bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid Chromatographic Analysis of Niacin in Fortified Food Products
Authors: Chase G William , Landen William O , Soliman Abdel-Gawad M , Eitenmiller Ronald R 
Published: February 2020

Abstract
An ion exchange liquid chromatographic (LC) method using an anion exchange resin column was developed for the determination of niacin in fortified foods. Samples were extracted by autoclaving with H2SO4 (1+1). Florisil open column chromatography was used to remove interferences from the sample extracts. Niacin levels were quantitated by an LC system using a 250 x 4.1 mm Hamilton PRP-X100 column, a mobile phase of 2% glacial acetic acid in water, and UV detection at 254 nm. The limit of detection was 0.11 μg niacin/mL, and the standard curve was linear from 0.24 to 0.80 jag niacin/mL. The system reproducibility was evaluated by completing 10 repetitive analyses on an infant formula and a macaroni product, which gave an average CV of 2.7%. Mean recovery (± standard deviation) was 99.8 ± 7.7 (n = 15). The results compared favorably with those by the AOAC microbiological method.
Liquid Chromatographic Determination and Liquid Chromatographic-Thermospray Mass Spectrometric Confirmation of Nicarbazin in Chicken Tissues: Interlaboratory Study
Authors: Leadbetter Mary G , Matusik Jean E ,   Collaborators:, Koscinski W W , Leadbetter M G , Matusik J E , Nightengale C T , Schenck F J , Vasco G A 
Published: February 2020

Abstract
The U.S. Food and Drug Administration sponsored an interlaboratory study of a liquid chromatographic determination with ultraviolet detection of nicarbazin in chicken liver and muscle tissues. The method determined the 4,4’-dinitrocarbanilide(DNC) portion of nicarbazin. The interlaboratory study of the determinative method was successful for nicarbazin at the 4 ppm level. Results showed good reproducibility for the fortified liver and muscle samples. Mean interlaboratory recoveries and percent coefficients of variation at about 4 ppm were 87.1 and 10.9%, respectively, for muscle and 87.4 and 7.5%, respectively, for liver. The interlaboratory analyses of the dosed liver and muscle tissues produced concentration levels similar to those obtained by the sponsor. The confirmatory procedure, which identified DNC in purified tissue extracts, used liquid chromatography-thermospray/mass spectrometry. The confirmatory procedure was successfully evaluated by one FDA laboratory.
Factors Affecting the Precision of Dietary Fiber Measurements in Potatoes
Authors: Wolynetz Mark S , Mullin William J 
Published: February 2020

Abstract
The measurement of dietary fiber in foods is becoming increasingly important. In the widely accepted gravimetric methods for measuring fiber, a common feature is the use of crucibles, with sintered glass frits, to collect insoluble and precipitated material; in this laboratory, P2 crucibles are used in insoluble fiber determinations. Evidence from 3 experiments indicated a significant amongcrucible variance component (P &lt;0.001) that was at least 50% larger than the residual variation; this component may be as large as the commonly encountered among-time component. The crucible effect has implications with respect to experimental design, data analysis, and measurement of insoluble fiber in particular materials such as biological reference materials.
Determination of Cephapirin and Desacetylcephapirin in Milk Using Automated Liquid Chromatographic Cleanup and Ion-Pairing Liquid Chromatography
Authors: Moats William A 
Published: February 2020

Abstract
A simple and sensitive method was developed for determination of cephapirin and its metabolite, desacetylcephapirin, in milk. For extraction/ deproteinization, 2 mL 0.2M tetraethylammonium chloride and 28 mL acetonitrile are added to 10 mL milk, and 20 mL clear filtrate (= 5 mL milk) is collected. Filtrate is evaporated to 1-2 mL and made up to 4 mL with water, filtered, and transferred to 4 mL autosampler vials. For cleanup, 2 mL filtrate is loaded onto a Supelcosil LC-18 column in 0.01 M KH2PO4 (A) using a Waters WISP autosampler. The column is eluted with an acetonitrile (B) gradient from 100%A (0-3 min) to 70%A:30%B (24 min). Fractions corresponding to cephapirin and desacetylcephapirin are collected. A 0.02M pH 2.26 buffer of 0.01 M decanesulfonate-acetonitrile was used for cephapirin (80 + 20) and 0.02M pH 1.96 buffer of 0.01 M decanesulfonate-acetonitrile was used for desacetylcephapirin (84 + 16) on a Polymer Laboratories PLRP-S column. Recoveries at 0.01-10 ppm were 91-98%; estimated detection limits were near 2 ppb and were comparable to sensitive screening tests.
Interiaboratory Evaluation of an Off-Line Supercritical Fluid Extraction/Infrared Spectrometric Method for Determination of Petroleum Hydrocarbons in Solid Matrixes
Authors: Lopez-Avila Viorica , Young Richard , Kim Robert , Beckert Werner F ,   Collaborators:, Bruce M , David P , Eckert-Tilotta S , Emery A P , Hecht C , Hedrick J , Levy J , Liebman S , McNally M E , Porter N , Pyle S , Snyder J L , Tehrani J 
Published: February 2020

Abstract
A collaborative study was conducted, with 14 laboratories participating, to determine the method accuracy and precision of the proposed U.S. Environmental Protection Agency Methods 3560 and 8440. These methods involve the extraction of petroleum hydrocarbons from solid matrixes with supercritical carbon dioxide at 340 atm and 80°C for 30 min (dynamic), collection of the extracted materials in tetrachloroethene (Method 3560), and analysis of the extracts by infrared (IR) spectrometry (Method 8440). The study design was based on the AOAC blind replicate design with balanced replicates. The study samples consisted of 4 solid matrixes that had petroleum hydrocarbon contents ranging from 614 to 32 600 mg/kg. Each of the 4 matrixes was extracted in triplicate, and the extracts were analyzed with 2 different IR spectrometers. In addition, each of the participating laboratories extracted a sample of unspiked clay soil, the same clay soil spiked with corn oil and reference oil at 1000 mg/kg each, and the same clay soil wetted to 30% water content and spiked with motor oil at 10 000 mg/kg (the latter 3 samples were extracted only once). Results indicated that the overall method accuracy for concentrations ranging from 614 to 32 600 mg/kg was 82.9%; the mean recoveries of petroleum hydrocarbons for each of the 4 solid matrixes ranged from 77.9 to 107% for analyses performed with the Perkin-Elmer Fourier transform IR spectrometer and from 75.9 to 101% for analyses performed with the Buck-Scientific IR spectrometer; the differences between the 2 instruments on a sample-bysample basis were less than 17% for the total petroleum hydrocarbon determinations. The interiaboratory method precisions (RSDR) appeared to be matrix-dependent and ranged from 17.3 to 45.4% for analyses performed with the Perkin- Elmer Fourier transform IR spectrometer and from 16.7 to 47.9% for the Buck-Scientific IR spectrometer. The intralaboratory method precisions (RSDr) appeared to be less matrix-dependent and ranged from 11.5 to 17.0% for analyses performed with the Perkin-Elmer FTIR spectrometer and from 11.1 to 18.2% for the Buck-Scientific IR spectrometer. Method accuracy and precision data are also presented for the 5 laboratories that used Isco supercritical fluid extraction systems and for the 7 laboratories that used vessels with volumes of 3.5 mL or less with different supercritical fluid extraction systems.
Continuous Flow and Liquid Chromatographic Determination of p-Toluenesulfonamide in Ice Cream: Interlaboratory Study
Authors: Beljaars Paul R , Dijk Remmelt Van , Brands Arie ,   Collaborators:, Anderegg M , Arnold M , Bodegraven P J , Bosman I , Burgers L , Gend H W , van der Horst G M , Hoven K , Kaman R , Leeuwen W van , Lukkenaer J , Nijboer L , Roukema J , Scholten J , Sens J , van Veldhuizen C J , Visschedijk M B C , Wijma E 
Published: February 2020

Abstract
A collaborative study of the continuous flow (CF) and liquid chromatographic determination of p-toluenesulfonamide (p-TSA) in ice cream was conducted by the Project Group on Collaborative Studies (PCS) of the Inspectorate for Health Protection, Food Inspection Service, The Netherlands. The procedure involves extraction of samples with water followed by cleanup of the extracts by dialysis in the CF system. Dialysates are injected by using a loop injector (500 μL) on a reversed-phase octadecylsilane bonded-phase (C18) column, chromatographed with methanol-water (25 + 75, v/v) as mobile phase, and quantitated by fluorescence detection at 230 nm (excitation) and 295 nm (emission). Seven ice-cream samples containing 0-6.35 mg/kg p-TSA at 4 different levels (1 blank and 3 pairs of split-level samples) were singularly analyzed according to the proposed procedure by 11 laboratories. The data were analyzed by the International Union of Pure and Applied Chemistry/ International Organization for Standardization/ AOAC protocol for statistics. No Cochran and Grubbs outliers were found among the participants. For all samples analyzed, repeatability relative standard deviations (RSDr) varied from 2.08 to 3.67%, whereas the reproducibility relative standard deviations (RSDR) ranged from 7.79 to 11.68%. The average p-TSA values for the split levels 1,2, and 3 were 0.55, 1.02, and 4.44 mg p-TSA/kg, respectively, with mean recoveries ranging from 76 to 79% (overall recovery range for all levels, 63-101%). No false-positive results were reported for the blank sample, and no interference was encountered by the presence of vanilla in samples.
Oligosaccharide Generation in Acidic Sugar Media
Authors: Cancalon Paul F 
Published: February 2020

Abstract
Oligosaccharides were shown to be present in beet medium invert sugar, but the origin of these molecules has remained obscure. The present study reveals that oligosaccharides are not a contaminant of purified beet sucrose. They appear during sucrose hydrolysis but are not specific to inversion. Sugars in a solution containing hydrogen ions generate oligosaccharides whose nature and proportion is determined by the original sugar composition. Because the sugar composition changes constantly during the course of sucrose inversion, the oligosaccharide pattern of a medium invert sugar is determined by the sugar distribution existing when the hydrolysis is stopped. As a consequence, the oligomer composition of a solution does not depend on the botanical origin of the sugar. Nearly identical oligosaccharide profiles were obtained from beet, cane, and citrus saccharides inverted in the laboratory or obtained from an industrial source. The amount of oligomers generated by an acidic solution increases exponentially with the sugar concentration. In diluted medium invert sugar solutions or in single-strength juices, the equilibrium between monomers and oligomers shifts toward depolymerization and eventually leaves only monosaccharides. In concentrated solutions of sugars or citrus juices, on the other hand, the process is directed toward oligomerization. These reactions occur slowly at room temperature but are greatly sped up by temperature. Therefore, results from the quantitation of oligosaccharides should be carefully interpreted if an accurate monitoring of medium invert sugar adulteration is to be performed. The nature of the product (single-strength or concentrate) and the types of treatment to which the product was submitted must be considered. Although monitoring of oligosaccharides provides a rapid method for the detection of added invert sugar, some results may need to be corroborated by methods such as isotopic analysis.
Simultaneous Determination of Xylazine and Its Major Metabolite, 2,6-Dimethylaniline, in Bovine and Swine Kidney by Liquid Chromatography
Authors: Holland David C , Munns Robert K , Roybal José E , Hurlbut Jeffrey A , Long Austin R 
Published: February 2020

Abstract
A liquid chromatographic (LC) method is described for the simultaneous determination of xylazine (XY) and its major metabolite, 2,6-dimethylaniline (2,6- DMA), in bovine and swine kidney in the 25– 100 ppb range. XY and 2,6-DMA are extracted from kidney with chloroform, followed by cleanup on an acidic Celite 545 column. A μBondapak phenyl column is used for LC separation with UV determination at 225 nm. The mobile phase is a mixture of acetonitrile, water, sodium acetate, and acetic acid. Mean recoveries from bovine kidney were 78.3% for XY, with a standard deviation (SD) of 7.45 and a coefficient of variation (CV) of 9.51 %, and 87.2% for 2,6-DMA, with an SD of 8.38 and a CV of 9.61 %. Mean recoveries from swine kidney were 80.8% for XY, with an SD of 5.92 and a CV of 7.33%, and 86.7% for 2,6-DMA, with an SD of 6.16 and a CV of 7.10%.
Combustion Method for Determination of Crude Protein in Meat and Meat Products: Collaborative Study
Authors: Marcia King Brink , Joseph G. Sebranek ,   Collaborators:, Anthony C , Coleman P , Cottingham B , Culmo R , Curtis R , Dingman L , Johnson R , Lehman G , Loughran J , Martinez S , Moody J , Paisley C , Radloff H , John A St , Schrader E , Sizemore J , Wenger J , White G 
Published: February 2020

Abstract
Twelve laboratories participated in a collaborative study to compare a combustion method with the AOAC mercury catalyst Kjeldahl method (928.08) for the determination of crude protein in meat and meat products. Three different combustion instruments were used; consequently, the combustion method for this study is written in generic terms describing the principle, the apparatus specifications, and the performance requirements needed. Fifteen sample pairs were used for the study; each pair consisted of the same commercial meat product from each of 2 different manufacturers. Protein content of all samples ranged from about 10 to 20%. In addition, nicotinic acid and lysine monohydrochloride were used as standards to assess combustion equipment performance. All laboratories and all instruments performed the combustion method satisfactorily on the basis of results for the standards. For the meat samples, repeatability standard deviations (sr) ranged from 0.11 to 0.40 for the Kjeldahl method and from 0.12 to 0.41 for the combustion method; the repeatability relative standard deviations (RSDr) ranged from 0.82 to 2.41% and from 0.60 to 2.23% for the Kjeldahl and combustion methods, respectively. Reproducibility standard deviations (SR) ranged from 0.20 to 0.49 for the Kjeldahl method and from 0.18 to 0.46 for the combustion method, whereas the reproducibility relative standard deviations (RSDR) ranged from 1.59 to 2.84% for the Kjeldahl method and from 1.32 to 3.35% for the combustion method. Overall grand means were 15.59% protein for the Kjeldahl method and 15.75% protein for the combustion method. The combustion method was adopted first action by AOAC International.
Determination of Free and Bound Cd, Zn, Cu, and Ag Ions in Lobster (Homarus americanus) Digestive Gland Extracts by Gel Chromatography Followed by Atomic Absorption Spectrophotometry and Polarography
Authors: Chou Chiu L , Uthe John F , Guy Robert D 
Published: February 2020

Abstract
Gel-permeation chromatography followed by atomic absorption spectrophotometric and polarographic analyses were used to measure free and bound divalent metal ions in lobster digestive gland extracts prepared with or without oc-toluenesulfonyl fluoride, a protease inhibitor. Chromatography on Sephadex G-50 or G-100 yielded 3 UV-absorbing peaks, which corresponded, respectively, to the void volume, a medium molecular weight fraction, and a low molecular weight fraction that contained free divalent metal ions. In protease-inhibited extracts, only Zn+2 was found, whereas Cd, Cu, and Ag were bound in high and medium molecular weight fractions. Cd+2 and Zn+2 were rapidly released from their bound forms in the absence of a protease inhibitor, and their presence was confirmed by polarography with EDTA. Gel-permeation chromatography coupled with atomic absorption spectrophotometry offers a rapid method for following changes in the concentrations of bound and free metal ions during processing of shellfishbased foodstuffs.
Ochratoxin A in Cow’s Milk and in Human Milk with Corresponding Human Blood Samples
Authors: Breitholtz-Emanuelsson Anna , Olsen Monica , Oskarsson Agneta , Palminger Ira , Hult Karl 
Published: February 2020

Abstract
A method for determining ochratoxin A in milk has been elaborated in which the sample was subjected to a liquid-liquid extraction step and then purified on a silica gel column packed in a Pasteur pipet. The purified samples were analyzed by ion-pair liquid chromatography with fluorescence detection. The detection and quantitation limits for determination of ochratoxin A in cow’s milk were 10 and 40 ng ochratoxin A/L milk, respectively. The same limits were valid for the analysis of human milk. A total of 36 cow’s milk and 40 human milk samples were analyzed. All samples were collected in Sweden. Ochratoxin A was found in 5 (14%) of the cow’s milk samples (range 10-40 ng/mL) and in 23 (58%) of the human milk samples (range 10-40 ng/L). Blood samples were collected from the mothers who gave milk samples. A total of 39 samples were analyzed. All blood samples contained ochratoxin A in concentrations exceeding the quantitation limit (60 ng/L blood). The mean concentration of ochratoxin A in the samples was 167 ng/L blood (range 90-940 ng/L). The concentration of ochratoxin A in human milk was ≤0.1 of that in the human blood.
Determination of Methyl 2-Benzimidazolecarbamate in Wine by Competitive Inhibition Enzyme Immunoassay
Authors: Bushway Rodney J , Paradis Lance R , Perkins Lewis B , Fan Titan S , Young Barbara E S , Walser Paul E 
Published: February 2020

Abstract
A benomyl polyclonal enzyme immunoassay (EIA) commercial kit was used to quantitate methyl 2- benzimidazolecarbamate (MBC), a degradation product of benomyl in wine. Total analysis time, including sample preparation, was 30 min. As many as 8 samples can be analyzed simultaneously with a limit of quantitation of 5 ppb. The assay logarithmic response was linear from 0.4 to 26 ppb MBC. Intra-assay percent coefficients of variation (%CVs) ranged from 2.4 to 13 for standards and from 7.4 to 21 for actual wine samples. Interassay %CVs varied from 2.6 to 15 for the standards and from 6.9 to 23 for the samples. Average recovery from samples spiked at 10–10 000 ppb was 93% for evaporated red and white wines. MBC was determined in 134 different wines by immunoassay and liquid chromatography (LC). Of these samples, 98 were positive for MBC by both methods with a correlation coefficient (r) of 0.986. The other 36 samples had MBC levels that either were not detectable by either procedure or were below the 10 ppb limit of quantitation for LC. Concentrations of MBC in wine ranged from 5 to 1329 ppb, with the majority ranging from 10 to 300 ppb. Also, a mini-study was conducted using the plate EIA format.
Supercritical Fluid Extraction of Poultry Tissues Containing Incurred Pesticide Residues
Authors: Snyder Janet M , King Jerry W , Rowe Loyd D , Woerner Julie A 
Published: February 2020

Abstract
A method using supercritical carbon dioxide to extract fat from poultry tissue was developed. Tissues used in this study were peritoneal fat, breast tissue, leg and thigh tissue, and liver from chickens fed rations containing heptachlor, dieldrin, and endrin. The fat was isolated from the peritoneal tissue by supercritical fluid extraction (SFE) and by thermal rendering. The fat was removed from the breast tissue, leg and thigh tissue, and liver by SFE and solvent extraction. The results indicate that recoveries of organochlorine pesticide from the peritoneal, breast, leg, and thigh tissues by SFE extraction are equivalent to those obtained by conventional extraction methods. The pesticide recoveries by SFE extraction of the liver were higher than those obtained by solvent extraction.
pH Method for Determination of Cholinesterase in Whole Blood: Collaborative Study
Authors: Imerman Paula Martin ,   Collaborators:, Banton M , Casteel S , Edwards W , Everson R , Felice L , Holcomb M , Landgraf W , Magera M , Reagor J , Rottinghaus G 
Published: February 2020

Abstract
A collaborative study of an indirect method for determination of cholinesterase activity was conducted with cattle blood. Ten collaborators analyzed 8 samples of varying degrees of cholinesterase inhibition. The sample is diluted with a buffer, and the pH change that results from the hydrolysis of acetylcholine is monitored. Repeatability relative standard deviations (RSDr) ranged from 6.6 to 8.6%, and reproducibility relative standard deviations (RSDR) ranged from 10.7 to 17.3% for mean activities of 0.60-0.40 ΔpH/h. All samples that were completely inhibited were detected. The method was adopted first action by AOAC International for determination of cholinesterase activity in whole bovine blood.
Structures and Environmental Significance of Heptachlor Epoxide Isomers
Authors: Donnelly Joseph R , Sovocool G Wayne , Titus Richard L 
Published: February 2020

Abstract
Historically, both endo- and exo-epoxides of heptachlor are known. The exo-epoxy isomer of heptachlor epoxide is a remarkably stable metabolite of heptachlor and is generally found in the environment where heptachlor was introduced. In this study, the nuclear magnetic resonance and mass spectral characteristics of the 2 epoxide-containing isomers ("A" and "B") were investigated to verify their structural assignments. We believe that the metabolite, Isomer B, is the only isomer found in the environment resulting from environmental contamination by chlordane and heptachlor.
Determination of Pesticides in Indoor Air and Dust
Authors: Roinestad Kurt S , Louis Judith B , Rosen Joseph D 
Published: February 2020

Abstract
Improved analytical and sampling methods were developed for the multiresidue determination of pesticides in indoor air. Air analysis consists of adsorption of the pesticides in 1 m3 of air onto Tenax TA via an air sampling pump, desorption with acetone, and determination and quantitation by gas chromatography/mass spectrometry (GC/MS) with chemical ionization on an ion trap mass spectrometer. Limits of detection for the 23 pesticides studied ranged from 0.5 ng/m3 for chlorpyrifos and diazinon to 30 ng/m3 for o-phenylphenol (approximately 0.5-30 parts per trillion on a w/w basis). A simple method for the detection of pesticides in dust was also developed. This method involves emptying the contents of a vacuum cleaner bag into a standard household food processor and extracting 1 g homogenized dust with acetone before GC/MS. Limits of detection were 25-100 ppb because of interferences by common household chemicals. However, pesticide concentrations were higher in dust than in air, therefore, analysis of dust is a better indicator of indoor pesticide exposure.
Pesticide Residues in Composited Milk Collected Through the U.S. Pasteurized Milk Network
Authors: Trotter William J , Dickerson Richard 
Published: February 2020

Abstract
The U.S. Food and Drug Administration (FDA) has implemented a comprehensive monitoring program to determine the incidence and levels of organohalogen pesticide residues in milk representing most of the U.S. supply consumed in metropolitan areas. Residue findings for 806 composite milks collected through the Pasteurized Milk Program by the U.S. Environmental Protection Agency (EPA) in 1990-1991 are reported. Milk was collected on a monthly basis from 63 stations selected by EPA for radionuclide monitoring. These stations provide an estimated 80% of the milk delivered to U.S. population centers. At each station, milk from selected sources had been composited to represent the milk routinely consumed in its metropolitan area. Portions of these composites were forwarded to an FDA contract laboratory for pesticide residue analysis. Pesticide residues were found in 398 (49.4%) of 806 test samples, on the basis of a 0.0005 ppm limit of detection for each residue on a whole-product basis. A total of 455 occurrences of pesticide residues were found; p,p’-DDE and dieldrin accounted for 384 (84.4%) of these occurrences. The highest level was 0.019 ppm p,p’- DDE.