bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interlaboratory Assessment of Dry Calibration Milk Powders for Calibrating Infrared Milk Analyzers
Authors: Van De Voort Frederick R , Elkashef Abdel Aziz , Blais Jean-Simon 
Published: February 2020

Abstract
An interlaboratory study was carried out to assess the performance of preformulated, preanalyzed, dry calibration milk powders designed for calibrating infrared milk analyzers. The calibration powders can be reconstituted to produce consistent calibrations within laboratories. The powders met AOAC specifications In terms of accuracy and repeatability, and provide calibrations with performance characteristics comparable to those produced with conventional calibration milks. The reconstituted solutions were shown to be stable for up to 6 h at 40°C, and can be stored under refrigerated conditions and used for repeated analyses for up to 21 days without apparent deterioration In calibration performance. In general, the calibration powders perform as well as, or better than, the conventional calibrants used by the laboratories participating in the study, and the calibrations could be switched without significantly changing the analytical results. Simulation and cross-calibration analyses indicated that the powdered calibrants produced more consistent results overall than fluid calibration milks. The powdered calibrants, as formulated, are shown to be suitable for any application requiring calibrations that meet AOAC specifications, Including payment applications. The calibration powders have the stability and performance characteristics to serve as a consistent, stable reference standard for monitoring instrument performance, and would be a useful tool for Interlaboratory standardization or accrediting payment and dairy herd analysis laboratories.
Gas Chromatographic/Mass Spectrometric Determination of α-Methylstyrene in Styrene-Based Polymers and Food Simulants
Authors: Tan Shigeru , Tatsuno Takashi , Okada Taro 
Published: February 2020

Abstract
A selected ion monitoring method is described for the analysis of styrene (St)-based polymers for a-methylstyrene (α- MSt) and for determining the level of α-MSt migration from St-based sheets Into 4 food simulants. The polymers are dissolved in dlchloromethane; α-MSt Is determined by direct Injection of the polymer solutions. α-MSt migration from St-based sheet to water, 4% acetic acid, 20% ethanol, and n-heptane was measured by gas chromatography/mass spectrometry, using multiple ion monitoring of Ions at mix 118,78, and 91. α-MSt can be quantltated at levels as low as 10 μ/g in the polymer and 0.01 μ/g In the food simulants. Recoveries were 83-113% from St-based sheets and 90-99% from food simulants, respectively.
Near Infrared Reflectance Spectroscopy. Part II. Effect of Calibration Set Selection on Accuracy of Method
Authors: Barton Franklin E 
Published: February 2020

Abstract
Tall fescue samples (Festuca arundenacea Schreb) were collected during 1983-1985. The 1983 and 1984 samples were used for calibration and the 1985 samples were used for validation. The combined 1983-1984 calibration set contained 382 samples. The program "SUBSET" was run and 74 samples were selected. The remaining samples from 1983- 1984 were divided Into 4 files of 77 samples each by taking every 4th sample. The "SUBSET" program was run on the 1985 set of 211 samples and 40 samples were selected that represented all the spectral diversity in the set. Separate sets of equations were developed with 2 regression programs, "BEST" and "CAL," and used to predict acid detergent fiber, neutral detergent fiber, permanganate lignin, and crude protein. The results show that while a random selection could sometimes produce a better set for calibration, the "SUBSET" program picks a set that consistently will produce a good calibration. In most instances, the "SUBSET" equations were the best or next to the best when measured by the standard error of performance corrected for bias.
Quality Management (QA/QC) in the Analytical Laboratory
Authors: Schultz Mary G , Brown William L 
Published: February 2020

Abstract
An effective quality management system in the analytical laboratory must be designed to satisfy customers' needs and expectations while serving the laboratory's interests. An understanding of total quality and its components Is essential for the development of a quality management system In the analytical laboratory. Quality systems are founded on quality laboratory practices; they have a strong quality control component, and, more recently, monitoring through quality assurance. Development of a quality Improvement component with more emphasis on quality planning Is also needed to provide the necessary system for quality management
Fast Turnaround Multiresidue Screen for Pesticides in Produce
Authors: Hsu Jong P , Schattenberg Herbert J , Garza Martha M 
Published: February 2020

Abstract
A rapid multiresidue screen for 110 pesticides was applied to 5628 produce samples. Samples were extracted, analyzed, and evaluated within 6 1/2 h of receipt. Analyses were confirmed within a 24 h period on those samples in which a potential residue was found above the U.S. Environmental Protection Agency's tolerance level. A thorough yet quick chromatographic interpretation program is also described
Limited Survey of Residual Tetracyclines in Tissues Collected from Diseased Animals in Aichi Prefecture, Japan
Authors: Oka Hisao , Ikai Yoshitomo , Kawamura Norihisa , Hayakawa Junko 
Published: February 2020

Abstract
Tissues were collected to survey the actual conditions of tetracycline antibiotics (TCs) residues in slaughtered animals that did not pass inspection at slaughterhouses in Aichi Prefecture, Japan, because of the presence of disease symptoms. Tissues were analyzed by liquid chromatography. Among 271 samples, 49 (18.1%) were positive for oxytetracycline (OTC), 5 (1.8%) for chlortetracycline (CTC), and 5 (1.8%) for doxycyclfne (DC), respectively. One sample (cattle kidney) was positive for both OTC and DC. However, tetracycline was not detected in any samples. Percentage frequencies of TCs residues were 29.1% (37/127) and 15.2% (22/144) for cattle and hogs, respectively. Kidney samples showed higher incidence of TCs residues and 1.5-7 times higher residual concentrations than liver and miscellaneous samples.
Monitoring Aldehyde Production During Frying by Reversed-Phase Liquid Chromatography
Authors: Lane Ralph H , Smathers Janis L 
Published: February 2020

Abstract
Acrolein (2-propenal) and other low molecular weight aldehydes (LMWAs) formed by degradation of the frying medium (triglycerides) were monitored by liquid chromatography (LC) during preparation of fried items. LMWA contents of coatings from codfish and of doughnuts and their volatiles that codistill with steam are monitored by trapping the vapors and distillate from the food matrix in a 2,4-dinitrophenylhydrazine solution. The resulting hydrazones are partitioned from the aqueous phase, first into isooctane and then into acetonitrile for LC analysis. The hydrazones are separated and quantified on a C18 reversed-phase column with acetonitrile-water as the mobile phase. LMWAs are confirmed by gas chromatography/mass spectrometry. No difference was found in LMWA content in coatings from fish fillets fried at 182 or 204°C. Cake doughnuts were higher in acrolein content than yeast-raised doughnuts prepared under similar conditions. Freshness of the frying medium, frying time, and batch size did not seem to influence LMWA production from doughnuts. Results indicated that most of the LMWAs formed codistilled with steam during frying rather than remaining with the food item.
Improved Method for Determination of Polynuclear Aromatic Hydrocarbons in Pharmacopoeial Paraffin and Mineral Oils
Authors: Geahchan Aziz , Le Gren I , Chambon Paul , Chambon Renee 
Published: February 2020

Abstract
An improved method has been developed for quantitative determination of poiynuciear aromatic hydrocarbons (PAHs) in pharmacopoeial paraffin and medicinal white oil samples. This new method combines 2 liquid-liquid partition and adsorption chromatography procedures with a 2-step purification on Sephadex LH 20 and liquid chromatography with fluorometric determination. Selective elution of PAHs results in absence of background fluorescence. The minimum detectable level ranges from 0.2 ppt for benzofluoranthene isomers to 200 ppt for acenaphthene. Recoveries of PAHs added at 7 ppm varied from 92.1 to 111.4%. When a variety of medicinal white oil samples were analyzed by this improved method, 27 PAHs were identified, including 11 suspected carcinogens. Their identities were confirmed by capillary gas chromatography.
Multipesticide Determination in Surface Water by Gas Chromatography/Chemical Ionization/Mass Spectrometry/Ion Trap Detection
Authors: Mattern Gregory C , Louis Judith B , Rosen Joseph D 
Published: February 2020

Abstract
An improved method for the determination of trace levels of pesticides in surface water has been developed and was used to analyze 20 target pesticides in New Jersey. Pesticides were extracted from 2 L water samples, using a mixture of XAD-2 and XAD-7 resins, and were determined by gas chromatography/chemical ionization mass spectrometry with ion trap detection. Average recoveries (performed in triplicate at the 1 ppb level, except for captan and chlorothalonil at 5 ppb) were between 75 and 113%, with an average coefficient of variation of 9%. Most of the pesticides (alachlor, atrazine, butylate, carbofuran, chlorpyrifos, diazinon, fonofos, isofenphos, metolachlor, metribuzin, parathion, and simazine) had limits of detection (LODs) of 0.005 ppb or lower, while some (carbaryl, cyanazine, fenamiphos, linuron, pendlmethalin, and terbufos) had LODs between 0.005 and 0.05 ppb. Captan and chlorothalonil had LODs of 1 ppb. Of 31 samples analyzed, 29 contained one or more of the following pesticides: alachlor, atrazine, carbaryl, chlorpyrifos, cyanazine, diazinon, isofenphos, linuron, metolachlor, and simazine in concentrations between trace (&lt;0.025 ppb) and 5.48 ppb.
Separation of Clethodim Herbicide from Acid and Photodegradation Products by Liquid Chromatography
Authors: Falb Linford N , Bridges David C , Smith Albert E 
Published: February 2020

Abstract
Clethodim, (E,E)-(±)-2-[1-[[(3-chloro-2-propenyl)oxy]lmino] propyl]-5[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one, is stable in acetonitrlie, but the Inclusion of water induced degradation in the dark. Addition of acetic acid to the mobile phase did not increase degradation; however, it did improve peak symmetry and liquid chromatographic (LC) separation, with the optimum resolution at 0.75% acetic acid. The extinction coefficient for clethodim at 254 nm did not change in acetonitrlie with addition of water or acetic acid. The LC detector responded linearly to clethodim in the 0.7-400 ppm range. Separate solvent gradient programs (40 min each) were developed for separation of acid degradation products (ADPs) and the photodegradation products (PDPs). The inclusion of cobalt or silver nitrate to the mobile phase did not improve separations. A minimum of 31 and 19 products formed during photolytic and hydrolytic degradation of clethodim, respectively. PDPs were more polar than ADPs. Reproducibility of this method was considered to be acceptable for separation of ADPs and PDPs of clethodim.
Determination of Ticarcillin and Clavulanic Acid in Serum by Liquid Chromatography
Authors: Wright Jennifer C , Durham Carl N , Dunbar Jacob R 
Published: February 2020

Abstract
A liquid chromatographic (LC) method using solidphase extraction for the determination of clavulanic acid and ticarcillin in human serum has been developed. Clavulanic acid and ticarcillin were extracted separately from 1 mL serum using C18 solid-phase extraction cartridges. Eluates were analyzed by the same reversed-phase LC system. The overall mean recovery of clavulanic acid from serum was 99.7 ±2.3%; the lowest level validated in serum was 0.5 μg/mL. The overall mean recovery of ticarcillin from serum was 101.5 ±3%; the lowest level validated in serum was 12.5 μg/mL. Detection limits for clavulanic acid and ticarcillin were 0.117 and 0.749 μg/mL, respectively.
Specification-Based Modified Control Limits in Quality Control of Trace Chemical Analyses
Authors: Grant C L , Mcgee I E , Jenkins T F , Stutz M H 
Published: February 2020

Abstract
Shewhart X and R charts were used to maintain and validate data quality of percent recovery estimates for 8 analytes determined by 4 procedures used routinely in 4 commercial laboratories over a 2-year period. However, because range (R) estimates of uncertainty did not Include lot-to-lot calibration variability, approximately 24% of the lots were "out-of-control." We extracted pooled standard deviations for So (repeatability within lot), SL (calibration variability), and SR (reproducibility), which represents the total variability. Values of So and SL were generally similar In size although there were some substantial differences between analytes and between laboratories for a given analyte. When control limits were based on reproducibility rather than repeatability, only about 6% of the lots were "out-of-control." However, these limits are less convenient to compute at the bench, wlthln-lot precision estimates are still required, and there Is still no Information on data acceptability. Capability estimates from the grand mean ±3 SR were surprisingly consistent for the 8 analytes. These values coupled with data quality objectives suggested the 82-115% range as the specifications for acceptable individual recoveries. A combination of repeatability limits plus modified limits anchored to specifications retains the simplicity of range computations while offering substantial administrative advantages. Examples are given to illustrate these points.
Liquid Chromatographic Determination
of Incurred Nitrofurazone Residues in Chicken Tissues
Authors: Parks Owen W , Kubena Leon F 
Published: February 2020

Abstract
One-day-old chicks were raised to maturity on a diet fortified with 0.0055% nitrofurazone. Analyses of tissue extracts by a liquid chromatography/electrochemlcal detection method revealed that the distribution of residues between liver, breast, and thigh muscle differed significantly from that previously reported In birds that were dosed with the drug before sacrifice. Differences between ground and unground tissues were also observed, suggesting that residues are not distributed evenly throughout the same tissue.
Extraction of Light Filth from Dried Bean Curd:
Collaborative Study
Authors: Nakashima Marvin J 
Published: February 2020

Abstract
Results are reported for a collaborative study of a method for the extraction of light filth from dried bean curd. A100 g test portion is dispersed in a 5.7% HCI solution. Residue from the No. 230 sieve is defatted In isopropanol, and the sieved residue is transferred to a Wildman trap flask. Light filth Is Isolated from 40% isopropanol by using Na4EDTA and mineral oil-heptane (70 + 30). Average recoveries by 6 collaborators for 3 spike levels of rat hairs (5,10, and 15) were 85,81, and 70%, respectively; for Insect fragments (5,15, and 30), recoveries were 72,83, and 72%, respectively. The method was adopted by AOAC International as first action.
Colorimetric Determination of Selenium
in Premixes and Supplements
Authors: Hurlbut Jeffrey A , Burkepile Roger G , Geisler Carolyn A 
Published: February 2020

Abstract
A colorimetric method Is described for the determination of 100-10 000 μg selenlum/g premix. Selenium Is present in premixes as either selenite or selenate. Moderate to high concentrations of several common minerals are tolerated. The premix is briefly digested In a sulfuric acid-perchloric acidsodium molybdate mixture, boiled in 10% NaCI solution, made basic, and centrifuged. Aliquots are taken if necessary. The mixture Is then acidified with formic acid, treated with hydroxylamlne hydrochlorlde- EDTA, and complexed with 3,3 - dlamlnobenzldlne. The pH Is adjusted, and an extraction Is performed with toluene. The absorbance is measured at 420 nm. Recoveries for 100- 10 000 μg selenlum/g premix ranged from 88 to 104%, with an average of 97%. The coefficient of variation ranged from 1.6 to 6.9%, with an average of 4.2%.
Determination of Monensin in Raw Material, Premix,
and Animal Feeds by Liquid Chromatography
with Correlation to Microbiological Assay
Authors: Rodewald J Matthew , Moran John W , Donoho Alvin L , Coleman Mark R 
Published: February 2020

Abstract
A method Is described for the detection and quantitation of monensin In raw material, premix, and feeds by liquid chromatography (LC) with postcolumn derlvatlzatlon with vanillin. Monensin was mixed with vanillin under acidic conditions and heated, and the resulting products were measured by a variable wavelength visible detector operating at 520 nm. The LC response of monensin and monensln-llke factors was determined and correlated to the microbiological response of each factor as determined with Streptococcus faeclum. Monensin reference standard was characterized In the same manner as the individual factors. The chemical composition of the reference standard and the relative microbiological potency values were used In combination to calculate the biopotency contribution of each of the monensin factors. A formula was used to transform chemical composition values of the reference standard to total microbiological activity as obtained directly from a microbiological assay. The formula was tested by comparing samples assayed by LC using the formula to report microbiological potency with samples assayed by the Autoturb method. Finally, the LC method was validated with raw material, premix, cattle rations (including liquid supplements), and poultry rations.
Automated Closed-System Headspace Determination
of Methyl Bromide in a Variety of Raw and Processed Nuts
Authors: Ford Joseph H , Legendre Michael G , Ladner Dorothy L , Dawson Joseph A , Raymond Caleph 
Published: February 2020

Abstract
An automatic gas chromatographic method was developed for determining methyl bromide residues In 11 different types of nuts. A 50 g sample Is placed In a modified stainless steel blender container and mixed with 200 mL 0.5M sodium sulfate. The blender container Is sealed with a screw lid, and the sample Is blended 3 min and equilibrated 17 mln in a bath-reclrculator at 26°C. The headspace gas Is automatically sampled and analyzed twice for methyl bromide residues. Recoveries are based on deviation from predetermined partitioning coefficients (p-values). The average p-values for the different nuts ranged from 0.28 to 0.43, and the CVs for their determinations ranged from 7.7 to 23.5%. The method Is sensitive, simple, and reproducible, and It is operated In a totally closed system. Over 1100 samples of assorted nuts were analyzed within a 6-month period
Fluorometric Determination of Thiamine Vitamers in Chicken
Authors: Fox Jay B , Ackerman Stanley A , Thayer Donald W 
Published: February 2020

Abstract
A comparison was made of the direct determination of thiamine In acidified heated chicken extracts, by either flow injection or chromatographic determination, with the standard method (acid and enzyme digestion, adsorption, and elutlon, followed by the fluorometric determination of thiochrome extracted by Isobutanol from K3Fe(CN)6-treated eluates). Liquid chromatography of extracts, followed by oxidation of thiamine vitamers to thlochromes, showed 1 light scatter emission peak and 2 thlochromes, the latter corresponding to thiamine and thiamine monophosphate. Both forms were determined quantitatively by flow Injection determination, the lower detection limit of which was about 60 femtomol. The determination was linear from 0.1 ng to 10 μg thlamlne/mL, and the pooled coefficient of variation was 4%. The determination of thiamine in chicken extracts provides a nondestructive method for determining thiamine and Its phosphate esters, either In toto by flow Injection determination or as individual components by chromatography.
Rapid Solvent-Efficient Method for Liquid Chromatographic Determination of Ochratoxin A in Corn, Barley, and Kidney: Collaborative Study
Authors: Nesheim Stanley , Stack Michael E , Trucksess Mary W , Eppley Robert M , Krogh Palle 
Published: February 2020

Abstract
A joint Interlaboratory study of a rapid, solvent-efficient liquid chromatographic method for determination of ochratoxin A (OTA) in barley, corn, and pork kidney tissue was conducted by AOAC, the International Union of Pure and Applied Chemistry, and the Nordic Committee on Food Analysis In 16 laboratories in Europe, Canada, and the United States. OTA was added to barley and corn at 10,20, and 50 ng/g and to kidney at 5,10, and 20 ng/g. Duplicate test portions were prepared at 20 ng/g for corn and barley and 10 ng/g for kidney. Mean recoveries of OTA ranged from 53 to 97%. Within-laboratory relative standard deviations were 7.9,20.1, and 15.7% for barley, corn, and kidney tissue, respectively. Between-laboratories relative standard deviations were 20.7-31.7% for all concentrations of OTA In barley and corn and 68.0,41.8, and 32.7% for OTA concentrations of 5,10, and 20 ng/g, respectively, In kidney. OTA Identity was confirmed by methyl ester derivatization followed by liquid chromatography. The method has been adopted first action by AOAC as quantitative at the levels tested for OTA determination In corn and barley.
Enzyme-Linked Immunosorbent Assay for Quantitation of Organophosphate Pesticides: Fenitrothion, Chlorpyrifos-methyl, and Pirimiphos-methyl in Wheat Grain and Flour-Milling Fractions
Authors: Skerritt John H , Hill Amanda S , Beasley Helen L , Edward Simone L , Mcadam David P 
Published: February 2020

Abstract
Simple, competitive enzyme-linked Immunosorbent assays (ELISAs) have been developed for the quantitation of each of 3 major organophosphate Insecticides: fenltrothlon (FN), chlorpyrifos-methyi (CPM), and plrlmlphos-methyl (PIRM). Performance of these assays on wheat grain and (for FN and CPM) on milling fractions such as flour, wheat germ, and bran has been assessed. Each assay is specific for the particular compound, i.e., no significant cross-reaction with the other 2 pesticides is observed. Only limited reactions were noted with major metabolites or analogs of these pesticides. Assay limits of detection of 0.3 ng FN, 0.2 ng CPM, and 0.02 ng PIRM, corresponding to limits of detection in whole grain of 0.08 ppm FN, 0.2 ppm CPM, and 0.03 ppm PIRM. Each compound In grain and milling fractions could be extracted quantitatively by simple shaking in neat methanol. Multiresidue analysis of the 3 insecticides was performed by simultaneously adding the cereal extract (diluted in phosphate buffer) to separate duplicate microwells coated with antibodies to FN, CPM, and PIRM and adding appropriate pesticide-horseradish peroxidase conjugates. High correlations between gas chromatography and the ELISA methods were obtained for Insecticide levels In whole wheat and In milling fractions. In general, the ELISA assays had precision similar to those of instrumental pesticide analyses.
Rapid Whole-Blood Cholinesterase Assay with Potential Use for Biological Monitoring During Chemical Weapons Disposal
Authors: Halbrook Richard S , Guzman Carmen E , Wilkinson Karen J , Watson Annetta P , Munro Nancy B , Shugart Lee R 
Published: February 2020

Abstract
A protocol Is described to determine whole-blood cholinesterase activity using an automated highspeed centrifugal analyzer. Throughput rate was increased 10-fold (from 6 to 60 samples/h), and precision, as measured by a reduction In Intra-allquot variation, was significantly Improved (from 4.7 to 3.0%) by using an automated system rather than a manual system. Similar cholinesterase activity was determined for samples analyzed by both the automated and manual protocols, and Interlaboratory comparison Indicated no change In accuracy. The lower limit of detection was estimated to be 0.10 μmol/mL/mln. The 10-fold Increase In throughput facilitates use of the automated protocol when many analyses must be performed in a limited time.