bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid Chromatographic Determination of Oxytetracychne in Swine Tissues
Authors: Kawata Shigeru , Sato Kazuhiko , Nishikawa Yuusuke , Iwama Kjmio 
Published: February 2020

Abstract
A simple and rapid method was developed for determination of oxytetracycline (OTC) in swine muscle and kidney by liquid chromatography (LC). The method involved homogenization of sample in acetonitrile–1M imidazole buffer containing 10 mM disodium ethylenediaminetetraacetic acid (Na2 EDTA) and 50 mM magnesium acetate (15 + 85) with added hexane, centrifugation, removal of the hexane phase, and ultrafiltration of the supernatant. L-column ODS (150 × 4.6 mm) with a mobile phase of acetonitrile–1M imidazole buffer containing 50 mM magnesium acetate and 10 mM Na2 EDTA (10 + 90) was used for the LC separation. A fluorescence detector was used at an excitation wavelength of 380 nm and an emission wavelength of 520 nm. The calibration graph was linear from 1.25 to 200 ng OTC. Recoveries of OTC from swine tissue fortified at levels of 0.05–1.0 μg/g ranged from 58.0 to 67.3%. The quantitation and detection limits were 0.05 and 0.04 μg/g, respectively.
Rapid Determination of Ampicillin in Bovine Milk by Liquid Chromatography with Fluorescence Detection
Authors: Ang Catharina Y W , Wenhong Luo 
Published: February 2020

Abstract
A rapid and sensitive liquid chromatographic (LC) method was developed for the determination of am- picillin residues in raw bovine milk, processed skim milk, and pasteurized, homogenized whole milk with vitamin D. Milk samples were deprote- inized with trichloroacetic acid (TCA) and acetonitrile. After centrifugation, the clear supernatant was reacted with formaldehyde and TCA under heat. The major fluorescent derivative of ampicillin was then determined by reversed-phase LC with fluorescence detection. Average recoveries of ampicillin fortified at 5,10, and 20 ppb (ng/mL) were all &gt;85% with coefficients of variation &lt;10%. Limits of detection ranged from 0.31 to 0.51 ppb and limits of quantitation, from 0.66 to 1.2 ppb. After appropriate validation, this method should be suitable for rapid analysis of milk for ampicillin residues at the tolerance level of 10 ppb.
Effect of Lipid Extraction Methods on Total Dietary Fiber and Nonstarch Polysaccharide Contents of Selected Nuts and Seeds
Authors: Li Betty W , Zhao Zhenkun , Jekot Jill J 
Published: February 2020

Abstract
Three extraction methods were used to remove lipid materials from 8 edible nuts and seeds before analysis for their total dietary fiber (TDF) and non- starch polysaccharide (NSP) contents. Portions of ground materials were extracted by: n-hexane, followed by 80% methanol, n-hexane-acetic acid (95 + 5, v/v), and supercritical carbon dioxide. Defatted samples were gelatinized in water and incubated with amyloglucosidase; 95% ethanol was added to the hydrolyzates, and the residues were collected on tared glass crucibles. TDF was calculated according to a simplified enzymatic-gravimetric method developed in our laboratory, and NSP was determined as described by Englyst and coworkers. Dietary fiber values obtained with any of the extraction methods range from 3.47 g/100 g for cashews to 28.56 g/100 g for sunflower seeds. Nonstarch polysaccharide values range from 2.43 g/100 g for pecans to 5.56 g/100 g for peanuts. With the exception of sunflower seeds, samples extracted with supercritical carbon dioxide had lower TDF contents but similar amounts of NSP compared with samples extracted by the other 2 methods.
A Sensitive Method for Evaluating Condoms as Virus Barriers
Authors: Lytle C David , Duff James E , Fleharty Bruce , Bidinger Randolph L , Cyr W Howard , Routson Licia B 
Published: February 2020

Abstract
A standard test is needed to evaluate condoms as barriers against sexually transmitted diseases, particularly those caused by viruses. The proposed method presented here consists of a previously published simple method using physi- ologic-based conditions plus improvements to increase test sensitivity and decrease confounding factors such as contamination. Limitations of the method were determined by measuring virus penetration through small, well-defined holes. The method can detect penetration of 2 nL (2 x 10-6 mL) of challenge virus suspension as well as a hole of 2 μm diameter in a latex condom. The data also indicated that virus penetration of latex condoms occurred quickly, and the hole was then apparently closed or blocked.
Simultaneous Determination of Metoprolol-Hydrochlorothiazide and Propranolol-Hydrochlorothiazide in Combined Formulations by Derivative Spectroscopy
Authors: Prasad Challapalli V N , Bharadwaj Vipin , Narsimhan Vidya , Chowdhary Rama T , Parimoo Pyare 
Published: February 2020

Abstract
A derivative spectrophotometric procedure was established for simultaneous determination of propranolol HCI (PP) with hydrochlorothiazide (HTZ) and metoprolol tartrate (MTP) with HTZ in tablet preparations. The method uses first- and second-derivative spectra of tablet extract in 0.01 N NaOH solution. Ratios of analyte concentrations in the mixture were determined by the compensation technique. The zero-crossing point (ZCP) was also used to estimate the amounts of PP and HTZ in the formulations, and results were compared with those from the compensation technique. The results were found to be precise and free from interferences.
Comparison of Sorbitol MacConkey and Hemorrhagic Coli Agars for Recovery of Escherichia coli 0157:H7 from Brie, Ice Cream, and Whole Milk
Authors: Hammack Thomas S , Feng Peter , Amaguaña R Miguel , June Geraldine , Sherrod Patricia S , Andrews Wallace H 
Published: February 2020

Abstract
The relative efficacies of hemorrhagic coli (HC) agar and several formulations of sorbitol Mac-Conkey (SorMac) agar, with and without 0.1 % (w/v) 4-methyllumbelliferyl-ß-D-glucuronide (MUG), in recovering unstressed and heat-stressed Escherichia coli 0157:H7 from Brie cheese, ice cream, and whole milk were determined. Recovery of unstressed E. coli 0157:H7 was determined quantitatively by spread-plating diluted samples onto different agars and performing plate counts. Recovery of stressed E. coli 0157:H7 was determined qualitatively by enriching samples in modified trypticase soy broth, streaking the incubated enrichments, and isolating E. coli 0157:H7 colonies from the agars. HC agar and the SorMac agar formulations did not differ significantly in their ability to recover unstressed E. coli 0157:H7 from ice cream and whole milk; however, HC agar recovered significantly more unstressed E. coli 0157:H7 from Brie cheese than did the SorMac agar formulations. Bacteriological Analytical Manual and Oxoid SorMac agar formulations made from individual ingredients, did not differ significantly in recovering unstressed E. coli 0157:H7 from Brie cheese. The efficiency of the commercially available Oxoid SorMac agar could not be determined because of overgrowth by indigenous microflora. HC and SorMac agars did not differ significantly in recovering stressed E. coli 0157:H7 from Brie cheese, ice cream, and whole milk. MUG had no apparent effect on recovery of either stressed or unstressed E. coli 0157:H7 from the dairy foods examined.
Liquid Chromatographic Determination of Folate Monoglutamates in Fish, Meat, Egg, and Dairy Products Consumed in Finland
Authors: Vahteristo Lusa T , Ollilainen Velimatti , Varo Pertti 
Published: February 2020

Abstract
A liquid chromatographic (LC) method with fluorescence and UV detection was used to determine the folate contents of fish, meat, fish and meat products, chicken, eggs, and milk consumed in Finland. 5-Methyltetrahydrofolate, tetrahydrofolate, 5-formyltetrahydrofolate, 10-formylfolic acid, and folic acid from 24 commodities obtained from supermarkets, retail stores, and different outlets in the Helsinki area were analyzed. Pooled samples were extracted at pH 6.0 in the presence of antioxidants and deconjugated with hog kidney deconjugase. Very low levels of folates were detected in meat and meat products. Fresh fish, fish sticks, and chicken meat contained reasonable amounts (3–13 μg/100 g) of tetrahydrofolate and 5-methyltetrahydrofolate. Egg yolk contained high concentrations of 5-methyltetrahydrofolate (140–150 μg/100 g); 10-formylfolic acid was also detected (14–17 μg/100 g). Between-species differences in folate monoglutamate distributions were observed. The highest levels of tetrahydrofolate, &gt;5 μg/100 g, were found in chicken meat and fillets of rainbow trout, whitefish, and baltic herring. Tetrahydrofolate was most abundant in fresh fish. LC was well suited for analyzing folate compositions of meat, fish, and other foods of animal origin. Recovery of added folates ranged from 49 to 96%.
Determination of Nonylphenol and Octylphenol Ethoxylates in Effluent by Liquid Chromatography with Fluorescence Detection
Authors: Mackay Lindsey G , Croft Marguerite Y , Selby David S , Wells Robert J 
Published: February 2020

Abstract
A robust liquid chromatographic (LC) method with fluorescence detection is described for the simultaneous determination of the nonionic surfactants nonylphenol ethoxylates (NPEO) and octylphenol ethoxylates (OPEO) in effluent samples from sewerage treatment plants. The cleanup procedure uses graphitized carbon black solid-phase extraction cartridges. A subsequent derivatization step removes matrix interferences that are no longer fluorescent after acetylation. The efficiency of the method is monitored by inclusion of a surrogate compound designed and synthesized specifically for this purpose. The limit of reporting for the method is 5 μg/L for 100 mL effluent samples. Studies on confirmation of identity of NPEO and OPEO by electrospray LC/mass spectrometry are described.
Gas Chromatographic Determination of Acephate in Technical Material and Soluble Powder Formulations: Collaborative Study
Authors: Kovacs Martin F , Michael Wehr H ,   Collaborators:, Belkind B A , Stein J , Bennett O O , Torkzadeh M , Bernes A , Galoux M , Bura L , Burns A , Fujie G , Gomez F , Lim T , Manso L , Parsons A H , Reeves P , Slahck S C , Harbin D , Sneddon R , Menasco M , Takahashi K , Fukunaga T 
Published: February 2020

Abstract
A gas chromatographic (GC) method was developed for quantitation of acephate (Orthene) in technical material and soluble powder formulations. Acephate is an organophosphate with broad spectrum contact and systemic insecticidal properties. Fourteen collaborators from 8 countries participated in a collaborative study of the method. Collaborators were provided with the method; samples of technical acephate and formulated soluble powder containing 95-99% and 71-75% acephate, respectively; an acephate reference standard; and internal standard. Samples were weighed, diluted to volume with internal standard, and quantitated by using GC peak area ratios. Relative standard deviation values for reproducibility (RSDR) were 1.03-2.55 for 95-99% technical acephate and 1.36-2.73 for formulated soluble powder containing 71-75% acephate. The GC method for determination of acephate in technical material and soluble powder formulations has been adopted by AOAC INTERNATIONAL
Assurance Enzyme Immunoassay for Detection of Enterohemorrhagic Escherichia coli 0157:H7 in Selected Foods: Collaborative Study
Authors: Feldsine Philip T , Falbo-Nelson Maria T , Brunelle Sharon L , Forgey Robin L ,   Collaborators:, Al-Hasani S , Ball C , Beatty S , Blanchfield B , Bowen B , Bremer N , Brookman D , Brookman S , Brushaber M , Bryant J , Bryant D , Bryant R , Chlebowski E T , Copeland F , Culak D A , Dalley E , Destro C , Finkenbiner D , Frissora R , Fung D Y C , Garcia G R , Gray M R , Hagen C J , Harshavardhan T , Hart-Thakur R , Inami G , Johnson S , Kandakai L V , Lessard D , Lin S , Liu V , Matiuck S , McAteer L , Miller L , Moon B , Nasri H , Pack L , Pilot K , Price C , Pruett P , Ramirez C , Richter D , Schmieg J A , Schultz G , Sloan E M , Sprague D M , Tebay D , Tomer J , Tuncan E , Warburton D , Watson M , West D 
Published: February 2020

Abstract
Five foods types were analyzed by the Assurance EHEC (Escherichia coli 0157:H7) enzyme immunoassay (EIA) and by the Bacteriological Analytical Manual (BAM) culture method. Each sample of each food type at each inoculation level was simultaneously analyzed by both methods. A total of 21 laboratories representing state and federal government agencies and private industry in the United States and Canada participated. Samples were inoculated with E. coli 0157:H7, except for one lot of poultry that was naturally contaminated. A total of 1304 samples and controls were analyzed and confirmed, of which 473 were positive and 818 were negative by both methods. Thirteen samples were positive by BAM but negative by EIA. Because of the study design, it was not possible for the BAM method to produce false-negative or falsepositive results. The Assurance method for detection of E. coli OI57:H7 in selected foods has been adopted first action by AOAC INTERNATIONAL.
Multivariate Statistics as a Classification Tool in the Food Laboratory
Authors: Kaufmann Anton 
Published: February 2020

Abstract
Multivariate statistics is a powerful tool for answering complex questions like the geographical origin of wine. Instead of expensive tests such as stable isotope measurements, less costly routine analysis data can be used. Problems like the choice of analysis parameters, the size of reference data, and the best suited statistical technique are addressed. Multivariate statistics was used very successfully with real samples in an official Swiss wine-tasting championship. Although the examples presented in the paper deal with wine, the principles, opportunities, and shortcomings may also apply to other food products.
Determination of Histidine by Atomic Absorption Spectroscopy
Authors: El-Brashy Amina M , Al-Ghannam Sheikha M 
Published: February 2020

Abstract
Two atomic absorption spectrophotometric methods are described for determination of histidine. The first is based on reaction of histidine with mercury(II) ions in phosphate buffer (pH 9). The second is based on reaction of histidine with iron(III) ions in neutral medium. The precipitate formed in both methods is separated by centrifugation, and the equivalent Hg(II) or Fe(III) ions as well as surplus ions in the filtrate are determined by atomic absorption at 253.6 and 248.3 nm for Hg and Fe, respectively. Amounts of histidine are calculated from calibration graphs prepared by standard addition methods or by regression equations. The procedures were successfully applied to assay of histidine in dosage forms after thin-layer chromatographic separation. Results compared favorably with those of the official method.
Predictive Microbiology of Dairy Products: Influence of Biological Factors Affecting Growth of Listeria monocytogenes
Authors: Brouillaud-Delattre Agnes , Maire Murielle , Collette Catherine , Mattei Cesar , Lahellec Cecille 
Published: February 2020

Abstract
The growth potential of Listeria monocytogenes was evaluated at low temperature in sterilized milk and raw dairy products. Sterilized and raw milk were inoculated with different strains of L. monocytogenes in 2 physiological states and at various contamination levels. Raw cheese was naturally contaminated with Listeria spp. The results suggest that some biological factors influence the growth capacity of L. monocytogenes in dairy products. Significant strain effect was observed at low temperature whatever the growth medium. By contrast, no inoculum effect was observed in the 3 dairy products. In raw matrixes, growth of L. monocytogenes was influenced greatly by bacterial interactions and physiological state of inoculum cells.
Use of the Microwave-Assisted Process in Extraction of Fat from Meat, Dairy, and Egg Products under Atmospheric Pressure Conditions
Authors: Paré J R Jocelyn , Matni Gisèle , Bélanger Jacqueline M R , Li Ken , Rule Cari , Thibert Benoît , Yaylayan Varoujan , Liu Zhun , Mathé Daniel , Jacquault Patrick 
Published: February 2020

Abstract
Fat from meat, dairy, and egg products was extracted by using Microwave-Assisted Process (MAP) technology under atmospheric pressure conditions. Fat content was determined gravimetrically after extraction with microwaves and organic solvents that are transparent to microwaves relative to the sample. (In situ hydrolysis was performed for dairy and egg products.) Fat from the food sample migrated completely to the extractant when samples were irradiated with focused microwave for a total of 3 min for meat products, 1 min for dairy products, and 4 min for egg products. Unlike current methods used for determining fat in meat products, the microwave-assisted method does not require a dry sample, because moisture in the sample (around 75%) enhances the efficiency of extraction. No preprocessing was required for meat samples other than homogenization, which is critical, as it is for other current methods. In addition to speed and ease of use, the features of this technology are low solvent consumption, low energy consumption, reproducibility, and recoveries similar to or even better than those of conventional extraction methods.
Quantitation of Aflatoxin B1-N7-Guanine Adduct in Urine by Enzyme-Linked Immunosorbent Assay Coupled with Immunoaffinity Chromatography
Authors: Vidyasagar Tfflrumurthy , Vyjayanthi Vadapalli , Sujatiia Nayak , Rao Beedu Sashidhar , Bhat Ramesh Venkataramana 
Published: February 2020

Abstract
IndiaA specific and sensitive method to quantitate aflatoxin B1-N7-guanine adduct in urine samples by immunoaffinity chromatography coupled with indirect competitive enzyme-linked immunosorbent assay (ELISA) is reported. A novel in vitro method to synthesize an antigen (bovine serum albumin-guanine-aflatoxin B1) and its use to produce polyclonal antibodies specific to the hapten aflatoxin B-N7-guanine are discussed. An indirect competitive ELISA developed to quantitate aflatoxin adduct showed a 50% inhibition at 15.6 pmol aflatoxin B1-N7-guanine (y=66.73+ (-19.8)x, r=-0.997). Interference by aflatoxin B1 was less than 5%, and no interference by guanine, aflatoxin Gι and aflatoxin M1 was observed. An immunoaffinity column was also developed, by using these polyclonal antibodies, for single-step purification of aflatoxin B1-N7-gua-nine. The immunoaffinity column and the indirect competitive ELISA were evaluated and validated by quantitation of aflatoxin B1-N7-guanine in urine from rats dosed with aflatoxin B1 (1 mg/kg body weight). Spiking studies with standard aflatoxin B1-N7-guanine adduct at 2 and 4 μg/mL phosphate- buffered saline gave 96 and 100% recoveries, respectively, for immunoaffinity cleanup column. The method also was tested successfully for quantitating aflatoxin B1-N7-guanine adduct in spiked human urine. Recoveries of the adduct were 79-90%.
Multiresidue Method for Analysis of Pesticides in Liquid Whole Milk
Authors: Bennett Dianne A , Chung Alex C , Mark Lee S 
Published: February 2020

Abstract
A multiresidue method to analyze liquid whole milk for 59 compounds was developed. The method involves a single extraction and cleanup strategy for many classes of compoundsorganophosphorus compounds (OPs), organochlorine compounds(OCs), yv-methylcarbamates (MCs), etc. Initial extraction is performed with ethanol-ethyl acetate as solvent and sodium sulfate as drying agent. A portion of the extract is concentrated to an oily consistency, and target analytes are partitioned into acetonitrile. Further cleanup is achieved by sequential solid-phase extractionsoctadecyl (C18)-bonded silica cartridges followed by aminopropyl (NH2)- bonded silica cartridges. The solvent is exchanged to acetone for analysis by gas chromatography (GC) with electrolytic conductivity, flame photometric (FPD) or mass spectrometric (MS) detection and to methanol for analysis by liquid chromatography with postcolumn derivatization. Typical limits of detection (LODs; peak-to-peak signal-to-noise ratio ≥3) were 0.3 ppb for OPs, 0.9 ppb for OCs and MCs, and 9 ppb for mass-selective detection. From the level of quantitation (LOQ = 3.33 x LOD) to 10 x LOQ, linear instrument response was observed for all detectors except the FPD which required a second- order calibration curve. Average recoveries for spikes at the LOQ ranged from 69 to 127%, with standard deviations of about 10%. Similar accuracy and precision were observed for fortifications at 5 x LOQ and 10 x LOQ. The method was used to analyze 20 milk samples from various liquid milk processing plants. Incurred residues were confirmed by high-resolution GC/MS and GC/MS/MS.
Use of Total Organic Carbon Analysis and Fourier-Transform Infrared Spectroscopy to Determine Residues of Cleaning Agents on Surfaces
Authors: Biwald Christopher E , Gavlick Walter K 
Published: February 2020

Abstract
Total organic carbon (TOC) analysis can be used in many cases as a nonspecific method of determining trace levels of organic residue on manufacturing equipment before and after cleaning. In this study, a swab sampling method followed by TOC analysis is used to determine organic residue levels associated with alkaline and acidic cleaning agents on a stainless steel surface. The alkaline cleaning agent was nonvolatile, resulting in favorable TOC analysis and validation. The acidic cleaning agent was very volatile, requiring more skilled sample handling and resulting in a more difficult validation. Fourier-transform infrared (FTIR) spectroscopy with a grazing-angle sample attachment can be used for direct surface measurements of cleaning-agent residues on a stainless steel surface. FTIR spectroscopic studies complement and support the TOC studies. One band chosen for each cleaning agent was monitored throughout the leaning process. cidic and alkaline
Determination of Emamectin Benzoate in Freshwater and Seawater at Picogram-Per-Milliliter Levels by Liquid Chromatography with Fluorescence Detection
Authors: Hicks Michael B , Payne Lori D , Prabhu Sunil V , Wehner Teresa A 
Published: February 2020

Abstract
Emamectin benzoate is a very effective agricultural insecticide applied to various crops at very low rates. A method to analyze emamectin benzoate in seawater and freshwater was developed. The method yields good recoveries with limits of quantitation of 20 pg/mL for freshwater and 24 pg/mL for seawater (signal-to-noise ratio [S/N] ≥ 10). The limit of detection is 10 pg/mL (S/N ≥ 3). Emamectin benzoateis concentrated from a 50 mL sample on a C8 solid-phase extraction cartridge and eluted with 1% ammonium acetate in methanol. The eluate is evaporated to 1 mL, diluted with 1 % ammonium acetate in water, and partitioned into ethyl acetate. The ethyl acetate extract is concentrated to about 0.5 mL and diluted to about 1 mL with acetonitrile. 1-Methylimidazole is added to the diluted sample, and then trifluoroacetic anhydride is added to form a fluorescent derivative. The derivatized sample is injected onto a reversed-phase liquid chromatographic system equipped with a fluorescence detector. Overall method recoveries for concentrations ranging from 20 to 1010 pg/mL were 84 ± 9.5% for tap water and 89 ± 11% for seawater. These results are equivalent to recoveries previously obtained with a more elaborate method (90 ± 8.8% for freshwater). Controls were free of interferences or coeluting impurities. Fluorescence detection provides high sensitivity and selectivity, enabling trace-level analysis.