bluuebunny/crossref_metadata_2025_split huggingface dataset:
Colorimetric Determination of Trace Iron in Water Samples by Using a Poly(Vinyl Chloride) Membrane Containing Bathophenanthroline as a Solid-Phase Extraction Medium
Authors: Saito Takashi 
Published: February 2020

Abstract
Trace iron was determined by solid-phase extraction using a polymer membrane as an extracting medium. The polymer membrane consisted of 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline) as a chelating agent, o-nitrophenyl octyl ether (o-NPOE) as the extracting solvent, and polyvinyl chloride) (PVC). When the PVC membrane came into contact with iron in the samples, the membrane changed from colorless to red, and the color intensity was proportional to the iron concentration. The iron concentration was calculated from a calibration graph, after the absorbance of the colored membrane was measured spectrophotometrically. With this method, iron concentrations ranging from 2.76 × 10−7 to 4.29 × 10−5M were determined quickly and easily.
Reversed-Phase Liquid Chromatographic Determination of Vitamin D in Milk
Authors: Hagar Arthur F , Madsen Lee , Wales Louis , Bradford Henry B 
Published: February 2020

Abstract
Vitamin D in milk is determined by a slight modification of the method of Sliva et al. [J. AOAC Int. (1992) 75,566–571] for infant formula and enteral nutritional products. The sample is saponified for 30 min at 60°C and extracted overnight into 60 mL of hexane. The hexane layer is washed, neutralized, and taken to dryness with a rotary evaporator. The sample is reconstituted in hexane and applied to 500 mg of Florisil in a solid-phase extraction column. Vitamin D is eluted with isopropyl alcohol. The eluate is evaporated to dryness under N2, and the sample is reconstituted in 1.0 mL of acetonitrile. The extract is analyzed on a C18 liquid chromatographic column (250 × 4.6 mm, 5 μm particle size) with UV detection at 265 nm. Milk samples of various fat content (i.e., skim, low fat, and whole milk) were analyzed. Spiked recoveries gave means of 81–96%; recoveries were inversely related to fat content. Assay precision ranged from 3.2 to 8.6%. The method can measure vitamins D2 and D3 individually, and no difference in the recoveries of the 2 vitamins was observed. Thus, vitamin D2 can be used as an internal standard for quantitating vitamin D3, and vice versa. The method is satisfactory for use in screening of milk for vitamin D content.
Determination of Narasin in Raw Material, Premix, and Animal Feeds by Liquid Chromatography and Correlation to Microbiological Assay
Authors: Rodewald John M , Moran John W , Donoho Alwin L , Coleman Mark R 
Published: February 2020

Abstract
A method is described for the detection and quantitation of narasin in raw material, premix, and feeds by liquid chromatography (LC) and postcolumn derivatization (PCD) with vanillin. Narasin was mixed with vanillin under acidic conditions and heated, and the resulting products were measured by a variable-wavelength detector operating at 520 nm. The LC responses of narasin and narasinlike factors were determined and correlated to the microbiological response of each factor as determined with Streptococcus faecium. Narasin reference standard was characterized in the same manner as the individual factors. The chemical composition of the reference standard (i.e., the amounts of narasin factors expressed in percent) combined with the relative microbiological potency value was used to calculate the biopotency contribution of each narasin factor. A formula was used to transform chemical composition values (amounts of narasin factors expressed in percent) of the reference standard to total microbiological activity as directly obtained from the microbiological assay. The LC method was validated by analyses of raw material, premix, and cattle and poultry rations.
Capillary Zone Electrophoretic Determination of Histamine in Fish
Authors: Mopper Barry , Sciacchttano Carl J 
Published: February 2020

Abstract
Histamine, the principal causative agent in scombroid food poisoning, was analyzed in seafood by a new, rapid, and sensitive method using capillary zone electrophoresis (CZE) with UV detection at 210 nm. Incurred histamine in methanolic fish extracts migrated within 4 min in a fused silica capillary filled with 0.02 M citrate buffer, pH 2.5, under an applied potential of 375 V/cm. The analytical response was linear from 0.5 to 100 ppm histamine (correlation coefficient, r = 0.999). The coefficients of variation for migration time and peak area response were &lt;1 and &lt;3%, respectively. Recovery of histamine in fortified fish composites was satisfactory. CZE was considered for alternative application in seafood speciation.
Determination of Monensin in Chicken Tissues by Liquid Chromatography with Postcolumn Derivatization
Authors: Moran John W , Matthew Rodewald J , Donoho Alvin L , Coleman Mark R 
Published: February 2020

Abstract
A method is described for the detection and quantitation of monensin in chicken tissues by liquid chromatography with postcolumn derivatization with vanillin. Monensin is extracted from the tissues by homogenization with methanol–water and is isolated and concentrated by liquid–liquid partition and sorbent extraction with silica gel. Monensin is mixed postcolumn with vanillin under acidic conditions and heated, and the resulting products are measured by a variable-wavelength detector operating at 520 nm. The method has a limit of quantitation of 0.025 μg/g and is validated for use in the analyses of chicken muscle, liver, and skin (with adhering fat tissues) for monensin. Standard recoveries from the 3 tissue types tested at 3 levels ranged from 82 to 96%. The method represents an improvement in specificity, accuracy, and analysis time over existing methods, which use microbiological techniques.
Direct Graphite Furnace–Atomic Absorption Method for Determination of Lead in Edible Oils and Fats: Summary of Collaborative Study
Authors: Firestone David 
Published: February 2020

Abstract
The IUPAC Commission on Oils, Fats, and Derivatives undertook development of a method and collaborative study for the determination of lead in oils and fats by direct graphite furnace–atomic absorption spectrophotometric method. Various types of graphite furnaces were used with or without platform. Twenty-three collaborators from 12 countries participated in the study. The materials tested were edible oils (soybean oil) and fats (cocoa butter) containing lead at 3 concentration levels (low, medium, and high). Each level was represented by 2 batches provided in duplicate (blind coded), so that each collaborator received a total of 24 test samples. Collaborators were instructed to analyze each in duplicate and report both results. Twenty collaborators returned the results of the study. After data from laboratories that did not follow the instructions were excluded, only 16 sets of data were evaluated statistically. The method for determination of lead in oils and fats by direct graphite furnace–atomic absorption spectrophotometry has been adopted first action by AOAC INTERNATIONAL as an IUPAC–AOCS–AOAC method.
Particle Concentration Fluorescence Immunoassay for Determination of Tylosin in Premix, Feeds, and Liquid Feed Supplement: Comparison with Tiirbidimetric Assay
Authors: Wicker Alan L , Mowrey Daniel H , Sweeney Daniel J , Coleman Mark R , Morris Deborah K , Brockus Catherine L 
Published: February 2020

Abstract
A rapid, competitive particle concentration fluorescence immunoassay (PCFIA) for the determination of tylosin (Tylan) concentrations in extracts of pre-mix, feeds (cattle, chicken, and swine), and liquid feed supplement is described. Tylosin-β-phyco-erythrin conjugate, tylosin standard or diluted sample extracts, and rabbit anti-tylosin antibody are incubated for 15 min in PCFIA plates. Rabbit anti-tylosin antibody is then captured, during a 15 min incubation, with goat anti-rabbit antibody that is attached to latex beads. Assay plates are washed to remove unbound tylosin-(β-phyco-erythrin and unbound, free tylosin. Fluorescence is measured with a fluorimeter. Tylosin concentration is inversely proportional to the β-phycoerythrin fluorescence signal. The method, evaluated and validated with an IDEXX Screen Machine, shows high specificity with regard to compounds expected to be found in the presence of tylosin, and results correlate well with traditional turbidimetric assay results. Hydrolysis of TUA (tylosin-urea ad-duct), necessary with microbiological methods, and cleanup of extracts beyond filtration are unnecessary with the PCFIA for tylosin.
Alternative Sieving Method for Extraction of Light Filth from Cheeses: Collaborative Study
Authors: Nakashima Marvin J 
Published: February 2020

Abstract
A collaborative study was conducted on an alternative sieving method for the extraction of light filth from cheeses. The alternative method was developed that is applicable to broad variety of cheeses. A 225 g test portion is dispersed in a solution of 5.7% HCI, Igepal CO-730, and Igepal DM-710. Digested cheese is wet-sieved on a No. 230 sieve. The residue is treated with Tergitol Anionic 4, transferred to 1% sodium lauryl sulfate solution, heated, and maintained at 65°-75°C for 10 min. The residue is washed with these 2 surfactants a maximum of 4 times until it is reduced to an amount that is filterable. The residue is filtered and the filter papers are examined microscopically at a magnification of ca 30×. Average recoveries by 9 collaborators for 3 spike levels of rat hairs (5,10, and 15) were 80, 68, and 81%, respectively; for insect fragments (5,15, and 30) recoveries were 97, 90, and 92%, respectively. The alternative sieving method for extraction of light filth from cheeses has been adopted first action by AOAC INTERNATIONAL.
Effect of Infrared Analyzer Homogenization Efficiency on Repeatability of Uncorrected Fat A and Fat B Signals
Authors: Smith Erika B , Barbano David M , Lynch Joanna M , Fleming J Richard 
Published: February 2020

Abstract
Poor repeatability by infrared milk analyzers may be caused by inefficient homogenization as a result of light scattering and the Christiansen effect. The objectives of this study were to identify instruments with good and poor homogenization efficiency and to determine if a difference exists in repeatability performance between instruments with good vs poor homogenization efficiency. Unhomo-genized and homogenized portions of the same milk were tested 20 times consecutively on 22 instruments. An instrument was considered to have poor homogenization efficiency if the mean difference in the uncorrected signal between unhomo-genized and homogenized portions of the same milk was ≥1.43% of the fat test (i.e., ≥0.05% at 3.5% fat). Instruments were evaluated for repeatability by calculating the sample standard deviation and the range of the latter 19 uncorrected readings for un-homogenized and homogenized milks. When repeatability was evaluated as a function of homogenization efficiency, there was a significant (p = 0.001) correlation between poor homogenization efficiency and poor repeatability when testing unho-mogenized milk but not when testing homogenized milk. Improved homogenizer performance within infrared milk analyzers is needed to improve the repeatability of raw milk testing.
Determination of Phthalates in Water and Soil by Tandem Mass Spectrometry Under Chemical Ionization Conditions with Isobutane as Reagent Gas
Authors: Brumley William C , Shafter Elizabeth M , Tillander Paul E 
Published: February 2020

Abstract
Eleven phthalate esters spiked in water and soil were determined by tandem mass spectrometry (MS) under positive chemical ionization mass spectrometry (CIMS) conditions with isobutane as reagent gas. Emphasis was placed on the determination step because tandem MS and CIMS are not widely adopted in current methods of the U.S. Environmental Protection Agency. Extraction by sonica-tion and cleanup by use of a solid-phase extraction cartridge were adopted. The relative response factors gave relative standard deviations (RSDs) of 12-30% when 2 unlabeled internal standards were used. The relative abundances of monitored ions gave relative abundance deviations of less than ± 8%. The method confirms identity, including molecular weight, and quantitates with high specificity. Results obtained with 2 unlabeled internal standards were compared with results obtained with a stable-isotope-labeled internal standard for dioctyl phthalate.
A Rapid Multiresidue Screen for Organophosphorus, Organochlorine, and N-Methyl Carbamate Insecticides in Plant and Animal Tissues
Authors: Holstege Dirk M , Scharberg David L , Tor Elizabeth R , Hart Laura C , Galey Francis D 
Published: February 2020

Abstract
A multiresidue screen for the quantitative determination of 43 organ op hosphorus, 17 orga no-chlorine, and 11 N-methyl carbamate insecticides in 10 g of plant or animal tissues is described. The insecticides are extracted with 5% ethanol in ethyl acetate (v/v). Samples with high lipid content are cleaned up by automated gel permeation chromatography with a 30% ethyl acetate in hexane (v/v) eluant and in-line silica gel minicolumns. Highly pigmented samples are cleaned up with class-specific solid-phase extraction columns. The concentrated extracts are analyzed by selective detection with gas chromatography or liquid chromatography. Recovery of 71 insecticides ranged from 77 to 113%. Analysis of fortified bovine liver (n = 5) resulted in an average recovery of 96 ± 4% at the 0.5 to 0.05 μg/g level. Analysis of fortified alfalfa hay (n = 5) resulted in a mean recovery of 94 ± 4% at the 0.06 to 0.5 μg/g level, and analysis of fortified fresh tomatoes (n = 5) resulted in an average recovery of 97 ± 3% at the 0.06 to 0.5 μg/g level. Method detection limits ranged from 0.02 to 0.5 μg/g for the compounds studied with a nominal 10 g sample.
Determination of Ethyl Carbamate in Alcoholic Beverages and Soy Sauce by Gas Chromatography with Mass Selective Detection: Collaborative Study
Authors: Canas Benjamin J , Joe Frank L , Diachenko Gregory W , Burns Gordon 
Published: February 2020

Abstract
A method using gas chromatography with mass selective detection for the determination of ethyl carbamate (EC; also known as urethane) in alcoholic beverages and soy sauce was collaboratively studied by 17 laboratories including authors’ laboratories. The method uses prepacked columns for extraction of liquids with methylene chloride, and n-propyl carbamate as the internal standard. A practice sample and 6 samples of distilled spirits, fortified wines, table wines, and soy sauces were analyzed by each collaborator. Each matrix included blind duplicates of incurred and fortified EC at 3 levels. Distilled spirits contained 50–330 ng EC/g (ppb), fortified wine 40–160 ppb, table wine 10–50 ppb, and soy sauce 15–70 ppb. The ranges of the repeatability relative standard deviations, excluding outliers, were 4.03–6.63% for distilled spirits, 4.01–5.05% for fortified wine, 3.94–6.73% for table wine, and 4.70–8.49% for soy sauce. The ranges of the reproducibility relative standard deviations, excluding outliers, were 8.53–9.49% for distilled spirits, 6.84–12.02% for fortified wine, 8.86–18.47% for table wine, and 13.87–27.37% for soy sauce. Recoveries of added EC ranged from 87 to 93%. Recoveries relative to reference values, labeled as the internal standard, obtained by using gas chromatography/ tandem mass spectrometry with a triple quadrupole mass spectrometer ranged from 89 to 100%.
Fractionation of Salad Dressings for Fatty Acid Profile and Soluble Sugar Determination Using the Ultracentrifuge
Authors: Patel Anasuya S 
Published: February 2020

Abstract
An analytical method was developed for fractionating small samples of salad dressing for fatty acid profiles and soluble sugar content by using an ultracentrifuge. The extracted oils were characterized and compared with those obtained by the official AOAC ether extraction procedure. Both methods gave similar results for fatty acid profiles and oil recoveries. The fatty acid profiles were determined by gas chromatography. In addition, the sugar content of the aqueous layer of the centrifuged samples could easily be obtained by refractometry. The proposed method is time and labor efficient and eliminates the use of hazardous and flammable ether.
Gas Chromatographic/Mass Spectrometric Confirmation of Ten N-Methylcarbamate Insecticides in Liver
Authors: Bakowski Ralph S , Ali M Sher , White Jerry D , Phillippo Evan T , Ellis Richard L 
Published: February 2020

Abstract
A gas chromatographic/mass spectrometric (GC/MS) confirmation procedure for 10 phenyl-N-methyl-carbamate insecticides in liver tissue was developed. The extract from liquid chromatography (LC) is purified with a C18 solid-phase extraction cartridge and then derivatized with heptafluorobutyric anhydride; the derivative is injected for analysis by GC/MS with electron ionization and multiple ion monitoring. The identity of the derivative is confirmed by comparison of its retention time and relative intensity data with those of a standard. Liver extracts from the LC procedure containing carbamates at 10 ppb levels were successfully confirmed by this procedure.
Evaluation of Two Field Screening Test Kits for the Detection of PCBs in Soil by Immunoassay
Authors: Waters Larry C , Smith Rob R , Stewart Joe H , Jenkins Roger A , Counts Richard W 
Published: February 2020

Abstract
Effective field screening methods could minimize the time and reduce the cost of characterizing and remediating hazardous waste sites. Rigorous evaluation of novel field screening methods is required before they can be considered as replacements for, or adjuncts to, currently used laboratory methods. Alternatives to standard laboratory analytical methods should be rapid, analyte-specific, cost-effective, accurate, and sensitive in the range at which the analyte is regulated. In this study, 2 immunoassay- based field test kits for polychlorinated biphenyls (PCBs) in soil were evaluated with reference to those criteria. PCBs were analyzed in both spiked and field soil samples. Based on laboratory performance, we estimate that 20 to 40 samples can be analyzed in the field per day. Sensitivity of the assay is in the 1 ppm range. Because the assay is based on the specificity of the antigen/antibody reaction, interferences are practically negligible. The method is accurate; the false-negative and false-positive results that were observed can be explained by differences in the immunoreactivities of the Aroclors present in the test samples and the Aroclors used as standards in the assay. The savings in time and expense to analyze PCBs in soil with the immunoassay-based test kits over conventional laboratory methods should be substantial.
Determination of Ardacin in Various Silage Feed Diets by a Rapid Liquid Chromatographic Assay
Authors: Fagan Sylvia V B , Gombatz Connie , Abdel-Kader Hafez , Menon Govind 
Published: February 2020

Abstract
A method is presented for the detection and quantitation of Ardacin in silage feed diets by liquid chromatography, using a cyano column and an acetonitrile–methanol water mobile phase modified with trifluoroacetic acid. This method includes comprehensive procedures for extracting Ardacin from various silage feed formulations, cleaning up the extracted sample by using solid-phase extractions, and analyzing the eluted solid-phase extract with a suitable liquid chromatographic system. Ardacin was extracted from the silage feed formulations with 50% acetonitrile and 50% 0.1 M KOH. The extract was cleaned up with a wide-pore butyl solidphase extraction cartridge. The sample extract was chromatographed and quantified at 220 nm, using an external method of calculation. Recoveries of the medicated silage feed formulation ranged from 72.1 ± 1.7% to 109.1 ± 2.4%, depending on the sites and types of formulation analyzed.
Rapid Supercritical Carbon Dioxide Extraction Method for Determination of Polychlorinated Biphenyls in Fish
Authors: Lee Hesg-Biu , Peart Thomas E , Niimi Arthur J , Knipe Charles R 
Published: February 2020

Abstract
An efficient and environmentally friendly supercritical fluid extraction (SFE) method for the determination of naturally contaminated polychlorinated biphenyls (PCBs) in fish tissues is described. The effect of various SFE conditions on lipid content and PCB recovery in fish extracts was studied. Optimal conditions for PCB extraction were nonmodified carbon dioxide at 100°C, pressure of 5000 psi, and flow rate of 2.5 mL/min. Recoveries of PCBs were ≥95% for both naturally contaminated and spiked fish, and this extraction procedure required less than 40 min per sample. By incorporating activated basic alumina with the sample in the extraction process, fish lipid was selectively retained by the adsorbent. The lipid content in the SFE extract varied from &lt;0.1% to 2.2% for the fish samples tested, including those samples with over 30% lipid by weight. In most cases, the remaining lipid was conveniently removed from PCBs by a down-sized Florisil column cleanup. The commonly found chlorinated insecticides, hexachlorobenzene, p,p′-DDE, and mirex were also extracted and determined simultaneously with PCBs.
Evaluation of Prechromatographic Oxidation for Liquid Chromatographic Determination of Paralytic Shellfish Poisons in Shellfish
Authors: Lawrence James F , Ménard Cathie , Cleroux Chantal 
Published: February 2020

Abstract
A liquid chromatographic (LC) method employing prechromatographic oxidation for the determination of paralytic shellfish poison (PSP) toxins was evaluated. A number of changes to an earlier method resulted in improved separation and quantitation of most PSP analogues. Modification of the periodate oxidation reaction for the h-hydroxy-containing toxins led to improved sensitivity and stability of the products, enabling automated overnight analyses. These changes also enabled quantitation of gonyautoxins 1 and 4 (together) in the presence of gonyautoxins 2 and 3. Decarbamoylsaxitoxin can be identified and quantitated after peroxide oxidation. A cleanup step using a strong-anion-exchange column removed the C toxins and B-2 from the extracts and enabled a more accurate quantitation of gonyautoxins 1 and 4 and neosaxitoxin. Chiral chromatography, employing a reversed-phase column and chiral mobile-phase additives (copper-proline complex), was briefly evaluated for the separation of the oxidation products of the isomer pairs, gonyautoxins 1 and 4 and gonyautoxins 2 and 3. A comparison of the method with the mouse bioassay for the determination of PSP in lobster hepatopancreas (58 samples) showed a reasonable correlation (0.90) over a concentration range of 40–500 (μg/100 g (saxitoxin equivalents), although the LC results were consistently higher than the mouse bioassay values by about 40%.
Detection of Marine Toxins Using Reconstituted Sodium Channels
Authors: Trainer Vera L , Baden Daniel G , Catterall William A 
Published: February 2020

Abstract
Specific binding of the marine toxins saxitoxin, tetrodotoxin, and brevetoxin to the rat brain sodium channel is demonstrated using purified sodium channels reconstituted into phospholipid vesicles. Restoration of sodium channel function and binding activity by incorporation into phospholipid vesicles provides the only rigorous proof that the purified protein contains the neurotoxin receptor sites. In addition, reconstitution provides a valuable experimental preparation for biochemical analysis of neurotoxin binding sites and may facilitate the development of a specific toxin detection system.