bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Fluoride in Fluoride Tablets and Solutions by Ion-Selective Electrode: Collaborative Study
Authors: Marzilli John R ,   Collaborators:, Acampora F L , Alexander L R , Alpert M Y , Baetz R A , Bohm G , Donovan J J , Landskov A O , McNerney F G , Simon P J , Tobias D Y , Votta R J 
Published: February 2020

Abstract
A proposed method using the fluoride (F) ion-selective electrode has been developed for determining the fluoride ion concentration in tablets and solutions containing sodium fluoride. The method has been subjected to collaborative study. Eight samples consisting of 2 authentic fluoride solutions, 2 commercial fluoride solutions, and 4 commercial fluoride tablets were sent to each of 11 collaborators together with a copy of the method. Single assays on the authentic fluoride solutions known to contain 1 mg F/5 mL were performed with average recoveries of 99.5 and 99.6% and relative coefficients of variation (CV) of 2.11 and 1.91%, respectively. Single assays of 2 commercial fluoride solutions declared at 1 mg F/5 mL gave mean values of 0.994 and 0.990 mg and relative CV values of 1.88 and 2.36%, respectively. Single assays of 2 commercial fluoride tablet preparations declared at 0.5 mg F gave mean values of 0.485 and 0.478 mg and relative CV values of 3.12 and 3.71 %, respectively. Single assays of 2 commercial fluoride tablet preparations declared at 1 mg F gave mean values of 0.991 and 0.981 mg and relative CV values of 2.99 and 2.85%, respectively. The method has been adopted official first action.
Effect of Residual Ascorbate on Determination of Nitrite in Commercial Cured Meat Products
Authors: Fox Jay B , Doerr Robert C , Gates Robert 
Published: February 2020

Abstract
Residual ascorbate in cured meat slurries results in different amounts of pigment being produced from different Griess reagent combinations. The phenomenon was used to study residual ascorbate in commercial cured meat products which had a variety of textures, acidities, moisture and meat content, fat, homogeneity, initial nitrite, and processing conditions. Diluting and heating the samples according to the AOAC procedure did not completely eliminate the ascorbate interference, but making the sample alkaline did. Determining nitrite separately in supernate and precipitate from the first dilution showed the effect of heating to be the elimination of interferences and solubilization or extraction of nitrite from the precipitate.
Liquid Chromatographic Determination of Sugars in Licorice Extracts: Collaborative Study
Authors: Vora Pramathesh S , Tuorto Raymond M ,   Collaborators:, Atchley F , Conway W , Hodge B , Norris K , Price B , Shuford C 
Published: February 2020

Abstract
A collaborative study to determine fructose, glucose, sucrose, and maltose in a variety of licorice extracts has been performed using liquid chromatography. Six collaborators participated in the study, and each collaborator was sent 5 samples which were analyzed in blind replicates. A practice sample was used with a specific range of 8-10% fructose, 10-12% glucose, and 5-7% sucrose. The individual sugar concentration of the 5 samples ranged from 2.0 to 10%. AH samples were quantitated by comparing results with a pure sugar standard containing fructose, glucose, sucrose, and maltose and analyzed under the same conditions. No significant problems were encountered running the practice or other samples despite the wide range of instruments and columns used. Results showed less deviation within laboratories compared with results obtained among laboratories. The method has been adopted official first action.
Genetic Methods for the Detection of Microbial Pathogens. Identification of Enterotoxigenic Escherichia coli by DNA Colony Hybridization: Collaborative Study
Authors: Hill Walter E , Payne William L ,   Collaborators:, Crouch R J , Davis V M , English L L , Ferreira J L , Gemski P , Jagow J A , Moseley S L , Noah C W , Silver R P , Singleton E , Weagant S D , Wohlhieter J A , Womble D D , Zink D L 
Published: February 2020

Abstract
Enteropathogenic Escherichia coli strains may produce a cholera-like, heat-labile enterotoxin (LT) as a virulence factor. The gene that codes for LT can be purified by recombinant DNA techniques and used as a genetic probe for DNA hybridization. These probes detect enterotoxigenic strains as well as strains that may not manifest toxin production but carry the genetic information to do so. In this study, 13 laboratories tested 3 known and 25 unknown (10 positive and 15 negative) cultures off. coli for the presence of the LT gene. The isolates had been tested and classified by the mouse Y-l adrenal cell test and an enzyme-linked immunosorbent assay. Cultures were spotted on nitrocellulose filters on MacConkey agar and incubated. Colonies were lysed in situ and their DNA was hybridized to 32P-labeled, purified LT gene DNA (provided to the collaborators). Positive colonies were identified by autoradiography. Of 325 samples, 315 (96.9%) were identified correctly and 10 were misclassified; there were 6 false negative and 4 false positive identifications. Chi-square values indicated that the method agreed with the previous classification and was equally efficient in distinguishing positive and negative samples (95.7 and 98.1%, respectively). The method has been adopted official first action.
Liquid Chromatography of Liquid Formulations Containing 2,4-D, Dicamba, and MCPP as Their Salts: Collaborative Study
Authors: Grorud Robert B , Forrette John E ,   Collaborators:, Bajovich J , Bath R L , Billings J L , Counts J L , Diuquid J , Foster B E , Hodgins E , Stevens T S , Stringham R W , Vernetti J B 
Published: February 2020

Abstract
A liquid chromatographic method for any liquid mixture of the 3 herbicides 2,4-D, MCPP, and dicamba, found in commercial formulations, has been collaboratively studied. Each collaborator received 4 samples, 3 of which were ternary formulations and one a binary formulation of amine salts. Concentrations in the formulations range from 0.02 to 2.32% for dicamba, 0.32 to 21.7% for 2,4-D, and 0.22 to 11.6% for MCPP. A binary solvent system and the use of a specified 25 cm column of RP 10 μm in the reverse phase ion suppression mode will selectively quantitate each herbicide, separating many impurities found in the technical products. Standard deviations in each of 11 columns of results obtained indicate good precision. The method has been adopted official first action.
Simple, Rapid Method for Determination of Total Extractable Fat in Canned Pet Foods
Authors: Maxwell Robert J 
Published: February 2020

Abstract
The rapid column method described, unlike AOAC method 7.056, determines both neutral ("crude") and total fat in canned pet foods, and uses nonflammable solvent mixtures and simple laboratory equipment. Neutral fat values are obtained by eluting the column with dichloromethane, whereas total fat values are determined by using dichloromethane-methanol (9 + 1). For 7 samples analyzed in triplicate, fat ranged from 2.9 to 10.8%. Neutral fat values by the dry column method were significantly lower (P &lt; 0.05) than were those by 7.056 (6.29 vs 6.49), although these differences were practically unimportant. Total fat determinations by the dry column method and by 7.056 yielded overall means of 7.40 and 6.49%, respectively. The 0.91% mean difference is significant (P &lt; 0.01) and represents a more complete extraction of polar lipids by the proposed method.
Gas Chromatographic and Mass Spectrometric Determination of Ametryn and Its N-Dealkylated Products
Authors: Bardalaye Promode C , Wheeler Willis B , Templeton James L 
Published: February 2020

Abstract
Gas chromatographic and mass spectrometric properties of ametryn and its N-dealkylated products were studied to establish the potential use in a recently reported method describing the residue analyses of these compounds by gas chromatography with N-P detection. Electron impact mass spectra show base peaks at the molecular ion (M+), and methane chemical ionization mass spectra give base peaks at (M + 1) ion for all the compounds studied. Characteristic mass spectral fragmentations of ametryn, GS-11354, GS-11355, and GS-26831 are presented. Combined gas chromatography-mass spectrometry rather than gas chromatography alone provides unambiguous residue characterization. The technique also allows quantitation of ametryn and its N-dealkylated products that cochromatograph with interfering materials present in a complex substrate.
Liquid Chromatographic Determination of Benzoyl Peroxide in Acne Preparations
Authors: Chou Chih-Kuang , Locke David C 
Published: February 2020

Abstract
A rapid, precise, and accurate liquid chromatographic (LC) method is described for the determination of benzoyl peroxide (BP) in acne preparations. BP is extracted from a water dispersion of the preparation with dichloromethane (DCM), and an aliquot is eluted from a C-18 reverse phase LC column with acetonitrile-O.lOM aqueous NaCI04. Selective and sensitive quantitation is accomplished with a reductive mode electrochemical detector. This detector is an order of magnitude more sensitive than a 240 nm UV absorption detector; the lower limit of detection is 2 ng for a 4 μL injection. The recovery of BP is 99.4% and the detector response is linear to at least 2 μg per 4 μL injection.
Difference Spectrophotometric Estimation of Santonin
Authors: Habib Abdel-Azim M , Omar Abdalla A , Sarg Taha M 
Published: February 2020

Abstract
Santonin gives a characteristic alkaline vs acidic difference spectrum. This was used for its estimation in pharmaceuticals and in the crude drug. Santonin was first extracted and purified through a specific partition procedure; then the difference absorbance was measured either at the maximum, 285 nm, or the minimum, 242 nm. The percentage of santonin can be calculated either by reference to the difference absorbance of a reference santonin sample, treated similarly, or by making use of the determined absorptivity. Measurement at the maximum is advisable, especially when the crude drug is assayed, because natural contaminants may interfere with the difference absorbance at the minimum.
Determination of Pantothenic Acid, Biotin, and Vitamin B12 in Nutritional Products
Authors: Hudson Thomas S , Subramanian Shyamala , Allen Rebecca J 
Published: February 2020

Abstract
Until recently, liquid chromatographic (LC) methodology for pantothenic acid, biotin, and B12 (cyanocobalamin) has been only marginally successful. These vitamins are difficult to determine by conventional LC techniques and UV detection at 254 or 280 nm, because either the chromophore is inadequate for detection or interference from co-eluting vitamins is overwhelming. Biotin and B12 are usually present in pharmaceutical products at concentrations 100-1000 times lower than other commonly occurring water-soluble vitamins. Co-extraction of all water-soluble vitamins results in gross interferences, especially in LC when the interfering vitamins co-elute with biotin or B12. In addition, pantothenic acid and biotin are colorless in solution and do not exhibit strong UV absorption above 240 nm. As a result, they must be quantitated either by using a low UV wavelength for detection or by derivatizing the vitamin to obtain an adequate chromophore. A description of procedures for LC determination of pantothenic acid, panthenol, cyanocobalamin, and biotin in pharmaceutical products is presented. Pantothenic acid has been measured by using both a derivatization technique and low UV wavelength detection. Biotin has been quantitated by using low UV wavelength detection. The limitations of these techniques are also discussed. Chromatographic separation of cyanocobalamin is complicated by co-eluting vitamins such as riboflavin. It is detected by using the 546 nm wavelength where riboflavin does not interfere.
Fecal Pellets from a Commensal Shrew (Suncus murinus) and a House Gecko (Gekkonidae)
Authors: Olsen Alan R 
Published: February 2020

Abstract
Examination of excreta pellets from commensal shrews (Suncus murinus) and tropical house geckos (Gekkonidae) showed several characteristics that were useful in distinguishing these pellets from those of commensal rodents. Commensal shrew pellets contained a large number of embedded insect fragments but no embedded hairs. Each shrew pellet was associated with a distinctive circular stain on the floor or container surface where it was found. Gecko pellets were composed entirely of tightly packed insect fragments with no intervening matrix. In contrast to both shrew and rodent pellets, there was no surface mucous coating. A small white body containing uric acid adhered to one end of each gecko pellet.
Determination of Total Dietary Fiber in Foods, Food Products, and Total Diets: Interlaboratory Study
Authors: Prosky Leon , Asp Nils-Georg , Furda Ivan , Devries Jonathan W , Schweizer Thomas F , Harland Barbara F 
Published: February 2020

Abstract
An interlaboratory study was conducted to determine the total dietary fiber (TDF) content of food, food products, and total diets, using a combination of enzymatic and gravimetric procedures. Thirteen unknown products including 2 mixed diets (one lacto-ovo vegetarian and the other nonvegetarian) were analyzed by 32 analysts. Duplicate samples of dried foods were gelatinized with Termamyl, a heat-stable alphaam) lase, and then enzymatically digested with protease and amyloglucosidase to remove the protein and starch present in the sample. Four volumes of 95% ethanol were added to precipitate the soluble dietary fiber. The total residue was filtered, and then washed with 74% ethanol, 95% ethanol, and acetone. After drying, the residue was weighed. One of the duplicates was analyzed for protein, and the other was ashed at 525°C and the ash was measured. TDF was calculated as the weight of the residue less the weight of protein and ash. Coefficients of variation for 10 of the samples ranged from 2.95 to 26.39%. For 3 of the samples high coefficients of variation were obtained. The results compared satisfactorily with those obtained previously by the best method available for the individual foods studied.
Liquid Chromatographic Determination of Sodium Fluoroacetate (Compound 1080) in Meat Baits and Formulations
Authors: Kramer Harvey L 
Published: February 2020

Abstract
A liquid chromatographic (LC) method is described for the determination of sodium fluoroacetate in meat baits and formulations. Baits were extracted with water, ultrafiltered, partitioned into butanone, back-partitioned into dilute base, and diluted with acetonitrile. Aqueous formulations of 1080 were diluted with acetonitrile. The solutions were esterified with p-bromophenacyl bromide, using crown ether catalysis, and chromatographed on a 10 μm reverse phase column. Ultraviolet absorbance was monitored at 260 nm. Samples spiked to contain 1 mg and 10 mg 1080/100 g meat gave recoveries of 84.0-103.4%.
Chemical Confirmatory Tests for Ochratoxin A, Citrinin, Penicillic Acid, Sterigmatocystin, and Zearalenone Performed Directly on Thin Layer Chromatographic Plates
Authors: Goliński Piotr , Grabarkiewicz-Szczęsna Jadwiga 
Published: February 2020

Abstract
Published tests have been improved and a new procedure is described for chemical confirmation of mycotoxins directly on thin layer plates. After extraction and preliminary cleanup chromatography with nhexane or chloroform, the mycotoxins ochratoxin A, citrinin, penicillic acid, sterigmatocystin, and zearalenone were easily separated by thin layer chromatography (TLC) using toluene-ethyl acetate-90% formic acid (6 + 3 + 1) developing solvent. In chemical confirmatory methods, the developed chromatogram was exposed to vapors of pyridine, acetic anhydride, or a mixture, or the mycotoxins were over-spotted. With this treatment, ochratoxin A, citrinin, penicillic acid, and zearalenone were converted to new fluorescent compounds, and observed under 365 nm light after re-chromatography with the same developing solvent. Sterigmatocystin was confirmed chemically using TLC plates impregnated with 0.6N H2S04 or 10% oxalic acid in methanol. The described procedures are satisfactory for confirming mycotoxins present in standards, artificially contaminated grain samples (barley, corn, oat, rye, and wheat), and extracts from both fungal cultures and naturally contaminated grain samples.
Liquid Chromatographic Determination of Allopurinol in Tablets: Collaborative Study
Authors: Shostak Donald ,   Collaborators:, Uribe M P , Poplawski T , Savage T S , Reed G D , Smith F S , Krieger D , Roberts S E 
Published: February 2020

Abstract
A liquid chromatographic method for the determination of allopurinolin tablets was collaboratively studied by 7 laboratories. The methoduses a C,8 reverse phase column, a 0.05M ammonium phosphate mobilephase, hypoxanthine as the internal standard, and photometric detectionat 254 nm. Collaborators were supplied with samples of 2 commercialtablets and 1 synthetic tablet powder. The mean recovery value of allopurinol from the synthetic tablet powder was 100.0%. The combinedmean coefficient of variation for all 3 types of sample analyzedwas less than 2%. The method has been adopted official first action.
Analytical Methods for Determining Ascorbic Acid in Biological Samples, Food Products, and Pharmaceuticals
Authors: Pachla Lawrence A , Reynolds Donald L , Kissinger Peter T 
Published: February 2020

Abstract
Over the last decade, numerous publications have appeared describing \ analyses for ascorbic acid in food products, pharmaceuticals, and biological samples. This review focuses on the chemistry associated with many of these procedures. The papers discussed have historical importance, are important to understanding the method, or have significantly advanced ascorbic acid analysis. The review has 4 major, sections: spectroscopic, electrochemical, enzymatic, and chromatographic methods of analysis.
Indirect Enzyme-Linked Immunosorbent Assay for Saxitoxin in Shellfish
Authors: Chu Fun S , Fan Titan S L 
Published: February 2020

Abstract
An indirect enzyme-linked immunosorbent assay (ELISA) was developed for the detection of saxitoxin (STX). Antibodies against STX were demonstrated in rabbits 5 weeks after immunizing with STX-bovine serum albumin (STX-HCHO-BSA). In the ELISA, STX-HCHO-BSA or polylysine-STX was coated onto the microtiter plate, followed by incubation with standard toxin and anti-STX antibody. The amount of antibody bound to the solid phase was determined by incubation with goat anti-rabbit IgG peroxidase conjugate and a reaction with chromogenic substrate. Competitive indirect ELISA revealed that the antiserum did not cross-react with either carbamoyl-neo-STX-suIfate or tetrodotoxin. The antibodies for STX cross-reacted with decarbamoyl- STX and neo-STX about 56% and 16% as much as they did with STX, respectively. The lower detection limits for STX, decarbamoyl-STX, and neo-STX in this sytem were about 25, 45, and 156 pg per assay, respectively. When STX added to clams or mussels was assayed, the detection limit for STX was about 50-100 ppb, and recoveries were in the range of 86.8-107%.
Extraction of Organic Acids by Ion-Pair Formation with Tri-w-Octylamine. Part 7. Comparison of Methods for Extraction of Synthetic Dyes from Yogurt
Authors: Puttemans Marc L , Voogt M De , Dryon Louis , Massart Desire 
Published: February 2020

Abstract
Synthetic dyes were extracted from yogurt by different methods, but all methods had in common a liberation of dyes from the food followed by ion-pair formation with tri-n-octylamine. Extraction with pH 5.5 phosphate buffer gave high recoveries for 5 of the 7 dyes investigated and was relatively fast. Precipitation of proteins followed by polyamide adsorption and desorption gave high yields for all the dyes but was tedious and long.
Gas Chromatographic Determination of Trans Unsaturation in Margarine: Collaborative Study
Authors: Gildenberg Lawrence , Firestone David 
Published: February 2020

Abstract
An international collaborative study of a gas chromatographic (GC) method for the determination of trans unsaturation in margarine was conducted in 1980. Thirteen collaborators analyzed a set of 2 of 3 known mixtures of methyl esters and 4 margarine methyl ester samples. Two of the margarine methyl ester samples were blind duplicates. The experimental data were subjected to statistical analysis to determine within- and between-laboratory variation. The statistical data were in excellent agreement with data from a collaborative study of the AOACIUPAC GC method for the determination of methyl esters of fatty acids. Coefficients of variation (CVs) for components in the range of 4-40% were comparable (CV 2-6% for soybean oil methyl esters (AOAC-IUPAC study) as well as for margarine methyl esters (this study)). Good recoveries of total trans acids were obtained and betweenlaboratory as well as within-laboratory CVs were consistently better for the determination of total trans acids by GC vs infrared analysis. The GC method for determining trans unsaturation in margarine has been adopted official first action.
Comparison of Interlaboratory Variation in Amino Acid Analysis and Rat Growth Assays for Evaluating Protein Quality
Authors: Sarwar Ghulam , Blair Robert , Friedman Mendel , Gumbmann Michael R , Hackler Ross L , Pellett Peter L , Smith Trevor K 
Published: February 2020

Abstract
Estimates of inter- and intralaboratory variation of protein efficiency ratio (PER), relative PER (RPER), net protein ratio (NPR), relative NPR (RNPR), and nitrogen utilization (NU) were compared with those of amino acid analysis in the same batches of 7 protein sources (ANRC casein, egg white solids, minced beef, soy assay protein, rapeseed protein concentrate, pea flour, and whole wheat flour). Interlaboratory variation (estimated as between-laboratories coefficients of variation, CV) of NPR and RNPR (up to 6.0%) was lower than that of PER (up to 20.2%) and RPER (up to 18.5%). The interlaboratory determination of NPR and RNPR was also more reproducible than that of most essential amino acids (CV up to 10.0%), especially tryptophan (CV up to 23.7%), cystine (CV up to 17.6%), and methionine (CV up to 16.1%). Intralaboratory variation (estimated as within-laboratories CV) of amino acid analysis (up to 4.7%), however, was comparable to that of protein quality indices in most protein sources (up to 6.0%). The significant (P &lt;0.01) positive correlations (r = 0.68-0.74) between amino acid scores and protein quality indices based on rat growth were further improved when amino acid scores were corrected for digestibility of protein (r = 0.73-0.78) or individual amino acids (r = 0.79- 0.82).
Amperometric Determination of Propantheline Bromide in a Flowing Stream at the Glassy Carbon Electrode
Authors: Shah Mumtaz H , Stewart James T 
Published: February 2020

Abstract
University of Georgia, College of Pharmacy, Department of Medicinal Chemistry, Athens, GA 30602 A flow-injection method is presented for the determination of propantheline bromide, based on electrochemical oxidation at the glassy carbon electrode. The amperometric method can determine propantheline bromide in the presence of phenobarbital, commonly found in its combination dosage forms. The procedure is stability-indicating for propantheline when an ether extraction of the dosage form is done before amperometric detection. At the electrode potential of + 1400 mV, the calibration curve is linear in the 2-16 p.g/mL concentration range, and minimum detectability is 20 ng (signal-to-noise ratio of 2). When applied to the analysis of propantheline bromide in selected pharmaceutical dosage forms, the method shows good accuracy and precision. Although automation was not used in this study, the method could readily be incorporated in automated systems because it uses the technique of continuous analysis in a flowing stream