bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fungal Growth and the Presence of Sterigmatocystin in Hard Cheese
Authors: Northolt Martin D , Van Egmond Hans P , Soentoro Poppie , Deijll Ellen 
Published: February 2020

Abstract
Molds isolated from visibly molded cheeses in shops, households, and warehouses have been identified. Mold flora of cheeses in shops and households consisted mainly of Penicillium verrucosutn var. cyclopium. On cheeses ripening in warehouses, Penicillium verrucosum var. cyclopium, Aspergillus versicolor, Aspergillus repens, and Penicillium verrucosum var. verrucosum were the dominant mold species. Cheeses ripening in warehouses and molded with A. versicolor were examined for sterigmatocystin. Nine of 39 cheese samples contained sterigmatocystin in the surface layer in concentrations ranging from 5 to 600 µg/kg
High Pressure Liquid Chromatographic Determination of Naphthaleneacetamide Residues in Apples
Authors: Cochrane William P , Lanouette Monique , Grant Ralph 
Published: February 2020

Abstract
A simple, rapid, and accurate method has been developed for the determination of naphthaleneacetamide (NAAmide) residues in apples. After extraction with chloroform, separation is performed on an RP-8 high pressure liquid chromatographic column using acetonitrile-water (30 + 70) buffered to pH 3.5 at a flow rate of 1.7 mi/min. Either a variable wavelength ultraviolet detector set at 220 nm or a fluorometric detector can be used for quantitation. Average recoveries at the 0.01 and 0.1 ppm spiking levels were 83 and 89%, respectively. Incorporation into a previously described method for naphthaleneacetic acid (NAA) residues in apples has resulted in a procedure for the simultaneous determination of NAA and NAAmide.
Extraction and Thin Layer Chromatographic Confirmation of Urine Residues: New Plate Development
Authors: Thrasher Joel J , Hansen Mary Ann ,   Collaborators:, Bradicich R , Kaminski J , Kodoma D , Larose J , Palmer W , Senff W 
Published: February 2020

Abstract
AOAC method 44.146–44.148 (12th ed.) yielded incomplete separation of compounds recovered from urine residues. Problems with decomposition of standard compounds, loss of sample during extraction/concentration, and development of excessive background color during plate spraying were encountered. Modifications were made to deal with these problems as follows: Allantoin standard is now stored in 90% acetone, 30 mL beakers are used instead of conical tubes during extraction, and smaller amounts of pDMAB are used during plate spraying. A collaborative study was conducted to compare sandwich chamber spot separation to larger tank separation. The study showed that total separation of all spots among all analysts was obtained with the sandwich chamber, whereas incomplete separation of spots was obtained with the tank. Also, standard deviation of spot Rr values was smaller with the sandwich chamber. The modified method has been adopted as official first action.
Membrane Filter-Deoxyribonucleic Acid Method of Somatic Cell Counting: Collaborative Study
Authors: Bremel Robert D ,   Collaborators:, Bredar T , Case R , Cathardi B , Ellis R , Kroenke D , Marable V , Meyer D , Meyer R , Miller J , Rothering T , Schwinghammer G , Smith R , Tjornehoj J 
Published: February 2020

Abstract
In the membrane filter-deoxyribonucleic acid test, somatic cells are trapped on a special filter. A chemical determination of the DNA of the trapped material gives an estimate of the number of cells. The MF-DNA was evaluated and compared with the direct microscopic somatic cell counts (DMSCCs) in 10 laboratories. Cell levels in the 10 bulk milk samples analyzed ranged from 380,000 to 1,700,000/mL. Regression analysis gave a relation of 0.181 absorbance at 490 nm, when 2.5 mL of milk was analyzed and 5.0 mL reagent was used for color development. The 95% confidence limits on the slope were 0.158-0.204. Analysis of variance showed that both procedures had significant (P&lt;0.001) systematic errors, but that only the DMSCC method showed a significant laboratory X sample interaction (P&lt;0.001). The repeatability standard deviation of the MF-DNA procedure was 117,000 cells/mL (14%), and the reproducibility standard deviation was 198,000/ mL (23%). This compared favorably with the DMSCC method which had a repeatability of I62,000/mL (19%) and a reproducibility of 287,000/mL (34%). The error of the MF-DNA was constant at all cell counts, whereas there was a tendency for the error to increase in the DMSCC method at high cell counts. This method has been adopted as official first action.
Evaluation of Methanol Extraction for Determination of Badtradn in Feeds
Authors: Ragheb Hussein S ,   Collaborators:, Black L , Brenneke D L , Harpester C , Holm N , Knotts L , Skiles C 
Published: February 2020

Abstract
Five laboratories evaluated methanol extraction for the determination of zinc and methylene disalicylate (MD) bacitracn in swine and poultry feeds at 100 g/ton and 2 premixes labeled 50 g/lb (MD bacitracin) and 40 g/lb (zinc bacitracin). Bacitracin activity was determined on each of 2 days with 2 dilutions on each day. No significant difference was found between dilutions within a day or between days for each sample. The kind of bacitracin or type of feed did not significantly affect results.
Determination of Geotrichum Mold in Cream Style Corn: Collaborative Study
Authors: Cichowicz Stanley M , Bandler Ruth ,   Collaborators:, Bandler R , Trauba R , Vassau N M 
Published: February 2020

Abstract
The official method for the determination of Geotrichum mold in canned fruits and vegetables, 44.079, is not satisfactory for use with cream style corn. The kernels are too small to be retained by the first 2 sieves, and the presence of starch interferes. The proposed method uses a smaller series of sieves (Nos. 16, 70, and 230), which enables more of the product to be separated from the mold before the No. 230 sieve, and specifies hot (45–55°C) wash water for the sieving steps to remove the starch. The method has been adopted official first action.
Gas-Liquid Chromatographic Determination of Organophosphorus Insecticide Residues in Fruits and Vegetables
Authors: Ferreira Julia R , Silva Fernandes Antonio M S 
Published: February 2020

Abstract
A method intended for regulatory purposes is described for the determination of organophosphorus insecticide residues in fruits and vegetables. Eighteen organophosphorus insecticides, azinphos-ethyl, chlorpyrifos, diazinon, dichlorvos, dimethoate, ethion, ethoate-methyl, fenitrothion, fenthion, formothion, malathion, methidathion, mevinphos, parathion, phosalone, phosphamidon, thiometon, and trichlorphon, and 7 metabolites, fenitrooxon, fenthion sulfoxide, fenthion sulfone, malaoxon, desethylphosphamidon, thiometon sulfoxide, and thiometon sulfone, were extracted from different crops with acetone and partitioned into hexane or ethyl acetate, according to their polarities. The hexane extract was cleaned up by eluting from a Florisil column with acetone-hexane (4+96). The ethyl acetate extract needs no cleanup. The concentrated extracts were analyzed by gasliquid chromatography using thermionic detectors. Recoveries conducted at fortification levels ranging from 0.1 to 2 mg/kg were in most cases above 80%. The limit of sensitivity is less than 0.1 mg/kg.
Modified Extraction Procedure for Direct Available P2O5 in Fertilizer
Authors: Sweeney Rose A 
Published: February 2020

Abstract
A modification of the direct available extraction procedure for P2O5 in fertilizer is presented. The modified extraction is used in our laboratory as a screening procedure to reduce work load associated with the lengthy official method. It is applicable to samples containing diammonium phosphate or other materials except triple superphosphate. Phosphorus is extracted from fertilizers with neutral ammonium citrate without prior removal of the water-soluble fraction. Samples are extracted by shaking 1 hr at 65°C on a water bath. The extract is cooled, diluted to volume, mixed, and an aliquot is taken for analysis. Average recovery of P2O5 from 9 selected Magruder samples by the modified extraction vs. the current official extraction was 99.5%, with a range of 98.7–99.9%. This study shows that the recovery of available P2O5 is not influenced by the level of CI P2O5 in the sample. Relative standard deviations for the modified extraction ranged from 0.20 to 0.86% with an average of 0.58%; relative standard deviation for the official extraction ranged from 0.30 to 0.89% with an average of 0.57%.
Difference Spectrophotometric Method for Estimation of Balsamic Acids in Presence of Resin Acids
Authors: Habib Abdel-Azim M , Saleh Mohamed R I 
Published: February 2020

Abstract
The acidic vs. alkaline difference spectra of cinnamic acid, benzoic acid, and total resin acids of tolu, benzoin, and colophony were studied. Characteristic maxima, minima, and isosbestic points of these spectra led to the development of a method for the quantitation of the individual balsamic acids and complete elimination of the spectral interference due to resin acids.
High Pressure Liquid Chromatographic Determination of Intermediates and Subsidiary Colors in FD&C Blue No. 2
Authors: Bailey John E 
Published: February 2020

Abstract
High pressure liquid chromatography (HPLC) is used in the reverse phase mode for the determination of intermediates and subsidiary colors in commercial samples of FD&C Blue No. 2. Isatin-5-sulfonic acid and the lower sulfonated subsidiary color are determined in one run. A second run at lower concentration is required to quantitate the isomeric subsidiary color, since it is present in large amounts and tends to saturate the detector. The calibration and recovery data are treated statistically to evaluate the performance of the method.
High Pressure Liquid Chromatographic Determination of Theobromine and Caffeine in Cocoa and Chocolate Products: Collaborative Study
Authors: kreiser Wesley R , Martin Robert A ,   Collaborators:, Bigornia R , Bond R , Cummings L J , Teja E de la , DeVries J W , Erwin R E , Heroff J C , Levi C , Maglone M , Schumacher D , Snyder K 
Published: February 2020

Abstract
Four duplicate samples of cocoa-containing materials, a practice sample, and standards were submitted to the collaborators for theobromine and caffeine analysis by HPLC. In the method the samples are defatted with petroleum ether, and dried. The fat-free residue is then extracted with water and an aliquot is injected into the chromatograph. Compounds are quantitated by comparison with internal or external standards, either by peak height or peak area. Results for all the analyses showed that few of the values were more than 2 standard deviations from the mean. The method has been adopted as official first action.
Gas Chromatographic Detection of the Mycotoxin Zearalenone in Blood Serum
Authors: Trenholm H Locksley , Warner Robert , Farnworth Edward R 
Published: February 2020

Abstract
A sensitive gas chromatographic method for the quantitative analysis of zearalenone in blood serum is described. Zearalenone is eluted from blood serum by column chromatography followed by base-acid extraction with dichloromethane as the organic phase. After epicoprostanol (internal standard) is added, the sample is evaporated to dryness, derivatized, and injected onto the gas chromatographic column. A number of silylating agents and reaction conditions were investigated. Derivatizing zearalenone with N-methyl-N-trimethylsilyltrifluoroacetamide in the presence of acetone at room temperature for at least 2 hr gave best results. Sensitivity limit is &lt;0.5 ng injected, equivalent to 100 ng zearalenone/mL blood serum. A linear standard curve is observed when 0.5–30 ng zearalenone derivative is injected onto the Perkin-Elmer gas chromatograph. For quantitation, a standard curve is prepared by plotting amounts of zearalenone (ng) injected vs. ratios for peak areas of zearalenone and epicoprostanol derivatives. The internal standard procedure improves the precision by minimizing variations in sample injections and detector response. Percent recovery from blood serum is 68–75 in the range of 1.6–8.0 Mg zearalenone/mL blood
Liquid Chromatographic Determination of Tenuazonic Acids in Tomato Paste
Authors: Scott Peter M , Kanhere Shriniwas R 
Published: February 2020

Abstract
Tenuazonic acid is a mycotoxin produced by Alternaria alternata (A. tenuis) occurring in isolates from tomato. Several liquid chromatographic (LC) systems were compared for suitability in analyzing tomato pastes for tenuazonic acid. Tenuazonic acid was extracted from tomato paste with methanol and n-hexane and was partitioned into methylene chloride from the aqueous methanol following acidification. It was further partitioned into 5% NaHCO3, acidified, and reextracted with methylene chloride. LC separation of tenuazonic acid from interferences was best on a C12- dien (4-dodecyldiethylenetriamine) loaded C18 reverse phase column with a mobile phase containing C12-dien, Zn(II), and ammonium acetate, or on a tetraalkylammonium anion exchange columnat pH 7.5. Two isomeric tenuazonic acids could be partially separated in the C12-dien/metal system using acetonitrile in the mobile phase. Amounts of standard tenuazonic acid as low as 2–5 ng could be detected by UV absorbance at 280 nm. Recoveries of tenuazonic acid or isotenuazonic acid added to tomato paste at levels of 0.4–10 μg/g were 67–94%. Small amounts of tenuazonic acid were detected in several commercial tomato pastes at levels of 0.01–0.1 μg/g. Gas liquid chromatography/ mass spectrometric (GLC/MS) single ion monitoring showed that both isomers were present.
Determination of Roquefortine in Blue Cheese and Blue Cheese Dressing by High Pressure Liquid Chromatography With Ultraviolet and Electrochemical Detectors
Authors: Ware George M , Thorpe Charles W , Pohland Albert E 
Published: February 2020

Abstract
A method is described for the determination of roquefortine in blue cheese and blue cheese dressing. The method involves sample extraction with ethyl acetate, cleanup by liquid-liquid partition, and determination by high pressure liquid chromatography with ultraviolet and electrochemical detectors connected in series. Recoveries of roquefortine added to cheese at levels of from 16 to 320 ng/g averaged 74.9%. This method was applied to the analysis of 12 samples of blue cheese and 2 samples of blue cheese dressing, all of which were produced in the United States; roquefortine was found in all of the samples at average levels of 424 ng/g for the blue cheese and 45 ng/g for the blue cheese dressing.
Kjel-Foss Automatic Analysis Using an Antimony-Based Catalyst: Collaborative Study
Authors: Bjarn0 Ole-Christian ,   Collaborators:, Fry J C , Hoffman P H , Jensen K , Kaltwasser P , Lundberg A , Nolte A , Smith C A , Waltl K 
Published: February 2020

Abstract
Collaborators in 7 Kjel-Foss laboratories and 1 manual Kjeldahl laboratory performed protein determinations on fishmeal: 10 with traditional mercury catalyst and 10 with a new antimonybased catalyst. Repeatability, interlaboratory variation, and variation vs. manual Kjeldahl were equal to or better with the new catalyst than with the mercury catalyst. In addition, 48 different products were analyzed: 5-10 determinations were made on each product with the mercury catalyst and 5–10 were made with the new catalyst. After the Kjel-Foss procedure was modified slightly with higher acid settings, the differences in recovery and repeatability of the 2 procedures were not more than ±1%.
Spectrophotometric Determination of Sulfites, Benzoates, Sorbates, Ascorbates, and Added Blood in Ground Beef: Collaborative Study
Authors: Maxstadt John J , Pollman Roger M ,   Collaborators:, Calkins H , Dolan T S , Gilger V , Highley W , Inouye P G , Mayer D , McGill D L , Nickelsen L E , Soderberg D L , Srader L M , Thompson G , Wesson A , Webb N , Ziemer W A 
Published: February 2020

Abstract
A method for the determination of sulfite, benzoate, sorbate, ascorbic acid, and added blood in ground beef reported previously was studied collaboratively. Eleven laboratories reported results on 18 samples analyzed for the preservatives plus 6 samples analyzed for added blood. Average recoveries for sulfite added at the 0.02 and 0.04% levels were 44.3 and 70.6%, respectively; average recoveries for benzoate at 0.02 and 0.05% were 83.5 and 85.9%; average recoveries for sorbate at 0.01 and 0.02% were 82.7 and 87.3%; average recoveries for ascorbic acid at 0.02 and 0.04% were 71.0 and 69.8%. Only 5 of the 11 collaborators reported accurate results on the 6 samples for added blood, and further study of this procedure is recommended. The preservative method has been adopted as official first action.
On-Column Periodate Reaction Method for Analysis of Ephedrine Sulfate in Solid Dosage Forms: Collaborative Study
Authors: Clark Charles C ,   Collaborators:, Brittan W , Hezeau C , Hughes D , Knott T , Frick F , Sanders G , Schafer P K 
Published: February 2020

Abstract
Seven laboratories collaboratively studied a method for the quantitative ultraviolet (UV) determination of ephedrine sulfate in solid dosage forms. Ephedrine is separated from water-soluble impurities and strong acids by elution from a weakly basic Celite column, and further cleaned up by retention on a weakly acidic column while the weak acids, weak bases, and organic-soluble neutrals are eluted. Ephedrine is eluted from the column after neutralization with NH3 and is converted to benzaldehyde via an on-column periodate reaction. The samples collaboratively studied consisted of 3 synthetic preparations of known ephedrine sulfate concentrations and 2 commercial preparations containing ephedrine sulfate. One commercial sample was submitted as a blind duplicate. Recoveries for the synthetic preparations averaged 101.7, 101.2, and 100.5% for mixtures containing 7.93, 9.35, and 6.85% ephedrine sulfate, respectively. The means and standard deviations for the commercial preparations were 24.72 ± 0.376 mg/dosage unit for the preparation labeled to contain 25 mg/dosage unit, and 22.46 ± 0.643 and 22.29 ± 0.339 mg/dosage unit for the blind duplicate labeled to contain 24 mg/dosage unit. The method has been adopted as official first action.
Specific Programmed Multiple Development–Thin Layer Chromatography of Furazolidone in Chicken, Turkey, Swine, and Bovine Tissues: Collaborative Study
Authors: Heotis James P , Mertz James L , Herrett Ronald J , Diaz Joseph R , Van Hart Daniel C , Olivard Joanne ,   Collaborators:, Colman W F , Hornish R E , Koster J , Lawrence W , Miller J A , Neff A W , Neuman J F , Zietlow D C 
Published: February 2020

Abstract
A specific method for assay of furazolidone at 2 ppb has been developed using programmed multiple development-thin layer chromatography (PMD-TLC) and the conversion of the drug to a fluorescent species which is quantitated by fluorodensitometry on the TLC plate. The method requires only 5 g tissue, specifies an automatic spotter for PMD-TLC, and is capable of measuring &lt;1 ng of drug when the fluorodensitometer is coupled with a computing integrator. This procedure requires an average of 2 man-hours per sample and can be completed in one day. Six laboratories collaboratively studied the method for assay of furazolidone at the 2, 3, and 6 ppb levels in chicken, turkey, swine, and bovine tissues. Tissues were fortified by each laboratory and then processed through extraction, solvent partition, programmed multiple development-thin layer chromatography, and fluorodensitometry. Results showed satisfactory recoveries and accuracy. A statistical comparison of the results demonstrated that 5 of the 6 laboratories obtained similar results. The higher responses from the sixth laboratory appeared to be due to an exceptional vacuum system and the use of silated flasks. The mean drug recovery response for the tissues spiked at 2 ppb from the 5 laboratories was 2.2324 ng ± 20.2% (SD), which at the 99.7% confidence level gives no overlap with control tissue data. The results can be expected to be repeatable within and among laboratories.
High Pressure Liquid Chromatographic Determination of Sulfamethazine or Sulfathiazole and Colorimetric Determination of Sulfathiazole in Feeds: Collaborative Studies
Authors: Cieri Ugo R ,   Collaborators:, Ameika L , Billings T , Brookhart G , Detablan N , Foster C L , Gardner A , George G M , Illuminati J C , Jeffres D , Jensen T , Lonn P D , Nandrea G , Reeves P 
Published: February 2020

Abstract
A high pressure liquid chromatographic method for sulfamethazine or sulfathiazole in feeds was studied collaboratively. The sample is extracted in 50% methanol and filtered, and an aliquot is injected into a liquid chromatograph. The column is μBondapak C18, the eluting solvent is acetonitrile–water (20+80), and the detection wavelength is 280 nm. Nine collaborators analyzed 3 different synthetic samples and 2 commercial samples labeled to contain 0.011% sulfamethazine, plus procaine penicillin and chlortetracycline. Average recoveries for the synthetic samples were 102.2% at the 0.005% level, 100.2% at the 0.01% level, and 103.6% at the 0.02% level; per cent standard deviations were 12.7, 10.4, and 8.67, respectively. Average sulfamethazine content of the 2 commercial samples was 77.8 and 82.9% of label with per cent standard deviations of 8.56 and 9.16. The same 2 samples, analyzed according to the official colorimetric procedure by 6 analysts, had an average sulfamethazine content of 81.7 and 89.4% of label with per cent standard deviations of 3.69 and 6.66. Eight collaborators analyzed 3 different synthetic samples and 2 commercial samples labeled to contain 0.011% sulfathiazole, plus procaine penicillin and chlortetracycline. Average recoveries of the synthetic samples were 101.6% at the 0.005% level, 103.0% at the 0.01% level, and 100.4% at the 0.02% level; per cent standard deviations were 9.52, 7.00, and 6.54. Average sulfathiazole content found by 9 collaborators was 0.0103% or 93.4% of label for Sample 1 and 0.0100% or 91.1% of label for Sample 2, with per cent standard deviations of 14.1 and 12.2. Colorimetric assays for sulfathiazole were made according to method 42.172–42.174 for sulfamethazine. Two synthetic samples were analyzed by 7 collaborators. Average recovery was 97.6% at the 0.01% level and 99.8% at the 0.02% level with per cent standard deviations of 5.05 and 8.16. The same 2 commercial samples used for the HPLC study were analyzed by 9 collaborators. Average sulfathiazole found was 86.4 and 87.9% of label with per cent standard deviations of 7.41 and 6.15.
Gas-Liquid Chromatographic Determination of Disulfoton in Formulations: Collaborative Study
Authors: Jensen Thomas L ,   Collaborators:, Audino J B , Bishop R , Chenery L , Conner D , Eggers R L , Ellis N D , Garret R A , Hodgins W E , Karr J J , Korger P , Topping A , Ullrich L , Wargacki R E , Willemsz-Geeroms B 
Published: February 2020

Abstract
A rapid method is described for the determination of disulfoton (0,0-diethyl S-[2-(ethylthio)-ethyl] phosphorodithioate) in formulations by gasliquid chromatography (GLC). Samples are dissolved in acetone, and, after an internal standard is added, the samples are diluted to volume with solvent. They are then injected into a gas chromatograph equipped with a flame ionization detector and quantitated by peak height or area measurements. Fourteen collaborators made duplicate determinations on 4 samples including the technical product, a liquid, and 2 granular formulations. The average coefficient of variation was 0.847% for the liquid samples and 1.90% for the granules. The method has been adopted as official first action.
Analytical Errors Resulting from Nitrate Contamination of Filter Paper
Authors: Muneta Paul 
Published: February 2020

Abstract
Certain brands and grades of filter paper can contribute significant errors up to 20–30 ppm nitrate nitrogen in the nitrate analysis of cured meats. Filter paper for qualitative filtration contained the largest quantity of nitrate. The brand of filter paper determined the nitrate extracted from the filter paper. Low ash or ashless quantitative filter paper contained no nitrate, except 1 box, from which a very small quantity of nitrate was extracted.