bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Residual Cephalexin in Chick Tissues by Bacillus stearothermophilus Paper
Disc Assay
Authors: Okada Junya , Higuchi Ikuji , Kondo Sadao , Saito Bun-Ichi 
Published: February 2020

Abstract
A paper disc method is described for determination of residual cephalexin (CEX) in chick tissues. A trichloroacetic acid extract of plasma and tissues is chromatographed on a macroreticular resin (Diaion HP-20) column to remove endogenous antibacterial substances interfering with the assay. The eluate is evaporated to dryness and the residue, dissolved in methanol-water (1 + 2), is subjected to a paper disc assay using Bacillus stearothermophilus var. calidolactis C953 NIZO as a test organism. The detection limit was 0.0375 ppm in tissue; the average recovery of CEX ranged from 72.4% in skin to 90.4% in plasma. Water containing 200 or 500 mg/L of CEX was given ad libitum to 2-week-old chicks for 10 days; the highest levels of CEX were found in the kidney, and the lowest were found in muscle at 0 h of withdrawal. CEX disappeared from most tissues at 24 h after withdrawal except from skin of chicks given 500 mg/ L. However, the drug was not detected in the skin at 48 h after withdrawal.
Evaluation of Abbreviated Enzyme Immunoassay Method for Detection of Salmonella in Low-Moisture Foods
Authors: Flowers Russell S , Klatt Mary Joan , Robison Barbara J , Mattingly Jerome A 
Published: February 2020

Abstract
A modified enzyme immunoassay method (EIA) utilizing an 18 h pre-enrichment, a 6-8 h selective enrichment, and a 14 h M-broth post-enrichment is compared to the standard culture method (AOAC/ BAM) on selected low-moisture foods. Tested samples included 238 inoculated, 30 naturally contaminated, and 30 uninoculated foods. By EIA, 235 samples were positive (optical densities greater than 0.2 at 405 nm), 233 of which were confirmed culturally. By the culture methods, 221 samples were positive. The EIA method was more productive in detecting salmonellae in inoculated samples of dry cheese powder, chocolate, and nonfat dry milk, whereas the culture method gave better recovery from naturally contaminated meat and bone meal. The modified EIA could be completed in 40 h and required no centrifugation.
Single-Laboratory Evaluation of EPA Method 8080 for Determination of Chlorinated Pesticides and Polychlorinated Biphenyls in Hazardous Wastes
Authors: Avila Viorica Lopez , Schoen Sarah , Milanes June , Beckert Werner F 
Published: February 2020

Abstract
Method 8080, as published in the Second Edition of "Test Methods for Evaluating Solid Waste," EPA Manual SW-846, has been evaluated in a single-laboratory study. The Florisil procedure recommended in Method 8080 for sample cleanup does not separate organochlorine pesticides (OCPs) from the polychlorinated biphenyls (PCBs). Consequently, gas chromatographic analysis of OCPs on the packed column recommended in the method may result in false identifications or in no identifications at all when PCBs are present. Therefore, silica gel was substituted for Florisil, a capillary column was substituted for the packed column, and a sulfur cleanup procedure was incorporated in the method. The revised method was evaluated with samples spiked at 3 concentrations. Precision and accuracy indicate that the revised method can be reliably applied to the determination of OCPs and PCBs in liquid and solid matrixes. Detection limits for liquid matrixes range from 0.02 to 0.09 μg/L for OCPs and from 0.5 to 0.9 (μgL for PCBs. Detection limits for solid matrixes range from 1 to 6 μg/kg for OCPs and from 60 to 70 μg/kg for PCBs
Gas Chromatographic-Mass Spectiometric Determination of Adipate-Based Polymeric
Plasticizers in Foods
Authors: Castle Laurence , Mercer Angela J , Gilbert John 
Published: February 2020

Abstract
A method for the quantitative determination of adipate-based polymeric plasticizers in foods is described. The procedure involves extraction from the food and transmethylation of the polymeric plasticizer to form dimethyladipate (DMA). The derivative is cleaned up by size-exclusion chromatography and determined by capillary gas chromatography-mass spectrometry with selected on monitoring. The use of a deuterated internal standard at the extraction stage enables quantitation by stable isotope dilution. A detection limit of 0.1 mg/kg of the polymeric plasticizer in foods and a relative standard deviation of 4% have been achieved routinely. The method has been applied successfully to the analysis of cheese, sandwiches, meat, biscuits, and cake that have been in contact with polymeric plasticized polyvinyl chloride) films.
Direct Gas Chromatographic Analysis of Trichlorfon for Its Decomposition Products
Authors: Slahck Stephen C 
Published: February 2020

Abstract
The analysis of trichlorfon by direct gas chromatography is discussed. A procedure is described for the determination of impurities in trichlorfon by using a fused silica capillary column and cold on-column injection. Attempts at quantitating trichlorfon using this system were unsuccessful due to problems with irreproducibility of the peak area. Although no derivatization was performed, there was no decomposition of the analyte as confirmed by mass spectrometry
Rapid Identification of Color Additives, Using the C18 Cartridge: Collaborative Study
Authors: Young Mary L 
Published: February 2020

Abstract
Nine laboratories collaboratively studied a method for the separation and identification of the 7 permitted FD&C color additives (Red Nos. 3 and 40; Blue Nos. 1 and 2; Yellow Nos. 5 and 6; Green No. 3) and the banned FD&C Red No. 2 in foods. The method is based on use of a commercial C18 cartridge and spectrophotometry or thin layer chromatography. Collaborators analyzed 5 commercial products (noodles, candy, carbonated soda, flavored gelatin, and powdered drink) and 2 dye mixtures (one containing FD&C Red Nos. 2,3, and 40; the other containing FD&C Green No. 3 and Red No. 3). All of the colors were identified with little or no difficulty by 8 collaborators. The method has been adopted official first action.
Simultaneous Determination of D- and L-Malic Acids in Apple Juice by Gas Chromatography
Authors: Agarwal Vipin K 
Published: February 2020

Abstract
A gas chromatographic (GC) method was developed for the simultaneous determination of D- and L-malic acids in apple juice. D-Malic- (R)-(-)-2-butyl ester and L-malic-(R)-(-)-2-butyl ester are prepared with (R)-(-)-2-butanol. These diastereomers are separated and quantitated by gas chromatography on a Carbowax 20M (30 m x 0.25 mm) fused silica capillary column. This procedure does not involve any extraction or cleanup step.
Liquid Chromatographic Methodology for the Characterization of Orange Juice
Authors: Perfetti Gracia A , Joe Frank L , Fazio Thomas , Page Samuel W 
Published: February 2020

Abstract
Liquid chromatographic (LC) methodology potentially useful for the characterization of orange juice, with particular regard to detecting adulteration of orange juice by computer pattern recognition analysis, has been developed. After dilution with methanol the juice is extracted with hexane to remove the carotenoids, which are chromatographed on a C18 column with an acetonitrile-methanol-methylene chloride mobile phase and detection at 450 nm. Further extraction of the juice with methylene chloride isolates the methoxylated flavones, which are chromatographed by reverse phase LC with an acetonitrile-methanol-water mobile phase and detection at 280 nm. The flavanone glycosides remaining in solution are chromatographed on a C18 column with an acetonitrile-water mobile phase and detection at 280 nm. The precisions of the heights of the 32 LC peaks selected for pattern recognition analysis were determined from 5 replicate analyses of a single juice. Coefficients of variation of the replicates ranged from 0.3 to 4.5%, with an average of 2.1%. Adulteration of products with sodium benzoate-fortified pulpwash or grapefruit juice can be detected by this method. Pattern recognition analysis of the data obtained for 80 authentic and 19 adulterated orange juices showed that the method is potentially useful for distinguishing between authentic and adulterated products.
High-Speed Liquid Chromatographic Determination of Monensin, Narasin, and Salinomycin in Feeds, Using Post-Column Derivatization
Authors: Lapointe Michel R , Cohen Huguette 
Published: February 2020

Abstract
A high-speed liquid chromatographic (LC) method using post-column derivatization is described for the determination of monensin, narasin, and salinomycin in a variety of animal feeds. The ionophores are extracted with hexane-ethyl acetate (90 + 10). A portion of the sample is evaporated, diluted to a known volume, and analyzed using a 6 cm 3 μm C18 column and an absorbance detector after post-column reaction with vanillin. The method has been applied to poultry and swine feeds with levels of 3-100 ppm added antibiotic. A comparison was also carried out with medicated poultry feed and beef feed lot supplement samples previously analyzed by 2 separate bioassay methods for monensin and salinomycin, respectively. Recoveries for the LC method ranged from 92.1 to 103% with an average recovery of 98.1% and a coefficient of variation of 3.65%.
Gas Chromatographic Screening Method for T-2 Toxin, Diacetoxyscirpenol, Deoxynivalenol, and Related Trichothecenes in Feeds
Authors: Rood Harold D , Buck William B , Swanson Steven P 
Published: February 2020

Abstract
A gas chromatographic method for screening trichothecene mycotoxins in feeds is described. Feed is extracted with acetonitrile-water, and the toxins are purified with charcoal-alumina-Celite, Florisil, and silica mini-columns. Deoxynivalenol (DON), nivalenol (NIV), diacetoxyscirpenol (DAS), T-2 toxin, and their fungal metabolites are hydrolyzed to their corresponding parent alcohols (DON, NIV, scirpentriol, or T-2 tetraol) by alkaline hydrolysis. After derivatization to their pentafluoropropionyl analogs, they are quantitated by capillary gas chromatography with electron capture detection. Identity can be confirmed and sensitivity can be increased by using negative chemical ionization mass spectrometry with no additional sample workup. Recoveries of DAS, DON, and T-2 toxin averaged, respectively, 80, 65, and 85% in corn; 84, 65, and 88% in soybeans; and 70, 57, and 96% in mixed feeds at concentrations ranging from 0.1 to 2.0 ppm. Recoveries of 15-monoacetoxyscirpenol (MAS), HT- 2, NIV, and T-2 tetraol were 97, 97, 86, and 56%, respectively, in corn at a concentration of 0.25 ppm. A detection limit of 0.02 ppm in corn, soybeans, and mixed feeds, and 0.05 ppm in silages is estimated.
Gas Chromatographic Determinatiion of Monoethylene Glycol and Diethylene Glycol in
Chocolate Packaged in Regenerated Cellulose Film
Authors: Castle Laurence , Cloke Helen R , Startin James R , Gilbert John 
Published: February 2020

Abstract
A method for the quantitative determination of monoethylene glycol (MEG) and diethylene glycol (DEG) in chocolate is described. The procedure involves dissolving the chocolate in hot water, defatting with hexane, removing sugars by precipitation, and analyzing as trimethylsilyl (TMS) ether derivatives by capillary gas chromatography. The use of butan-l,4-dioI as an internal standard corrects for recovery, which is between 50 and 60%, to give a relative standard deviation of 10 -11 % for the determination of both glycols at the level of 50 mg/kg. The presence of MEG and DEG in chocolate is confirmed by full scanning gas chromatography/mass spectrometry of the TMS derivatives
Liquid Chromatographic Determination of Scopoletin in Hydroalcoholic Extract of Oak Wood
and in Matured Distilled Alcoholic Beverages
Authors: Puech Jean-Louis , Moutounet Michel 
Published: February 2020

Abstract
A liquid chromatographic (LC) method is described for determination of the coumarins esculin, umbelliferone, scopoletin, and 4-methyl umbelliferone in hydroalcoholic extracts of oak wood and in matured distilled alcoholic beverages. Samples were injected directly into the LC column (30 m, 5μm C18) and detected by fluorescence detector. Under these experimental conditions, only scopoletin (detection limit, 200 pg) was found in hydroalcoholic oak wood extracts and in spirits matured in oak wood. Applications of this method to spirits distilled from wine, grain, and sugar cane aged in oak barrels showed that amounts varied from 0.026 to 1.57 ppm
Determination of Reserpine and Hydrochlorothiazide in Commercial Tablets by Liquid
Chromatography with Fluorescence and UV Absorption Detectors in Series
Authors: Cieri Ugo R 
Published: February 2020

Abstract
A procedure is presented for the determination of reserpine and hydrochlorothiazide in commercial tablets by liquid chromatography (LC). Reference and sample solutions are prepared in methanol. For LC, a normal phase column is used, methanol is the eluting solvent, and 2 detectors are arranged in series. A fluorescence detector set at an excitation wavelength of 280 nm and emission wavelength of 360 nm quantitates reserpine, and a UV absorption detector set at 345 nm determines hydrochlorothiazide. Several synthetic mixtures containing the 2 ingredients in the amounts approximately present in commercial tablets were analyzed by the proposed method. Two samples of commercial tablets were also analyzed; for each sample, 5 determinations were made on a ground composite of 20 tablets; 10 individual tablets were also analyzed. For comparison, some of the solutions were analyzed for each ingredient by an alternative procedure.
Liquid Chromatographic Determination of Carbamazepine in Tablets
Authors: Walker Ella S 
Published: February 2020

Abstract
A simple and rapid liquid chromatographic method is described for the qualitative and quantitative determination of carbamazepine in tablet composites and individual tablets, using the internal standard technique. Analyses were performed on a C-18 reverse-phase column with tetrahydrofuran-methanol-water (8 + 37 + 55) as the mobile phase. A linear relationship was obtained between detector responses at 254 nm and amounts of carbamazepine injected ranging from 0.2 to 1.7 ng. The coefficient of variation for 10 consecutive injections of a standard preparation was 0.4%. Recoveries of carbamazepine from 100 and 200 mg tablets averaged 101.4 and 99.7%, respectively. Assay results for commercial tablets analyzed by the proposed method agreed favorably with those obtained by the method of USP XXI. The assay results for individual tablets indicated that deviations from the average value and the range of individual values are much wider with the compendial method than with the proposed method
Simplified Multiresidue Method for Liquid Chromatographic Determination of /V-Methyl
Carbamate Insecticides in Fruits and Vegetables
Authors: Chaput Daniel 
Published: February 2020

Abstract
A simplified method is described for determining 7 N-methyl carbamates (aldicarb, carbaryl, carbofuran, methiocarb, methomyl, oxamyl, and propoxur) and 3 related metabolites (aldicarb sulfoxide, aldicarb sulfone, and 3-hydroxy carbofuran) in fruits and vegetables. Residues are extracted from crops with methanol; coextractives are then separated by gel permeation chromatography (GPC) or GPC with on-line Nuchar-Celite cleanup for crops with high chlorophyll and/or carotene content (e.g., cabbage and broccoli). Carbamates are separated on a reverse-phase liquid chromatography column, using a methanol-water gradient mobile phase. Separation is followed by postcolumn hydrolysis to yield methylamine, and the formation of a fluorophore with o-phthalaldehyde and 2-mercaptoethanol prior to fluorescence detection. Recovery data were obtained by fortifying 5 different crops (apples, broccoli, cabbages, cauliflower, and potatoes) at 0.05 and 0.5 ppm. Recoveries averaged 93% at both fortification levels except for the very polar aldicarb sulfoxide for which recoveries averaged around 52% at both levels. The coefficient of variation of the method at both levels is &lt;5% and the limit of detection, defined as 5 times baseline noise, varies between 5 and 10 ppb, depending on the compound
Comparison of Values Derived from Selected Flours by Fat Acidity Methods of the American
Association of Cereal Chemists and the International Organization for Standardization
Authors: Lane Ralph H , Erickson Richard L 
Published: February 2020

Abstract
Fat acidity values were determined on 8 commercially available flours by the American Association of Cereal Chemists method (AACC- 02-01 A) and by the International Organization for Standardization method (ISO-7305). Comparisons of means obtained by these 2 methods indicated that the ISO method produced results that were 1.4- 2.5 times greater (P &lt; 0.001) than those for the AACC method. These data are consistent with a previous report which indicated that acidic materials (phosphates and amino acids) other than fatty acids are extracted by 95% alcohol (ISO method), whereas fatty acids alone are extracted by petroleum ether (AACC method). Fat acidity values obtained by AACC methodology employing Soxhlet and continuous extraction were also compared. No difference in fat acidity means existed with respect to extraction technique except for an aged whole wheat flour sample which produced a higher value (P = 0.05) by continuous extraction.
Identification of Escherichia coli from Shellfish and Related Environments by Automicrobic
System
Authors: TardiÓ Joseph L , O'brien Kevin , Latt Thomas 
Published: February 2020

Abstract
A total of 463 fecal coliform positive isolates obtained from shellfish and related samples gave typical Escherichia coli IMViC reactions. E. coli identifications for 458 (99%) of these isolates were confirmed using a combination of the Automicrobic System (AMS) and the API 20E system (reference system). The AMS (test system) identified 433 isolates as E. coli; the remaining 25 (5%) isolates were identified as E. hermanii by the test system and as E. coli by the reference system. Additional tests performed on the isolates identified as E. hermanii confirmed those AMS identifications to be incorrect
Liquid Chromatographic Method for Analysis of Elemental Sulfur in Pesticide Formulations
Authors: Bushway Rodney J , Brian Perkins L 
Published: February 2020

Abstract
A nonaqueous reverse-phase liquid chromatographic (LC) method has been developed to determine elemental sulfur in pesticide formulations. Samples were extracted in 50 mL of stabilized tetrahydrofuran (THF) by gentle swirling while sonicating for 1 min. A 5 pL aliquot was injected into the LC instrument equipped with a Vydac 218 TP 54 column. The mobile phase was methanol-acetonitrilestabilized tetrahydrofuran (58.5 + 40 + 1.5). Sulfur was monitored at 280 nm. Retention time was approximately 5 min with total analysis time of 7 min. For 6 different products analyzed 12 times each, the coefficients of variations were all less than 3.5%. Purity of each sulfur peak was checked by using a photodiode array detector in the spectrum and absorbance ratio modes. No impurities were observed at the monitoring wavelength
Listeria Methods Development Research at the Eastern Regional Research Center,
U.S. Department of Agriculture
Authors: Buchanan Robert L , Smith James L , Stahl Heidi G , Archer Deborah L 
Published: February 2020

Abstract
Listeria methods research at the U.S. Department of Agriculture, Eastern Regional Research Center, has concentrated on 2 areas during the past year. The first was development of techniques for assessing isolation methods for their ability to detect sublethally stressed cells. It appears that a number of widely used media do not accurately detect Listeria that have been injured by thermal processing or acidification. The second was development of improved plating media. One, modified Vogel-Johnson agar, shows promise; it is highly selective and quantitative, and eliminates the need to select colonies on the basis of a blue color when illuminated with reflected light
Comparative Studies of Nucleic Acid Hybridization Assay for Listeria in Foods
Authors: Klinger Jeffrey D , Johnson Andrew , Croan Daniel , Flynn Pauline , Whippie Kevan , Kimball Margaret , Lawrie Jonathon , Curiale Michael 
Published: February 2020

Abstract
A nucleic acid hybridization assay has been developed for Listeria spp. in dairy foods and environmental samples. The assay is based on detection of unique Listeria 16S rRNA sequences by using a 32Plabeled synthetic DNA probe. Inclusivity and exclusivity of the probe were confirmed with 139 Listeria isolates representing all known species, and 73 non-Listeria bacterial strains. In this paper, we present results from our preliminary studies comparing the hybridization assay with conventional culture on a total of 575 specimens that represent a variety of inoculated and uninoculated foods and environmental samples. The assay, which is done in a filter manifold format after 2 days of cultural enrichment, requires a total assay time of less than 2.5 days. The false-negative rate for all sample groups tested using the GENE-TRAK hybridization assay was less than the rate for culture. Thus, the new assay allows rapid screening of the indicated product groups and provides reliable numerical results
Identification and Enumeration of Beta-Hemolytic Listeria monocytogenes in Naturally
Contaminated Dairy Products
Authors: Datta Atin R , Wentz Barry A , Hill Walter E 
Published: February 2020

Abstract
A DNA probe was used to identify hemolytic Listeria monocytogenes in naturally contaminated dairy products: unpasteurized milk, ricotta cheese, and imported semisoft cheeses. Of 34 milk samples, 12 were suspected to contain hemolytic L. monocytogenes; 1 contained &gt;6000 viable organisms/g. The ricotta cheese, although temperature-abused, had a titer of 3.6 x 10-6 beta-hemolytic L. monocytogenes cells/g, whereas the semisoft cheeses reached a maximum of 5.6 x 10-6 cells/g. Pure cultures of L. monocytogenes isolated from both types of cheese were found positive by the CAMP test and the DNA probe