bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas Chromatographic Detection of Tris(2-chloroethyl) and Tris(2-butoxyethyl)phosphate in Groundwater by Large-Sample-Volume Injection
Authors: Suzuki Toshesari , Yaguchi Kumiko , Ohnishi Kazuo , Yamagishi Tatsunori 
Published: February 2020

Abstract
A capillary gas chromatograph equipped with a flame photometric detector (GC–FPD) for splitless injection of large sample volume was developed. The GC–FPD effectively diverted dichloromethane from the analytical column through a solvent diversion column and quantitatively retained tri(2-chloroethyl) phosphate (TCEP) and tris(2-butoxyethyl)- phosphate (TBXP) on a cold-trap column in front of the analytical column. The optimum conditions for 100 uL injections of TCEP and TBXP in dichloromethane at concentrations from 1 to 100 ng/mL were investigated. With the GC–FPD, relative standard deviations of the peak area and the retention time of the triesters injected at 10 ng/mL were less than 7.0 and 0.05%, respectively. These results were similar to those from normal splitless injection of 1 μL at 1 μg/mL in dichloromethane. A screening method for TCEP and TBXP in groundwater combined with liquid–liquid extraction with dichloromethane permitted detection at low nanogram-per-liter levels. Recoveries of TCEP and TBXP in 500 mL of groundwater were greater than 77.2 and 81.4%, respectively, each at fortified level of 10ng/L.
Determination of Metsulfuron Methyl and Its Two Metabolites in Crops by Liquid Chromatography with Ultraviolet Detection
Authors: Zhou Mjn , Li Gui-Yun , Whalen Stephanie A 
Published: February 2020

Abstract
Metsulfuron methyl, its hydroxy metabolite (A1), and its glucose conjugate metabolite (A) were determined in several crops by liquid chromatography (LC) using a simple extraction and cleanup scheme. After the parent and 2 major metabolites were extracted from crops with methanol, metabolite A was enzymatically hydrolyzed to metabolite A1 with β-glucosidase. The treated extracts were cleaned up chromatographically, and then metsulfuron methyl and metabolite A1 were quantitatively determined by reversed-phase LC with UV detection at 254 nm. Recovery of metsulfuron methyl and its 2 metabolites was 90 ± 6% over a range of 0.005 to 0.4 ppm from fortified samples of brown grain, wheat, barley, sugarcane stalk, and oat straw. Method detection limits (MDLs) were 0.005 ppm for metsulfuron methyl, 0.006 ppm for metabolite A, and 0.003 ppm for metabolite A1 in such crops as brown grain, wheat, barley, and sugarcane, and 0.01 ppm for metsulfuron methyl, 0.015 ppm for metabolite A, and 0.01 ppm for metabolite A1 in oat straw. The MDLs were estimated on the basis of a signal-to-noise ratio of 5 within a confidence interval of 95%. The method has potential application for the analyses of these analytes in other crops and feeds and may be applicable to other sulfonylurea herbicides.
Use of Trimmed Duplicates Derived from Laboratory Data To Estimate Standard Deviation
Authors: Johnson Richard L , Latimer George W , Spiegelman Cliff 
Published: February 2020

Abstract
Improved standard deviation estimates from possibly biased duplicate measurements can be derived from appropriately trimmed plots of standard deviation estimates using pairs of replicates vs the quantiles of a half-normal distribution. Simulated studies show that these estimates exhibit generally lower mean-squared errors and biases than do more standard robust estimators of location—¾ times the interquartile range and 3/2 times the mean absolute deviation from the median.
Estimation of Parameters Relating Crude Fiber in Feeds to Acid–Detergent Fiber
Authors: Jones Neil E 
Published: February 2020

Abstract
By regression analysis of data from 80 check samples from the Association of American Feed Control Officials and applying the least-squares cubic method to the problem of statistical errors in both variables, it was determined that the best linear relation between the percent crude fiber value of a feed and the corresponding percent acid–detergent fiber value is crude fiber (%) = 0.77 × acid–detergent fiber (%) − 0.49.
Voltammetric Determination of Acid Values of Fats and Oils
Authors: Kusu Fumtyo , Fuse Tetsuo , Takamura Kiyoko 
Published: February 2020

Abstract
A new method for determining acid values of fats and oils was developed based on measurement of reduction prepeak current of 2-methyl-1,4-naphthoquinone (VK3) from 8 × 10−6 to 6 × 10−3 M, due to free fatty acid (e.g., linoleic acid). Acid value of 11 samples was determined. The relative standard deviation of acid value for 5 replicates of each sample was less than 2.5%. The method is superior to conventional titration methods in sensitivity and overcomes inaccuracy due to vagueness in color change of acidbase indicators in organic solvents.
International Survey on Dietary Fiber: Definition, Analysis, and Reference Materials
Authors: Lee Sungsoo C , Prosky Leon 
Published: February 2020

Abstract
An international survey was conducted to get the views of 147 professionals in the field on the definition of dietary fiber. The survey also solicited opinions on analytical methods for nutrition labeling, quality control, and nutrition research. The survey finds that dietary fiber is generally defined as polysaccharides and lignin that are not hydrolyzed by human alimentary enzymes. Support is strong for expansion of the definition to include oligosaccharides that are resistant to hydrolysis by human alimentary enzymes. Among techniques for nutrition labeling and quality control, enzymatic-gravimetric methods get the highest support. For nutrition research, more detailed methods such as gas-liquid chromatography and liquid chromatography were considered more appropriate. Respondents support labeling of total, soluble, and insoluble dietary fiber or total dietary fiber alone as sufficient for nutrition labeling of food packages. However, for nutrition research, detailed analytical methods, improvements in accuracy (i.e., closer simulation of in vitro techniques to conditions of human gastrointestinal tract), and improvements in precision and simplicity are suggested. Less than 20% of the participants use reference materials for dietary fiber analysis.
Liquid Chromatographic Methods for Fluoxetine Hydrochloride, Its meta Isomer, and Related Compounds in Raw Materials
Authors: Lacrok Pauline M , Yat Patrick N , Lovering Edward G 
Published: February 2020

Abstract
Liquid chromatographic (LC) methods were developed for assay of fluoxetine hydrochloride, its meta isomer, and 12 related compounds in drug raw materials. The method for assay and determination of the meta isomer requires an Exsil ODS-B column; a mobile phase consisting of tetrahydrofuran, acetonitrile, and buffer; a flow rate of 1 mL/min; and detection at 214 nm. The method for related compounds specifies a Spherisorb nitrile column; a mobile phase consisting of tetrahydrofuran, acetonitrile, and buffer; a flow rate of 1 mL/min; and detection at 214 nm. The limits of quantitation in the presence of the drug are 0.1% for the meta isomer and 0.05% or less for the related compounds. Assay precision was less than 1.0% on triplicate weighings. Drug contents of 4 raw material samples were between 98.8 and 100.1%. Impurity levels in the 4 samples ranged from 0.14 to 0.45%. In addition, one sample contained ca 0.13% of the meta isomer. A second analyst, using columns from different suppliers, obtained similar results.
Stability-Indicating Proton Nuclear Magnetic Resonance Spectroscopic Method for Determination of S-Adenosyl-L-Methionine in Tablets
Authors: Revelle Larry K , d’Avignon D André , Reepmeyer John C , Zerfing Richard C 
Published: February 2020

Abstract
We present a simple, accurate, stability-indicating nuclear magnetic resonance (NMR) method for determining active (S,S) and inactive (R,S) epimers of S-adenosyl-L-methionine (SAM) in tablets. The SCH3 resonances of SAM epimers were well resolved at 300 MHz. Individual assays of 5 SAM tablets gave SAM values of 101.3 ± 1.7% of declared amounts. Tablet solutions were assayed at a level of 8.0 mg/mL, but the method was linear for SAM concentrations ranging from 64 to 1 mg/mL (correlation coefficient, 0.9996). Reproducibility was indicated by a relative standard deviation of 0.33% for 6 replicate assays for total SAM at a concentration of 8 mg/mL. In contrast to the propietary liquid chromatographic (LC) method, which requires SAM as an external standard, the NMR method uses sodium trimethylsilylpropionate-d4 (TSP) both as an internal standard and as a chemical shift reference. The method was used to test the stability of SAM analytes under various pH levels and temperatures. We found 8% inactivation of SAM due to epimerization over a 24 h period at room temperature and pH 5. SAM solutions showed no detectable inactivation after 14 days when stored below 0°C.
Production of Monoclonal Antibodies Specific to Clostridium botulinum Type B Neurotoxin
Authors: Noah Charles W , Poteet Sherilyn S , Ramos Nora C , Perez John C , Huang Shyi Y 
Published: February 2020

Abstract
Four monoclonal antibodies were produced for use in a rapid method to detect Clostridium botulinum type B neurotoxin. Cells of mouse myeloma cell line SP2/0 were fused with splenocytes of immunized BALB/c mice. An immunoblot assay of semipurified commercial neurotoxins of C. botulinum types A, B, C, D, E, and F was used to show specificity. All the monoclonal antibodies reacted with type B neurotoxin but did not cross-react with the other types. The monoclonal antibodies, separately and combined, did not neutralize the toxin in mice, and all showed specificity to the whole neurotoxin molecule and the heavy-chain component by immunoblot. No evidence of specific binding to the hemagglutinin molecule was noted. When tested against concentrated cultured supernatants of C. botulinum types A, B, E, and F, the 4 monoclonal antibodies reacted only against type B strains. They will be incorporated into a rapid assay with other specific monoclonal antibodies to detect C. botulinum neurotoxins from pure cultures or suspect foods.
Gas Chromatographic Method for Quantitation and Confirmation of Trichothecenes in Wheat
Authors: Furlong Eliana B , Valente Soares Lucia M 
Published: February 2020

Abstract
A capillary gas chromatographic method with flame ionization detection was evaluated for quantitation and confirmation of 7 trichothecenes known to occur in grain crops. The method was applied to spiked and naturally contaminated wheat samples. Samples were extracted with methanol-aqueous KCI. After clarification with ammonium sulfate and partition to chloroform, a charcoal–alumina–Celite column cleanup was used. Heptafluorobutyryl derivatives of trichothecenes were quantitated with a methyl eicosanoate internal standard. Confirmation of identity was achieved by comparing the chromatographic behavior of suspected samples with those of standards after acetylation and hydrolysis for group A trichothecenes, and acetylation and reduction for group B trichothecenes. Limits of detection ranged from 0.1 to 0.5 μg/g. Average recoveries for diacetoxyscirpenol (DAS) and nivalenol (NIV) determined at 7 levels of contamination were 88 and 93%, respectively. Average recoveries for deoxynivalenol, NIV, DAS, T2 tetraol, and T2 triol at a single level of contamination were 85,87,83,87, and 91 %, respectively. Relative standard deviations for determinations of naturally contaminated samples ranged from 2.8 to 12.9%. For spiked wheat samples, the relative standard deviations ranged from 4.6 to 11.9%.
Synchronous Spectrofluorimetric Determination of Total Amounts of the Six Polycyclic Aromatic Hydrocarbons Officially Designated as Indicators of Drinking Water Quality
Authors: De Alda-Villaizan Maria J López , García-Falcon Soma , Lage-Yusty Maria A , Simal-Lozano Jesús 
Published: February 2020

Abstract
We report a quick, simple method for determination of the joint concentration of the 6 polycyclic aromatic hydrocarbons (PAHs) designated by current legislation as quality indicators for drinking water and for surface waters destined for use as drinking water. Water samples are extracted with hexane, and total indicator PAH concentration is determined by synchronous spectrofluorimetry (optimal instrumental parameters are reported). The detection limit (5.0 ng/L), quantitation limit (8.4 ng/L), precision (coefficient of variation, 3.8%), and accuracy (recovery, 77%) were well within the legal bounds for reference methods.
Identification of Lead and Other Elements in Ceramic Glazes and Housewares by 109Cd-Induced X-Ray Fluorescence Emission Spectrometry
Authors: Anderson David L , Cunningham William C , Lemdstrom Tyler R , Olmez Ilhan 
Published: February 2020

Abstract
Radioisotope x-ray fluorescence spectrometry was investigated as a potential screening method for Pb and other elements in housewares. Thirty-six commercial houseware items and 87 ceramic test tiles (85 fired with hobby glazes and 2 blank bisques) were examined qualitatively for the presence of Pb by using 109Cd-induced L x-ray fluorescence emission spectrometry. For the housewares, the technique provided fast, nondestructive analysis of areas with about 10 cm diameters (general regions) to about 4 mm diameters (isolated design regions). Pb was found in 25 of 28 ceramicware items, in all 8 other housewares, and in all the testtile glazes above the limit of detection of 1 count per second (cps) for Pb Lβ x-rays. For housewares, Pb identification did not always correspond to Pb leachability. For 68 test-tile glazes labeled as containing Pb (39 of which were also labeled ‘dinnerware safe’ or ‘safe for food containers’), count rates ranged from 290 to 730 cps, whereas for the other 17 glazes labeled (with one exception) ‘nontoxic,’ much lower count rates (5–61 cps) were obtained. Other elements found in the housewares or test glazes were As, Au, Ca, Co, Cr, Cu, Fe, Mn, Nb, Ni, Rb, Sr, Y, Zn, and Zr.
Supercritical Fluid Extraction and Gas Chromatography/Ion Trap Mass Spectrometry of Pentachloromtrobenzene Pesticides in Vegetables
Authors: Lehotay Steven J , Ibrahim Medina A 
Published: February 2020

Abstract
An analytical approach using supercritical fluid extraction (SFE) followed by gas chromatography/ion trap mass spectrometry (GC/ITMS) was developed for the analysis of the fungicide pentachloromtrobenzene and several analogues in vegetables. The method was tested in the analysis of carrots, potatoes, green beans, celery, and radishes fortified with pentachloronitrobenzene, tetrachloronitrobenzene, pentachloroanisole, pentachlorothioanisole, pentachlorobenzene, hexachlorobenzene, and pentachloroaniline. An incurred carrot sample analyzed by the method was shown to contain hexachlorobenzene at 7 ± 3 ng/g, which agreed with the concentration (8 ± 4 ng/g) determined using a traditional solvent-based method. The SFE method consisted of the following steps: (1) homogenizing a 50 g vegetable sample and weighing a 3 g subsample; (2) mixing 2 g sorbent (Hydromatrix) with the subsample to absorb moisture and packing a 10 mL extraction vessel; (3) extracting with 40 mL C02 at 200 atm, 40°C, and a flow rate of 3 mL/min; and (4) collecting the extract on a 1 g alumina basic trap at 25°C and flushing with 8 mL isooctane. Collection of the extract on alumina efficiently removed chlorophyll and other matrix interferences. GC/ITMS in the electron-impact mode confirmed and quantitated the analytes at concentrations as low as 1 ng/g.
Validation of an Analytical Instrumental Method by Standard Addition Methodology
Authors: Rodríguez Luis Cuadros , Campaña Ana M García , Barrero Fermin Alés , Linares Carlos Jiménez , Ceba Manuel Román 
Published: February 2020

Abstract
A statistical procedure to validate an analytical methodology by standard addition methodology is described. The data set obtained in 3 calibration experiments with standard solutions, standard additions, and portions of sample is used. The accuracy of the analytical results is checked by comparison of analyte contents in the different calibrations and from the recovery. Mathematical expressions to estimate the statistical parameters are proposed. The statistical protocol has been applied to fluorimetric determination of molybdenum with alizarin S in vegetable tissues.
Adaptation of a Dry Ashing Procedure for Determination of Selenium by Fluorimetry in High-Fat Foods
Authors: Bellanger Jacques R 
Published: February 2020

Abstract
The wet ashing–dry ashing procedure for destruction of organic matter in high-fat foods for subsequent fluorimetric determination of selenium was investigated. Samples were decomposed by predigestion with nitric acid and dry-ashed with magnesium nitrate and hydrochloric acid. Selenium was recovered quantitatively through the total procedure. Detection limit was about 4 ppb. Accuracy was tested by analysis of several reference materials and by comparison with the wet-digestion method. The present method can be used conveniently for selenium determination in high-fat foods.
Rapid Extraction and Cleanup for Liquid Chromatographic Determination of Domoic Acid in Unsalted Seafood
Authors: Quilliam Michael A , Xie Mie , Hardstaff William R 
Published: February 2020

Abstract
Domoic acid is the toxin responsible for incidents of amnesic shellfish poisoning. A rapid extraction and cleanup for the liquid chromatographic determination of domoic acid in unsalted seafood is reported. The method uses a single-step extraction with 50% aqueous methanol and a selective cleanup and preconcentration with strong-anion exchange, solid-phase extraction. Determination is performed by liquid chromatography with ultraviolet absorbance detection. The detection limit was 20–30 ng/g. Recoveries of 93% were achieved from 0.2 to 20 μg/g in mussel tissues. The method gave a precision of less than 3% for concentrations greater than 2 μg/g and less than 6% at 0.2 μg/g. A linear dynamic range of 104 can be achieved. The method was successfully applied to a variety of seafood products, including mussels, razor clams, crabs, and anchovies.
Analysis of Diarrhetic Shellfish Poisoning Toxins in Shellfish Tissue by Liquid Chromatography with Fluorometric and Mass Spectrometric Detection
Authors: Quilliam Michael A 
Published: February 2020

Abstract
Diarrhetic shellfish poisoning (DSP) is a severe gastrointestinal illness caused by consumption of shellfish contaminated with toxigenic dinoflagellates. The main toxins responsible for DSP are okadaic acid (OA), DTX-1, DTX-2, and DTX-3, the latter being a complex mixture of 7-O-acyl derivatives of the first 3. In this study, existing methods based on liquid chromatography (LC) combined with mass spectrometry (LC–MS) and LC with fluorometric detection (LC–FLD) of anthryldiazomethane (ADAM) derivatives were improved upon to achieve a high degree of accuracy and precision for the determination of DSP toxins in a new mussel tissue reference material (MUS-2). All experimental parameters were examined comprehensively, and a new internal standard and a new solid-phase extraction cleanup method were introduced. Quantitative extraction of DSP toxins from shellfish tissue was achieved by exhaustive extraction with aqueous 80% methanol. Cleanup was accomplished by partitioning the crude aqueous methanol extract with hexane to remove lipids and then with chloroform to isolate the toxins. A further cleanup based on an aminopropylsilica column was useful for LC-MS and looks promising for the ADAM/LC-FLD method. The internal standard, 7-O-acetylokadaic acid, synthesized by partial acetylation of OA, improved accuracy and precision by correcting for incomplete recoveries in extraction, cleanup, and derivatization steps and for volumetric errors and instrumental drift. An improved silica cleanup after ADAM derivatization also was developed by controlling the activities of both sorbent and solvents. The methods were tested with various mussel tissue samples. The resulting improved methods will be useful to analysts involved in routine monitoring of DSP tox ins.
U.S. Food and Drug Administration Monitoring of Lead in Domestic and Imported Ceramic Dinnerware
Authors: Baczynskyj William M , Yess Norma J 
Published: February 2020

Abstract
The U.S. Food and Drug Administration (FDA) conducted a survey of domestic and imported ceramic dinnerware from January to February 1992 to determine the status of lead leaching from this ware. Ceramicware was screened at the collection point by using the Quick Color Test (QCT); if the QCT was positive, the ware was analyzed in the laboratory by using atomic absorption spectroscopy (AAS). For imports, 5222 lots were examined using the QCT. Of these lots, 46 exceeded FDA’s 1991 guidelines as determined by using AAS. For domestic ware, 676 lots were examined using the QCT, and 17 lots exceeded the 1991 guidelines. The violation rates, 0.9% for imports and 2.5% for domestic ware, were about twice as high as they would have been under the 1980 guidelines.
Survey of Deoxynivalenol in U.S. 1993 Wheat and Barley Crops by Enzyme-Linked Immunosorbent Assay
Authors: Trucksess Mary W , Thomas Frederick , Young Kathryn , Stack Michael E , Fulgueras Wendy J , Page Samuel W 
Published: February 2020

Abstract
Wheat and barley from the 1993 crop year were analyzed for deoxynivalenol (DON). A total of 630 samples were collected by the Federal Grain Inspection Service in 25 states and analyzed using a commercially available, direct competitive, enzyme-linked immunosorbent assay. The limit of determination was about 0.5 μg/g. DON contamination in the 483 wheat samples averaged 2.0 μg/g and ranged from &lt;0.5 to 18 μg/g. DON contamination in the 147 barley samples averaged 4.2 μg/g and ranged from &lt;0.5 to 26 μg/g. About 40% of the wheat samples and 57% of the barley samples contained DON levels that were greater than the U.S. Food and Drug Administration 1982 advisory level of 2 μg/g for DON in wheat designated for milling (human consumption).
Determination of Sulfadimethoxine and Sulfamethazine Residues in Animal Tissues by Liquid Chromatography and Thermospray Mass Spectrometry
Authors: Boison Joe O , Keng Lily J-Y 
Published: February 2020

Abstract
A simple, sensitive, and rapid method for simultaneous determination of sulfamethazine and sulfadimethoxine residues in animal tissues by liquid chromatography (LC) with on-line confirmation by thermospray mass spectrometry is reported. Tissue extracts, after cleanup on C18 cartridges, were injected into a reversed-phase C18 column, and the sulfa drugs were determined by ultraviolet (UV) detection at 265 nm. On-line confirmation of sulfamethazine and sulfadimethoxine in the extracts by mass spectrometry was obtained by feeding the sulfa drugs eluting from the chromatographic column after UV detection directly into the ion source of a mass spectrometer with a thermospray ionization LC interface. Analytical results obtained with the LC method, which has detection limits of 2 and 10 ng/g of tissue, for sulfamethazine and sulfadimethoxine, respectively, compared favorably with those obtained with the official thin-layer chromatographic–densitometric method.
Identification of an Impurity in Commercial Sources of the Tomato Glycoalkaloid Tomatine
Authors: Bushway Rodney J , Perkins Lewis B 
Published: February 2020

Abstract
Three commercial sources of tomatine showed 2 peaks of approximately equal size when determined by liquid chromatography (LC). Analysis by liquid chromatography/mass spectroscopy (LC/MS) showed one LC peak having an [M + H] ion at 1035, which corresponds to tomatine. The other peak had an [M + H] ion at 1033, which indicates a tomatine-like molecule that has tomatidenol for the aglycone instead of tomatidine or solasodine. Ultraviolet data support a delta C-5–C-6 double bond in the aglycone. LC of tomatine hydrolysate indicated the presence of tomatidine and tomatidenol and the absence of solasodine. Thus, the impurity was dehydrotomatine. Purity calculations based on mass spectral data showed that the tomatine standards were 80% pure.