bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fumonisin Production by Fusanum Species on Solid Substrates
Authors: Nelson Paul E , Juba Jean H , Ross P Frank , Rice Larry G 
Published: February 2020

Abstract
Fumonisins were produced by strains of Fusarium moniliforme and F. proliferatum on a medium consisting of 500 g yellow corn kernels and 500 mL distilled water added to a 30.5 × 61 cm autoclavable polyethylene bag. The corn was inoculated by drawing a suspension from a lyophilized culture into a sterile 5 mL syringe fitted with a 19 gauge needle and injecting 1 mL through the side of each polyethylene culture bag. Bags of inoculated com were incubated in the dark at 20° to 22°C for 4 weeks. Seven to 8 days after inoculation, holes were punched near the tops of the bags to promote aeration. After a 4 week incubation, cultures were soaked in chloroform–acetone (50 + 50, v/v) in 4 L flasks overnight to kill fungus and to remove water. Next, the culture media was filtered through 2 mm nylon mesh screens and air dried from 24 to 48 h. Fumonisin concentrations were determined by liquid chromatography/o-phthalaldialdehyde fluorescence. Confirmation was by gas chromatography/mass spectrometry. We observed that the 3 most important factors in the production of fumonisins in bulk corn cultures were temperature control, moisture, and aeration. Extraction by acetonitrile–water (50 + 50, v/v) for 30 min produced the highest yields of fumonisins. Measurable concentrations were reduced by as much as 50% when culture material was heated at 50°C overnight. Fusarium moniliforme strains consistently produced fumonisin B1 as the major component, but some strains of F. proliferatum produced fumonisin B2 and/or fumonisin B3 at higher concentrations than fumonisin B1. Results were calculated on the basis of dried culture material.
Stability and Problems in Recovery of Fumonisins Added to Corn-Based Foods
Authors: Scott Peter M , Lawrence Guillaume A 
Published: February 2020

Abstract
Because the natural occurrence of fumonisins is so far known almost exclusively in corn, we have limited our investigations on their stability to corn-based foods. In these studies, distinction must be made between real losses, binding, and any matrix-related method problems. Fumonisins B1 (FB1) and B2 (FB2) were about 40% recovered when heated in corn meal at 190°C, about 20–30% recovered when heated in moist corn meal at 190°C, and completely unstable in corn meal at 220°C. Average recoveries of FB1 and FB2 added to blank heated matrixes were 69–107% in control experiments. Baking corn meal muffins spiked with 2.5 μg FB1 and FB2/g corn meal at 220°C also resulted in losses of fumonisins. Little or no fumonisins were recovered from corn bran flour when methanol–water (3 + 1) was used as extraction solvent. However, when methanol-borate buffer (pH 9.2) (3 + 1) was used, recoveries averaged 91 ± 17 and 84 ± 9%, respectively, for FB1 and FB2; and natural contamination of the corn bran flour with FB1 and FB2 at levels of 1.9 and 0.95 μg/g, respectively, was revealed. Comparable recoveries were observed for 1 brand of a corn bran breakfast cereal, but the binding effect was not seen with a second brand, for which methanol-water (3 + 1) alone was a good extraction solvent. Recoveries of FB1 and FB2 from a mixed cereal for babies were only about 50% with either extraction solvent mixture. Additives present in the mixed cereal—calcium carbonate, dibasic calcium phosphate, and reduced iron (iron filings)—did not affect recoveries of FB1 and FB2 when added to ground corn or corn flakes, although hydrated ferrous sulfate did.
Determination of Zinc in Serum, Blood, and Ultrafiltrate Fluid from Patients on Hemofiltration by Graphite Furnace/Atomic Absorption Spectroscopy or Flow Injection Analysis/Atomic Absorption Spectroscopy
Authors: De Blas Oroncio Jimenez , Rodriguez Ramon Seisdedos , Mendez Jesus Hernandez , Sanchez Tomero Jose Antonio , Gomez B De Leon , Gonzalez Secundino Vicente 
Published: February 2020

Abstract
Two methods were optimized for the determination of zinc in samples of blood, serum, and ultrafiltrate fluid from patients with chronic renal impairment undergoing hemofiltration. In the first procedure, after acid digestion of the samples, Zn in blood and serum is determined by a system coupled to flow injection analysis and atomic absorption spectros-copy. The method is rapid, automated, simple, needs small amounts of sample, and has acceptable analytical characteristics. The analytical characteristics obtained were as follows: determination range of method, 0.05-2.0 ppm of Zn; precision as coefficient of variation (CV), 5.3%; recovery, 95-105%; and detection limit (DL), 0.02 ppm. The second method is optimized for ultrafiltrate fluid because the sensitivity of the first procedure is not suitable for the levels of Zn (ppb or ng/mL) in these samples. The technique chosen was atomic absorption spectroscopy with electrothermal atomization in a graphite furnace. The analytical characteristics obtained were as follows: determination range of method, 0.3-2.0 ppb Zn; CV, 5.7%; recovery, 93-107%; and DL, 0.12 ppb. The methods were used to determine zinc in samples of blood, serum, and ultrafiltrate fluid from 5 patients with chronic renal impairment undergoing hemofiltration to discover whether there were significant differences in the zinc contents of blood, serum, and ultrafiltrate fluid after the hemofiltration process. An analysis of variance of the experimental data obtained from a randomly selected group of 5 patients showed that zinc concentrations in the ultrafiltrate fluid, venous blood, and venous serum do not vary during hemofiltration (p &lt; 0.05), whereas in arterial blood and serum, the time factor has a significant effect.
Packed-Column Gas Chromatographic Method for the Simultaneous Determination of 10 Pyrethroid Insecticide Residues in Fruits, Vegetables, and Grains
Authors: Pang Guo-Fang , Fan Chun-Lin , Chao Yan-Zhong , Zhao Tee-Sheng 
Published: February 2020

Abstract
A simple, rapid, packed-column gas chromatographic method was developed for simultaneous determination of 10 pyrethroid insecticide residues (allethrin, biphenthrin, cyhalothrin, permethrin, cyfluthrin, flucythrinate, fenvalerate, fluvalinate, deltamethrin, and py-115) in fruits, vegetables, and grains. These multiresidues are extracted from various crops with acetone–petroleum ether and cleaned up on a Florisil column (for the fruits and vegetables) or on a Florisil–charcoal–alumina column (for the grains) prior to their determination by gas chromatography with an electron capture detector. Recoveries of 10 pyrethroid compounds from 12 different crops (maize, soybeans, wheat, sorghums, paddy, potatoes, cucumbers, cauliflowers, spinaches, apples, bananas, and oranges) fortified at levels of 0.02–5.00 ppm ranged from 58 to 130%. In a separate precision study, coefficients of variation were 5.5–14.6% at 0.1–0.5 ppm (n = 10, maize), and 4.1–12.1% at 0.010–0.050 ppm (n = 10, apples). The detection limits of the method ranged from 2.0 to 10.0 ppb on a crop basis.
Voltametric Behavior of Zopiclone: Polarographic Determination in Tablets
Authors: Squella Juan A , Sturm Juan C , Alvarez-Lueje Alejandro , Núñez-Vergara Luis J 
Published: February 2020

Abstract
Electrochemical reduction of zopiclone at different pHs and concentrations was studied by polarography and cyclic voltametry. Both techniques revealed a reduction process with weak adsorption of both zopiclone and its reduction derivative. Zopiclone exhibited 2 differential pulse polarographic peaks at the dropping mercury electrode. The first peak was used to develop a differential pulse polarographic analytical procedure for determining the drug in pharmaceutical dosage forms. Reproducibility and recovery coefficients of variation were 1.6 and 2.2%, respectively. Analysis of commercial zopiclone tablets showed uniformity in zopiclone content. The method is simple and rapid because separation of excipients is unnecessary.
Automated Analysis with Computerized Information Transfer in a University Hospital
Authors: Bachmann Claude , Boulat Olivier 
Published: February 2020

Abstract
The organization of a central clinical chemistry laboratory of a university hospital, which in 1992 analyzed 880 000 results, is presented. Automation with midsize selective analyzers, which run in parallel and are able to do positive sample identification on the primary bar-coded tubes, in connection with a laboratory computer system and a central hospital computer allowed for reliable and timely obtainment of results. The output of the results is made on laser printers in the medical wards, thus alleviating the pneumatic sample transport systems. Assessment of the turnaround time show that it can be kept below one hour. Such a setup without sorting out emergency demands allows a simplified sample flow. Thus, there is no need for a laboratory to make “stat” requests.
Development of Data Sets for the Validation of Analytical Instrumentation
Authors: Ellison Stephen L R , Cox Maurice G , Forbes Alastatr B , Butler Bernard P , Hannaby Simon A , Harris Peter M , Hodson Susan M 
Published: February 2020

Abstract
Analytical chemistry makes use of a wide range of basic statistical operations, including means; standard deviations; significance tests based on assumed distributions; and linear, polynomial, and multivariate regression. The effects of limited numerical precision, poor choice of algorithm, and extreme dynamic range on these common statistical operations are discussed. The effects of incorrect choice of algorithm on calculations of basic statistical parameters and calibration lines are illustrated by examples. Some approaches to validation of such software are considered. The preparation of reference data sets for testing statistical software is discussed. The use of ‘null space’ methods for producing reference data sets is described, and an example is given. These data sets have well-characterized properties and can be used to test the accuracy of basic statistical procedures. Specific properties that are controlled include the numerical precision required to represent the sets exactly and the analytically correct answers. A further property of some of the data sets under development is the predictability of the deviation from the expected results resulting from poor choice of algorithm.
Automation and Quality in Analytical Laboratories
Authors: Valcárcel Miguel , Ríos Angel 
Published: February 2020

Abstract
After a brief introduction to the generic aspects of automation in analytical laboratories, the different approaches to quality in analytical chemistry are presented and discussed to establish the following different facets emerging from the combination of quality and automation: automated analytical control of quality of products and systems; quality control of automated chemical analysis; and improvement of capital (accuracy and representativeness), basic (sensitivity, precision, and selectivity), and complementary (rapidity, cost, and personnel factors) analytical features. Several examples are presented to demonstrate the importance of this marriage of convenience in present and future analytical chemistry.
Screening Procedure for Organochlorine and Organophosphorus Pesticide Residues in Eggs using a Solid-Phase Extraction Cleanup and Gas Chromatographic Detection
Authors: Schenck Frank J , Wagner Roberta , Hennessy Michael K , Okrasinski Joseph L 
Published: February 2020

Abstract
A solid-phase extraction (SPE) screening procedure for the isolation and gas chromatographic (GC) determination of organochlorine and organophosphorus pesticide residues in eggs is described. Eggs are extracted with acetonitrile. The extract is subjected to a cleanup on tandem C18 and Florisil SPE columns. Organochlorine and organophosphorus pesticide residues are determined by GC with electron capture and flame photometric detection, respectively. Because the injected extracts are free from matrix interferences, the amount of residue present is easy to calculate. The average recoveries of 9 spiked organochlorine pesticide residues (0.01–1.0 ppm) ranged from 80.9 to 91.1 %. The average recoveries of 7 spiked organophosphorus pesticide residues (0.02–0.50 ppm) ranged from 80.3 to 89.5%. The SPE method results in a 90% reduction in organic solvent consumption and an 85% reduction in hazardous waste production compared with the AOAC methodology.
Influence of pH, Ionic Strength, and Physical State on the Near-Infrared Spectra of Model Compounds
Authors: Reeves James B 
Published: February 2020

Abstract
The accuracy of near-infrared spectroscopy (NIRS) when applied to high-moisture samples (i.e., silages) does not match that with dried materials. Previous work showed that the presence of water could cause shifts in the spectra of organic compounds, the degree of which depended on the material and the water concentration. For some solids, such as sugars, large spectral changes occur on dissolution. The objective of this study was to determine the effect of pH, ionic strength, and physical state on the NIR spectra of model compounds. The results show that pH has large effects on the spectra of amines and acids but little if any on the spectra of ketones, alcohols, and sugars. The spectra of peptides and proteins also were pH dependent, but that of cellulose was not. Ionic strength differences (deionized water vs saturated NaCI solution as the diluting media) had only minor or no effect on the spectra of the materials studied. The effect of physical state was far more complicated; the spectra of freeze-dried glucose and glycine were different from that of the crystalline forms, but the spectrum of serine was not. The spectra of molten compounds often appeared like those of solutions. These results, in agreement with earlier work, may explain the poorer performance of NIRS with wet materials compared with dry samples. They also have serious implications for the analysis of dried samples, if pH, ionic strength, or drying method varies among samples.
Preparation of Milk Samples for Immunoassay and Liquid Chromatographic Screening Using Matrix Solid-Phase Dispersion
Authors: Barker Steven A , Long Austin R 
Published: February 2020

Abstract
The use of drugs to maintain the health and maximize the output of dairy cattle has made the monitoring of milk for such agents essential. Screening tests based on immunological, microbial inhibition, and bacterial receptor assays have been developed for the detection of violative levels of therapeutic substances. However, such assays are not infallible, and false positive or negative results can occur when contaminants bind receptors or compete for the binding of the target residues. Such effects may arise from dietary sources, diseases, or other variables. Thus, a violation by such a test is not definitive until further confirmation is obtained. Our laboratory has developed extraction procedures for several drugs used in dairy production. Our method uses matrix solid-phase dispersion (MSPD) to isolate drugs away from contaminants and to eliminate many possible interferences. MSPD can also be used to enhance the specificity of such assays by fractionating various classes of drugs that may cross-react. Similarly, such methods may be used for liquid chromatographic screening and confirmation of a suspect sample.
Improvement of Chemical Analysis of Antibiotics. Part XIX1: Determination of Tetracycline Antibiotics in Milk by Liquid Chromatography and Thin-Layer Chromatography/Fast Atom Bombardment Mass Spectrometry
Authors: Oka Hisao , Ikai Yoshttomo , Hayakawa Junko , Masuda Katsuyoshi , Harada Ken-Ichi , Suzuki Makoto 
Published: February 2020

Abstract
A precise liquid chromatographic (LC) determination with high sensitivity and a reliable mass spectrometric (MS) confirmation were established for the determination of tetracycline antibiotics (TCs) in milk. The determination of the TCs was based on C18 cartridge cleanup followed by LC separation. Recoveries of TCs from milk fortified at 20 ppb were 73.0–81.8%, and coefficients of variation were 2.6–4.6%. With this method, concentrations of oxytetracycline and tetracycline as low as 10 ppb and chlortetracycline and doxycycline as low as 20 ppb were determined readily. Thin-layer chromatography (TLC)Zfast atom bombardment (FAB) MS with a condensation technique was used to confirm TCs in milk. After the C18 cartridge cleanup, separation on a C18 TLC plate, and application of the sample condensation technique, FAB mass spectra were measured. TCs in milk at 50 ppb were reliably confirmed by TLC/FABMS.
Extraction and Enzyme Immunoassay of Sulfadimethoxine Residues in Channel Catfish (Ictalurus punctatus) Muscle
Authors: Walker Calvin C , Barker Steven A 
Published: February 2020

Abstract
Four commercially available enzyme immunoassays were evaluated for the detection of sulfadimethoxine (SDM) residues in channel catfish muscle. Matrix solid-phase dispersion (MSPD) extracts of samples (n = 60, 0.5 g) fortified with SDM at 0, 25, 50, 100, and 250 ng/g were used in all assays. Intra-assay variations for 2 MICROTITER well-based quantitative assays, SIGNAL sulfamethazine test and IDS SDM One-Step ELISA (enzyme-linked immunosorbent assay), were 5.6 and 7.7%. Interassay variations for these tests were 7.9 and 16.6%. The agreements between evaluators for 2 membrane-based, visually determined assays, CITE Sulfa Trio and EZ-SCREEN: SDM, were 77 and 95%. Performance values, as indicated by sensitivity, specificity, efficiency, and positive and negative predictive values, were 100, 92, 95, 89, and 100%, respectively for the SIGNAL test; 100, 94, 97, 92, and 100% for the IDS test; 98, 71, 82, 69, and 98% for the CITE test; and 98, 94, 96, 92, and 99% for the EZSCREEN assay. Eight sulfonamides cross-reacted in the SIGNAL test; EC-50 values (concentrations causing 50% inhibition of color development compared with blanks) varied from &lt;0.1 to 45 μg/mL. The EC-50 value for SDM was 0.25 μg/mL. The CITE test cross-reacted with sulfachloropyridazine at 10 μg/mL. The IDS and EZ-SCREEN tests had no significant cross-reactivity with other sulfonamides. N-Acetyl SDM reacted like the parent SDM in all assays. Performance results indicated that MSPD extracts of catfish muscle may be used in these immunoassays to screen catfish muscle samples for violative levels of SDM residue.
Gas Chromatographic Determination of Total Fat Extracted from Food Samples Using Hydrolysis in the Presence of Antioxidant
Authors: House Stephen D , Larson Paul A , Johnson Rodney R , DeVries Jon W , Martin Dianna L 
Published: February 2020

Abstract
A method for the quantitative measurement of total fat in foodstuffs is described. Fat is extracted by hydrolysis and interesterified to fatty acid methyl esters for gas chromatographic analysis. Total fat and fatty acid patterns are calculated to comply with the regulations for food label declaration under the Nutrition Labeling and Education Act of 1990. Quantitative recovery of fat from soy oil is obtained in the presence of the antioxidant pyrogallol. Extraction and measurements of fat from a variety of food samples (e.g., cereal, baked goods, dairy, and fish) are also reported, and fat levels ranged from 0.8 to 95% (w/w). Coefficients of variation of ≤5% demonstrate the efficiency of the method.
Performance Evaluation of the Babcock and Ether Extraction Methods: 1989 through 1992
Authors: Lynch Joanna M , Barbano David M , Healy Patrick A , Richard Fleming J 
Published: February 2020

Abstract
Results of the collaborative studies of the performance of the Babcock method (989.04) and the modified Mojonnier ether extraction method (989.05) for the determination of the fat content of raw milk were published in 1988. Method performances were characterized by using the harmonized International Organization for Standardization–International Union of Pure and Applied Chemistry–Association of Official Analytical Chemists (ISO/IUPAC/AOAC) guidelines for method validation, and the methods were approved official first action. During 1989 through 1992, the split-sample collaborative study format was used to monitor the performance of these methods as a part of an ongoing quality assurance program for a group of laboratories. Seven blind duplicate samples of raw milk were sent from a central laboratory once every 2 months to each participating laboratory (11 to 17 laboratories). Data were analyzed by using the same statistical procedures used in the 1988 study. Over time, both the within- and between-laboratory performances of both methods were as good as or, in most cases, better than the results from 1988. The data demonstrate that the statistical protocol for collaborative studies can be used effectively as the basis for a multilaboratory quality assurance program and that the method performance achieved in a collaborative study can be maintained and even improved with time.
Ion Chromatographic Method for Dissolved Hexavalent Chromium in Drinking Water, Groundwater, and Industrial Wastewater Effluents: Collaborative Study
Authors: Edgell Kenneth W , Longbottom James E , Joyce Robert J 
Published: February 2020

Abstract
A collaborative study was conducted by the U.S. Environmental Protection Agency (U.S. EPA) and the American Society for Testing Materials (ASTM) on an ion chromatographic method for the determination of hexavalent chromium (U.S. EPA method 218.6, and the ASTM equivalent method). This study was designed to determine the mean recovery and precision of analyses for hexavalent chromium in reagent water, drinking water, groundwater, and industrial wastewaters. The study design was based on Youden’s nonreplicate plan for collaborative studies of analytical methods. The test waters were spiked with hexavalent chromium at 8 concentration levels, prepared as 4 Youden pairs. A fifth Youden concentration pair was also included to determine method performance close to the method detection limit. Twenty-one laboratories were instructed to filter their test waters through a 0.45 μm filter and to adjust the pH of the filtrate to 9–9.5 with an ammonium sulfate/ammonium hydroxide buffer solution before spiking with the hexavalent chromium concentrates. A known volume, 50–250 (μL, was injected into an ion chromatograph which separated the Cr(VI), as CrO42−, on an anion exchange column. After separation, the Cr(VI) was derivatized with diphenylcarbazide and the colored complex was detected at 530 nm. The submitted data were corrected for background concentrations and analyzed by applying ASTM D-2777-86 statistical procedures and a U.S. EPA computer program. U.S. EPA method 218.6 and the equivalent ASTM method were judged acceptable for the measurement of hexavalent chromium concentrations at 1–1000 μg Cr(VI)/L. The study found that the use of a single linear calibration extending over 3 orders of magnitude yielded biased results at the very lowest concentration levels. Shorter range calibration curves yielded more accurate results. Analysis of variance (ANOVA) tests indicated that method performance was significantly different between the reagent water matrix and the other matrixes used. The recovery of Cr(VI) from the other matrixes was lower at all concentration levels with slightly less precision when compared with the reagent water data set. For reagent water, the mean recovery and the overall and single-analyst relative standard deviations were 105%, 7.8% and 3.9%, respectively. For the other matrixes, the same values were 96.7%, 11.9% and 6.3%, respectively. The method was adopted first action by AOAC INTERNATIONAL.