bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid Chromatographic Assay of Dimetridazole, Ipronidazole, and Ronidazole in Feeds and Premixes
Authors: Tollomelli B , Laffi R , Rossato S , Colpo G 
Published: February 2020

Abstract
A rapid method has been developed for the determination of dimetridazole (DMZ), ipronidazole (IPZ), and ronidazole (RNZ) in turkey feeds, swine feeds, and premix. The compounds are extracted from samples with warm methanol, the extract is purified over a short alumina column, and an aliquot of the eluate is analyzed by reversed-phase liquid chromatography and UV detection at 309 nm. Alumina cleanup of premixes is not essential, although the resulting chromatograms are cleaner. Recoveries of DMZ from feed formulations ranged from 97 to 103% at the 10.0,50.0, and 100.0 ppm levels, with a standard deviation (SD) of 0.62-3.2%. Recoveries of IPZ ranged from 94.4 to 101.2% at the 5.0,50.0, and 100.0 ppm levels (SD, 0.42-4.4%). RNZ recoveries ranged from 95 to 100.7% at the 6.0,60.0, and 120.0 ppm levels (SD, 1.2-5.33%).
Determination of Total Aflatoxin Levels in Peanut Butter by Enzyme-Linked Immunosorbent Assay: Collaborative Study
Authors: Patey Alan L , Sharman Matthew , Gilbert John 
Published: February 2020

Abstract
Laboratories in Australia, Japan, Spain, the United Kingdom, and the United States participated in a collaborative study to evaluate a commercial enzyme- linked immunosorbent assay for the determination of total aflatoxin. Collaborators were sent 10 randomly numbered samples (5 blind duplicates) of roasted peanut butter. Two pairs were "blank" peanut butters to which aflatoxin B1, B2, G1, and G2 standards had been added. The other 3 pairs of peanut butters were 1 low aflatoxin level sample and 2 naturally contaminated samples. The assay is based on indirect competition. Test samples containing (free) aflatoxin, added to aflatoxin-coated microwells, compete for specific monoclonal rat anti-aflatoxin. As the concentration of aflatoxin in the test samples increases, the amount of rat antiaflatoxin binding to the aflatoxin attached to the well decreases. After a wash step to remove unbound material, the amount of rat anti-aflatoxin bound to the well is determined by its reaction with peroxidase conjugated rabbit anti-rat globulin. Bound peroxidase activity is then determined by the addition of a substrate, whose color development is inversely proportional to the aflatoxin concentration and is measured by absorbance. Coefficients of variation (CV) for total aflatoxin concentrations, for mean levels of 9,30, and 89µg/kg, were between 28 and 37% for the low level and 2 naturally contaminated samples, which contained mainly aflatoxin B1. CVs for the spiked samples were lower (24-25%) for mean levels of 11 and 20 µg/kg; recoveries were 84 and 89%, respectively. Ranges for relative standard deviations for repeatabilty and reproducibility were 9-30% and 25-37%, respectively. The method has been adopted first action by AOAC International.
Stable Carbon Isotope Ratio Method For Detection Of Corn-Derived Acetic Acid In Apple Cider Vinegar: Collaborative Study
Authors: Krueger Dana A 
Published: February 2020

Abstract
The stable carbon isotope ratio analysis method for determining the presence of corn-derived acetic acid in cider vinegar has been collaboratively studied. The method is based upon natural differences in the 13C /12C ratio; pure cider vinegars yield δ13C results near -25 %o, while corn vinegar yields results near -10 %o. Samples are combusted at 500 C in sealed glass tubes over CuO. The purified CO2 is analyzed by isotope ratio mass spectrometry relative to the Pee Dee belemnite limestone (PDB) standard. The precision of this method was observed to be similar to that of other isotope ratio methods that have been collaboratively studied: SR ranged from 0.6 to 1.2, while sr ranged from 0.1 to 1.1. The results indicate that as little as 10% added corn vinegar may be detected in cider vinegar. On the basis of published data of the natural variability of cider vinegar 13C /12C ratios, it is recommended that samples yielding results more positive than -22.0 %o be classified as not pure cider vinegar using this method. This method has been adopted first action by AOAC International.
Liquid Chromatographic Determination of Sucralfate in Dental Cream
Authors: Gargiullo Robert J 
Published: February 2020

Abstract
A simple, rapid liquid chromatographic method is described for quantitative determination of sucralfate in dental cream. Analyses were performed on a weak anion exchange column with 0.6M ammonium sulfate-0.005M tetrabutylammonium hydrogen sulfate as the mobile phase and refractive index detection. The method was linear over a range of 0.0 to 20.0% sucralfate in dental cream. The coefficient of variation was 3.2%. Standard recoveries were concentration dependent and ranged from 97.2 to 104.9%.
Pesticide Residue Survey of Produce from 1989 to 1991
Authors: Schattenberg Herbert J , Hsu Jong-Pyng 
Published: February 2020

Abstract
A pesticide residue screening program for 111 pesticides was performed on 6970 produce samples. Of the 81 varieties of samples, 2.4% contained illegal levels of pesticide residues (that is, higher than U.S. Environmental Protection Agency [EPA] tolerance or no tolerance specified), and 13.3% contained levels within tolerable limits established by EPA. Pesticide results are presented both by commodity and category type. The nature of violative residues is discussed.
Determination of Total Mercury in Seafood and Other
Protein-Rich Products
Authors: Landi Silvio , Fagioli Francesco , Locatelli Clinio 
Published: February 2020

Abstract
A previously developed wet-digestion method for the determination of total mercury in plants by cold vapor atomic absorption spectroscopy (CVAAS) was extended to the analysis of seafood and other products rich in proteins. Oxidation of matrixes is accomplished by K2Cr2O7 in the presence of diluted H2SO4; a simple air condenser is used to reflux vapors released from the boiling mixture. The original procedure (A) and 2 modifications (B and C), which differ with respect to the mode of acidification and/or digestion time and the types of condensers used, were compared for precision and accuracy by means of National Institute of Standards and Technology Research Material 50 Albacore Tuna and proved to be reliable (Hg present, 0.95 ± 0.1 μg/g; Hg found, 0.97 ± 0.029 μg/g [A], 0.98 ± 0.018 μg/g [B], and 0.94 ± 0.025 μg/g [C]). The modified procedures were tested further in Hg recovery experiments on a variety of biological matrixes with different spiking substances and again showed good analytical characteristics (overall average recoveries = 98 ± 5.1 % for seafood and 100 ± 3.6% for protein-rich baby foods)
Interlaboratory Study on the Analysis of Chlorobiphenyl
Congeners
Authors: De Boer Jacob , Duinker Jan C , Calder John A , Van Der Meer Jaap 
Published: February 2020

Abstract
An intercompanson exercise on the determination of individual chlorobiphenyls (CBs) in marine media was organized by the International Council for Exploration of the Sea, the Intergovernmental Oceanographic Commission, and the Oslo and Paris Commissions. Sixty-two laboratories from 16 countries participated in the first part of this exercise, which consisted of determining 10 CBs in a standard solution. Considerable emphasis was placed on optimization of the gas chromatographic analysis, which has led to better agreement than former intercalibration exercises on CB analysis. Standard errors of 1.10-1.12 for the reproducibility were obtained for all CBs, except CB 52 for a group of 47 laboratories. It was demonstrated that the linear range of the electron capture detector was restricted to a factor of 5 in the concentration range 15-750 pg. About half of the participants used calibration solutions with CB concentrations outside the linear range. More than half of the participants had difficulties in separating the peaks of CB 28 and CB 31. Results based on peak heights showed better reproducibility than results based on peak areas
Determination of N-Methylcarbamate Insecticides in Vegetables, Fruits, and Feeds Using Solid-Phase Extraction Cleanup in the Normal Phase
Authors: Page Michael J , French Mark 
Published: February 2020

Abstract
A liquid chromatographic (LC) method is described for the simultaneous determination of 8 carbamate pesticides in vegetable, fruit, and feed crops. Carbamates are extracted and then partitioned from vegetable, fruit, and feed crop samples using procedures previously developed. An aliquot is taken from the sample partitioning, evaporated by a nitrogen stream, and reconstituted in 5 mL 5% methylene chloride-hexane. Sample cleanup is accomplished by aspirating through an aminopropyl Bond Elut (NH2) solid-phase extraction column. Following aspiration, the sample is eluted with 10 mL 2% methanol-methylene chloride. The eluate is evaporated, again under nitrogen, and reconstituted in methanol for fluorometric LC analysis. The method provides an excellent cleanup for all matrixes studied. Initial recoveries of 98,90, and 91% were obtained for fortifications of 0.05,0.5, and 5.0 ppm, respectively. Linear range recovery studies demonstrated results that agreed with the initial recovery study. An intralaboratory study of the method was conducted in quadruplicate, using 10 assorted vegetable, fruit, and feed crops. With no exceptions, the overall average pesticide recovery for this study was 92%, with a standard deviation of 7.1 (n = 253). Carbamate recoveries varied from 80 to 105%, with coefficients of variation (CVs) that compared favorably to the intralaboratory Horwitz CV. Detection limits of less than 0.01 ppm are obtainable with the described method
Determination of Eight Organochlorine Pesticides at Low
Nanogram/Liter Concentrations in Groundwater Using Filter
Disk Extraction and Gas Chromatography
Authors: Tomkins Bruce A , Merriweather Roosevelt , Jenkins Roger A , Bayne Charles K 
Published: February 2020

Abstract
Eight organochlorine pesticides may be quantitated routinely at levels below 10 parts per trillion (ng/L) in natural groundwaters. Analytes are extracted rapidly from 1 L groundwater samples by using conditioned Teflon filter disks impregnated with silica containing bonded octadecyl phase. Filter is dried briefly under vacuum, and pesticides are eluted with 10 mL ethyl acetate. The extract is dried with about 1 g anhydrous sodium sulfate and then concentrated to exactly 1 mL. Pesticides are separated in a gas chromatograph equipped with a capillary column, detected by a high-sensitivity electron capture detector, and quantitated by the method of external standards. Certified reporting limit (CRL) values for the 8 pesticides ranged between 2 and 7 ng/L. Preliminary data demonstrated that the organochlorine pesticides could be collected on the filter disks and stored up to 4 weeks in the dark at either refrigerated or ambient temperature without obvious degradation of the sample. Calculated CRL values are comparable (within a factor of 2) to method detection limit values defined by the U.S. Environmental Protection Agency.
Gas Chromatographic/Mass Spectrometric Determination
of Oxolinic, Nalidixic, and Piromidic Acid in Fish
Authors: Takatsuki Keigo 
Published: February 2020

Abstract
A gas chromatographic/mass spectrometric (GC/MS) method using selected ion monitoring (SIM) mode has been developed for determination of oxolinic, nalidixic, and piromidic acid in fish. Drugs are extracted with ethyl acetate from a sample homogenized with phosphate buffer (pH 6.0). The extract is partitioned into 3% sodium bicarbonate solution, and the aqueous phase is re-extracted with ethyl acetate after neutralization. After evaporation, the residue is dissolved in methanol and reduced with sodium tetrahydroborate. The reaction mixture is treated with acid, extracted with ethyl acetate, and re-extracted with ethyl acetate after alkalinization. The combined ethyl acetate extract is passed through an alumina cartridge column, concentrated, and analyzed by GC/MS in SIM mode. Percent recoveries and coefficients of variation (CV%) from silver salmon fortified at the 0.1 ppm level were 92.2 (4.4) for oxolinic, 100.6 (12.8) for nalidixic, and 92.1 (3.8) for piromidic; at the 0.01 ppm level, they were 80.5 (6.2) for oxolinic, 81.5 (8.2) for nalidixic, and 69.6 (8.5) for piromidic. The detection limit is 0.003 ppm
Quantitation of Sulfamethazine in Pork Tissue by Thin-Layer Chromatography
Authors: Unruh Joseph , Schwartz Daniel P , Barford Robert A 
Published: February 2020

Abstract
Our earlier method to detect and quantitate sulfamethazine (SMZ) in milk at the 10 ppb level was modified to quantitate SMZ in pork tissue. Sulfabromomethazine (SBZ) is added to the tissue as an internal standard. SMZ and SBZ are extracted from the tissue into water as the supernatant of a centrifuged, aqueous homogenate and are cleaned up and concentrated by a series of solid-phase extractions. The sulfonamide-containing eluate is then separated on a silica gel thin-layer chromatographic plate. SBZ and SMZ are derivatized with fluorescamine, and their fluorescence is quantitated with a scanning densitometer. The limit of detection was estimated at 0.25 ppb (signal-to-noise ratio, 3:1). The average accuracy over the analysis range (0.54-21.8 ppb [μg/kg]) was 95.6% (standard deviation = 29.4%, n = 54).
Liquid Chromatographic Detection of a Variety of Inexpensive Sweeteners Added to Pure Orange Juice
Authors: Wudrich Gerald G , McSheffrey Sandra , Low Nicholas H 
Published: February 2020

Abstract
Liquid chromatography with pulsed amperometric detection was used to analyze pure orange juice adulterated with a variety of inexpensive sweeteners. This method can be used to detect low levels (5-10%) of high fructose com syrup (42 and 55), cane sugar hydrolysates (50 and 80%), and beet sugar hydrolysates (chemically or enzymatically prepared).
Spectrophotometric Determination of Boron in Dates of Some Cultivars Grown in Saudi Arabia
Authors: Al-Warthan A A , Al-Showiman S S , Al-Tamrah S A , BaOsman A A 
Published: February 2020

Abstract
The formation of a red complex between boron and the quinalizarin reagent was investigated and used as the basis for a simple and sensitive spectrophotometric method for boron in date cultivars. At 620 nm, the absorbance was linear (r= 0.999) over the 0.25-2.5 μg/mL concentration range. The molar absorptivity was found to be 2.23 x 103mol-1cm-1 and the relative standard deviation for 10 replicates (1.0 μg/mL) was 0.97%.
Rapid Determination of Listeria monocytogenes in Foods Using a Resuscitation/Selection/Kit System Detection
Authors: Martin Alain , Katz Stanley E 
Published: February 2020

Abstract
A resuscitation medium consisting of a trypticase soy broth base supplemented with 0.5% yeast extract, 0.25% sodium pyruvate, 0.01 % sodium thiogly col late, and 0.1 % chicken fat was used in the resuscitation of heat-injured and freeze-injured cells of Listeria monocytogenes. After a resuscitation period of 4-h, the medium was made selective through the addition of nalidixic acid, acriflavin, and cycloheximide. The organisms were incubated in the selectivized medium at 35°C for an additional 16 h. The numbers of resuscitated Listeria monocytogenes cells rose from 101 to 107 cells/mL in 20 h. Similar numbers of Staphylococcus aureus, Escherichia coli, and Salmonella bonn were grown together with Listeria monocytogenes; these organisms did not inhibit the growth of Listeria monocytogenes nor interfere with its detection by the Listeria-Tek kit system. The resuscitation/selection/ kit system (RSK) was compared with the methodology in the Bacteriological Analytical Manual (BAM) for the detection of Listeria monocytogenes in 22 naturally contaminated cheese samples: 8 of these were positive by the BAM system and 12 were positive by the RSK system. The 8 Listeria positives found by the BAM system were positive by the RSK system. All 12 Listeria-presumptive positive samples by the RSK system were confirmed to be Listeria monocytogenes. The use of the RSK system enhanced the recovery of the pathogen, and detection was accomplished within 24 h.
Simultaneous Determination of Linuron and Trifluralin Residues in Carrots and Their Pulp by Liquid Chromatography and Gas Chromatography
Authors: Amato Angela D' , Semeraro Isabella , Bicchi Carlo 
Published: February 2020

Abstract
A simple method is described for determining trifluralin and linuron in carrots and their pulp. Samples are extracted with hexane-ethyl ether (1+1), cleaned up with a disposable Florisil cartridge, and eluted first with hexane-ethyl ether (99 + 1) (for trifluralin), and then with hexane-ethyl ether (3 + 7) (for linuron). Trifluralin is then analyzed by electron capture gas chromatography (GC/ECD), and linuron by GC/ECD and liquid chromatography with ultraviolet detection (LC/UV). Recoveries were determined by spiking untreated carrot and carrot pulp homogenates with trifluralin and linuron at 0.04, 0.16, and 0.32 μg/g. Six determinations were performed at each level for both compounds. GC/ECD average recoveries were 87.1% for trifluralin and 93.6% for linuron in carrots and 89.9% for trifluralin and 94.2% for linuron in carrot pulp. LC/UV recoveries for linuron were 91.5% for carrots and 92.8% for carrot pulp.
Polyclonal Enzyme Immunoassay Method for Detection of Motile and Non-Motile Salmonella in Foods: Comparative Study
Authors: Feldsine Philip T , Falbo-Nelson Maria T , Hustead David L 
Published: February 2020

Abstract
A new enzyme immunoassay (EIA) method for detection of motile and non-motile Salmonella was examined in a comparative study. This method uses a proprietary formulation of polyclonal antibodies to Salmonella and is controlled to maintain specificity. Sensitivity is enhanced with an additional antibody reaction designed to minimize false-negative reactions attributable to steric interference that can occur during conjugate binding in immunoassay procedures. Twenty food types representative of a wide variety of food products were analyzed by both the EIA method and the AOAC/Bacteriological Analytical Manual (BAM) method, 967.26. Of the 1000 samples analyzed, there was a 95.6% agreement rate between the EIA method and the AOAC/BAM method. False-negative rates for the 2 methods were comparable for all foods and all Salmonella levels except ground poultry, where the EIA method detected significantly more confirmed positive samples than did the AOAC/BAM method. Twenty-seven samples were positive by EIA but negative by the culture method, and 17 samples were negative by EIA but positive by the culture method. There were no false-positive isolates detected in the comparative study.
Pararosaniline as a New Chromogen for the Extractive Spectrophotometric Determination of Trace Amounts of Hydrogen Sulfide in Air
Authors: Kumar B S M , Balasubramanian N 
Published: February 2020

Abstract
A sensitive spectrophotometric method for the determination of trace amounts of hydrogen sulfide H2S) in air, after fixing in a zinc acetate–disodium ethylenediaminetetraacetate–sodium hydroxide solution, is described. The reaction of iodate with the fixed H2S in the presence of acid and an excess of chloride leads to the formation of ICI2 ions. The resulting IC-2 species forms an ion par with pararosaniline cation, and the product is extracted into isopentyl alcohol. The color system obeys Beer’s law over the range of 0 to 5.0 μg H2S. The molar absorption coefficient of the color system is 1.8 × 104 L mol-1 cm-1 . The coefficient of variation is 3.3% for 10 determinations at 3.0 μg H2S. The effect of interfering gases on the determination is discussed. The method was applied to the determination of residual amounts of H2S present in a laboratory fume cupboard, and results were compared to those obtained by the widely used methylene blue method. The current method can be used to determine residues as low as 0.2 μg H2S.
Rapid Determination of Cholesterol in Single and Multicomponent Prepared Foods
Authors: Al-Hasani Sami M , Hlavac Jan , Carpenter Mark W 
Published: February 2020

Abstract
A rapid method has been developed for cholesterol determination in single and multicomponent foods. The method involves alcoholic KOH saponification of the samples, extraction of the nonsaponif iable fraction with hexane, and injection of concentrated extract into the gas chromatograph without derivatizations. It has been applied to a wide variety of frozen and refrigerated foods. More than 300 samples were analyzed with a coefficient of variation (CV) ranging from 0.5 to 8.6%. The average recoveries of cholesterol from spiked oil and tomato vegetable soup samples were 100 ±1.5% and 99.7 ±1.6% and the CVs were 1.5 and 1.6%, respectively. This method reduces labor by &gt;70%, eliminates dangerous chemicals, and minimizes solvent use, compared to the AOAC method and other methods cited in the manuscript. The method was used successfully on a wide variety of multicomponent foods. We recommend this method for collaborative study under the AOAC guidelines for method approval.
Extension of a Liquid Chromatographic Method for N-Methylcarbamate Pesticides in Cattle, Swine, and Poultry Liver
Authors: Sher Ali M , White Jerry D , Bakowski Ralph S , Stapleton Nancy K , Williams Kay A , Johnson Robyn C , Phillippo Evan T , Woods Robert W , Ellis Richard L 
Published: February 2020

Abstract
Liver samples of bovine, swine, and poultry were fortified with 0,5,10, and 20 ppb mixed standards of an additional 6 carbamates as part of a method extension study. Each of the 3 species in this study was analyzed 4 times at 0,5,10, and 20 ppb fortification levels. The average of 12 recoveries of 6 carbamates at all 3 fortification levels was greater than 90%, with a maximum coefficient of variation less than 18%.
Discriminating Between Adult Mandibles of Oryzaephilus surinamensis and Oryzaephilus mercator Using Setal Brush Length
Authors: Wheeler Mark M 
Published: February 2020

Abstract
The setal brush was identified as a diagnostic characteristic which can be used to distinguish between the mandibles of adult Oryzaephilus surinamensis and O. mercator. The right and left setal brushes of 50 specimens from each species were measured. Statistical analysis showed that the mean brush lengths of the 2 species were significantly different (ρ = 0.0001). A demarcation value was established to distinguish between the mandibles. By using this value it is possible to reliably classify the mandibles of O. surinamensis and O. mercator. A mandible with setal brush &gt;0.0296 mm would be classified as O. mercator, a mandible with a setal brush &lt;0.0296 mm would be classified as O. surinamensis.
Indirect Fluorometric Determination of Lactic Acid in Wine
Authors: Burini Giovanni 
Published: February 2020

Abstract
A sensitive, specific, and reliable fluorometric method for the determination of lactic acid in wine is described. After the wine sample was boiled and diluted, lactic acid was fluorometrically determined by evaluating the concentration of fluorophore derived from the reaction between acetaldehyde, a product of the oxidation of lactic acid, and 1,3-cyclohexanedione. The best oxidation conditions were a temperature of 90°C for 2 min and a Ce(SO4)2 concentration of 2 mg/mL in 0.5M H2S04. These values are not strictly critical, because the time value ranged from 1 to 2.6 min, temperature from 82 to 93.6°C, Ce(SO4)2 concentration from 1 to 2.6 mg/mL, and H2SO4 concentration from 0.125 to 0.72M; the values yielded fluorescence intensity decrements of &lt;5% relative to the optimum. Six wine samples (3 red and 3 white) as well as those spiked with 1 and 2 g lactic acid/L were analyzed. The average recoveries ranged from 98.3 to 100.1%, with the relative standard deviation ranging from 1.3 to 3.4. The results of the fluorometric analyses compared with those obtained from the known liquid chromatographic method gave good agreement. The proposed method appears to be sensitive, specific, and reliable but not advantageous for routine analysis.