bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential Determination of Furfural and Hydroxymethylfurfural by Derivative Spectrophotometry
Authors: Mansilla Espinosa A , Salinas F , Nevado Berzas J J 
Published: February 2020

Abstract
Derivative spectrophotometric methods have been developed for determining furfural and hydroxymethylfurfural and for resolving their binary mixtures on the basis of the UV spectra and the Winkler reaction. The latter method permits the simultaneous determination of both compounds in orange and grapefruit juices without previous separations.
Modified Colorimetric DNA Hybridization Method and Conventional Culture Method for Detection of Salmonella in Foods: Comparison of Methods
Authors: Foster Kim , Garramone Susan , Ferraro Karen , Groody E Patrick 
Published: February 2020

Abstract
A new, improved colorimetric DNA hybridization method for detection of Salmonella in food was developed. A new modified Colorimetric GENETRAK ® Salmonella Assay (m-DNAH) is similar to the current Colorimetric GENE-TRAK Salmonella Assay (c-DNAH) except that the number of assay steps has been reduced, indicator dyes have been added to some reagents to facilitate the tracking of reagent additions, and the probe set has been modified so that subgenus V Salmonella can be detected. The new probe set detected 453/453 Salmonella strains representing at least 239 serovars and 50 somatic antigen groups, including 8 strains of subgenus V Salmonella that were not detected by the current probe set. In addition, a total of 225 nonsalmonellae representing highly homologous organisms such as Enterobacter agglomerans, Escherichia coli, and Citrobacter freundii were all nonreactive with the modified probe set. Overall, a comparison of m-DNAH to the conventional Bacteriological Analytical Manual/AOAC culture method using 240 inoculated food samples and 80 naturally contaminated raw poultry samples showed that both methods were equally effective for detecting Salmonella in food products. The method has been adopted first action by AOAC International to replace method 990.13.
Equivalency of Gas Chromatographic Conditions in Determination of Nicotine in Environmental Tobacco Smoke: Minicollaborative Study
Authors: Ogden Michael W 
Published: February 2020

Abstract
Alternative gas chromatographic (GC) conditions were collaboratively studied for equivalency with conditions specified in the official AOAC method 990.01 for nicotine in environmental tobacco smoke (ETS). Test conditions under evaluation were the use of a 30 m x 0.32 mm id fused silica capillary column with split injection as compared to the method-specified 30 m x 0.53 mm id fused silica capillary column with direct or on-column injection. The 6 samples analyzed in duplicate by 7 laboratories included 3 spiked samples (concentration ranging from 0.18 to 1.8 µ.g nicotine per sample) and 3 ETS samples (concentration in air ranging from 4 to 36 µg nicotine/cu m). Four laboratories used the AOAC approved GC conditions and 3 used the test conditions. Data analysis detected no difference in results (P= 0.72) obtained using either the 0.32 mm or 0.53 mm id column (and associated conditions). Average repeatability (RSDr) and reproducibility (RSDR) relative standard deviations for the 0.53 mm id column were 5.2 and 8.3%, respectively, for spiked nicotine samples, and 5.3 and 8.5%, respectively, for ETS samples. Average repeatability (RSDr) and reproducibility (RSDR) relative standard deviations for the 0.32 mm id column were 4.1 and 4.7%, respectively, for spiked nicotine samples, and 3.5 and 6.3%, respectively, for ETS samples. The method incorporating the use of the 0.32 mm id column and associated conditions is recommended for adoption as official first action.
Liquid Chromatographic Determination of Methylene Blue and Its Metabolites in Milk
Authors: Munns Robert K , Holland David C , Roybal José E , Meyer John G , Hurlbut Jeffrey A , Long Austin R 
Published: February 2020

Abstract
A method is described for the liquid chromatographic (LC) determination of trace levels of methylene blue (MB) and its metabolites in milk. The cleanup involves protein precipitation with acetonitrile, extraction into chloroform of MB and its metabolites (azure A [AZA], azure B [AZB], and azure C [AZC]), extraction by chloroform of thionin at pH 10, and solid-phase extraction on a disposable carboxylic acid column. LC separation and quantitation are performed with an isocratic acetonitrile-acetate buffer mobile phase on a cyano column. Average recoveries (5-20 ppb levels) of MB, AZA, AZB, and thionin from fortified milk were 83.2,60.0, 84.4, and 22.5%, respectively. Some incurred MB metabolites in milk are bound organically to a fraction of the milk substrate, whereas others are free demethylated forms of MB. Analysis of milk collected 8 h after administration of MB contained the following average levels (n = 6) of free MB and metabolites: MB, 31.0 ppb; AZA, 21.3 ppb; and AZB, 54.1 ppb. Depletion of free MB and metabolites AZA and AZB from milk after administration of MB to lactating cows occurred in less than 40 h. Metabolites of MB that formed complexes with organic compounds were hydrolyzed in part to the free forms. The leuco form of MB cou
Gas Chromatographic Methods for Doxepin Isomers, Related Compounds, and Organic Volatile Impurities in Raw Materials and Doxepin Isomers in Capsules
Authors: Cyr Terry D , Lawrence Robert C , Lovering Edward G 
Published: February 2020

Abstract
Gas chromatographic methods have been developed for the determination of doxepin as the sum of the resolved E and Z isomers, 4 doxepin-related compounds, and organic volatile impurities in drug raw material. Minimum quantifiable amounts of the related compounds in raw materials are less than 0.05%. A method for assay of doxepin, as the total of the E and Z isomers, in capsules was also developed; relative standard deviation is less than 1% for the drug assay. Eleven raw material and 18 capsule samples were examined. No drug-related compounds or U.S. Pharmacopeia- or European Pharmacopeia-limited organic volatile impurities were detected in any of the samples.
Immunoassay of Ochratoxin A, Using Antibodies Developed Against a New Ochratoxin-Albumin Conjugate
Authors: Breitholtz-Emanuelsson Anna , Dalhammar Gunnel , Hult Karl 
Published: February 2020

Abstract
A derivative of ochratoxin A was linked to bovine serum albumin in such a way that the carboxylic group of ochratoxin A was left unmodified. Lysine was substituted for phenylalanine in ochratoxin A, and the ε-amino group was linked to the protein. The conjugate was injected into 2 rabbits; antibodies against ochratoxin A were developed and used to develop an indirect competitive enzyme-linked immunosorbent assay. The detection limits for ochratoxin A in incubation buffer were 0.07 and 0.02 ng ochratoxin A/mL with the 2 antisera, respectively. Three hundred human plasma samples were purified by a novel sample preparation method and were analyzed by the immunosorbent assay. The detection limits for ochratoxin A in plasma samples were 0.2 and 0.1 ng ochratoxin A/mL with the 2 antisera, respectively. The cross-reactivity of the 2 antiochratoxin A sera was high for the ochratoxin A methyl ester, about 20% for ochratoxin C, and low for (4R)-4-hydroxyochratoxin A, ochratoxin α, ochratoxin B, and 4-hydroxyochratoxin B. No cross-reactivity was seen for phenylalanine and lysine.
Liquid Chromatographic Determination of Pesticides in Finished Drinking Waters: Collaborative Study
Authors: Edgell Kenneth W , Erb Elizabeth J , Longbottom James E , Lopez-Avila Vlorica 
Published: February 2020

Abstract
A joint U.S. Environmental Protection Agency (EPA)/AOAC International collaborative study was conducted on EPA National Pesticide Survey Method 4, Determination of Pesticides in Finished Drinking Water by High Performance Liquid Chromatography with an Ultraviolet Detector, to determine mean recovery and precision for analyses of 18 pesticides and metabolites in reagent water and finished drinking waters. The study design was based on Youden's nonreplicate plan for collaborative studies of analytical methods. The waters were spiked with 18 pesticides and metabolites at 6 concentration levels, prepared as 3 Youden pairs. Ten volunteer laboratories extracted the spiked test waters with methylene chloride, performed a solvent exchange with methanol, and analyzed an aliquot of each extract by liquid chromatography using an ultraviolet detector at 254 nm. Results were analyzed using an EPA computer program that calculated recovery and precision for each of the 18 compounds and compared method performance between water types. The method was judged useable for all analytes tested. Recoveries were good for 16 of the analytes. The method exhibited poor recovery but acceptable between-laboratory precision for metribuzin DADK and metribuzin DK. The method performance statistics for carbofuran phenol and linuron were calculated to be significantly different for reagent water and finished drinking water. Similar statistical differences were observedfor metribuzin DADK, but these effects were not considered of practical significance due to the poor recovery (&lt;25%) in both waters. In reagent water, the overall relative standard deviation (RSDR) range was 7.8-24.1% for all 18 compounds and 5.5-38.6% in finished drinking water. The single- analyst relative standard deviations (RSDr) range was 5.7-17.6% in reagent water and 4.0- 18.7% in finished drinking water. The method has been adopted first action by AOAC International.
Predicting the Environmental Distribution of Compounds with Unknown Physicochemical Properties from Known Pesticide Properties
Authors: Prasad Surya S 
Published: February 2020

Abstract
Disposing of pesticides improperly can have environmental consequences. This study examines those properties discussed in published literature or derived from semiempirical mathematical models that are most likely to affect pesticides' environmental distribution, then assesses their migration between environmental media (soil, water, air, and biota). In particular, it examines how pesticide characteristics such as water solubility, molecular weight, bioconcentration, volatility, and soil adsorption affect soil-to-water mobility, water-to-air dissipation, and water-to-biota accumulation when present in the environmental medium of preferred residence. The study concludes that chemicals that have low water solubilities tend to adsorb to soil, those that have low vapor pressures tend to dissipate slowly from water, and those that have relatively high octanol-to-water partition coefficients or low water solubility have a high potential for bioconcentration. Under these situations, environmental restoration might best be achieved by removal of the contamination at the source. By drawing analogies from these findings, researchers should be able to predict the mobility of pesticides belonging to a particular category or family of compounds with unknown physicochemical properties, determine the harm that might result from their distribution under worst-case scenarios, and recommend ways to restore the environment. Received
Using Experimental Design To Optimize a Microbial Diffusion Assay
Authors: Renard Laurent , Moulin Gerard , Sanders Pascal 
Published: February 2020

Abstract
As a prerequisite to validation of the cylinder plate diffusion assay for the antibiotic colistin sulfate in plasma, the assay needed to be optimized. Bordetella bronchiseptica (ATCC 4617) was the test organism for optimization. Ionic strength of buffer, quantity of test organism, duration of prediffusion, and volume of agar layer were studied. The effects of each factor were examined according to an experimental design. A 4 h prediffusion at 4°C increased sensitivity. Repeatability was improved by using 100 mL agar per bioassay dish, dilution of the plasma with buffer (3 + 1), and prediffusion. The slope of the standard response line was steeper with prediffusion. The reduced quantity of test organism contributed to better sensitivity and good repeatability. No significant interaction between these factors was found. Experimental designs were used successfully to rapidly set up a microbial method requiring a limited number of runs
Effect of Cold-Temperature Storage on Stability of Benzylpenicillin Residues in Plasma and Tissues of Food-Producing Animals
Authors: Boison Joe O , Korsrud Gary O , Macneil James D , Yates William D G , Papich Mark G 
Published: February 2020

Abstract
A recently developed liquid chromatographic method is used to determine benzylpenicillin residues in incurred tissue and plasma samples from experimental animals stored at freezer temperatures of -20°C and -76°C. It was observed that penicillin- incurred plasma samples stored at -20°C for 2 months were relatively stable, showing a gradual loss of only 10-20% of the residues present at the beginning of the storage period. Loss of penicillin residues from bovine kidney and liver stored at -20°C occurred at a rate that was more rapid than from plasma. Losses in benzylpenicillin concentrations of up to 20% were observed in kidney and liver samples stored at -20C after as little as 10 days of storage. Gluteal muscle samples stored at the same temperature showed almost 50% reduction in benzylpenicillin concentration after only 10 days of storage. However, incurred tissue samples stored at -76°C remained stable. The depletion of benzylpenicillin residues from edible tissues and biological fluids follows a first-order rate law.
Liquid Chromatographic Method for the Simultaneous Analysis of Sulfadimethoxine and Ormetoprim in Animal Feeds
Authors: Duke Paul D , Weiss George , Macdonald Alexander 
Published: February 2020

Abstract
An analytical method was developed to simultaneously determine sulfadimethoxine (SDM) and ormetoprim (OMP) in medicated animal feeds. SDM and OMP are extracted from the feed into methylene chloride at pH 10 following the addition of tetrabutylammonium hydroxide to form an ion pair with SDM. After the methylene chloride extract is dried over sodium sulfate, an aliquot is purified by solid-phase extraction using a PrepSep silica extraction column. Both compounds are separated by liquid chromatography on an Ultrasphere ionpair column at 3°0C with UV detection at 275 nm. The average recoveries for OMP and SDM in feeds fortified between 0.01 and 0.5% total combined drug ranged from 96.4 to 101.4%, respectively. Replicate assays of typical feeds yielded coefficients of variation of 1.7-3.1%.
Incidence of Fungi in Shared-Use Cosmetics Available to the Public
Authors: Mislivec Philip B , Bandler Ruth , Allen Geraldene 
Published: February 2020

Abstract
A survey was conducted to assess both the potential health risk from shared-use cosmetics caused by microorganisms and the microbial efficacy of preservatives in cosmetics. Samples of 3027 shared-use cosmetic products were collected from 171 retail establishments nationwide. Fungi were present in 10.4% of the products, and 3.9% contained fungal pathogens or opportunistic pathogens. The 423 fungal isolates identified represented 33 genera and at least 69 species. A disproportionately large share of the fungal isolates were from eye products; fewer were from lip products. Pathogenic or opportunistic pathogens made up 32.2% of the fungal isolates. A slightly lower percentage of samples that contained preservatives had fungi, a fact suggesting that preservatives reduce the incidence of fungi in cosmetics. Results of this survey indicate potential microbiological problems concerning the safety of shareduse cosmetics.
Unified Procedure for the Determination of Antibiotics in Animal Feeds
Authors: Salvatore Michael J , Katz Stanley E 
Published: February 2020

Abstract
A new method was developed for the determination of antibiotics in animal feeds. This qualitative and quantitative method can be applied to 17 antibiotics currently accepted for use in animal feeds. A solvent prewash step is used to differentiate groups of antibiotics and individuals of the same class of antibiotics and to remove interfering substances. Agarose gel electrophoresis at pH 6.0 and 8.0 is used to further differentiate the individual antibiotics and as an agar diffusion assay. Minimum detectable concentrations of antibiotics currently accepted for use in animal feeds were determined against selected microorganisms.
Gas Chromatographic/Chemiluminescence Detection (Thermal Energy Analyzer-Nitrogen Mode) Method for the Determination of Dibutylamine in Hams
Authors: Fiddler Walter , Doerr Robert C 
Published: February 2020

Abstract
A gas chromatographic (GC) procedure is described for the determination of dibutylamine (DBA) in ham at less than 1 ppm. Sample is extracted with 0.5N HCI, centrifuged, made basic, and then extracted with isopropyl alcohol. Final determination is by GC/thermal energy analysis in the nitrogen mode. Six replicate analyses of ham fortified with 0.5 ppm DBA gave a recovery of 90.2 ± 3.4%. Over a range of 0.5 to 3.0 ppm DBA, the repeatability was 0.07 ppm, and the coefficient of variation was 6.07%. Limit of detection was 01 ppm. Effectiveness of the procedure was demonstrated on selected ham samples.
Selective Determination of Methyl Mercury in Biological Samples by Means of Programmed Temperature Gas Chromatography
Authors: Lorenzo R A , Carro A , Rubí E , Casais C , Cela R 
Published: February 2020

Abstract
A programmed temperature gas chromatographic method is presented by which it is possible to carry out routine analysis of methyl mercury in biological samples prepared according to the AOAC official first action recommendations without the need for preliminary treatment of the columns. This method greatly extends the life of the columns as well as the useful time for analysis; it has good linearity and repeatability. With the proposed method a total of 36 samples can be analyzed daily.
Fractional Factorial Design Approach for Optimizing Analytical Methods
Authors: Oles Philip J 
Published: February 2020

Abstract
Experimental designs based on procedures of Taguchi are described for optimizing analytical methods. Methods were efficiently developed, with improvements in precision and accuracy, for the determination of cholesterol in foods, magnesium in feed premix, and moisture in mayonnaise. Significant factors and interactions were identified by using 2-level designs, analysis of variance techniques, and commercially available computer software. The designs were prepared by using Taguchi linear diagrams. The methods developed as a result of these experiments have proven to be rugged and reliable.
Performance of Two Immunochemical Assays in the Analysis of Peanuts for Aflatoxin at 37 Field Laboratories
Authors: Dorner Joe W , Blankenship Paul D , Cole Richard J 
Published: February 2020

Abstract
A study was conducted to measure the precision of 2 rapid aflatoxin assay systems in use at 37 peanut buying points during the 1991 harvest season. Aflatoxin laboratories were established at the 37 buying points to analyze peanut samples from all incoming farmers’ stock loads as part of a joint project sponsored by various segments of the U.S. peanut industry and the U.S. Department of Agriculture. Eighteen laboratories were equipped with Neogen’s veratox FSP rapid assay system, whereas 19 laboratories used Vicam’s Aflatest rapid assay system. To monitor the performance of the field laboratories during the project, 3 portions of each of six 27 kg samples of ground peanuts were sent to each laboratory for analysis over a period of 6 weeks. Aflatoxin concentrations ranged from 0 to 300 ng/g when eight 200 g subsamples of each sample were analyzed by liquid chromatography (LC). For the 5 samples contaminated with aflatoxin, relative standard deviations for repeatability (RSDr) for laboratories using veratox FSP ranged from 18.66 to 53.29%, and the relative standard deviations for reproducibility (RSDR) ranged from 22.79 to 59.29%. For laboratories using the Aflatest system, RSDr values ranged from 18.70 to 41.48%, and RSDR values ranged from 23.84 to 47.56%. Horwitz ratios &lt; 2.0 were found for 4 of the 5 contaminated samples for both methods, indicating that the overall precision of the 2 methods used in the project was good. Mean aflatoxin concentrations, as determined with the rapid assay systems, were generally lower than those determined by LC, particularly for more highly contaminated samples. This could not be attributed to instability of aflatoxin in peanut paste, because additional information gathered in the study indicated that the stability of aflatoxin in peanut paste stored for 58 days was good.
Comparison of Methylation Methods for the Quantitation of Conjugated Linoleic Acid Isomers
Authors: Shantha Nalur Chandrasekaran , Decker Eric Andrew , Hennig Bernhard 
Published: February 2020

Abstract
Four methylation methods were evaluated for use in the gas chromatographic (GC) quantitation of conjugated linoleic acid (CLA) isomers, which are potential anticarcinogen. The methods were (1) sodium methoxide in methanol (NaOMe-MeOH), (2) American Oil Chemists' Society (AOCS) procedure Ce 2-66, which involves methanolic sodium hydroxide followed by boron trifluoride in methanol, (3) tetramethylguanidine in methanol (TMG-MeOH), and (4) direct transesterification with methanolbenzene- acetyl chloride (DAC). Purified methyl esters of isomerized linoleic acid containing 86% CLA isomers were methylated and analyzed by GC. The AOCS and DAC methods resulted in 3 and 50% losses in cis-9,trans-11-octadecadienoic acid (9c, 111 CLA isomer) and trans-10,cis-12 octadecadienoic acid (10t, 12c CLA isomers), respectively. Compared with the control, the AOCS and DAC methods increased the yield of the trans,trans CLA isomers (trans-9,trans-11- and trans-10, trans-12-octadecadienoic acid) by 1.07-fold and a 10-fold, respectively. A non-CLA artifact that eluted close to CLA peaks was formed during methylation by the AOCS and DAC methods. Thus, the DAC and AOCS methods are not suitable for quantitation of CLA isomers. The NaOMe-MeOH and TMG-MeOH methods, however, are suitable for quantitation of CLA isomers in fats containing low concentrations of free fatty acids.
Depletion of the Monoamino Metabolites of Zoalene During Frozen Storage
Authors: Parks Owen W 
Published: February 2020

Abstract
3-Amino-5-nitro-o-toluamide and 5-amino-3-nitro-o-toluamide, the principal metabolites in the tissues of chickens fed a diet containing Zoalene (3,5- dinitro-o-toluamide), were shown to deplete in frozen liver tissues stored up to 1 year at -20°C, but not at -70°C. A slight loss of 5-amino-3-nitro-otoluamide also occurred in thigh muscle at -20°C. Evidence is presented that demonstrates that the depletion of the metabolites was partially the result of their transformation to glucopyranosyl derivatives; both the α- and β-anomers of the 5-amino-3-nitro-otoluamide conjugate were observed in liquid chrcmatograms of tissue extracts.
Simultaneous Determination of Flavor Enhancers Inosine 5´-Monophosphate and Guanosine 5´-Monophosphate in Food Preparations by Derivative Spectrophotometry
Authors: Durán-Merás Isabel , Salinas Francisco , Peńa Arsenio Muńoz de la , Rόsas Miguel Lopez 
Published: February 2020

Abstract
A derivative spectrophotometry method was developed for the quantitative determination of 2 flavor enhancers, inosine 5´-monophosphate (IMP) and guanosine 5´monophosphate (GMP), in the presence of monosodium glutamate (MSG). Procedures for determining IMP and GMP singly and in binary mixtures are described. Overlapping absorption spectra of both compounds were resolved by using first-derivative spectrophotometry. By measuring the first-derivative signals of IMP and GMP at 253 and 248 nm, respectively, simultaneous determination was possible for IMP and GMP at 5–40 μg/mL, in the presence of up to 5000 μg/mL MSG. The method was satisfactorily used to determine IMP and GMP in several food preparations.