bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stability and Molar Absorptivity of Aflatoxin M1 in Acetonitrile-Benzene (1 + 9)
Authors: Stubblefield Robert D 
Published: February 2020

Abstract
A solvent mixture of acetonitrile-benzene (1+9) was investigated as a means to eliminate instability of aflatoxin M1 standard solutions prepared with chloroform. Solutions (10.0 μg/mL) were prepared and sealed in glass ampules that were opened as needed for absorbance measurements on the individual solutions over a 13-month period. A coefficient of variation of 0.69& for the absorbance readings indicated that the solutions were stable. In addition, numerous powdered milk extracts containing aflatoxin M1 were dissolved in both chloroform and acetonitrile-benzene (1+9), and the solutions were spotted on TLC plates and developed. Densitometric measurement of the developed zones showed no differences due to the spotting solvent. The molar extinction coefficient was determined in acetonitrilebenzene (1+9) on 4 different M1 solutions from 2 separate crystalline aflatoxin M1 preparations; the value was 18,815 ± 24.
Sephadex LH-20 Cleanup, High Pressure Liquid Chromatographic Assay, and Fluorescence Detection of Zearalenone in Animal Feeds
Authors: Cohen Huguette , Lapointe Michel R 
Published: February 2020

Abstract
A high pressure liquid chromatographic (HPLC) method is described to determine zearalenone in animal feeds at levels as low as 0.01 ppm. Samples are extracted with chloroform-ethanol and initially purified using a SEP-PAK silica cartridge, followed by column chromatography using Sephadex LH-20. Separation by normal phase HPLC is followed by fluorescence detection. Recoveries at levels of 1.0–0.01 ppm averaged greater than 90%. Confirmation included HPLC analysis of the sample and a zearalenone standard, using 3 different excitation wavelengths, and comparison of fluorescence responses obtained. The method was successfully applied to the analysis of 1 corn and 3 cornmeal samples. Zearalenone was detected in all 4 samples at levels of 0.379–19.2 ppm.
Semiautomated Method for Analysis of Nitroglycerin in Sublingual Tablets: Collaborative Study
Authors: Juhl Yvonne H ,   Collaborators:, Alpert M Y , Holmes A , Perrizo C H , Roberts R W , Thornton L K 
Published: February 2020

Abstract
This method is a semiautomated version of the current USP XX method for content uniformity testing of nitroglycerin tablets. Nitroglycerin is hydrolyzed to nitrite in aqueous alkali. The nitrite thus formed diazotizes procaine, which then is coupled with Bratton-Marshall reagent; the absorbance of the resultant color is read at 550 nm. Six collaborators were supplied with 6 composites of sublingual tablets, representing 3 different dosage levels. Results agreed with those obtained by the author using the USP composite assay method. The coefficients of variation ranged from 0.20 to 0.70%. The method is sensitive enough for individual tablet assays (0.15 mg nitroglycerin). The method has been adopted as official first action.
Gas-Liquid Chromatographic Determination of Organochlorine Pesticides and Polychlorinated Biphenyls in Human Milk
Authors: Tessari John D , Savage Eldon P 
Published: February 2020

Abstract
A method for the detection of organochlorine pesticides and polychlorinated biphenyls (PCBs) in human milk is described. The method involves quantitative extraction of human milk with acetone and hexane. The pesticide and PCB residues are extracted from the milk fat with acetonitrile (ACN) and then partitioned back into hexane by aqueous dilution of the ACN extract. The ACN partitioning is followed by cleanup with Florisil column chromatography, eluting with 6 and 15% mixtures of ethyl ether-hexane. The 6% eluate is concentrated and transferred to a silicic acid column for separation of PCBs from pesticide residues. Compounds are quantitated by gas-liquid chromatography. Recovery studies demonstrated that the procedure provides 68–103% recovery for pesticides and PCBs.
Atomic Absorption Methods for Analysis of Soil Extracts and Plant Tissue Digests
Authors: Isaac Robert A 
Published: February 2020

Abstract
The principles of operation and basic equipment of atomic absorption spectroscopy are described. Its advantages over flame emission include higher specificity, fewer interferences, improved detection limits, lower flame temperature requirements, and simpler instrumentation. Analysis procedures which have proved successful in our laboratories are detailed. They include dry ashing and wet digestion for analysis of plant tissues, and exchangeable cations, extractable cations, and acid dissolution for soils analysis.
Detection of Adulterated Maple Products by Stable Carbon Isotope Ratio
Authors: Carro Odette , Hillaire-Marcel Claude , Gagnon Marcel 
Published: February 2020

Abstract
The relatively low 13C content in sugar from maple (Acer saccharum Marsh) indicates a C3 photosynthetic cycle. Cane and corn sugars are characterized by a C4 photosynthetic cycle having a higher content of 13C. Thus, it is possible to detect the addition of cane or corn sugar to maple products. Analyses carried out on hundreds of sap, syrup, and sugar samples from many locations established a calibration curve for mixtures of cane or corn sugar with maple sugars or syrups. Because of the natural range of maple sugar 13C content, an optimum detection level of 3% adulteration is possible on a maple sugar sample of unknown origin. Thus, the isotopic composition 13C/12C is proposed as a method of determining authenticity and detecting adulteration of maple products.
Automated Determination of Salts in Water-Soluble Certifiable Color Additives by Ion Chromatography
Authors: Fratz D Douglas 
Published: February 2020

Abstract
A previously developed ion chromatographic method for the determination of salts in watersoluble certifiable color additives was automated, using a Model 12 Dionex ion chromatograph equipped with a program controller and programmable computing integrator. Programs were written for the program controller for continuous automated analysis of up to 59 samples in about 20 h, with periodic regeneration of the suppressor column and automatic shut-down. All data were processed through the integrator, programmed to give results in weight/weight percent. Recoveries were performed on 4 anions: chloride, phosphate, bromide, and sulfate. Twenty-five color additives could be analyzed by the method. Standard deviations in the determinations ranged from 0.01 to 0.16 at addition levels of 0.20–9.45; with 6 replications. Recoveries for addition levels of 0.2–5.0; with 2 replications fell within the range of 84.0–105.0;. Approximate lower limits of detection for each anion were as follows: chloride, 0.07;; phosphate, 0.10;; bromide, 0.06;; sulfate, 0.07;.
High Performance Liquid Chromatographic Determination of Vitamin A in Margarine, Milk, Partially Skimmed Milk, and Skimmed Milk
Authors: Thompson James N , Hatina George , Maxwell William B 
Published: February 2020

Abstract
Saponification and subsequent evaporation of extracts can cause losses of vitamin A during analysis and thus cause erratic results. These steps were therefore avoided by measuring retinyl palmitate and β-carotene directly in hexane extracts of milk and margarine. Extracts were purified before high performance liquid chromatography(HPLC) by washing with aqueous alcohol. Retinyl palmitate was measured at 325 nm after chromatography on LiChrosorb Si60, 5 μm, using ethyl ether–hexane (2+98) as the solvent system. Milk (2 mL) was shaken with absolute ethanol (5 mL) and hexane (5 mL). Water (3 mL) was added and, after mixing and centrifugation, 100 μL hexane layer was injected. Margarine (5 g) was dissolved in hexane (100 mL). After 5 mL of the hexane solution was washed with 60% ethanol and centrifuged, a 50 μL aliquot was injected. The results of the retinyl palmitate estimation in milk agreed with those obtained by a fluorometric method; the results in margarine agreed with those obtained by saponification, extraction, and HPLC. The coefficients of variation on analysis of 10 replicate samples of milk and margarine were 3 and 4.5%, respectively. The analysis of margarine for vitamin A was completed by measuring β-carotene with a detector set at 453 nm; the coefficient of variation of this measurement was 3% (10 replicates).
Turbidimetric Microbiological Determination of Oxytetracycline Hydrochloride in Finished Feeds and a Feed Premix: Collaborative Study
Authors: Mueller-Brennecke Dorothy L , Reed Shirley J , Waisner Debra L ,   Collaborators:, Ahrens S , Barbiers A R , Black L , Bryant H H , Carter G G , Hasselberger M L , Inglis J M , Koester J , Kunold L , Mayernik J J , Plude R J , Ragheb H S , Rippere R A , Scheiner J M , Schock D , Scroggs R E , Winely C L , Wood R T 
Published: February 2020

Abstract
New automated and manual turbidimetric microbiological assay methods for oxytetracycline (OTC) in finished feeds and a feed premix were submitted to 17 collaborating laboratories for comparison with the official AOAC method. Six finished feeds of 50 and 100 g/ton levels and one premix containing 20 g OTC/lb were sent to the collaborators. Results were received from 12 laboratories. Six laboratories provided results derived from the Autoturb System and 7 laboratories performed the turbidimetric analyses manually. All 12 laboratories assayed the samples by the AOAC cylinder-plate method. Ranges of recoveries expressed as percent were 89.5–102.0, 91.2–97.0, and 91.4–96.0 for the AOAC, Autoturb turbidimetric, and manual turbidimetric methods, respectively. Average recoveries were 96.3, 93.4, and 93.6%, respectively. The mean relative standard deviation values were 5.7, 6.3, and 7.2, respectively. There was little significant difference between the turbidimetric methods and the AOAC method; however, the turbidimetric methods were faster.
DC Polarographic and Spectrophotometric Determination of Ampicillin Capsules
Authors: Squella Juan A , Nunez-Vergara Luis J , Aros Maximo 
Published: February 2020

Abstract
Polarographic and spectrophotometric methods are proposed for the determination of ampicillin in capsules. Acidic hydrolysis of ampicillin with 1% HCHO in 0.3N HCl yields a degradation product identified as 2-hydroxy-3-phenyl-6-methylpyrazine. This compound has a well defined UV absorption band at 380 nm and a polarographic wave at –0.55 V vs SCE, which can be used for analytical purposes. Individual capsule assays, composite assays, and recovery studies are described. The average recovery values and standard deviations (SD) for UV and polarographic determinations were 99.20% (SD 0.95) and 100.85% (SD 1.09), respectively
Determination of Residues of Fensulfothion and Its Metabolites in Chinese Cabbage, Japanese Radish, and Turnips
Authors: George Donald A 
Published: February 2020

Abstract
A method was developed using a selective nitrogen-phosphorus detector to determine the combined total residues, as the oxygen analogs, of fensulfothion (O,O-diethyl O-[p-(methylsulfinyl)-phenyl] phosphorothioate) and its 3 metabolites. The procedure was used to determine harvest residues in Chinese cabbage, Japanese radish, and turnips treated with 2 application rates of fensulfothion. Residues found after application of 2 oz active ingredient (AI)/100 lineal ft of row ranged from 0.026 ppm for Japanese radish to 1.543 ppm for turnip greens. When the application rate was doubled, the amount of residue found was approximately doubled.
Gas-Liquid Chromatographic Determination of Tertiary-Butylhydroquinone (TBHQ) in Dried Fish, Frozen Shrimp, Vegetable Oils, Butter, and Margarine
Authors: Toyoda Masatake , Ogawa Shunjiro , Tonogai Yasuhide , Ito Yoshio , Iwaida Masahiro 
Published: February 2020

Abstract
Tertiary-butylhydroquinone (TBHQ) is extracted from foods with ethyl acetate, the solvent is evaporated, the residue is dissolved in n-hexane–ethyl acetate (99+1), and the TBHQ is selectively transferred into an aqueous layer (2% sodium chloride) as a separation from food interferences. Finally, TBHQ is reextracted with n-hexane–ethyl acetate (1+1), concentrated, and determined by flame ionization gas-liquid chromatography. Dried fish, frozen shrimp, vegetable oils, and edible fats were analyzed by the method. More than 85% was recovered when the samples were fortified with 100 ppm TBHQ. Detection limit was 1.0 ppm TBHQ.
Enzyme Immunoassay for Staphylococcal Enterotoxin A
Authors: Kauffman Peter E 
Published: February 2020

Abstract
An enzyme immunoassay procedure specifying alkaline phosphatase-labeled enterotoxin A was used to determine enterotoxin in standardized solutions and food extracts. Staphylococcus aureus Cowan 1 cells were used to separate unbound from antibody-bound enterotoxin. The method is sensitive to 2 ng enterotoxin A/mL; cross reactions with other staphylococcal enterotoxins did not interfere with the specificity. The method is sensitive and precise enough to serve as a reliable alternative to radioimmunoassay for enterotoxin A.
Radiocarbon (14C) Method for Authenticating Natural Cinnamic Aldehyde
Authors: Hoffman Patrick G , Salb Mary Conjour 
Published: February 2020

Abstract
A method has been developed using quantitation of 14C by liquid scintillation to differentiate natural from synthetic cinnamic aldehyde. The method uses the isolation of cinnamic aldehyde from cinnamon and the determination of the percent modern carbon (14C), to detect the presence of petroleum-derived cinnamic aldehyde.
Comparison of Methods for Determining Penicillamine in Bulk Drug and Formulations
Authors: Vollmer Paul J , Lee Jenny , Jaffe Thomas G 
Published: February 2020

Abstract
The mercuric acetate method (Method I) cited in the Code of Federal Regulations (CFR) as the official method for determining the penicillamine content of a drug was compared with a nonaqueous amine titration (Method II), a nonaqueous acid titration (Method III), and a hydroxylamine assay (Method IV). Quantitative determinations were made for 3 types of penicillamine samples: commercial lots of bulk drug, capsules, and test solutions containing known amounts of penicillamine and EDTA. Method III proved unsatisfactory in the bulk drug determinations. Method II, although slightly less precise than Method I, gave generally satisfactory results for the bulk drug and capsule samples. Method IV was the only method to give satisfactory results in the presence of EDTA.
Mass Spectral Identification and Gas-Liquid Chromatographic Determination of Methyl 4-Chloroindolyl-3-Acetate in Canned and Frozen Peas
Authors: Heikes David L 
Published: February 2020

Abstract
Methyl 4-chloroindolyl-3-acetate (MCIA), a naturally occurring auxin, has been identified in canned and frozen peas by gas-liquid chromatography (GLC)/mass spectrometry. Eight samples were analyzed for MCIA using slightly modified official AOAC multiple pesticide residue procedures employing GLC with microcoulometric detection. Levels of MCIA averaged 0.20 ppm for canned peas and 0.16 ppm for frozen peas. Recovery of MCIA from a fortified sample was 40%.
High Pressure Liquid Chromatographic Determination of Satratoxins G and H in Cereal Grains
Authors: Stack Michael E , Eppley Robert M 
Published: February 2020

Abstract
A high pressure liquid chromatographic (HPLC) method is described for the detection and quantitative determination of satratoxins G and H in cereal grains. The toxins are extracted from the sample by blending with methanol-water (55+45) in the presence of hexane, followed by partitioning into chloroform. The chloroform extract is further purified on a 10 g silica gel column. A high pressure liquid chromatograph, equipped with a microparticle silica gel column and a 254 nm absorbance detector, is used for the determination. Additional confirmation of identity is obtained by mass spectrometry or by a brine shrimp bioassay of the HPLC eluates corresponding to the retention times of satratoxins G and H. The recoveries of added satratoxins G and H from wheat samples averaged 65% for G and 71% for H (200–1000 mg/kg). The coefficients of variation (CV) were 15% for G and 14% for H. The lower limit of detection was 200 μg/kg for wheat. Analysis of corn, oats, and barley samples (400 μg/kg of each toxin added) gave comparable recoveries. Only the corn extract exhibited HPLC interferences at the retention time for satratoxin H. The method was also used to analyze samples of corn, oats, wheat, barley, and rice on which Stachybotrys atra had been cultured.
Comparison of Gas and Liquid Chromatography for Determination of Anilazine in Potatoes and Tomatoes
Authors: Lawrence James F , Panopio Luz G 
Published: February 2020

Abstract
Anilazine (2,4-dichloro-6-(2-chloroanilino)-1,3,5-triazine), a triazine fungicide, is extracted from potatoes or tomatoes with acetonitrile. An aliquot of the filtered extract is partitioned between methylene chloride and water. The organic phase is concentrated and passed through a 3% deactivated Florisil column for cleanup. The eluted anilazine is then concentrated and determined by liquid chromatography (LC) on LiChrosorb RP-8 column with a mobile phase of acetonitrile–water (55+45) and detection at 275 nm, the absorption maximum of anilazine. Twenty-five nanograms produces a 5 cm peak under the conditions used. Detection limit is about 0.02 ppm in both vegetables. A comparison is made with gas chromatography, using either an electron capture (EC) or nitrogen–phosphorus alkali-flame ionieation (NP) detector. Separations are carried out on a 4% SE-30 + 6% SP-2401 column at 195°C at 40 mL/min. Detection limits for all systems studied are about 0.02–0.05 ppm in the samples studied. Recoveries over a concentration range of 0.2–10.0 ppm are greater than 80% with the extraction procedure employed and LC determination.
Comparison of Three Methods for Determining Aflatoxins in Sunflower Seed Meals
Authors: Trucksess Mary W , Stoloff Leonard 
Published: February 2020

Abstract
Methods developed for the determination of aflatoxins in peanut products, in cottonseed products, and in ginger were compared for their applicability to sunflower seed meal. The peanut products method was inapplicable. Separation from interferences adequate to obtain a limit of determination for aflatoxin B, around 1 ng/g and recovery of total added aflatoxins of about 97% could be achieved with either the cottonseed or ginger methods. The cleanest extract and the most rapid operation were obtained with the ginger method.
Evaluation of High Pressure Liquid Chromatography and Gas-Liquid Chromatography for Quantitative Determination of Sugars in Foods
Authors: Iverson John L , Bueno Martin P 
Published: February 2020

Abstract
A method has been developed for separation and determination of 5 sugars in foods. Mixtures of sugars were separated by high pressure liquid chromatography (HPLC) with a μBondapak/carbohydrate column and acetonitrile-water (80 + 20) as the mobile phase. For the gas-liquid chromatographic (GLC) determination, the sugars were reacted with hydroxylamine hydrochloride to give the oximes, which were then converted to trimethylsilyl derivatives. The derivatives were separated on an 8 ft column containing 3% JXR as the liquid phase. The GLC preparative time was considerably longer than that for HPLC. Both methods were applied to the determination of fructose, glucose, sucrose, maltose, and lactose in processed foods. Recovery studies showed better accuracy for the HPLC method. Because of incomplete derivatization and/or the formation of anomers, the GLC method was not applicable to all foods.
High Performance Liquid Chromatographic Determination of Aflatoxins in Animal Tissues and Products
Authors: Gregory III Jesse F , Manley Doris 
Published: February 2020

Abstract
A method was developed for the determination of aflatoxins M1, B1, G1, B2, and G2 in animal tissues, meat, eggs, and dairy products by high performance liquid chromatography (HPLC). Previous extraction procedures were modified to optimize the precision and recovery of the method. HPLC is performed isocratically with a 5 μm microparticulate octadecylsilica column and fluorometric detection. The analysis is based on treatment of the purified sample extract or standard with trifluoroacetic acid (TFA) to catalyze the hydration of aflatoxins M1, B1, and G1 to the highly fluorescent M2a, B2a, and G2a derivatives. Analysis by HPLC with and without TFA treatment of the extract provides quantitative and qualitative data. The recovery of added aflatoxins and the precision of the recovery depend on the type of sample; mean coefficient of variation for all recovery values was 19.7±11.0% for the analysis of liver, ground beef, dairy products, and eggs. The method was sensitive, with a detection limit of 0.05+0.10 ng/g for each aflatoxin. This procedure provides an alternative to existing thin layer chromatographic methods for determining aflatoxins in animal tissues and products.
Identification of Cephalosporins. I. Spectroscopic Methods
Authors: Roets Eugéne E , Hoogmartens Jos H , Vanderhaeghe Hubert J 
Published: February 2020

Abstract
The ultraviolet, infrared, and proton magnetic resonance spectra of 16 commercially available cephalosporins were recorded. The spectra are interpreted, and their value for identification is discussed.
Gas-Liquid Chromatographic Determination of Congeners in Alcoholic Products with Confirmation by Gas Chromatography/Mass Spectrometry
Authors: Martin Glenn E , Burggraff James M , Dyer Randolph H , Buscemi Peter C 
Published: February 2020

Abstract
A procedure is described for the separation and determination of the following compounds which are found as congeners in alcoholic products: acetaldehyde, ethyl acetate, methanol, ethanol, n-propanol, isobutanol, n-butanol, acetic acid, and the amyl alcohols (2-methyl-l-butanol and 3-methyl-l-butanol). These compounds were separated by gas-liquid chromatography (GLC) using 5% Carbowax 20M on Carbopack B as the column packing. The results obtained by using this method were compared with those obtained using the present AOAC methods for these compounds. GLC chromatograms show better resolution by the method presented.
Extraction of Thrips and Other Whole or Equivalent Insects from Frozen Blackberries and Raspberries: Collaborative Study
Authors: Dent Russell G ,   Collaborators:, Boese J , Chaput M P , Floyd D , Glaze L E , Nakashima M J , Washbon E C 
Published: February 2020

Abstract
A method was developed for the extraction of thrips and other whole or equivalent insects from frozen blackberries and raspberries. The method consisted of a thawing and drained weight step, followed by acid maceration. Berries were wet-sieved over a No. 25 sieve nested in a No. 80 sieve. The berry tissue retained on the No. 80 sieve was dehydrated with isopropanol and then treated with chloroform. The chloroform was stripped from the residue with isopropanol. The berry residue was extracted with light mineral oil from a 40% isopropanol-Tween 80- Na4EDTA mixture. The collaborative study was successfully completed with 83.3% average recoveries of thrips and a 19.2% coefficient of variation. The method has been adopted official first action.
Simultaneous Determination of Aluminum, Iron, Calcium, and Magnesium in Wet-Process Phosphoric Acid by DC Argon Plasma Emission Spectrometry
Authors: Hunter G Bradley , Woodis Terry C , Johnson Frank J 
Published: February 2020

Abstract
A method has been developed for the simultaneous determination of Al, Fe, Ca, and Mg in wet-process phosphoric acid by dc argon plasma emission spectrometry. The suppression of Ca and Mg emission by phosphate encountered in flame analyses was nonexistent, and other interferences were minimal. Results obtained by the procedure were compared with those obtained by atomic absorption spectrometry. The paired t-test showed no significant difference between the 2 methods at the 95% confidence level.