bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Gold in Animal Tissue by Graphite Furnace
Atomic Absorption Spectrophotometry
Authors: Kehoe Daniel F , Sullivan Darryl M , Smith Randall L 
Published: February 2020

Abstract
Historically, compounds that contain gold have been used to treat conditions such as rheumatoid arthritis in humans. However, understanding of the metabolic fate of gold in biological tissues has been limited by lack of sensitive quantitative methods of analysis. We addressed this problem by developing a graphite furnace atomic absorption (GFAA) spectrophotometric method to measure trace amounts of gold. This method was validated on small samples of beef liver, kidney, and bone. The samples were digested in micro-Kjeldahl flasks with a mixture of sulfuric, perchloric, and nitric acids; the residue was treated with aqua regia and extracted into methylisobutyl ketone (MIBK); levels of gold were then measured by GFAA. All the reagents were of an ultra-pure grade and were monitored for gold content. We established that the linear range of quantitation was from 1 to 2500 ppb. Multiple extractions with MIBK were not necessary to recover all the gold, and, in most cases, use of ultra-pure acids was not necessary. A scan of the extracts by inductively coupled argon plasma atomic emission spectrophotometry revealed no appreciable concentration of elements that would be most likely to interfere with the determination of gold. Average recoveries of gold ranged from 102 to 111%, and the overall coefficient of variation was 5.5%
Determination of Thiamphenicol in Bovine Plasma by Liquid Chromatography
Authors: Felice Lawrence , Abdennebi El Hassane , Ashraf Muhammed 
Published: February 2020

Abstract
A liquid chromatographic method is described for the measurement of thiamphenicol in bovine plasma. The plasma (1 mL) is extracted with ethyl acetate. After the solvent is evaporated under a stream of nitrogen, the residue is reconstituted in methanol-water and analyzed by reverse-phase liquid chromatography with UV detection at 224 nm. The intra-day recoveries for bovine plasma spiked with 5 and 50 μg/mL of thiamphenicol were 102 and 101%, respectively, with coefficients of variation of 2.40 and 0.28%, respectively. The interday recoveries for the 5 and 50 μg/mL samples were 103 and 101%, respectively, with coefficients of variation of 3.40 and 0.94%, respectively. The sensitivity of the method allows quantitation to at least the 100 ng/mL level
Development of Milk Powder Reference Materials Certified for Aflatoxin Mt Content (Part
II): Certification of Milk Powder RM 283
Authors: Van Egmond Hans P , Wagstaffe Peter J 
Published: February 2020

Abstract
The development of a full cream milk powder reference material, certified for its aflatoxin M, content (target concentration: 0.1 fig/ kg), is described. The material (RM 283) was prepared and certified within the Reference Material Programme of the Community Bureau of Reference, along with other members of a series of milk powder reference materials. Homogeneity, evaluated by determining the aflatoxin M, content of 30 units, was found to be acceptable (coefficient of variation of analysis results: 9.1%); stability has been demonstrated in a long-term study. The certification exercise involved 7 laboratories. Calibration, control of recoveries, blank values, and independence of the replicate measurements were emphasized. All sets of results of the certification exercise were accepted for statistical evaluation. A certified value for the aflatoxin M, content: 0.09(+0.04)(-0.02) Mg/kg was derived. The certification of RM 283 completes the series of 4 milk powder reference materials having certified aflatoxin M, contents
Gas Chromatographic-Mass Spectrometric Determination of Epoxidized Soybean Oil
Contamination of Foods by Migration from Plastic Packaging
Authors: Castle Laurence , Sharman Matthew , Gilbert John 
Published: February 2020

Abstract
A method for the quantitative determination of epoxidized soybean oil (ESBO) in foods is described. The procedure involves addition of a diepoxidized fatty acid ester internal standard, followed by lipid extraction from the food and transmethylation under basic conditions. Without further cleanup, the methylated fatty acid epoxides are derivatized to form 1,3-dioxolanes, which are then determined by capillary gas chromatography-mass spectrometry with selected ion monitoring. A detection limit of 2.0 mg/kg of epoxidized soybean oil in foods and a relative standard deviation of 7% have been achieved routinely. The method has been applied successfully to the analysis of cheeses, sandwiches, cakes, and microwave-cooked meals which have been contaminated with ESBO by migration from PVC film.
Disinfectant Testing Using a Modified Use-Dilution Method: Collaborative Study
Authors: Cole Eugene C , Rutala William A , Samsa Gregory P 
Published: February 2020

Abstract
An initial collaborative study of the AOAC use-dilution method (UDM), used for bactericidal disinfectant efficacy testing, demonstrated extreme variability of test results among the 18 laboratories testing identical hospital disinfectants. In an effort to improve the method, 32 changes were made by the UDM Task Force. These changes represented improvements in quality assurance practices and elimination of method variability; however, the basic framework of the method was retained. A second collaborative trial was conducted to determine if the interlaboratory variability of test results could be reduced to an acceptable level using the modified UDM. Twelve of the original 18 laboratories participated in the second study. Each laboratory processed 60 penicylinders (P) for each of the 6 randomly selected, federally registered disinfectants and 3 test organisms {Staphylococcus aureus, Salmonella choleraesuis, Pseudomonas aeruginosa). The number of positive penicylinders (&gt;1 positive P/60 replicates = failure) for the 6 products when P. aeruginosa was used as the challenge organism ranged 1-30, 0-36, 0-15, 0-5, 0-3, and 0-60 for the 3 quaternaries and 3 phenolics, respectively. The results of the variance components analysis for P. aeruginosa and the other 2 organisms showed that the variance components for laboratories were not significantly reduced for any organism in this study. Such interlaboratory variability of results questions the use of the original or the modified UDM for registration purposes
From Parochial to International
Authors: Williams Alex 
Published: February 2020

Abstract
The customers for analytical measurement services have international requirements; they require data of proven validity that will be accepted internationally. This means that well researched and tested analytical methods must gain better international acceptance. The methods should be capable of producing results to the accuracy required by the customer. They need to be supported by the use of appropriate certified reference materials, and the analyst, in reporting results, should give an estimate of the accuracy obtained. In addition, an independent accreditation is needed of the quality assurance procedures of the laboratory to assure customers that the analytical methods have been used correctly.
Methods of Analysis for Toxic Elements in Food Products. 2. Review of USSR Standards on Determinations of Heavy Metals and Arsenic
Authors: Skurikhin Igor M 
Published: February 2020

Abstract
Methods of analysis prescribed by USSR standards for Hg, Pb, Zn, As, Cd, Cu, Fe, and Sn in foods are described: for Hg—colorimetry of tetraiodide mercurate and atomic absorption spectroscopy (AAS); for Pb, Cd, Zn, and Cu—polarography; for Cu—colorimetry with sodium diethyldithiocarbamate and zinc dibenzyldithiocarbamate; for As—colorimetry with silver diethyldithiocarbamate; for Sn— colorimetry with quercetin; and for Fe—colorimetry with o-phenanthroline. All of the methods have the necessary metrological characteristics, including intralaboratory repeatability value (r), interlaboratory reproducibility value (R), minimum quantity of the element to be determined in the analytical test portion (MQSM), and the coefficients that account for mercury and arsenic losses during analysis. Establishing constant r- and R-values for the methods under consideration is expedient because (a) the methods suggested are used for safety purposes; and (b) the optimum amount of the element studied in the test sample is determined, to a certain degree, by the mass of the test portion.
Large-Scale Preparation of Potassium Hydroxide-Modified Silica Gel Adsorbent
Authors: Lebo Jon A , Zajicek Jim L , May Thomas W , Smith Lawrence M 
Published: February 2020

Abstract
A large-scale method, using custom-made apparatus, is described for making potassium hydroxide-modified silica gel. Batches as large as 2.3 kg can be made in 16 man-hours. A smaller-scale version of the method, requiring no specialized apparatus, is also described. The method can be used to integrate this adsorbent into many sampleenrichment procedures.
Derivative Spectrophotometric Determination of Clotrimazole in Single Formulations and in Combination with Other Drugs
Authors: Bedair Mono M , Korany Mohamed A , Elsayed M Abd El-Hady , Fahmy Ossama T 
Published: February 2020

Abstract
First (D1) and second (D2) derivative spectrophotometric methods are presented for the determination of clotrimazole after its acid hydrolysis. Mixtures of clotrimazole with azidamfenicol and dexamethasone have been assayed using D2 measurement at 302 nm after acid hydrolysis for clotrimazole, D1 measurement at 288 nm for azidamfenicol, and D1 measurement at 436 nm after reaction with phenylhydrazinium sulfate for dexamethasone. Reproducible results with relative standard deviations of &lt;2% are obtained. The proposed method has been successfully applied to the analysis of creams, topical solutions, and vaginal tablets.
Liquid Chromatographic Determination of Residual Reactants and Reaction By-Products in Polyethylene Terephthalate
Authors: Begley Timothy H , Hollifield Henry C 
Published: February 2020

Abstract
A precipitation procedure and liquid chromatography (LC) were used to measure the residual reactants and reaction by-products in polyethylene terephthalate (PET) polymers and food packages. The polymer is dissolved in l,l,l,3,3,3-hexafluoro-2-propanol/methyIene chloride and then precipitated with acetone. The filtered solution is evaporated almost to dryness, and the concentrate is diluted with dimethylacetamide for LC analysis. Recoveries for terephthalic acid (TA), bis(2-hydroxyethyl) terephthalate (BHET), and the PET cyclic trimer averaged 95,104, and 98%, respectively. The residual levels of TA, BHET, monohydroxy ethylene terephthalic acid, and the PET cyclic trimer were measured in commercial resins and food packages.
Criteria for the Detection of Analytes in Test Samples
Authors: Ruig Willem G De , Stephany Rainer W , Dijkstra Geo 
Published: February 2020

Abstract
Analytical control must be carried out by validated methods. Validation of methods for all possible situations, i.e., for all kinds of analytes in many different matrixes, by interlaboratory studies of meticulously described methods is unworkable because of the financial burden, the lack of analytical capacity, and the impossibility of standardizing highly sophisticated instrumentation between laboratories. Yet methods, particularly those used in regulatory control, must be validated. To overcome this dilemma, we suggest another approach for validation of quantitative analytical methods, viz., the application of certain "criteria." Such criteria are presented here for a number of analytical methods, including low and high resolution mass spectrometry, infrared spectroscopy, gas and liquid chromatography, thin-layer chromatography, spectrometric detection after TLC and LC, as well as general consideration of the whole analytical procedure. The criteria for a given method must be adopted by a board of experts for that method. Then, once an analysis fulfills the adopted criteria of the applied method, the presence of the investigated analy te can be taken as proved within the limits of ambiguity of the method. The criteria are already incorporated in a European Communities Commission Decision for detecting residues of substances having hormonal or thyrostatic action; criteria are submitted for a Commission Decision on analysis of residues of organic compounds in general.
Mycotoxin Analysis by Fast Atom Bombardment Tandem Mass Spectrometry
Authors: Uyakul Duangchan , Isobe Minoru , Goto Toshio 
Published: February 2020

Abstract
Positive fast atom bombardment tandem mass spectrometry is demonstrated to be an effective technique for determination of crude aflatoxins and sterigmatocystin-related compounds. The molecular ion was selected by the first system and bombarded to produce characteristic daughter ions that could be used to identify mycotoxins in mixtures and with the same molecular weight.
Liquid Chromatographic Determination and Gas Chromatographic-Mass Spectrometric Confirmation of Lasalocid Sodium in Bovine Liver: Interlaboratory Study
Authors: Newkirk David R , Barnes Charlie J 
Published: February 2020

Abstract
An analytical method has been developed that can reliably measure the metabolic marker residue of lasalocid. The method monitors this marker residue in food samples to ensure that the total residue of toxicological concern is not being exceeded. Interlaboratory studies of the liquid chromatographic determinative procedure and the gas chromatographic/mass spectrometric confirmatory procedure for lasalocid sodium at the 0.7 ppm level and higher were successful.
Evaluation of EPA Method 8120 for Determination of Chlorinated Hydrocarbons in Environmental Samples
Authors: Avila, Viorica Lopez , Dodhiwala S N , Milanes June , Beckert Werner F 
Published: February 2020

Abstract
Method 8120 of EPA Manual SW-846 has been evaluated in a singlelaboratory study. Several modifications made to the current method were implemented to allow determination of selected chlorinated hydrocarbons in complex environmental samples. The 2 packed gas chromatographic columns specified in Method 8120 were replaced with 2 megabore fused-silica open tubular columns chemically bonded with trifluoropropylmethyl siloxane and polyethylene glycol, respectively. The list of target compounds was expanded from 15 to 22 to include all possible trichlorobenzenes, tetrachlorobenzenes, and hexachlorocyclohexane (BHC) isomers. The Florisil cleanup procedure was modified to allow quantitative recovery of 20 of the 22 target compounds. A procedure that uses 1 g Florisil disposable cartridges and hexane-acetone (9:1) eluant was developed. This latter procedure gives quantitative recovery of all 22 target compounds from all matrixes tested. The revised method was tested with a variety of sample matrixes. Detection limits for water samples ranged from 1.4 ng/L for hexachlorobutadiene to 1300 ng/L for 2-chloronaphthalene; detection limits for 15 compounds were below 40 ng/L. Because of background contamination, detection limits for soil and sediment samples need to be determined on a case-by-case basis.
Evaluation of Modifications to Extraction Procedures Used in Analysis of Environmental Samples from Superfund Sites
Authors: Valkenburg Cornelius A , Munslow William D , Butler Larry C 
Published: February 2020

Abstract
Recoveries from an aqueous sample of the semi-volatile analytes listed on the EPA Target Compound List (TCL) are compared using 6 different methylene chloride extraction procedures. Four experimental designs incorporating a continuous extraction apparatus are evaluated, and 2 experimental designs using separatory funnel methods are tested. In addition, 2 concentration procedures are compared, and the loss of analytes associated with both extraction and concentration procedures are determined. These studies indicate that the most efficient and economical technique for the extraction of these compounds from an aqueous matrix is a single continuous extraction procedure performed at pH 2.
Amino Acid Rating Method for Evaluating Protein Adequacy of Infant Formulas
Authors: Sarwar Ghulam , Botting Herbert G , Peace Robert W 
Published: February 2020

Abstract
Amino acid profiles and/or protein digestibility (by the rat balance method) were determined for various forms (powder, ready-to-use, liquid concentrate, etc.) of cow's milk- and soy-based infant formulas obtained from 4 manufacturers. The essential amino acid data of the formulas were compared with that of human milk for the calculation of amino acid scores (based on the single most limiting amino acid). The product of amino acid score and total protein (g/100 kcal) was then termed "amino acid rating." Amino acid scores for the milk- and soy-based formulas ranged from 59 to 90 and from 59 to 81%, respectively, due to deficiencies in sulfur amino acids and/or tryptophan. Because of significantly higher total protein contents (g/100 kcal) of soy- (2.65-3.68) and milk-based (2.20-2.95) infant formulas compared to human milk (1.5), the relative amino acid ratings (human milk = 100) for all infant formulas except 2 liquid concentrates (having values of 87%) were above 100%. Values for true digestibility of protein in milk- and soy-based formulas ranged from 87 to 97 and from 92 to 95%, respectively. When corrected for protein digestibility, the relative amino acid ratings for all the milk-based liquid concentrates were below 100% (77-98%).
Visual and Semiquantitative Spectrophotometric ELISA Screening Method for Aflatoxin Bi in Corn and Peanut Products: Follow-up Collaborative Study
Authors: Park Douglas L , Miller Brinton M , Nesheim Stanley , Trucksess Mary W , Vekich Alan , Bidigare Barbara , Mcvey James L , Brown Lois H 
Published: February 2020

Abstract
A joint AOAC/IUPAC (International Union of Pure and Applied Chemistry) interlaboratory study of an enzyme-linked immunosorbent screening assay (ELISA) for aflatoxins was conducted in laboratories in Canada, France, Japan, The Netherlands, Switzerland, Tunisia, and the United States. Twelve raw and roasted peanut and corn portions containing various concentrations of natural aflatoxins and supplemented when appropriate with aflatoxin Bi were distributed to participating laboratories for testing. The assay is based on competition between an enzyme-conjugated aflatoxin Bj and (free) aflatoxins in the test sample for aflatoxin-specific antibodies coated onto interior surfaces of microtiter wells. After a wash step to remove all unbound aflatoxins, a substrate added to each well is catalyzed from a colorless to a blue solution by any bound enzyme-conjugated aflatoxin Bj present. The intensity of the color decreases as the amount of free aflatoxin Bt in the test portion increases. Final determination of aflatoxin concentrations can be made by either visual comparison with standard solutions or spectrophotometric comparisons (at 650 nm) to knowns. Overall correlation was good between ELISA and thin-layer chromatographic results for corn and roasted peanut products, with 93 and 98% correct responses for visual and instrumental determinations, respectively. For instrumental determinations of aflatoxin in corn and roasted peanuts in the &lt;20 ng/g range, the relative standard deviations for repeatability (RSDr) were 14.9 and 41.4%, respectively, and the relative standard deviations for reproducibility (RSDR) were 45.7 and 43.5%, respectively. For instrumental determination of &gt;20 ng/g, the respective RSDr and RSDR values were 19.4 and 52.7% for corn and 23.3 and 23.3% for roasted peanuts. For visual determinations in the &lt;20 ng/g range, the respective RSDr and RSDR values for corn were 38.5 and 60.7% and for roasted peanuts 73.7 and 73.7%. The respective RSDr and RSDR values for determinations of &gt;20 ng/g for corn were 13.5 and 59.5% and 24.3 and 57.3% for roasted peanuts. The ELISA method has been approved interim official first action as a screening method to determine the presence or absence of aflatoxin Bt at a concentration of ≥ 20 ng/g in corn and roasted peanuts.
Simulation of Aflatoxin Testing Plans for Shelled Peanuts in the United States and in the Export Market
Authors: Whitaker Thomas B , Dickens W J 
Published: February 2020

Abstract
The 1987 United States aflatoxin testing plan for shelled peanuts was designed with a final accept level of 25 parts per billion (ppb) total aflatoxin. Some of the importers of U.S. peanuts use aflatoxin testing plans with accept levels lower than 25 ppb. For example, the accept level of a testing plan used in The Netherlands is 5 ppb Bi or 10 ppb total aflatoxin. Whenever export lots are re-tested for aflatoxin by an importing country, some lots accepted in the United States will be rejected by the importing country's aflatoxin testing plan. Computer models were developed to determine the effects of decreasing the final accept level of the U.S. testing plan on the number of lots accepted and rejected in the United States and the number of exported lots accepted and rejected by The Netherlands testing plan. Decreasing the final accept level of the U.S. testing plan from 25 to 5 ppb increased the number of lots rejected in the United States by 371% while reducing the number of exported lots rejected by 51%. For every additional 8.3 lots rejected in the United States, one less export lot will be rejected.
Gamma-Ray Spectroscopic Determination of Iodine-131 and Cesium-137 in Foods: Two Collaborative Studies
Authors: Baratta Edmond J , Easterly David G 
Published: February 2020

Abstract
The AOAC method for iodine-131, cesium-137, and barium-140 in milk by gamma-ray spectroscopy (48.025-48.029) was extended to include other foods for the radionuclides iodine-131 and cesium-137. Two collaborative studies were performed to validate this extension. In the first study, a food sample containing 119 pCi ,3,I/kg and 53 pCi 137Cs/kg was sent to each of 45 laboratories for triplicate analyses. For 25 responses, the mean of the reported values was 123.8 pCi/kg for iodine-131, and for 27 responses, the mean was 53.4 pCi/kg for cesium-137. Repeatability (within-laboratory) standard deviations (sr) for iodine-131 and cesium-137 were 4.6 and 3.7 pCi/kg, respectively. Reproducibility (among-laboratories) standard deviations (sR) for iodine-131 and cesium-137 were 12.1 and 6.0 pCi/kg, respectively. In the second study, a food sample containing 25 pCi 13,I/kg and 27 pCi 137Cs/kg was sent to each of 54 laboratories for triplicate analyses. For 21 responses, the mean of the reported values was 25.0 pCi/kg for iodine-131, and for 19 responses, the mean was 28.9 pCi/kg for cesium-137. sr Values were 4.0 and 1.6 pCi/kg for iodine-131 and cesium-137, respectively, and SR values were 5.0 and 2.8 pCi/kg, respectively. The method extension was adopted official first action.