bluuebunny/crossref_metadata_2025_split huggingface dataset:
GC/ITMS Measurement of Carbonyls and Multifunctional Carbonyls in PM2.5 Particles Emitted from Motor Vehicles
Authors: Rao Xin , Kobayashi Reiko , White-Morris Rochelle , Spaulding Reggie , Frazey Paul , Charles M Judith 
Published: February 2020

Abstract
A method was developed and tested to identify and quantitate carbonyls and multifunctional carbonyls in fine particulate matter (PM2.5; &lt;2.5 μm aerodynamic diameter). The method relies on ultrasonic extraction of particulate matter on filters at −8°C; derivatization with O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine (PFBHA), and PFBHA along with bis (trimethylsilyl) trifluoroacetamide (BSTFA); and detection of the derivatives by gas chromatography/ion trap mass spectrometry. Ultrasonic extraction of model compounds from enriched particles was affected by solvent polarity (water &gt; methylene chloride &gt; toluene–isopropanol (2 + 1, v/v). Water provided the highest recovery for dihydroxy acetone, pyruvic acid, and hydroxy acetone, compared to methylene chloride, and toluene–isopropanol. Lowering the ultrasonication bath temperature from 0° to −8°C improved the recoveries of the less water soluble and more volatile species—methacrolein, methyl vinyl ketone, 2,3-butanedione, and tolualdehyde. The power of the method was demonstrated by identification and quantitation of carbonyls and multifunctional carbonyls in sample extracts of fine particulate matter (PM2.5) collected in the Caldecott tunnel, CA. The identities of crotonaldehyde, 2,3-butanedione, glyoxal, 9H-fluoren-9-one, glycolaldehyde, glyoxylic acid, levulinic acid, and 3-hydroxybenzaldehyde were confirmed by comparing the relative retention time and mass spectra of the analyte in the sample extract with an authentic standard. Quantitation of crotonaldehyde, glyoxal, 2,3-butanedione, glyoxylic acid, and levulinic acid was accomplished. This is the first report of glyoxylic acid, levulinic acid, and 3-hydroxybenzaldheyde in PM2.5 particles sampled in a roadway tunnel. It is also the first report of a C10 carbonyl with the molecular formula of C10H16O2, a hydroxy carbonyl with the molecular formula of C17H21NO2, and a hydroxy or dihydroxy carbonyl with the molecular formula of C16H14O2 or C9H10O3. The high-molecular weight hydroxy carbonyls, which were found only in the heavy-duty (diesel) bore, may be tracers of diesel emissions in air.
Speciation of Zinc in Low Molecular Weight Proteins of Breast Milk and Infant Formulas by Size Exclusion Chromatography/Flame Atomic Absorption Spectroscopy
Authors: Bermejo Pilar , Peña Elena M , Fompedriña Diego , Domínguez Raquel , Bermejo Adela , Cocho José A , Fernández José R , Fraga José M 
Published: February 2020

Abstract
Size exclusion chromatography (SEC) and flame atomic absorption spectroscopy (FAAS) were used for the separation of metal-containing species in milk whey. After milk ultracentrifugation, the sample was injected into a TSK-Gel G2000 glass column and eluted with 0.2M NH4NO3–NH3, pH 6.7. Low molecular weight proteins were fractionated, and the fractions were characterized by molecular weight. Zinc distributions were obtained by FAAS using a high performance nebulizer. The method was very sensitive (limit of detection = 2.6 × 10−3 μg/mL; limit of quantitation = 8.9 × 10−3 μg/mL) and precise (RSDs ≤ 10%). This method was applied to the determination of Zn in binding compounds in breast milk whey and in commercial cow's milk-based formulas. Distribution patterns were different. The presence of Zn in most fractions in breast milk was most significant, whereas in infant formulas Zn was detected only in fractions of molecular weight &lt;5 kDa and in the highest molecular weight peak.
Determination of Heavy Metals and Pesticides in Ginseng Products
Authors: Khan Ikhlas A , Allgood James , Walker Larry A , Abourashed Ehab A , Schlenk Daniel , Benson William H 
Published: February 2020

Abstract
Medicinal plants may carry residuals of environmentally persistent pesticides or assimilate heavy metals in varying degrees. Several factors may influence contaminant accumulation, including species, level and duration of contaminant exposure, and topography. As part of a program for assessment of the quality of herbal medicines, we have analyzed 21 over-the-counter ginseng (Panax ginseng) products in various dosage forms. Chromium, mercury, and arsenic were undetectable above their limits of detection in both liquid and solid samples; while cadmium, lead, and nickel were present in the majority of samples. The chlorinated pesticide levels varied widely. In most samples, the total concentration of pesticides was below 100 ppb; while in 5 samples the total concentration exceeded 100 ppb.
A Statistical Model To Evaluate Analyte Homogeneity for a Material
Authors: McClure Foster D 
Published: February 2020

Abstract
An underlying assumption for collaborative studies is that the analyte variation among test samples of the material (i.e., matrix and analyte concentration combination) under study has a negligible influence on the estimates of precision for the method. This assumption is expected to be fulfilled when the material under study is prepared (i.e., thoroughly mixed) such that the analyte is distributed uniformly throughout the matrix. Statistical design and intra-class correlation analysis procedures are proposed to assess the similarity oragreement among analytical results among- and within-containers for single and multiple occasions of use (e.g., collaborative and proficiency studies).
Determination of Pyrimethamine in Animal Tissue and Egg by Liquid Chromatography with Fluorescence Detection
Authors: Horii Shozo , Nishi Masatoshi , Oku Naoto , Miyakawa Hiroyuki , Tezuka Masakatsu 
Published: February 2020

Abstract
A sensitive and selective liquid chromatographic (LC) assay was developed to determine the concentration of pyrimethamine in animal tissue and egg by fluorescent derivative. Animal samples were extracted with acetonitrile, centrifuged, and purified by hexane. Fluorescent derivatization was performed by reacting pyrimethamine with chloroacetaldehyde and subjected to LC with fluorescence detection (excitation wavelength 300 nm, emission wavelength 420 nm). The limit of detection was 10 ng/g (10 ppb) and the standard calibration curve was linear in the range of 1–100 ppb (0.01–1 ng/10 μL). Recoveries from samples fortified at levels of 0.1 and 1 ppm (μg/g) were 61.0–77.4 and 65.5–81.2%, respectively. The method was applied to the monitoring of marketed samples. Pyrimethamine was not determined in any of the 70 samples: 20 swine muscle; 20 chicken muscle; 10 chicken liver; and 20 egg.
Determination of Organic Acids of Low Molecular Weight and Phosphate in Soil by Capillary Electrophoresis
Authors: Ahumada Ines , Mendoza Jorge , Escudero Paula , Mossert Katerina , Ascar Loreto 
Published: February 2020

Abstract
Capillary zone electrophoresis with indirect UV detection at 254 nm was found to be suitable for the determination of organic acids and phosphate in aqueous extracts of soil. The best support electrolyte solution was found to be 10mM p-hydroxybenzoic acid with 0.5mM tetradecyltrimethylammonium bromide to reverse electroosmotic flow. This methodology was tested with 9 analytes found in soils: acetate, citrate, formate, phosphate, lactate, oxalate, pyruvate, succinate, and tartrate. The results obtained show that the methodology is adequate for most of the analytes. The sensitivity to oxalate and citrate was low, and the high concentrations of major inorganic anions interfered with the detection of the former. The methodology was applied to the analysis of aqueous extracts of soil samples. Formate, phosphate, lactate, and acetate anions were detected in most of the samples.
Determination of Phenolic Xenoestrogens in Environmental Samples by Liquid Chromatography with Mass Spectrometric Detection
Authors: Petrović Mira , Barceló Damià 
Published: February 2020

Abstract
A method is proposed for the determination of several phenolic xenoestrogens in aqueous and solid environmental samples. The method uses solid-phase extraction (preceded by ultrasonic solvent extraction for solid samples), reversed-phase liquid chromatographic separation, and mass spectrometric detection using both atmospheric pressure chemical ionization and electrospray ionization. This method was developed to support several studies undertaken to obtain aquatic and sedimentary data for rivers and seashores in Spain that are likely to be contaminated by endocrine-disrupting compounds (EDCs) as a consequence of wastewater discharge. Nonylphenol polyethoxylates (NPEOs), nonylphenoxy carboxylates (NPECs), nonylphenol (NP), octylphenol (OP), and bisphenol A (BPA) were determined in various samples of surface water and sediment, collected at different locations upstream and downstream from outfalls of municipal wastewater treatment plants (WWTPs). Seawater and marine sediments were collected in different harbor areas in Spain. Additionally, WWTP influent and effluents were analyzed to monitor the occurrence and transformation of phenolic EDCs during physicochemical and biological treatment. Rather high concentrations of the compounds investigated were found in some samples. Concentrations of NP were ≤590 μg/kg in sediments and ≤15 μg/L in water samples. NPEOs and NPECs were found in water samples in concentrations ≤41 and ≤35 μg/L, respectively. In solid samples (river sediment), concentrations of NPEO were ≤818 μg/kg and those of NP1EC were 95 μg/kg.
Culture Age and Drying Time as Variables of the AOAC Sporicidal Test
Authors: Miner Norman A , Taylor Michelle A , Bernal Sara E , Harris Valerie L , Sichinga Mashike J 
Published: February 2020

Abstract
In the United States, the AOAC Sporicidal Activity of Disinfectants Method 966.04 is the standard for identifying a liquid chemical germicide as a sterilant. Furthermore, the highest level of a disinfectant must also be a sterilant as defined by Method 966.04, when used in its sterilant mode for a longer exposure time. The AOAC Sporicidal Test is also used as a part of the standard test methods to define a sterilant for Australia and the European Union. Many laboratories have identified variables of this test that can affect the sterilization exposure time for sterilants, or even the ability to classify a chemical as a sterilant. Method 966.04 requires spore-labeled porcelain penicylinders (cylinders) and silk suture loops, collectively referred to as carriers, to be dried for 24 h, but allows these carriers to be used for at least 7 days, in effect allowing a drying time of 24 h to at least 7 days. We tested the resistance of cylinders that had been labeled with Bacillus subtilis spores cultured for 72, 96, and 120 h, and dried for 24, 48, and 72 h against a 60 min exposure to 2.0%alkaline glutaraldehyde, and 2, 5, 10, 15, and 20 min exposures to 2.5N HCl. All the culture incubation and drying times met the standard of resistance to 2.5N HCl for at least 2.0 min at 20°C, and all carriers contained at least 105 colony-forming units (CFU) of B. subtilis per carrier. However, for 3 repeated tests, regardless of incubation time, an average of 96%of the carriers were sterilized by the 2.0%glutaraldehyde after drying for 24 h, and an average of 61%were sterilized after drying for 48 or 72 h. We propose that the variable of drying time be eliminated from Method 966.04.
Determination of Organochlorine Pesticides and Chlorobenzenes in Strawberries by Using Accelerated Solvent Extraction Combined with Sorptive Enrichment and Gas Chromatography/Mass Spectrometry
Authors: Wennrich Luise , Popp Peter , Köller Gábor , Breuste Jürgen 
Published: February 2020

Abstract
An analytical scheme for the determination of several organochlorine pesticides like hexachlorocyclohexanes (HCHs) and DDX compounds (p,p′-DDE, p,p′-DDD, and p,p′-DDT) as well as chlorobenzenes in strawberries has been developed. The procedure is based on aqueous accelerated solvent extraction (ASE) followed by solidphase microextraction (SPME) or stir bar sorptive extraction (SBSE) and subsequent thermodesorption–gas chromatography/mass spectrometry analysis. A 65 μm polydimethylsiloxane/divinylbenzene fiber was chosen for the SPME experiments. Significant SPME and ASE parameters were optimized using spiked water and strawberry samples. For the ASE of the organochlorine compounds, a water–acetone mixture (90 + 10, v/v) as the extraction solvent, an extraction temperature of 120°C, and 2 cycles of 10 min extraction proved optimal. The developed method was evaluated with respect to precision and limits of detection (LOD). The relative standard deviations of replicate ASE–SPME determinations (n = 5) were in the range of 4–24%. LOD values between 1 and 10 μ g/kg were achieved with the exception of DDT and DDE (40 μg/kg). Using SBSE, the LOD of these compounds could be improved (2 and 5 μg/kg). The main advantages of this method are the avoidance of cleanup and concentration procedures as well as the significant reduction of the required volume of organic solvents. The described method was applied to the determination of the pollutants in strawberry samples collected from different allotment gardens in a potentially polluted area, the Bitterfeld-Wolfen region (Germany).
The Role of Planar Chromatography in Medicinal Plant Research
Authors: Nyiredy Szabolcs 
Published: February 2020

Abstract
This paper summarizes the role of planar chromatography (PC) in medicinal and aromatic plant (MAP) research and development, and demonstrates the importance of the technique, after extraction, in the analysis of MAP (identification and quantitative determination of the separated compound/s), in the purification and isolation process, and in different types of screening procedure. Special attention is paid to analytical, micropreparative and preparative forced-flow techniques, for example overpressured-layer chromatography (OPLC) and rotation planar chromatography (RPC). The special features of analytical, micropreparative, and preparative layer chromatography (PLC), OPLC, and RPC are compared in tables. Purification and isolation procedures using forced-flow techniques are shown in flowcharts. Some applications, relating to different classes of substance, are presented to demonstrate the versatility of various planar chromatographic techniques.
Application of High-Performance, Thin-Layer Chromatography to Quality Control of Antimetabolite Analogue Infusion Bags
Authors: Perello Laurent , Demirdjian Sylvie , Dory Alexandre , Bourget Philippe 
Published: February 2020

Abstract
A global postproduction quality program was developed to secure chemotherapy infusion at the Gustave Roussy Institute. Despite rigorous procedures and computerized prescriptions, an analytical check was necessary to improve the quality of ready-to-use solutions of cytotoxic drugs in our Centralized Antineoplastics Reconstitution Unit. High-performance, thin-layer chromatography was selected as the analytical tool to assay 12 anticancer drugs. One of the analytical methods can separate 4 antimetabolite substances, i.e., fludarabine (FDB), cytarabine (CTB), gemcitabine (GTB), and fluorouracil (5 FU). For all infusion bags manufactured, up to 26 samples could be assayed per series using a double standard calibration (GTB and 5 FU).
Determination of Clopidol Residues in Chicken Tissues by Liquid Chromatography: Part III. Quality Control Analysis of Export Chickens
Authors: Pang Guo-Fang , Cao Yan-Zhong , Fan Chun-Lin , Zhang Jin-Jie , Li Xue-Min 
Published: February 2020

Abstract
A summary is presented of the liquid chromatographic (LC) determination of clopidol residues in export chickens from 1992 to 1999. Over the past 8 years, we analyzed &gt;7000 chicken samples. A total of 0.66% of samples contained clopidol residues, ranging from 0.005 to 0.79 mg/kg; however, none exceeded 3 mg/kg, the Chinese maximum residue limit. In comparison with 1992, the number of samples multiplied 70-fold, and the frequency of clopidol found in samples decreased 148-fold in 1999. The chickens inspected were exported to foreign countries; all were cleared by the buyers with no disputes. This report also introduces the critical control points of the proposed LC method as well as identification of false-positive procedures by both experience and LC/mass spectrometric confirmation. Our experiences over the past 8 years have demonstrated that the ruggedness of the proposed LC method is quite good.
Liquid Chromatographic/Mass Spectrometric Determination of Desmedipham and Phenmedipham and Their Metabolites in Soil
Authors: Perret Daniela , Gentili Alessandra , Marchese Stefano , Marino Aldo , Bruno Federica 
Published: February 2020

Abstract
A simple method is described for the simultaneous determination of residues of 2 carbamate herbicides (phenmedipham and desmedipham) and related metabolites (m-aminophenol, aniline, and m-toluidine) in soil. The analytes are extracted from spiked soils with methanol. The solvent/soil suspension is centrifuged, and the supernatant is directly injected, without any further cleanup, into a reversed-phase liquid chromatography/mass spectrometry apparatus equipped with a TurboIonSpray interface. The method was tested on 5 soils having different physicochemical properties. Recoveries from the soil types, spiked over the range of 50–200 ppb, were essentially quantitative for each analyte. The detection limits of the method are ≤25 ng/g.
Determination of N-Nitrosodimethylamine in Environmental Aqueous Samples by Isotope-Dilution GC/MS–SIM
Authors: Raksit Asit , Johri Saima 
Published: February 2020

Abstract
An analytical method for the determination of N-nitrosodimethylamine (N-NDMA) in environmental aqueous samples has been developed using isotope dilution gas chromatography/mass spectrometry in the selected ion monitoring mode (GC/MS–SIM). After deuterated N-nitrosodimethylamine (d6-N-NDMA) as surrogate standard was added to the samples, the analytes were extracted with methylene chloride, dried with anhydrous sodium sulfate, and concentrated in a rotary evaporator. The concentrated extracts were analyzed by GC/MS–SIM after adding N-nitrosodiethylamine as an internal standard. The method detection limit for N-NDMA was 0.003 pg/μL and was validated by an analysis of a fortified water sample. The method was applied to real samples.
Determination of Zearalenone Content in Cereals and Feedstuffs by Immunoaffinity Column Coupled with Liquid Chromatography
Authors: Fazekas Bela , Tar Andrea 
Published: February 2020

Abstract
The zearalenone content of maize, wheat, barley, swine feed, and poultry feed samples was determined by immunoaffinity column cleanup followed by liquid chromatography (IAC–LC). Samples were extracted in methanol–water (8 + 2, v/v) solution. The filtered extract was diluted with distilled water and applied to immunoaffinity columns. Zearalenone was eluted with methanol, dried by evaporation, and dissolved in acetonitrile–water (3 + 7, v/v). Zearalenone was separated by isocratic elution of acetonitrile–water (50 + 50, v/v) on reversed-phase C18 column. The quantitative analysis was performed by fluorescence detector and confirmation was based on the UV spectrum obtained by a diode array detector. The mean recovery rate of zearalenone was 82–97% (RSD, 1.4–4.1%) on the original (single-use) immunoaffinity columns. The limit of detection of zearalenone by fluorescence was 10 ng/g at a signal-to-noise ratio of 10:1 and 30 ng/g by spectral confirmation in UV. A good correlation was found (R2 = 0.89) between the results obtained by IAC–LC and by the official AOAC–LC method. The specificity of the method was increased by using fluorescence detection in parallel with UV detection. This method was applicable to the determination of zearalenone content in cereals and other kinds of feedstuffs. Reusability of immunoaffinity columns was examined by washing with water after sample elution and allowing columns to stand for 24 h at room temperature. The zearalenone recovery rate of the regenerated columns varied between 79 and 95% (RSD, 3.2–6.3%). Columns can be regenerated at least 3 times without altering their performance and without affecting the results of repeated determinations.
Detection of Preformed Type A Botulinal Toxin in Hash Brown Potatoes by Using the Mouse Bioasssay and a Modified ELISA Test
Authors: Ferreira Joseph L , Eliasberg Stacey J , Harrison Mark A , Edmonds Paul 
Published: February 2020

Abstract
A foodborne illness caused by type A toxin-producing Clostridium botulinumwas investigated by using the standard mouse bioassay and a rapid invitro test for toxin detection. The patient, who consumed improperly stored hash brown potatoes that contained the preformed toxin, was diagnosed with type A botulism. C. botulinum type A toxin was detected in the hash brown potatoes as well as in the tryptone–peptone–glucose–yeast extract (TPGY) medium subcultures of this food using the mouse bioassay and an amplified ELISA technique. The mouse bioassay revealed preformed toxin at 10 000 minimum lethal dose (MLD)/g uncooked product and the amplified ELISA an equivalent 50 000 MLD/g. The cultural toxin from the uncooked product killed mice at the 106 dilution and a modification of the ELISA procedure was positive at the 103 dilution. Cooked food obtained from the consumer's waste can contained 100 MLD/g and the ELISA was also positive at the same dilution of the product. The culture of the cooked product obtained from the waste can was lethal for mice at the 107 dilution and positive using the modified ELISA at the 104 dilution. The unmodified amplified ELISA method indicated a toxin level of approximately 1 ng/mL (equivalent to 5 × 105 MLD/mL) in diluted culture fluid from the uncooked food and the culture of cooked food obtained from the waste can. The hash brown potatoes were negative for types B, E, and F preformed and cultural botulinal toxins using both assays.
Detection of Added Beet or Cane Sugar in Maple Syrup by the Site-Specific Deuterium Nuclear Magnetic Resonance (SNIF-NMR®) Method: Collaborative Study
Authors: Martin Yves-Loïc ,   Collaborators:, Christoph N , Blanch-Cortès A -I , Dennis J , Giraudon S , Guillon C , Hermann A , Le Leuch A , Mazac J , Naulet N , Parent M -J , Remaud G , Wittkowski R 
Published: February 2020

Abstract
Results of a collaborative study are reported for the detection of added beet or cane sugar in maple syrup by the site-specific natural isotope fractionation–nuclear magnetic resonance (SNIF-NMR®) method. The method is based on the fact that the deuterium content at specific positions of the sugar molecules is different in maple syrup from that in beet or cane sugar. The syrup is diluted with pure water and fermented; the alcohol is distilled with a quantitative yield and analyzed with a high-field NMR spectrometer fitted with a deuterium probe and fluorine lock. The proportion of ethanol molecules monodeuterated at the methyl site is recorded. This parameter (D/H)I is decreased when beet sugar is added and increased when cane sugar is added to the maple syrup. The precision of the method for measuring (D/H)I was found to be in good agreement with the values already published for the application of this method to fruit juice concentrates (AOAC Official Method 995.17). An excellent correlation was found between the percentage of added beet sugar and the (D/H)I isotopic ratio measured in this collaborative study. Consequently, all samples in which exogenous sugars were added were found to have a (D/H)I isotopic ratio significantly different from the normal value for an authentic maple syrup. By extension of what is known about plants having the C4 cycle, the method can be applied to corn sweeteners as well as to cane sugar. One limitation of the method is its reduced sensitivity when applied to specific blends of beet and cane sugars or corn sweeteners. In such case, the C13 ratio measurement (see AOAC Official Method 984.23, Corn Syrup and Cane Sugar in Maple Syrup) may be used in conjunction.