bluuebunny/crossref_metadata_2025_split huggingface dataset:
Macroprolactinemia Detection by Magnetically Assisted Polyethylene Glycol Precipitation: Potential for Automation
Authors: Smith Thomas , Stern Eric , Tan Enqing , Vacic Aleksandar , Fahie-Wilson Michael 
Published: February 2020

Abstract

Background
Macroprolactin is an immunoglobulin-prolactin complex that is not bioactive in vivo but the prolactin component remains immunoreactive. The complex is a universal source of interference in prolactin immunoassays and commonly results in misdiagnosis of hyperprolactinemia with consequent clinical mismanagement of patients. Removal of macroprolactin by precipitation with polyethylene glycol (PEG) is an effective technique for identifying such patients but unfortunately not universally employed due to the manual nature of the procedure.

Methods
We developed a modified PEG precipitation technique using magnetic nanoparticles that we termed Magnetically Assisted PEG Precipitation (MAPP). This procedure was verified against an established PEG precipitation procedure.

Results
The MAPP procedure we developed was robust, reproducible, and affords the potential for automation of macroprolactin screening in clinical laboratories. Comparisons of prolactin levels obtained following MAPP in sera from patients with either true hyperprolactinemia or macroprolactinemia generated results comparable to that of conventional PEG precipitation.

Conclusions
The MAPP technique yields results comparable to those of traditional PEG precipitation. Elimination of the need for centrifugation affords the possibility of automation and hence more widespread adoption of routine PEG screening by clinical laboratories.
Comparison of Paired-Ion Liquid Chromatographic Method with AOAC Fluorometric and Microbiological Methods for Riboflavin Determination in Selected Foods
Authors: Reyes Erlinda S P , Norris Kathleen M , Taylor Cheryl , Potts Donald 
Published: February 2020

Abstract
A paired-ion liquid chromatographic (LC) technique coupled with fluorometric detection to determine riboflavin in various food matrices is described. Chromatograms of many foods showed 2 peaks of interest due to presence of riboflavin and flavin mononucleotide (FMN). Relatively high levels of FMN were found in raw beef, corned beef, chicken liver, and canned mushrooms. When riboflavin and FMN contents were summed, LC values were comparable to those obtained by the AOAC standard procedures. The LC technique was sensitive, rapid, and simple, yielding a mean standard deviation of 3.1% which was comparable to the AOAC fluorometric method (3.0%) and better than the AOAC microbiological assay (9.6%). Mean spike recoveries were 91.8% for LC compared to 90.5% and 89.6% for the AOAC fluorometric and microbiological methods, respectively.
Stability-Indicating Liquid Chromatographic Determination of Alpha-Ionone in Toothpaste
Authors: Trivedi Ramesh J 
Published: February 2020

Abstract
A simple, sensitive, and rapid liquid chromatographic method for quantitating α-ionone in toothpaste at levels of 20 ppm in the presence of large amounts of flavor has been developed. The method is accurate, precise, cost-effective, and specific for α-ionone. Average recovery of a laboratory-prepared sample was 99.0% with the relative standard deviation was 1.29% (n = 6).
Potentials of a Synchronized Culture of Tetrahymena pyriformis for Toxicity Studies of
Mycotoxins
Authors: Bijl Jan P , Rousseau Dominique M , Dive Daniel G , Van Peteghem Carlos H 
Published: February 2020

Abstract
A synchronized culture of Tetrahymena pyriformis is proposed for toxicity testing of mycotoxins. Toxicity is evidenced through a delay in the division of the synchronized culture. Newly developed equipment for the synchronization consists of a double-walled culture flask built in an alternating water circuit at 28°C (optimum) and 34°C (sublethal), respectively, controlled by a time switch. The cultures are used for the detection of 16 mycotoxins for which the detection threshold is given. Synchronous cultures of Tetrahymena pyriformis appear to be very suitable for the detection of tr ichothecenes. Preliminary experiments on artificially contaminated corn samples demonstrate the possibility of prescreening of cereals,
Determination of Tri-w-Butyltin and Di-/i-Butyltin Compounds in Fish by Gas Chromatography with Flame Photometric Detection
Authors: Sasaki Kumiko , Ishizaka Takashi , Suzuki Takashi , Saito Yukio 
Published: February 2020

Abstract
An analytical method is described for the simultaneous quantitative determination of tri-n-butyltin and di-n-butyltin compounds in fish. The sample was extracted with 0.5N HCl-methanol, and the methanol solution was extracted with hexane. The extract was purified by gel permeation chromatography and treated with Grignard reagent to yield the methyl derivatives, which were determined by gas chromatography with flame photometric detection operated in the tin mode (610 nm). Recoveries of tri-n-butyltin chloride (Bu3SnCl) and di-n-butyltin dichloride (Bu2SnCl2) spiked to fish at the levels of 0.2 and 1.0 ppm ranged from 80 to 105%. Detection limits were 0.02 μg/g for both compounds. Tri-n-butyltin compounds equivalent to Bu3SnCl levels of 0.07-2.0 ppm and di-n-butyltin compounds equivalent to Bu2SnCl2 levels of 0.02-0.11 ppm were found in reared yellowtails, and these values showed good agreement with the results from gas chromatographic-mass spectrometry analysis.
Liquid Chromatographic Determination of Medroxyprogesterone Acetate in Tablets
Authors: Fatmi Aqeel A , Williams Gregory V , Hickson Elizabeth A 
Published: February 2020

Abstract
A reverse-phase liquid chromatographic method is described for the assay of medroxyprogesterone acetate in tablets. An octadecylsilane (C18) column with a mobile phase of methanol-O.OlM dibasic ammonium phosphate (80 + 20 v/v, pH 7.2 ± 0.1) and photometric detection at 254 nm separates medroxyprogesterone acetate from excipients. Detector responses were linear to concentrations of medroxyprogesterone acetate over the range 50-150 μg/mL (r = 0.999). Mean recovery of medroxyprogesterone acetate added to tablet excipients was 100.8%. Mean assay results were 101.3% (n = 3). The assay results are comparable to those obtained by the compendial liquid chromatographic method
Determination of Moisture in Cheddar Cheese by Near Infrared Reflectance Spectroscopy
Authors: Wehling Randy L , Pierce Michelle M 
Published: February 2020

Abstract
Near infrared reflectance (NIR) spectroscopy was used to determine the moisture content of Cheddar cheese. Through multiple linear regression analysis, a 3-wavelength calibration was developed for use with a commercial filter monochromator instrument. For a validation set of 47 samples, the correlation coefficient squared (r2) between the NIR and oven moisture methods was 0.92, with a standard error of performance (SEP) of 0.38%. Sample temperature was found to significantly affect the spectral response; therefore, it was necessary to equilibrate all samples to a uniform temperature prior to NIR analysis. Aging may also affect the NIR characteristics of cheese, although it was possible to develop a successful calibration that encompassed a wide range of aging times
Continuous Interlaboratory Test Program for Monitoring the Quality of Analytical Results in
Butter
Authors: Werdmuller Geziena A , Boelsma S 
Published: February 2020

Abstract
For almost 25 years, the central government laboratory of The Netherlands has administered a continuous program for the quality control of dairy products. The analytical work is conducted by private laboratories but monitored by the government laboratory. The design and results obtained by this program are illustrated by the determination of water and milk solids-not-fat contents in butter, using data collected monthly over a period of 19 years. Under this strict system of control, the within-laboratory reproducibility (i.e., over an extended period) is almost equal to the between-laboratory reproducibility. Most of this within-laboratory variation is from month to month, indicating that in this case the time variability dominates the between-laboratory variability
Determination of Sulfur Amino Acids and Tryptophan in Foods and Food and Feed
Ingredients: Collaborative Study
Authors: Allred Maryann C , Macdonald John L 
Published: February 2020

Abstract
Samples of 4 foods, 1 animal feed, isolated soy protein, and 0-lao toglobulin were analyzed by 9 laboratories to determine concentrations of cysteine as cysteic acid, methionine as methionine sulfone, and tryptophan. Sulfur amino acids were determined by AOAC method 43.A08-43.A13 for food and feed ingredients, in which samples are oxidized with performic acid before protein hydrolysis with 6N HC1. Tryptophan was determined after protein hydrolysis with 4.2N NaOH. In both methods, free amino acids were separated by ionexchange or reverse-phase chromatography. Each laboratory was provided with detailed methods and with sealed vials containing solutions of standards. Samples were analyzed in duplicate, and variation between laboratories was determined. Coefficients of variation between laboratories for the 6 samples ranged from 5.50 to 11.8% for methionine as methionine sulfoxide, 8.59 to 17.3% for cysteine as cysteic acid, and 3.87 to 16.1% for tryptophan. Amino acid recoveries were determined by analysis of β-lactoglobulin and were based on expected levels of each amino acid obtained from amino acid sequence data. The mean recovery of cysteine was 97% with a range of 88-119%. For methionine, mean recovery was 98% (range 89-115%) and for tryptophan, 85% (range 59-102%). Method 43.A08- 43.A13 for food and feed ingredients has been adopted official first action for determination of cysteine and methionine in processed foods. The alkaline hydrolysis method has been adopted official first action for determination of tryptophan in foods and food and feed ingredients
Direct Plating Technique for Enumeration of Listeria monocytogenes in Foods
Authors: Golden David A , Beuchat Larry R , Brackett Robert E 
Published: February 2020

Abstract
The advantages and disadvantages of various techniques for detecting and enumerating Listeria monocytogenes in foods are reviewed, and results from a study designed to compare 14 direct plating media for their suitability to recover uninjured cells of L. monocytogenes from 4 foods are summarized. McBride Listeria agar (MLA), gum base nalidixic acid tryptone soy agar (GBNTSA), modified Despierres agar (MDA), and modified MLA (MMLA) performed best for recovering all inoculum populations from milk and ice cream mix. For Brie cheese, MLA, MDA, MMLA, and Dominguez Rodriguez isolation agar were superior for recovering L. monocytogenes; GBNTSA, MDA, MMLA, and Donnelly's Listeria enrichment agar were best for recovering the organism from cabbage. Direct plating procedures without prior enrichment can be utilized successfully for recovering L. monocytogenes from foods such as pasteurized milk and ice cream mix, which contain low populations of background microflora. However, recovery of L. monocytogenes from foods such as raw cabbage and Brie cheese, which contain high populations of other microorganisms, was not satisfactory using direct plating procedures
Flow Cytometry for Automated Analysis of Milk Containing Listeria monocytogenes
Authors: Donnelly Catherine W , Baigent Gregory J , Briggs Elizabeth H 
Published: February 2020

Abstract
This paper describes the application of flow cytometry to the analysis of milk for the presence of Listeria monocytogenes. A total of 939 raw milk samples from 54 farms were analyzed for the presence of L. monocytogenes by cold enrichment vs flow cytometry, which incorporated a selective enrichment step. Analyzed samples consisted of milk from individual farm bulk tanks; string samples which represented milk from 25 to 40 cows; and combination samples representing milk from 200 cows. Raw milk samples were directly enriched for 24 h at 37°C and analyzed by flow cytometry following fluorescence labeling of bacterial populations, or were cold enriched for 1 month at 4°C. Following cold enrichment, samples were streaked to McBride's Listeria agar, and suspect colonies were biochemically identified as L. monocytogenes. L. monocytogenes was isolated from only 15 of the analyzed samples, all of which were common to one farm. Results of flow cytometry analysis yielded a 5.86% false positive rate and a 0.53% false negative rate when compared with culture procedures
Evaluation of Enrichment and Plating Media for Isolating Listeria monocytogenes
Authors: Swaminathan B , Hayes Peggy S , Przybyszewski Vincent A , Plikaytis Brian D 
Published: February 2020

Abstract
We compared selective enrichment broths used by the U.S. Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA), Food Safety and Inspection Service, for their efficiency in the quantitative recovery of Listeria monocytogenes from a naturally contaminated Brie cheese that was obtained as part of an epidemic investigation. Quantitative recovery of Listeria in FDA broth (&gt;2.4 x 10s colony forming units/mL) was significantly better than recovery in USDA broth (9.3 x 103 colony forming units/mL). When USDA broth was supplemented with i&gt;glucose and Phytone (papaic digest of soy protein), its recovery efficiency improved but did not equal that of FDA broth for isolating L. monocytogenes from Brie cheese. A comparison of 4 selective plating media [modified McBride's agar, gum base nalidixic acid agar, lithium chloride-phenylethanol-moxalactam agar (LPM), and acriflavine-ceftazidime agar (AC)] showed that 3 L. monocytogenes strains belonging to serotype l/2a were partially or completely inhibited on LPM and AC agars. One strain of serotype l/2a formed microcolonies on modified McBride's agar after 48 h of incubation
Industry Perspectives on Listeria monocytogenes
Authors: Knight Michael T , Black James F , Wood David W 
Published: February 2020

Abstract
Industry concerns and our ongoing research on Listeria are discussed in this report. Topics include sampling for analysis; sanitizers and their use in manufacturing facilities; precautions on use of the FDA method for Listeria; use of the Vitek Gram Positive Identification Card; and a brief discussion on findings of Listeria in environmental samples taken from the same site at the same time of year in 1986 and 1987.
Sulfamethazine and Sulfathiazole Determination at Residue Levels in Swine Feeds by Reverse-Phase Liquid Chromatography with Post-Column Derivatization
Authors: Smallidge Robert L , Kentzer Elzbieta J , Stringham Kelly R , Kim Eun H , Lehe Connie , Stringham Rodger W , Mundell Elizabeth C 
Published: February 2020

Abstract
Twenty g sample, to which sulfamerazine has been added as internal standard, is extracted with 0.3N HC1 + 1.5% diethylamine in 25% methanol. The sample extract is chilled (to aid clarification), centrifuged, and filtered. The sulfonamides are separated from each other and from co-extracted materials on a C-18 reverse-phase column and detected at 450 nm following post-column derivatization with dimethylaminobenzaldehyde. Two isocratic mobile phases have been tested: (1) acetonitrile-2% acetic acid (17 + 83), with an analysis time of 13 min; and (2) acetonitrile-methanol-2% acetic acid (4 + 16 + 80), with an analysis time of 20 min but an improved analysis for some samples. As many as 40 samples have been analyzed at one time unattended with the aid of an autosampler. A total of about 1500 field samples have been assayed using the method. Method sensitivity is 0.1 ppm for either analyte in a hog finishing feed. Linearity for each of the analytes is satisfactory over a range of 0.4-25 ppm in spiked feeds. Coefficients of variation range from 13% at 0.5 ppm to 2% at 13 ppm as tested over a period of time in naturally contaminated samples. The absolute recovery of sulfamethazine varies with sample matrix, but, in the presence of sulfamerazine as internal standard, recovery has been 96.7-99.7% over the range of 0.1-10 ppm. Sulfamerazine and sulfamoxole were tested for their suitability as internal standards. Sulfamerazine is a good internal standard for sulfamethazine; neither is ideal for sulfathiazole. A recovery factor is necessary for estimating the level of sulfathiazole in feeds when either internal standard is used; however, either standard is satisfactory for correcting for feed matrix variation
Simple and Accurate Method for Determination of Ethylene Chlorohydrin in Dried Spices and Condiments
Authors: Aitkenhead Paul , Vidnes Arne 
Published: February 2020

Abstract
A simple and accurate method is described for the determination of ethylene chlorohydrin (ECH) by using capillary gas chromatography (GC) and flame ionization detection. Acetonitrile-methanol was chosen as the extraction solvent in preference to other solvents because its use reduced the number of compounds detected by the GC system, thus enabling easier identification and quantitation of ECH. The coefficient of variation for the method is 2.7% at 5 ppm, and recovery is good, even for the standard addition of 1 ppm. Fifteen different spices and condiments were analyzed using this method; 20% were identified as positive for ECH. The method also identifies the related compound ethylene bromohydrin (EBH).
Determination of Fat in Raw Milk: Comparison of Mojonnier (Ether
Extraction) and Gerber Method
Authors: Kleyn Dick H , Trout J Richard , Weber Maurice 
Published: February 2020

Abstract
Results are compared for the approved Gerber method that specifies a TC 11.07 mL pipet and 2 modifications that specify a TC 10.77 mL pipet or a weighed 11.125 g sample of milk rather than a pipetted sample. All results were also compared with results obtained with the Mojonnier method for determining the fat content of raw milk. The standard deviation is somewhat lower for the Mojonnier method than for any of the Gerber methods; among the Gerber methods, the standard deviations were lower for the TC 10.77 mL and 11.125 g modifications. It is recommended that one of these modifications replace the current specified TC 11.07 mL pipet method.
Improved Reagent for Detection of Allantoin in Thin-Layer Chromatographic Method for
Urine Stains on Foods and Packaging
Authors: Ferrera Robert S , Boese Jack L , Thrasher Joel J 
Published: February 2020

Abstract
Ten detection reagents known to react with either primary amine groups or indole derivatives were tested to improve sensitivity for allantoin (ALN) and indican (IND) in the official AOAC thin-layer chromatographic method for urine metabolites (44.175-44.177). The lowest levels found using the official method were 500 ng ALN and 6 ng IND. The best reagent was /7-dimethylaminocinnamaldehyde (pDMAC), which yielded intensely colored spots with both compounds. The lowest amounts consistently found were 125 ng ALN and 13 ng IND. pDMAC was also used as an overspray for ALN after the spray specified in the official method, /7-dimethylaminobenzaldehyde (pDMAB), was applied. This resulted in a detection limit of 250 ng. The overspray procedure was incompatible with IND detection, but provided an easy way to gain slightly greater sensitivity for ALN when use of pDMAB gave negative or borderline results. The combined use of pDMAC for ALN, and the official sprays (pDMAB and sodium acetate) for IND, maximized sensitivity for both compounds.
Liquid Chromatographic Method for Determination of Chloridazon in Technical Concentrates
and Formulated Products: Comparison with CIPAC Method
Authors: Sanchez-Rasero F , Heras Pena A 
Published: February 2020

Abstract
A liquid chromatographic method for determination of chloridazon in technical concentrates and formulated products has been developed and compared with the present CIPAC method. The new method uses the same procedures and reagents as does the CIPAC method, but a microbore column and a diode array detector are used instead of a normal-phase column and a single wavelength detector. A technical product, a wettable powder, and a suspension concentrate were analyzed by both methods; the results (g chloridazon/kg) were 836.7 ± 6.3 (RSDr 1.05%) and 822.1 ± 8.2 (RSDr 1.39%); 648.7 ± 7.6 (RSDr 1.64%) and 641.1 ± 6.7 (RSDr 1.45%); and 350.5 ± 5.6 (RSDr 2.24%) and 351.1 ± 4.0 (RSDr 1.57%) by the CIPAC method and the new method, respectively. Although precision, accuracy, and resolution are very similar for the 2 methods, the microbore column, diode array detector, and multichannel integrator specified in the new method give more information on the integration process and on the purity of peaks, and save on operating costs. Therefore, the authors propose that CIPAC methodology use this type of apparatus as soon as it is more generally available in laboratories.
Sensitive Enzyme Immunoassay of Cephalexin Residues in Milk, Hen Tissues, and Eggs
Authors: Kitagawa Tsunehiro , Gotoh Yukio , Uchihara Kazuyo , Kohri Youko , Kinoue Tihoko , Fujiwara Kunio , Ohtani Wataru 
Published: February 2020

Abstract
A sensitive enzyme immunoassay for cephalexin (CEX) was developed using the rabbit antiserum to CEX, Β-D-galactosidase-labeled CEX, and a double-antibody separation method. The immunogen of CEX was prepared by coupling the amino group of CEX to thiol groups introduced into bovine serum albumin by the use of N-(mmaleimidobenzoyloxy) succinimide as a cross-linker. Highly titered antiserum to CEX was produced in rabbits immunized with the immunogen. Enzyme labeling of CEX with Β-D-galactosidase was done by using 7V-(gamma-maleimidobutyryloxy)succinimide as the crosslinker. The limit of detection was 30 ng CEX/mL sample solution. Application of the method to CEX drug residues detected 30 ng/mL in milk, 60 ng/g in egg yolk, and 400 ng/g in hen tissue.
Determination of Seven Artificial Sweeteners in Diet Food Preparations by Reverse-Phase Liquid Chromatography with Absorbance Detection
Authors: Lawrence James F , Charbonneau Claudette F 
Published: February 2020

Abstract
The artificial sweeteners aspartame, saccharin, cyclamate, alitame, acesulfam-K, sucralose, and dulcin are determined in diet soft drinks and tabletop sweetener preparations. Samples are diluted, filtered, and analyzed directly by liquid chromatography on a C-18 reversephase column with a mobile phase gradient ranging from 3% acetonitrile in 0.02M KH2P04 (pH 5) to 20% acetonitrile in 0.02M KH2P04 (pH 3.5). Diet puddings and dessert toppings are extracted with ethanol, filtered, and diluted with mobile phase for analysis. The sweeteners, except sucralose and cyclamate, were detected by UV absorbance at either 200 or 210 nm. Sucralose was determined at 200 nm or by refractive index. Cyclamate was determined after post-column ion-pair extraction. The sweeteners stevioside and talin were not detected. Additives such as caffeine, sorbic acid, and benzoic acid did not interfere.
Gas Chromatographic Determination Of Residue Levels Of The Herbicides Trifluralin, Benefin,
Ethalfluralin, And Isopropalin In Soil With Confirmation By Mass Selective Detection
Authors: West Sheldon D , Weston Jack H , Day Edgar W 
Published: February 2020

Abstract
A method is presented for the simultaneous or individual determination of the dinitroaniline herbicides trifluralin, benefin, ethalfluralin, and isopropalin in soil. The herbicides are extracted with acetonitrile- water (99 + 1), and the extracts are purified with small, disposable Florisil cartridges prior to analysis by gas chromatography using an electron capture detector or a mass selective detector. When electron capture detection is used as the primary detection system, confirmation with selective detection can be obtained using gas chromatography-mass spectrometry with a mass selective detector and a capillary column operated in the split mode. The limit of detection is 0.01 ppm, and recoveries averaged 95-112% for the 4 herbicides in several different soil types fortified at levels of 0.01- 0.33 ppm