyrantel tartrate level; σo = 0.0065%, σx = 0.0090% (10% of grand mean) for 0.0965% pyrantel tartrate level; and σo = 0.0415%, σx = 0.0743% (10% of grand mean) for 0.7902% pyrantel tartrate level. The mean theoretical recovery values for feeds containing 0.0103, 0.0965, and 0.7902% were 100, 97, and 96%, respectively. The method was adopted as official first action for feeds or concentrates containing 0.0106–0.8811% pyrantel tartrate.
High Pressure and Gas-Liquid Chromatographic Methods for the Determination of Parathion in Formulations: Collaborative Study
Authors: Jackson Edwin R 
Published: February 2020

Abstract
The official first action high pressure (HPLC) and gas-liquid (GLC) chromatographic methods for the determination of methyl parathion were adapted to analyze technical parathion, and 25 and 50% parathion emulsifiable concentrates. A technical parathion sample was analyzed and then used to prepare 5 of the 6 collaborative samples. At a 95% confidence level, only 1 of the 10 means was significantly different from the theoretical value. There was no significant difference in the CLC and HPLC means for each sample. The average of the coefficients of variation for the 6 CLC determinations (15 collaborators) was 0.86%. For the HPLC determinations (8 collaborators), the average was 0.81%.
Potential Uses of Lead Isotope Ratios in Gunshot Cases
Authors: Keisch Bernard , Callahan Robert C 
Published: February 2020

Abstract
The determination of lead isotope ratios in 14 bullets, and in material taken from 9 hand swabs and 5 primers shows that there are potentially valuable forensic uses for such a method. While a more complete study is required, this method could possibly be used to prove (or disprove) relationships between bullets and manufacturers, weapons, or persons firing the weapons. Sample size requirements (1 ≧g or less) are such that damaged or fragmented bullets, or minute particles therefrom, may be used for the required analyses. An experiment showed that gunshot residue from a test-fired weapon was detectable even after washing the hands.
Thin Layer Chromatographic Screening Method for Sulfadiazine Residues in Calf Tissues, Plasma, and Urine
Authors: Woolley Joseph L , Murch Oliver , Sigel Carl W 
Published: February 2020

Abstract
Because of the lack of specificity of the Bratton-Marshall procedure for assaying sulfonamides, a sensitive, specific tissue residue assay for sulfadiazine (SDZ) was developed. The methodology has been extended to provide a highly sensitive screen for sulfonamide residues, which employs 2-dimensional thin layer chromatography in conjunction with fluorescamine derivatization. The procedure described, which has been developed for SDZ in calf tissues, involves direct ethyl acetate extraction of tissue homogenates. Following evaporation of the organic phase, a portion of the residue is spotted on a 20x20 cm silica gel 60 plate, which is then developed in 2 dimensions with solvent systems devised to separate SDZ from endogenous substances as well as from 12 other sulfonamides that might be present in calf tissues. The presence of SDZ at a concentration of 0.1 ppm or its absence is easily demonstrated in calf kidney, liver, muscle, plasma, and urine. The basic method can be modified for a particular sulfonamide in a target tissue and can be used as a quantitative assay for sulfonamide residues.
Total Solids in Nonfat Dry Milk by Atmospheric Drying in a Forced Air Oven
Authors: Sherbon John W , Mickle James B , Ward William D 
Published: February 2020

Abstract
Laboratories using forced air atmospheric ovens at 100°C to determine total solids in milk are interested in using the same equipment to measure total solids in nonfat dry milk powder (NFDM). Results of several studies previously were presented to the Association. Another collaborative study involving 5 laboratories was done this year. The results of the new study confirm the previous work; the forced air method gives results not significantly different from the official vacuum oven procedure. Throughout these studies, it was noted that strong thermal gradients in some vacuum ovens made it difficult to uniformly subject each sample to the specified amount of heat. It was also found that fresh whole milk and reconstituted NFDM can be tested successfully when the steam bath step is omitted from the official method for milk by increasing the drying time to 4½ hr.
Methods of Analysis Approved by the Codex Alimentarius Commission. II. Determination of the Loss on Drying of Lactose: Collaborative Study1
Authors: Bourland Charles T , Weik Robert W , Anderson Randall L , Horwitz William 
Published: February 2020

Abstract
A collaborative study was performed on the method recommended by the Codex Alimentarius Commission for determining loss on drying of lactose at 120°C for 16 hr. Eight samples of lactose were analyzed by 9 laboratories. Although there was no significant difference between the means of the values obtained with the convection and forced draft ovens, the precision attained by the 3 laboratories using a forced draft oven was considerably better than that attained by the laboratories using a convection oven. There is evidence that the directions for preparing samples of coarse crystals and lumpy products are inadequate
Gas-Liquid Chromatographic Determination of Ethopabate in Feed Premixes
Authors: Smallidge Robert L 
Published: February 2020

Abstract
A gas-liquid chromatographic method is presented for determining ethopabate in 0.8 and 8.0% premixes. A sample is extracted with tetrahydrofuran containing an internal standard, by sonication or overnight soaking. The extract is clarified by centrifugation, diluted if necessary, and injected into a gas chromatograph equipped with a flame ionization detector. Average per cent recoveries for spiked blank samples were 100.6 at the 0.8% level and 100.4 at the 8.0% level. Precision, as indicated by replicate analyses of several premixes, ranged from 0.5 to 1.7% relative standard deviation
Colorimetric Determination of Terreic Acid Produced by Aspergillus terreus
Authors: Subramanian Thirugnana , Namasivayam Kuppuswamy Mohan , Shanmugasundaram Edayathimangalam R B 
Published: February 2020

Abstract
Two methods have been developed for determining terreic acid, which is a mycotoxin produced by Aspergillus terreus, a common food contaminant. The organism was grown independently in synthetic minimal medium, bread, and rice. After 15 days of growth, the toxin was extracted with ethyl acetate, cleaned up by thin layer chromatography, and determined colorimetrically, using Folin's reagent or 2,4- dinitrophenylhydrazine. The production of terreic acid was greater on bread than on rice or minimal medium. Recoveries of 200–400 ≧g terreic acid/100 g bread and rice ranged from 62 to 98%. The lower limit of detection was 200 ≧g/100 g.
High Pressure Liquid Chromatographic Determination of Xanthomegnin in Corn
Authors: Stack Michael E , Brown Nathan L , Eppley Robert M 
Published: February 2020

Abstract
A method is described for the detection and quantitative analysis of xanthomegnin in corn samples. Initial extraction with CHCI3 in the presence of 0.5M H3PO4 is followed by additional purification using silica gel column chromatography. A high pressure liquid chromatograph equipped with a microparticle silica gel column and a 405 nm absorbance detector is used for detection and quantitation of the xanthomegnin. The identity of xanthomegnin is confirmed by thin layer chromatography on silica gel plates developed with benzenemethanol- acetic acid (90-(-5+5). The recovery of xanthomegnin added to corn samples at levels of 0.75–9.6 mg/kg averaged 41% with a coefficient of variation of 25%.
Purity of Schaeffer's Salt
Authors: Marmion Daniel M 
Published: February 2020

Abstract
Twenty-one samples of Schaeffer's salt from 8 countries were evaluated for purity, using a variety of instrumental and chemical methods. The properties considered include strength, moisture, insoluble materials, inorganic salts, 2-naphthol, 2-naphthol-3,6-disulfonic acid, 2-naphthol-6,8-disulfonic acid, 6,6'-oxybis(2- naphthalenesulfonic acid), pH, ultraviolet purity, and absorptivity. One unknown was detected in the samples studied, and poor analytical totals obtained on several samples suggest the possible presence of others.
Gas-Liquid Chromatographic Quantitation of Cocaine.HC1 in Powders and Tablets: Collaborative Study
Authors: Clark Charles C 
Published: February 2020

Abstract
Eight laboratories collaboratively studied a method for the quantitative gas-liquid chromatographic (GLC) determination of cocaine. HC1 in solid forms. The cocaine.HQ and other water solubles are dissolved in dilute HC1. The aqueous solution is made weakly basic with K2HPO4, and the organic solubles are extracted into CHC13 for the GLC determination of cocaine. Tetracosane (n-C24) is incorporated in the extracting CHC13 as an internal standard. Five samples of known cocaine.HC1 concentration and one sample of commercial ground tablets were collaboratively studied. The cocaine. HC1 content ranged from 6 to 100%. Recoveries ranged from 98.7 to 103%; coefficients of variation ranged from 0.89 to 3.16. The method was adopted as official first action.
Separation of Krebs Cycle Acids with Beaded Diethylaminoethyl Cellulose
Authors: Bruinsma Bernard L , Le Tourneau Duane 
Published: February 2020

Abstract
A method is described for separating Krebs cycle organic acids on a column of beaded diethylaminoethyl cellulose (DEAE Sephadex A-25). Depending on the acids contained in the mixture, separation can be achieved in 4–8 hr and does not require pH or solvent gradients. After elution, the solvent (ethyl ether-formic acid-water (10+2-(-l)) is removed in a vacuum oven (aspirator). The contents of the tubes can be titrated for quantitative analyses or pooled, recrystallized, and used for qualitative analyses, such as infrared spectroscopy. The method was used to separate and isolate fumaric, a-ketoglutaric, malic, oxalic and succinic acids from culture medium following the growth of the fungus Sclerotinia sclerotiorum (Lib.) D. By.
Method for Maintaining Viability of Clostridium perfringens in Foods During Shipment and Storage: Collaborative Study
Authors: Harmon Stanley M , Placencia Ana M 
Published: February 2020

Abstract
A collaborative study was conducted in 12 laboratories to determine the effectiveness of a new method for maintaining vegetative cells of Clostridium perfringens in viable condition during storage and transport of food specimens to the laboratory. The collaborative results showed that treatment of brown gravy and roast beef samples with an equal amount by weight of sterile buffered glycerol-sodium chloride solution to give a final 10% glycerol concentration and storage with Dry Ice for 10 days at — 56°C resulted in plate counts of C. perfringens which were 2—4 log cycles higher with 2 different strains than counts with untreated specimens stored by the usual method at — 20°C. Plate counts obtained with the treated specimens stored with Dry Ice were less than 1 log cycle lower than counts made with identical specimens before freezing for storage and shipment to the collaborators. The results with treated specimens were also more uniform among the different laboratories. Because the new method for storage and shipment of food samples was so effective for maintaining viability of the organism, the official first action method for C. perfringens (46.B01) was changed to incorporate these procedures as part of the method.
High Pressure Liquid Chromatography of Zearalenone in Cereals
Authors: Möller Tord E , Josefsson Egon 
Published: February 2020

Abstract
A high pressure liquid chromatographic method has been developed for determining zearalenone in cereals. The sample is extracted with phosphoric acid and chloroform. The extract is cleaned up by washing on a silica gel column with benzene-hexane or cyclohexaneethylene dichloride-ethyl ether and eluting with chloroform, and further purified by extracting into alkaline solution, washing with water, adjusting pH, and back-extracting into chloroform. Zearalenone is determined by using a liquid chromatograph with 2 columns in series packed with Spherisorb 10 μm ODS and with an ultraviolet detector set at 236 nm. The detection limit of the method is 2 μg/kg. Recovery is about 90% when benzene-hexane is used in the washing step and about 80% when cyclohexane-ethylene dichloride-ethyl ether is used.
Confirmatory Test for Aflatoxin M1 on a Thin Layer Plate
Authors: Van Egmond Hans P , Paulsch Walter E , Schuller Pieter L 
Published: February 2020

Abstract
The identity of aflatoxin M1 can easily be confirmed directly on a thin layer plate by reacting aflatoxin M1 with trifluoroacetic acid (TFA). This confirmation reaction is carried out on the thin layer plate which has been developed in 2 dimensions and used for the quantitation of aflatoxin M1 in the sample. TFA is superimposed on the separated M1 spot. The plate is kept in the dark 3 min, heated to 75°C for 5 min, and developed with chloroformmethanol-acetic acid-water (92+8+2+0.8). The Rf value of the blue-fluorescent derivative is compared with that for the M1 standard. The method was used successfully on extracts of milk, cheese, and liver. M1 quantities on the plate as low as 0.5 ng can be confirmed by this method. The method is also suitable for simultaneous confirmation of aflatoxin B1.
Gas-Liquid Chromatographic Determination of Pydrin, a Synthetic Pyrethroid, in Cabbage and Lettuce
Authors: Lee Young W , Westcott Neil D , Reichle Randy A 
Published: February 2020

Abstract
Pydrin, a-cyano-3-phenoxybenzyI 2-(4-chlorophenyl)-3-methylbutyrate, a synthetic pyrethroid ester, is extracted from vegetables with acetonitrile, partitioned into petroleum ether before cleanup on a Florisil column, and analyzed by electron capture gas-liquid chromatography. Recoveries of 88-102% at 0.01 ppm, 99-102% at 0.1 ppm, and 98—104% at 1.0 ppm were obtained from fortified cabbage and lettuce samples. The method appears applicable to detection of the residues of Pydrin in the foliage of many types of crops.
Extraction of Light Filth from Coconut: Collaborative Study
Authors: Thrasher Joel J 
Published: February 2020

Abstract
The official method for filth in coconut, 44.029, frequently produces filter papers with excessive plant debris and low hair recoveries. To overcome these deficiencies, 3 changes in the method were made: (1) the defatting step was modified to use sodium lauryl sulfate in combination with borax for better defatting; (2) 40% isopropanol was substituted for 60% ethanol as the aqueous phase for cleaner papers; and (3) mineral oil was substituted for n-heptane to improve hair recoveries. These changes resulted in higher, more reproducible recoveries of rodent hairs and insect fragments and cleaner filter papers. The method has been adopted as official first action to replace 44.029.
Improved Fluorometric Method for Determining Selenium
Authors: Whetter Phyllis A , Ullrey Duane E 
Published: February 2020

Abstract
A previously reported method for selenium analysis of biological materials has been modified to reduce equipment requirements and labor, resulting in 40—80 determinations in an 8-hr period. Digestions are performed on hot plates in Erlenmeyer flasks, and neutralization, chelation with EDTA, complexing with 2,3- diaminonaphthalene, and extraction of the piazoselenol into cyclohexane are completed in the same vessel. Flotation of the cyclohexane layer into the neck of the flask with water allows convenient transfer to fluorometer tubes. Representative analytical values for serum, skeletal muscle, liver, kidney, corn, and alfalfa hay are presented. The mean recovery (± standard deviation) of added selenite selenium in 84 determinations was 98.1±7.1%. The mean coefficient of variation (± standard error) of repeated analyses of the same samples was 6.98±0.78%. The mean difference (± standard error) between values determined by the proposed method and the AOAC method was -0.03±0.60%.
Differential Pulse and AC Polarography of Reserpine, Using an Aprotic Organic Solvent System
Authors: Taira Albert , Smith Donald E 
Published: February 2020

Abstract
Previously demonstrated advantages of aprotic organic solvent for analysis of organic pharmaceuticals have been applied to the assay of reserpine tablets. A procedure using high sensitivity electroanalytical relaxation methods was developed which is simpler and more sensitive than the USP assay. Most data were obtained with a commercial differential pulse polarograph which is widely available. However, less extensive measurements with other instruments established the general applicability of the differential pulse method, as well as various ac polarographic techniques. The results of differential pulse polarographic (DPP) and USP assays of synthetically formulated reserpine tablets compare favorably. The DPP method yields an average recovery for 0.1 mg reserpine/tablet of 100%, with a range of 97.6-102.3%. Corresponding data for 0.25 mg reserpine/ tablet are 99.3%, with a range of 97.6-100.6%. Satisfactory results also were obtained in content uniformity studies, using single 0.1 and 0.25 mg tablets.
Spectroscopic and Chromatographic Identification of Precursors, Intermediates, and Impurities of 3,4-Methylenedioxyamphetamine Synthesis
Authors: Lukaszewski Theodore 
Published: February 2020

Abstract
The ultraviolet, infrared, nuclear magnetic resonance, and mass spectra of a number of precursors, intermediates, and impurities of 3,4-methylenedioxyamphetamine (MDA) synthesis are presented as well as gas-liquid and thin layer chromatographic data. Test results are given on the precursors safrole, isosafrole, and piperonal; the intermediates isosafrole glycol, N-formyl-MDA, and l-(3,4-methylenedioxyphenyl)- 2-nitro-l-propene; the impurities di[l- (3,4-methylenedioxyphenyl) -2-propyl] amine, di[l - (3,4 - methylenedioxyphenyl) -2- propyl] methylamine, and 3,4-methylenedioxyphenyIpropane; and the product MDA. The data are discussed and 2 methods of MDA synthesis are summarized, in which the precursors, intermediates, and impurities are encountered.
Gas-Liquid Chromatographic Determination of Volatile Organic Acids as Benzyl Esters with Applications to Tuna, Shrimp, and Eggs
Authors: Staruszkiewicz Walter F , Fernandez-Flores Enrique , Bond John F 
Published: February 2020

Abstract
Volatile acids are recognized as useful indicators of decomposition in a variety of foods. A method has been developed for the rapid preparation of benzyl esters of formic, acetic, propionic, isobutyric, and butyric acids and for their quantitative determination by gas-liquid chromatography. Esters were formed by reaction with BCl3-benzyl alcohol, followed by washing with aqueous ammonia before storage. They were chromatographed, using tetradecane as an internal standard, and were separated at 140°C on columns having DC-200 and SP-1000 as liquid phases. The method offers significant advantages, especially for the determination of formic acid, over the present official AOAC method, 17.042-17.046. Recoveries of volatile acids added to steam distillates of tuna extracts were ≥ 91% with mean recoveries for the 5 volatile acids of 96—104%. Applications to the analysis of canned tuna, frozen headless shrimp, and frozen whole egg resulted in recoveries of ≥ 8 2% with mean recoveries for the 5 acids of 91—101%. The method was compatible with an automated gas chromatograph-data processing system.
Determination of Fluoride in Deboned Meat
Authors: Dolan Thomas , Legette Liston , Mcneal Jon , Malanoski Anthony J 
Published: February 2020

Abstract
A rapid analytical procedure was investigated for measuring the fluoride content of deboned meat, using a specific ion electrode. The method involves a defatting procedure followed by chelation with EDTA before final solubilization and measurement. Fluoride content is determined by comparison to a standard curve on 2-cycle semi-logarithmic graph paper of fluoride ion vs. millivolt readings. The method is applicable to hand and mechanically deboned pork, beef, and poultry within a range of from 0.7 to 25.0 ppm fluoride. Higher concentrations may be measured by analyzing additional standards and extending the curve into a third cycle. The curve is not linear below 0.7 ppm. Samples less than 0.7 ppm may be estimated by extrapolation. Studies with fortified samples indicate average recoveries of 92±4.2%. The standard deviation of duplicates within the laboratory is 0.5 ppm in the range stated above.
Separating Meat and Nonmeat Proteins by Using Disc Electrophoresis
Authors: Richardson Florence M 
Published: February 2020

Abstract
Meat and nonmeat proteins were separated by using an adaptation of the disc electrophoresis method. Milk and soy proteins, at the 3.0, 2.0, 1.0, and 0.5% levels, were incorporated into cooked sausage products. Nonmeat proteins required a denaturing treatment in the final gel preparation step. The entire process of polymerization, staining, and destaining can be completed in 1 day. Densitometer tracings of the band patterns confirmed the reproducibility of the proposed method.
Gas Chromatographic Identification of Propellants and Aerating Agents in Aerosol Whipped Toppings and Sprayed Pan Coatings
Authors: Page B Denis 
Published: February 2020

Abstract
A gas chromatographic procedure is described for the identification of a variety of propellants and aerating agents in aerosol whipped toppings and antistick pan coatings. The aerosol product is dispensed into a flask containing ethanol and the headspace is analyzed by gas chromatography. Carbon dioxide, nitrous oxide, chloropentafluoroethane, octafluorocyclobutane, propane, dichlorodifluoromethane, isobutane, and fluorotrichloromethane are identified by their retention times relative to ethanol.