bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Two Immunochemical Methods with Thin-Layer Chromatographic Methods for Determination of Aflatoxins
Authors: Trucksess Mary W , Young Kathryn , Donahue1 Kevin F , Morris Deborah K , Lewis Ernie 
Published: February 2020

Abstract
Three different methods were compared for the determination of total flatoxins in corn and peanuts naturally contaminated with aflatoxins and In corn, peanuts, cottonseed, peanut butter, and poultry feed spiked with aflatoxins Bi, B2, and d . The 3 methods were an enzyme-linked Immunosorbent assay (ELISA) screening test; a monoclonal antibody-affinity column-solld-phase separation method; and the AOAC official thin-layer chromatography (TLC) methods for all except poultry feed, for which Shannon's TLC method for mixed feed was used. The ELISA test is designed to provide only positive results for total aflatoxins at &gt;20 ng/g or negative results at &lt;20 ng/g. The affinity column separation Is coupled with either brominatlon solution fluorometry to estimate total aflatoxins or liquid chromatography (LC) to quantltate Individual aflatoxins. Fluorodensitometry was used to determine aflatoxins In commodities analyzed by the TLC methods. The LC and TLC results were In good agreement for all the analyses. The results for the affinity column using brominatlon solution fluorometry were similar except those for cottonseed, which were about 60% higher. The ELISA screening method correctly Identified naturally contaminated corn and peanut positive samples. No false positives were found for controls. The correct response for spiked corn, raw peanuts, peanut butter, and cottonseed at &gt;20 ng aflatoxlns/g was about 90%. The correct response for spiked poultry feed at &gt;20 ng aflatoxlns/ g was about 50%.
Solid-Phase Extraction of Carbofuran, Atrazine, Simazine, Alachlor, and Cyanazine from Shallow Well Water
Authors: Nash Ralph G 
Published: February 2020

Abstract
Extraction of several nitrogen-containing pesticides from water on solid-phase C18 cartridges was rapid and accurate. One analyst can extract &gt;48 samples/day. Recovery efficiencies were 77, 95, 92, 90, and 99% with detection limits of 0.20, 0.05, 0.05, 0.20, and 0.10 /μg/L for carbofuran, atrazine, simazine, alachlor, and, cyanazine, respectively. Extraction of the atrazine and simazine dealkylation products (deethylatrazlne and deethylsimazine) was less efficient, e.g., 26 and 9%, respectively. Comparisons with 10 U.S. Geological Survey samples gave similar results
Sensitive Streptavidin-Biotin Enzyme-Linked Immunosorbent Assay for Rapid Screening of Chloramphenicol Residues in Swine Muscle Tissue
Authors: Water Cornelis Van De , Haagsma Nel 
Published: February 2020

Abstract
A sensitive, competitive enzyme-linked Immunosorbent assay (ELISA) for chloramphenicol (CAP) in swine muscle tissue has been developed. The ELISA Is based on an earlier procedure. To Improve sensitivity, different optimization procedures were Investigated. The introduction of a streptavldln- biotln system and the use of a coating antigen with a lower CAP Incorporation resulted In the most sensitive ELISA: the CAP concentration giving 50% Inhibition decreased from 125 ng/mL to 3.0 ng/mL. This ELISA procedure was applied for a rapid screening of CAP residues In swine muscle tissue. The tissues were extracted with demlneral- Ized water. A concentrated phosphate-buffered saline solution was added to the filtered aqueous extract and this sample solution was directly submitted to the ELISA procedure. The results were compared to values obtained by analysis of a corresponding blank. This blank was prepared by treating a part of the aqueous sample solution with an immobilized monoclonal antibody preparation. This treatment was necessary because aqueous extracts of different swine muscle tissues showed a high variation In dose-response curves, probably caused by the complexity and variability of the matrix. In spiked tissues, the presence of CAP at concentrations of 10 μg/kg and higher can be easily demonstrated.
Study of Carbendazin Residue Accumulation on Greenhouse and Field-Grown Strawberries, after Successive Treatments with Benomyl
Authors: Mònico-Pifarré A , Xirau-Vayreda M 
Published: February 2020

Abstract
Benomyl, a systemic fungicide used In preharvest treatments to prevent Botrytls and other fungal diseases, metabolizes to carbendazlm (MBC). A study was undertaken to determine if the total residues of MBC of greenhouse and field-grown Douglas strawberries accumulate In fruits after successive fortnightly treatments with a commercial preparation of benomyl. Statistical analysis of the data obtained Indicates that residues of MBC do not accumulate In fruits; on the contrary, they decrease over time.
Determination of Nitrite in Cured Meats by Ion-Exclusion Chromatography with Electrochemical Detection
Authors: Kim Hie-Joon , Conca Karen R 
Published: February 2020

Abstract
A rapid liquid chromatographic (LC) method was developed for a sensitive determination of nitrite In cured meats, using ion-exclusion chromatographic separation and electrochemical detection (IEC-EC). The current AOAC colorimetric method requires 2 h shaking In a steam bath to eliminate Interference from reducing compounds such as ascorbic acid. In the present method, nitrite was analyzed In the presence of ascorbic acid without interference, and the extraction time was reduced to 1 mln. The extracted nitrite was determined by ion chromatography using anion-excluslon/ HS column and amperometric detector equipped with platinum or glassy carbon electrode operating at +1.0 V vs Ag/ AgCI reference electrode. The detection limit was 1 ppb as NO-2. The recoveries of 50 ppm nitrite added to frankfurter and meat stick were 103 and 99.6%, respectively, with relative standard deviations less than 4%. The high speed, sensitivity, and selectivity make the new method a useful alternative to the AOAC colorimetric method.
Integration of Enzyme-Linked Immunosorbent Assay with Conventional Chromatographic Procedures for Quantitation of Aflatoxin in Individual Cotton Bolls, Seeds, and Seed Sections
Authors: Lee Louise S , Wall James H , Cotty Peter J , Bayman Paul 
Published: February 2020

Abstract
Integration of an enzyme-linked Immunosorbent assay (ELISA) with conventional chromatographic methods proved the versatility of ELISA as a research tool and allowed for rapid assessment of aflatoxin In Individual cottonseeds, parts of cottonseed, and composite samples of seeds taken from Individual cotton bolls. Aqueous acetone was substituted for methanol In the extraction procedure prescribed by ELISA. The substitution allowed the use of a common extract for all analytical methods. An aliquot of the extract was used to screen samples by ELISA. Negative samples were Identified, and toxin levels between 1 and 70 ng/g were quantltated by ELISA. Samples with toxin levels beyond the upper limit of detection by ELISA were then subjected to more time-consuming conventional cleanup prior to quantitation by liquid chromatography (LC) or thin-layer chromatography (TLC). Toxin levels detected by LC or TLC ranged from 100 to 845 000 ng/g sample. The screen by ELISA detected large numbers of toxin-negative cotton bolls or Individual seeds in minimum analysis time. The combination of techniques verified the presence of seed with no toxin adjacent to toxincontaining seed In the same lock. Toxin-negative portions of Individual seed with high toxin In another portion were Identified for the first time. Integration of techniques provided needed Information on distribution patterns of aflatoxin In cotton so that preventive measures can be developed.
Establishment of Standard Reference Material Purity by Using 31P FT-NMR Comparison to Surrogate Material
Authors: Slahck Stephen C 
Published: February 2020

Abstract
Chromatography, thermal methods, and other associated physical determinations have been applied to the assignment of purities to standard reference materials. Each of these techniques has limitations, and each generally requires a primary standard of known purity. The establishment of purities on organophosphorus compounds can easily be performed without the availability of a typical primary standard by using proton decoupled 31P FT-NMR comparison to surrogate materials of known purity. A proposed analytical standard reference material of oxydemeton-methyl was evaluated using a 7.3 Tesla FT-NMR (300 MHz proton) using inverse-gated WALTZ decoupling. The resulting phosphorus singlet was compared with that of trlmethyl phosphate. This technique for purity assignment was confirmed by 2 additional experiments: (1) comparison of an established standard and a blind sample of demeton-S-methyl (Metasystox-I®) , with trlmethyl phosphate and (2) comparison of an established standard of disulfoton (Dl-Syston®) vs 0,0,0-trimethyl phosphorothloate.
Improved Hydrophobic Grid Membrane Filter Method, Using EF-18 Agar, for Detection of Salmonella in Foods: Collaborative Study
Authors: Entis Phyllis 
Published: February 2020

Abstract
A collaborative study was carried out in 30 laboratories to validate Improvements to the official final action hydrophobic grid membrane filter (HGMF) screening method for Salmonella in foods, 985.42, by comparing the performance of the improved HGMF method against that of the AOAC/BAM conventional culture method. Six products were Included In the collaborative study: milk chocolate, raw deboned poultry meat, black pepper, soy flour, egg yolk powder, and nonfat dry milk. The raw deboned poultry meat was naturally contaminated with Salmonella, and the remaining 5 products were each Inoculated In advance with low levels of Individual Salmonella serotypes. The AOAC/BAM method produced 11 false negative results and the Improved HGMF method produced 18 false negative results. The improved HGMF Salmonella method has been approved Interim official first action for all foods to replace the HGMF official final action method, 985.42.
Artifact Formation During Smoke Trapping: An Improved Method for Determination of iV-Nitrosamines in Cigarette Smoke
Authors: Caldwell William S , Conner James M 
Published: February 2020

Abstract
Studies In our laboratory revealed artlfactual formation of Nnltrosamlnes during trapping of mainstream and sldestream tobacco smoke by the method of Hoffmann and coworkers (2, 4). Both volatile and tobacco-specific Af-nltrosamlnes were produced. This artifact formation took place on the Cambridge filter, which Is part of the collection train used In the previously published procedure. When the filter was treated with ascorbic acid before smoke collection, artifact formation was inhibited. The improved method resulting from these studies was applied to a comparative analysis of Nnltrosamlnes In smoke from cigarettes that heat, but do not burn, tobacco (the test cigarette) and several reference cigarettes. Concentrations of volatile and tobacco-specific Af-nltrosamlnes In both mainstream and sldestream smoke from the test cigarette were substantially lower than In the reference cigarettes
Liquid Chromatographic Determination of Multiple Sulfonamide Residues in Bovine Milk
Authors: Smedley Michael D , Weber John D 
Published: February 2020

Abstract
A liquid chromatographic method has been developed for simultaneous determination of residues of 10 sulfonamide drugs at 10 ppb and above In raw bovine milk. The method Is based on a chloroform-acetone extraction, evaporation of organic phase, dissolution of residues in an aqueous potassium phosphate solution, and extraction of fatty residue Into hexane. The aqueous layer is collected, filtered, Injected onto an LC system, and detected by ultraviolet absorption at 265 nm. To elute all 10 sulfonamides Isocratlcally, 2 chromatographic conditions are required. Seven sulfonamides can be quantltated with 12% methanol in the mobile phase; 4 sulfonamides can be quantltated with 30% methanol. Sulfamethazine, the most widely used sulfonamide, Is detected on both systems. Recoveries are 44-87% for Individual sulfonamides, with only 2 below 60%. Coefficients of variation are 3-13% at 10 ppb.
Turbidimetric Assay of Tylosin in Animal Feeds Containing Urea
Authors: Coleman Mark R , Mowrey Daniel H 
Published: February 2020

Abstract
A turbidimetric method Is described for determination of tylosin in animal feeds containing urea. This method Includes several modified or new steps to existing turbidimetric and AOAC plate assays that Improve the extraction of tylosin, remove interferences from feeds, free tylosin activity, concentrate tylosin from low-level feeds, and reduce variability of assay results. A larger analytical sample size has been incorporated Into the assay to decrease variability of assay results. A methanol-phosphate buffer extraction solution has replaced the hot buffer and methanol extraction solution. A hydrolysis step, which Is not contained in the AOAC plate assay, was developed to free tylosin from the tylosin urea adduct that forms over time In feeds containing urea. A disposable C18 column was used to concentrate tylosin from feeds at levels less than 15 ppm. By Increasing the analytical sample size from 25 to 100 g, the coefficient of variation for 12 weighings of cattle feed was reduced from 28.4 to 9.3%. Average recoveries from cattle rations containing tylosin at levels of 8,10, and 100 ppm were 94, 94, and 91 %, respectively.
Simultaneous Determination of Benefin and Trifluralin in Pesticide Formulations by Gas Chromatography
Authors: Fitzpatrick Timothy M , Gehrig Connie C 
Published: February 2020

Abstract
Formulations containing benefin and trifluralin are extracted In hexane and determined using direct splltless capillary gas chromatography with flame Ionization detection. Resolution of the Isomers Is approximately 0.8 for run times of 20 mln. Least-squares regression of peak areas against concentrations for the simultaneous determination of the 2 Isomers produced correlation coefficients of 0.9999 and 0.9990 for benefin and trifluralin, respectively. These compare favorably with the linearities of each Isomer Individually. Quadruplicate analyses of 4 ground fertilizer formulations produced an average relative standard deviation of 1.98%. Recoveries were erratic for granular fertilizer formulations but were 105 ± 3.6% for a liquid trifluralin formulation spiked with both trifluralin and benefin.
Determination of Sulfur Dioxide in Grapes: Comparison of the Monier-Williams Method and Two Ion Exclusion Chromatographic Methods
Authors: Kim, Hie-Joon , Conca Karen R , Richardson Michelle J 
Published: February 2020

Abstract
Results for determination of sulfur dioxide In grapes were compared by 3 methods: the modified Monier-Wllllams method, acid dlstlllatlon/lon exclusion chromatography with electrochemical detection (AD/IEC-EC), and alkali extraction/ ion exclusion chromatography with electrochemical detection (AE/IEC-EC). An unusual positive response was observed during the later stage of the Monier-Wllllams distillation of both control grapes and sulfited grapes. Development of volatile acidic compounds in parallel with this Monier- Wllllams response and darkening of sample was also observed by collection In an alkali trap and analysis using anion exclusion chromatography and photodlode array detection. No parallel Increase In sulfite was observed by the more selective AD/IEC-EC method, which clearly demonstrated that the response observed during the later stage of the Monier-Wllllams method Is a false positive, probably due to caramellzatlon reaction products. Monier-Williams results for grapes containing ca 10 ppm sulfite were In reasonably good agreement with those by either the AD/IEC-EC or AE/ IEC-EC methods, presumably because the false positive response In the Monier-Wllllams analysis compensated for the somewhat Incomplete recovery of sulfite. The AE/IECEC method Is recommended because it is rapid, sensitive, straightforward, and free from interference. Accurate results by Monier-Wllllams analysis could be obtained by limiting distillation to 60 min and correcting for recovery.
High-Volume Enzyme Immunoassay Test System For Sulfamethazine in Swine
Authors: Ram Bhanu P , Singh Prithipal , Martins Lorelei , Brock Teri , Sharkov Nikolai , Allison David 
Published: February 2020

Abstract
A high-volume enzyme immunoassay (EIA) system for slaughterhouse screening of sulfamethazine In swine plasma/ serum has been developed. The system Includes a robotic sample processor that performs most of the liquid handling requirements in the assay. The assay gives good correlation with the widely used thin layer chromatographic method for determination of sulfamethazine in serum and plasma (r = 0.826). Inter- and Intra-assay coefficients of variation are less than 10%. Approximately 2,400 serum/ plasma samples can be analyzed In a normal working day (8 h) with this system.
A Model for Statistical Evaluation of Precision Parameters of Microbiological Methods: Application to Dry Rehydratable Film Methods and IDF Reference Methods for Enumeration of Total Aerobic Mesophilic Flora and Coliforms in Raw Milk
Authors: Piton Christine , Grappin Rémy 
Published: February 2020

Abstract
A new statistical approach for collaborative study data of microbiological methods Is proposed. This Includes a confirmatory test to the Polsson distribution of the number of colonies. In addition, 2 new statistical parameters are used to express precision as a percent of the original unit: the geometric relative standard deviation (GRSD) and the critical relative difference between 2 measurements (RD95). This statistical approach was applied to an Interlaboratory study to assess and compare the precision of both dry rehydratable film (PetrlfUrn® SM and Petrifllm® VRB) methods and International Dairy Federation (IDF) reference methods [total aerobic mesophilic plate count (TAMPC) and violet red bile lactose agar (VRBL) methods] for estimation of total bacteria and collform, respectively, in raw milk. Each of the 14 laboratories In the study analyzed 40 laboratory samples (20 different materials In blind duplicates) for total bacteria and collform counts by both the Petrifllm and standard methods. Repeatability standard deviations (In log10 unit) of TAMPC, Petrifllm SM, VRBL, and Petrifllm VRB were 0.106, 0.089, 0.219, and 0.171, respectively; their reproducibility standard deviations were 0.170,0.167,0.348, and 0.199, respectively.
Direct Aqueous Injection-Liquid Chromatography with Post-Column Derivatization for Determination of N-Methylcarbamoyloximes and N-Methylcarbamates in Finished Drinking Water: Collaborative Study
Authors: Edgell Kenneth W , Biederman L Anne , Longbottom James E 
Published: February 2020

Abstract
An Interlaboratory method validation study was conducted on EPA Method 531.1, Measurement of N-Methylcarbamoyloxlmes and N-Methylcarbamates In Water by Direct Aqueous Injection HPLC with Post Column Derivatization, to determine the precision and mean recovery for determination of 10 carbamate pesticide compounds In reagent water and In finished drinking waters. The study design was based on Youden's nonreplicate plan for collaborative tests of analytical methods. The waters were spiked with 10 carbamate pesticides at 6 concentration levels, as 3 Youden pairs. Eight laboratories analyzed the samples by direct aqueous injection, with separation by reverse-phase liquid chromatography and post-column hydrolysis of the carbamates and carbamoyloxlmes to methylamine, followed by reaction of the methylamine with 𝑜-phthalaldehyde and 2-mercaptoethanol using fluorescence detection. Results were analyzed using an EPA computer program, which measured precision and recovery for each of the 10 compounds and compared the performance of the method between water types. The method was acceptable for all analytes tested. After removal of a nonrepresentatlve data set for aldlcarb sulfoxide, no matrix effects were observed; the statistics for the pooled drinking waters were not significantly different from the statistics for the reagent waters. The method has been adopted official first action by AOAC.
Conductometric and Colorimetric Determination of Volatile Acidity of Vinegars by Flow-Injection Analysis
Authors: Tubino Matthieu , Barros Flavio G 
Published: February 2020

Abstract
Recent methods for determination of the volatile acidity of vinegars are relatively slow (about 40 mln) and involve techniques subject to a variety of errors (ca 2.5%). The present paper describes a method that provides results in a shorter time (ca 2 mln, Including dilution), with a smaller relative error rate (ca 1%). Conductometric analysis consists of the Injection of the sample In a deionlzed water stream that then flows past a PTFE membrane separator. Acetic acid diffuses through the membrane to another deionlzed water stream that passes through a conductivity cell. Colorimetric analysis also consists of sample injection into a deionlzed water stream that passes through the same PTFE membrane separator. However, the acetic acid diffuses into a bromocresol purple solution stream at pH 7. This solution passes through a flow cell In a spectrophotometer set at 540 nm. Before injection, samples were treated with hydrogen peroxide to ensure complete oxidation of sulfite to sulfate. Results of the proposed method were also compared with another similar method. At a 95% confidence level, the statistical t-test Indicates no significant difference between them. Typical estimates of the relative standard deviations obtained with the new methods are ca 1%. Analyses were performed with red and white wine vinegars.
Determination of Total Dietary Fiber in Japanese Foods
Authors: Nishimune Takahiro , Sumimoto Tatsuo , Yakusiji Tsumoru , Kunita Nobuharu , Ichikawa Tomio , Doguchi Masao , Nakahara Sumio 
Published: February 2020

Abstract
Total dietary fiber was determined In Japanese foods by the Prosky-AOAC method. To accomplish the analyses of unsuitable samples, we Introduced a few minor modifications to the versions for (I) seaweed and fruits, (II) cereals, and (ill) fish and meats. These modified methods were used together with the standard method to obtain results with reasonably good relative standard deviation for 231 foods and 21 groups of mixed foods. In this study, dietary fiber was defined so as not to exclude the nondlgestlble polysaccharide portions of animal foods. A method was proposed which could estimate more accurately the fiber components of animal foods by measuring the "nondlgestlble protein" of the fiber sample by the Biuret colorimetric method, Instead of the Kjeldahl method, to avoid deducting the values for aminopolysaccharides. In Japanese diets, the amount of fiber obtained from animal foods was less than 5 % of the total Intake of dietary fiber.
Liquid Chromatographic Determination of Chloramphenicol in Calf Tissues: Studies of Stability in Muscle, Kidney, and Liver
Authors: Sanders Pascal , Guillot Philippe , Dagorn Michele , Delmas Jean Michel 
Published: February 2020

Abstract
A liquid chromatographic method has been developed for the measurement of chloramphenicol (CAP) in muscle, liver, and kidney. The mean recovery levels were 82.6, 75.3, and 79.2% in muscle, liver, and kidney, respectively. The method was repeatable and reproducible for CAP measurement in muscle, with a detection limit of 1 μg/kg. Investigation of CAP stability in muscle, liver, and kidney showed that CAP stability in muscle was good at -20°C; for spiked liver and kidney, degradation of CAP was observed, and the use of piperonyl butoxlde (PB) for metabolism Inhibition was recommended for recovery and linearity studies. However, PB was unnecessary for preservation of treated animal tissues if samples were cut into cubes and cooled at —20°C, Just after slaughter, pending analysis. With these limitations, CAP can be measured in liver and kidney.