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Sample records for acid sample preparation

  1. Hands-free sample preparation platform for nucleic acid analysis.

    PubMed

    Baier, T; Hansen-Hagge, T E; Gransee, R; Crombé, A; Schmahl, S; Paulus, C; Drese, K S; Keegan, H; Martin, C; O'Leary, J J; Furuberg, L; Solli, L; Grønn, P; Falang, I M; Karlgård, A; Gulliksen, A; Karlsen, F

    2009-12-01

    A Lab-On-Chip system with an instrument is presented which is capable of performing total sample preparation and automated extraction of nucleic acid from human cell samples fixed in a methanol based solution. The target application is extraction of mRNA from cervical liquid based cytology specimens for detection of transformed HPV-infections. The device accepts 3 ml of sample and performs the extraction in a disposable polymer chip of credit card size. All necessary reagents for cell lysis, washing, and elution are stored on-chip and the extraction is performed in two filter stages; one for cell pre-concentration and the other for nucleic acid capture. Tests performed using cancer cell lines and cervical liquid based cytology specimens confirm the extraction of HPV-mRNA by the system. PMID:19904407

  2. Highly simplified lateral flow-based nucleic acid sample preparation and passive fluid flow control

    SciTech Connect

    Cary, Robert E.

    2015-12-08

    Highly simplified lateral flow chromatographic nucleic acid sample preparation methods, devices, and integrated systems are provided for the efficient concentration of trace samples and the removal of nucleic acid amplification inhibitors. Methods for capturing and reducing inhibitors of nucleic acid amplification reactions, such as humic acid, using polyvinylpyrrolidone treated elements of the lateral flow device are also provided. Further provided are passive fluid control methods and systems for use in lateral flow assays.

  3. Sampling and Sample Preparation

    NASA Astrophysics Data System (ADS)

    Morawicki, Rubén O.

    Quality attributes in food products, raw materials, or ingredients are measurable characteristics that need monitoring to ensure that specifications are met. Some quality attributes can be measured online by using specially designed sensors and results obtained in real time (e.g., color of vegetable oil in an oil extraction plant). However, in most cases quality attributes are measured on small portions of material that are taken periodically from continuous processes or on a certain number of small portions taken from a lot. The small portions taken for analysis are referred to as samples, and the entire lot or the entire production for a certain period of time, in the case of continuous processes, is called a population. The process of taking samples from a population is called sampling. If the procedure is done correctly, the measurable characteristics obtained for the samples become a very accurate estimation of the population.

  4. Universal nucleic acids sample preparation method for cells, spores and their mixture

    DOEpatents

    Bavykin, Sergei

    2011-01-18

    The present invention relates to a method for extracting nucleic acids from biological samples. More specifically the invention relates to a universal method for extracting nucleic acids from unidentified biological samples. An advantage of the presently invented method is its ability to effectively and efficiently extract nucleic acids from a variety of different cell types including but not limited to prokaryotic or eukaryotic cells and/or recalcitrant organisms (i.e. spores). Unlike prior art methods which are focused on extracting nucleic acids from vegetative cell or spores, the present invention effectively extracts nucleic acids from spores, multiple cell types or mixtures thereof using a single method. Important that the invented method has demonstrated an ability to extract nucleic acids from spores and vegetative bacterial cells with similar levels effectiveness. The invented method employs a multi-step protocol which erodes the cell structure of the biological sample, isolates, labels, fragments nucleic acids and purifies labeled samples from the excess of dye.

  5. Microchip Module for Blood Sample Preparation and Nucleic Acid Amplification Reactions

    PubMed Central

    Yuen, Po Ki; Kricka, Larry J.; Fortina, Paolo; Panaro, Nicholas J.; Sakazume, Taku; Wilding, Peter

    2001-01-01

    A computer numerical control-machined plexiglas-based microchip module was designed and constructed for the integration of blood sample preparation and nucleic acid amplification reactions. The microchip module is comprised of a custom-made heater-cooler for thermal cycling, a series of 254 μm × 254 μm microchannels for transporting human whole blood and reagents in and out of an 8–9 μL dual-purpose (cell isolation and PCR) glass-silicon microchip. White blood cells were first isolated from a small volume of human whole blood (<3 μL) in an integrated cell isolation–PCR microchip containing a series of 3.5-μm feature-sized “weir-type” filters, formed by an etched silicon dam spanning the flow chamber. A genomic target, a region in the human coagulation Factor V gene (226-bp), was subsequently directly amplified by microchip-based PCR on DNA released from white blood cells isolated on the filter section of the microchip mounted onto the microchip module. The microchip module provides a convenient means to simplify nucleic acid analyses by integrating two key steps in genetic testing procedures, cell isolation and PCR and promises to be adaptable for additional types of integrated assays. PMID:11230164

  6. Final Report Nucleic Acid System - PCR, Multiplex Assays and Sample Preparation Project

    SciTech Connect

    Koopman, R.P.; Langlois, R.G.; Nasarabadi, S.; Benett, W.J.; Richards, J.B.; Hadley, D.R.; Miles, R.R.; Brown, S.B.; Stratton, P.L.; Milanovich, F.P.

    2001-04-20

    The objective of this project was to reduce to practice the detection and identification of biological warfare pathogens by the nucleic acid recognition technique of PCR (polymerase chain reaction). This entailed not only building operationally functional instrumentation but also developing the chemical assays for detection of priority pathogens. This project had two principal deliverables: (1) design, construct, test and deliver a 24 chamber, multiplex capable suitcase sized PCR instrument, and (2) develop and reduce to practice a multiplex assay for the detection of PCR product by flow cytometry. In addition, significant resources were allocated to test and evaluation of the Hand-held Advanced Nucleic Acid Analyzer (HANAA). This project helps provide the signature and intelligence gathering community the ability to perform, on-site or remote, rapid analysis of environmental or like samples for the presence of a suite of biological warfare pathogens.

  7. Modular microfluidic system for biological sample preparation

    SciTech Connect

    Rose, Klint A.; Mariella, Jr., Raymond P.; Bailey, Christopher G.; Ness, Kevin Dean

    2015-09-29

    A reconfigurable modular microfluidic system for preparation of a biological sample including a series of reconfigurable modules for automated sample preparation adapted to selectively include a) a microfluidic acoustic focusing filter module, b) a dielectrophoresis bacteria filter module, c) a dielectrophoresis virus filter module, d) an isotachophoresis nucleic acid filter module, e) a lyses module, and f) an isotachophoresis-based nucleic acid filter.

  8. Microscopic and mesoscopic structural features of an activated carbon sample, prepared from sorghum via activation by phosphoric acid

    SciTech Connect

    Temleitner, László; Pusztai, László; Rubio-Arroyo, Manuel F.; Aguilar-López, Sergio; Pizio, Orest

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► Preparation of a new activated carbon sample from sorghum. ► Characterization by adsorption/desorption methods. ► Determination of the structure by synchrotron X-ray diffraction. ► The sample is amorphous and contains distorted graphene fragments. ► A characteristic nanoscale distance is established from the radial distribution function. -- Abstract: An acidic chemical activation procedure has been used for preparing activated carbon with a surface area exceeding 1000 m{sup 2}/g from sorghum. In order to reveal structural features, synchrotron X-ray diffraction measurements have been performed. The structure of the material has been characterized by the total scattering structure factor and the radial distribution function describing short-range arrangement of atoms at distances of the order of a few atomic diameters as well as correlations at a longer scale, of the order of nanometers. The atomic arrangement has been found to be consistent with that of amorphous graphite-like carbon. As far as the mesoscopic structure is concerned, the presence of a characteristic distance is suggested on the basis of the clear nanometer scale oscillations of the radial distribution function, which distance may be assigned as the mesopore size in the material. It is suggested that the approach devized here may later be applied routinely for other activated carbon samples, too, for characterizing atomic and nanoscale order simultaneously.

  9. Rapid and automated sample preparation for nucleic acid extraction on a microfluidic CD (compact disk)

    NASA Astrophysics Data System (ADS)

    Kim, Jitae; Kido, Horacio; Zoval, Jim V.; Gagné, Dominic; Peytavi, Régis; Picard, François J.; Bastien, Martine; Boissinot, Maurice; Bergeron, Michel G.; Madou, Marc J.

    2006-01-01

    Rapid and automated preparation of PCR (polymerase chain reaction)-ready genomic DNA was demonstrated on a multiplexed CD (compact disk) platform by using hard-to-lyse bacterial spores. Cell disruption is carried out while beadcell suspensions are pushed back and forth in center-tapered lysing chambers by angular oscillation of the disk - keystone effect. During this lysis period, the cell suspensions are securely held within the lysing chambers by heatactivated wax valves. Upon application of a remote heat to the disk in motion, the wax valves release lysate solutions into centrifuge chambers where cell debris are separated by an elevated rotation of the disk. Only debris-free DNA extract is then transferred to collection chambers by capillary-assisted siphon and collected for heating that inactivates PCR inhibitors. Lysing capacity was evaluated using a real-time PCR assay to monitor the efficiency of Bacillus globigii spore lysis. PCR analysis showed that 5 minutes' CD lysis run gave spore lysis efficiency similar to that obtained with a popular commercial DNA extraction kit (i.e., IDI-lysis kit from GeneOhm Sciences Inc.) which is highly efficient for microbial cell and spore lysis. This work will contribute to the development of an integrated CD-based assay for rapid diagnosis of infectious diseases.

  10. Microfluidic Sample Preparation for Immunoassays

    SciTech Connect

    Visuri, S; Benett, W; Bettencourt, K; Chang, J; Fisher, K; Hamilton, J; Krulevitch, P; Park, C; Stockton, C; Tarte, L; Wang, A; Wilson, T

    2001-08-09

    Researchers at Lawrence Livermore National Laboratory are developing means to collect and identify fluid-based biological pathogens in the forms of proteins, viruses, and bacteria. to support detection instruments, they are developing a flexible fluidic sample preparation unit. The overall goal of this Microfluidic Module is to input a fluid sample, containing background particulates and potentially target compounds, and deliver a processed sample for detection. They are developing techniques for sample purification, mixing, and filtration that would be useful to many applications including immunologic and nucleic acid assays. Many of these fluidic functions are accomplished with acoustic radiation pressure or dielectrophoresis. They are integrating these technologies into packaged systems with pumps and valves to control fluid flow through the fluidic circuit.

  11. Preparing Protein Samples

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Cindy Barnes of University Space Research Association (USRA) at NASA's Marshall Space Flight Center pipettes a protein solution in preparation to grow crystals as part of NASA's structural biology program. Research on Earth helps scientists define conditions and specimens they will use in space experiments.

  12. Effect of sample preparation on the measurement of sugars, organic acids, and polyphenols in apple fruit by mid-infrared spectroscopy.

    PubMed

    Bureau, Sylvie; Scibisz, Iwona; Le Bourvellec, Carine; Renard, Catherine M G C

    2012-04-11

    The objectives of this study were (i) to test different conditions of freezing, thawing, and grinding during sample preparation and (ii) to evaluate the possibility of using mid-infrared spectroscopy for analyzing the composition of sugars, organic acids, and polyphenols in apples. Seven commercial apple cultivars were chosen for their large variability in composition (total polyphenols from 406 to 1033 mg kg(-1) fresh weight). The different conditions of sample preparation affected only the phenolic compounds and not sugars or organic acids. The regression models of the mid-infrared spectra showed a good ability to estimate sugar and organic acid contents (R(2) ≥ 0.96), except for citric acid. Good predictions were obtained for total phenolic, flavan-3-ols, and procyanidins (R(2) ≥ 0.94) provided oxidation was avoided during sample preparation. A rapid and simple procedure was then proposed for phenolic compounds using sodium fluoride during sample homogenization at ambient temperature and freeze-drying before spectra acquisition. PMID:22409403

  13. Statistical evaluation of fatty acid profile and cholesterol content in fish (common carp) lipids obtained by different sample preparation procedures.

    PubMed

    Spiric, Aurelija; Trbovic, Dejana; Vranic, Danijela; Djinovic, Jasna; Petronijevic, Radivoj; Matekalo-Sverak, Vesna

    2010-07-01

    the second principal component (PC2) is recorded by C18:3 n-3, and C20:3 n-6, being present in a higher amount in the samples treated by the modified Soxhlet extraction, while C22:5 n-3, C20:3 n-3, C22:1 and C20:4, C16 and C18 negatively influence the score values of the PC2, showing significantly increased level in the samples treated by ASE method. Hotelling's paired T-square test used on the first three principal components for confirmation of differences in individual fatty acid content obtained by ASE and Soxhlet method in carp muscle showed statistically significant difference between these two data sets (T(2)=161.308, p<0.001). PMID:20579492

  14. Microfluidic Tools for Biological Sample Preparation

    SciTech Connect

    Visuri, S R; Ness, K; Dzenitis, J; Benett, B; Bettencourt, K; Hamilton, J; Fisher, K; Krulevitch, P

    2002-04-10

    Researchers at Lawrence Livermore National Laboratory are developing means to collect and identify fluid-based biological pathogens in the forms of proteins, viruses, and bacteria. To support detection instruments, we are developing a flexible fluidic sample preparation unit. The overall goal of this Microfluidic Module is to input a fluid sample, containing background particulates and potentially target compounds, and deliver a processed sample for detection. We are developing techniques for sample purification, mixing, and filtration that would be useful to many applications including immunologic and nucleic acid assays. Sample preparation functions are accomplished with acoustic radiation pressure, dielectrophoresis, and solid phase extraction. We are integrating these technologies into packaged systems with pumps and valves to control fluid flow and investigating small-scale detection methods.

  15. Synchrotron/crystal sample preparation

    NASA Astrophysics Data System (ADS)

    Johnson, R. Barry

    1993-07-01

    The Center for Applied Optics (CAO) of the University of Alabama in Huntsville (UAH) prepared this final report entitled 'Synchrotron/Crystal Sample Preparation' in completion of contract NAS8-38609, Delivery Order No. 53. Hughes Danbury Optical Systems (HDOS) is manufacturing the Advanced X-ray Astrophysics Facility (AXAF) mirrors. These thin-walled, grazing incidence, Wolter Type-1 mirrors, varying in diameter from 1.2 to 0.68 meters, must be ground and polished using state-of-the-art techniques in order to prevent undue stress due to damage or the presence of crystals and inclusions. The effect of crystals on the polishing and grinding process must also be understood. This involves coating special samples of Zerodur and measuring the reflectivity of the coatings in a synchrotron system. In order to gain the understanding needed on the effect of the Zerodur crystals by the grinding and polishing process, UAH prepared glass samples by cutting, grinding, etching, and polishing as required to meet specifications for witness bars for synchrotron measurements and for investigations of crystals embedded in Zerodur. UAH then characterized these samples for subsurface damage and surface roughness and figure.

  16. Synchrotron/crystal sample preparation

    NASA Technical Reports Server (NTRS)

    Johnson, R. Barry

    1993-01-01

    The Center for Applied Optics (CAO) of the University of Alabama in Huntsville (UAH) prepared this final report entitled 'Synchrotron/Crystal Sample Preparation' in completion of contract NAS8-38609, Delivery Order No. 53. Hughes Danbury Optical Systems (HDOS) is manufacturing the Advanced X-ray Astrophysics Facility (AXAF) mirrors. These thin-walled, grazing incidence, Wolter Type-1 mirrors, varying in diameter from 1.2 to 0.68 meters, must be ground and polished using state-of-the-art techniques in order to prevent undue stress due to damage or the presence of crystals and inclusions. The effect of crystals on the polishing and grinding process must also be understood. This involves coating special samples of Zerodur and measuring the reflectivity of the coatings in a synchrotron system. In order to gain the understanding needed on the effect of the Zerodur crystals by the grinding and polishing process, UAH prepared glass samples by cutting, grinding, etching, and polishing as required to meet specifications for witness bars for synchrotron measurements and for investigations of crystals embedded in Zerodur. UAH then characterized these samples for subsurface damage and surface roughness and figure.

  17. Free Amino Acid Profiles from 'Pinot Noir' Grapes are Influenced by Vine N-status and Sample Preparation Method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study examined the impact of extraction method on ammonia, free amino acids, and YAN (yeast assimilable nitrogen) concentrations in 'Pinot noir' berries obtained from a vine nutrition study (altered supply of N, P, or K). Berries were either juiced or exhaustively extracted as whole berries pri...

  18. Students prepare biological space samples

    NASA Technical Reports Server (NTRS)

    2001-01-01

    High school students screen crystals of various proteins that are part of the ground-based work that supports Alexander McPherson's protein crystal growth experiment. The students also prepared and stored samples in the Enhanced Gaseous Nitrogen Dewar, which was launched on the STS-98 mission for delivery to the ISS. The crystals grown on the ground will be compared with crystals grown in orbit. Participants include Joseph Negron (shown), of Terry Parker High School, Jacksonville, Florida; Megan Miskowski, of Ridgeview High School, Orange Park, Florida; and Sam Swank, of Fletcher High School, Neptune Beach, Florida. The proteins are placed in plastic tubing that is heat-sealed at the ends, then flash-frozen and preserved in a liquid nitrogen Dewar. Aboard the ISS, the nitrogen will be allowed to evaporated so the samples thaw and then slowly crystallize. They will be analyzed after return to Earth. Photo credit: NASA/Marshall Space Flight Center.

  19. Students prepare biological space samples

    NASA Technical Reports Server (NTRS)

    2001-01-01

    High school students screen crystals of various proteins that are part of the ground-based work that supports Alexander McPherson's protein crystal growth experiment. The students also prepared and stored samples in the Enhanced Gaseous Nitrogen Dewar, which was launched on the STS-98 mission for delivery to the ISS. The crystals grown on the ground will be compared with crystals grown in orbit. Participants include Joseph Negron, of Terry Parker High School, Jacksonville, Florida; Megan Miskowski (shown), of Ridgeview High School, Orange Park, Florida; and Sam Swank, of Fletcher High School, Neptune Beach, Florida. The proteins are placed in plastic tubing that is heat-sealed at the ends, then flash-frozen and preserved in a liquid nitrogen Dewar. Aboard the ISS, the nitrogen will be allowed to evaporated so the samples thaw and then slowly crystallize. They will be analyzed after return to Earth. Photo credit: NASA/Marshall Space Flight Center.

  20. Students prepare biological space samples

    NASA Technical Reports Server (NTRS)

    2001-01-01

    High school students screen crystals of various proteins that are part of the ground-based work that supports Alexander McPherson's protein crystal growth experiment. The students also prepared and stored samples in the Enhanced Gaseous Nitrogen Dewar, which was launched on the STS-98 mission for delivery to the ISS. The crystals grown on the ground will be compared with crystals grown in orbit. Participants include Joseph Negron, of Terry Parker High School, Jacksonville, Florida; Megan Miskowski, of Ridgeview High School, Orange Park, Florida; and Sam Swank (shown), of Fletcher High School, Neptune Beach, Florida. The proteins are placed in plastic tubing that is heat-sealed at the ends, then flash-frozen and preserved in a liquid nitrogen Dewar. Aboard the ISS, the nitrogen will be allowed to evaporated so the samples thaw and then slowly crystallize. They will be analyzed after return to Earth. Photo credit: NASA/Marshall Space Flight Center.

  1. Full Genome Virus Detection in Fecal Samples Using Sensitive Nucleic Acid Preparation, Deep Sequencing, and a Novel Iterative Sequence Classification Algorithm

    PubMed Central

    Cotten, Matthew; Oude Munnink, Bas; Canuti, Marta; Deijs, Martin; Watson, Simon J.; Kellam, Paul; van der Hoek, Lia

    2014-01-01

    We have developed a full genome virus detection process that combines sensitive nucleic acid preparation optimised for virus identification in fecal material with Illumina MiSeq sequencing and a novel post-sequencing virus identification algorithm. Enriched viral nucleic acid was converted to double-stranded DNA and subjected to Illumina MiSeq sequencing. The resulting short reads were processed with a novel iterative Python algorithm SLIM for the identification of sequences with homology to known viruses. De novo assembly was then used to generate full viral genomes. The sensitivity of this process was demonstrated with a set of fecal samples from HIV-1 infected patients. A quantitative assessment of the mammalian, plant, and bacterial virus content of this compartment was generated and the deep sequencing data were sufficient to assembly 12 complete viral genomes from 6 virus families. The method detected high levels of enteropathic viruses that are normally controlled in healthy adults, but may be involved in the pathogenesis of HIV-1 infection and will provide a powerful tool for virus detection and for analyzing changes in the fecal virome associated with HIV-1 progression and pathogenesis. PMID:24695106

  2. Final Report BW Sample Collection& Preparation Device

    SciTech Connect

    Koopman, R P; Belgrader, P; Meyer, G; Benett, W J; Richards, J B; Hadley, D R; Stratton, P L; Milanovich, F P

    2002-01-31

    The objective of this project was to develop the technique needed to prepare a field collected sample for laboratory analysis and build a portable integrated biological detection instrument with new miniaturized and automated sample purification capabilities. The device will prepare bacterial spores, bacterial vegetative cells, and viral particles for PCR amplification.

  3. 40 CFR 761.323 - Sample preparation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Remediation Waste Samples § 761.323 Sample preparation. (a) The comparison study requires analysis of a minimum of 10 samples weighing at least 300 grams each. Samples of PCB remediation waste used in the... PCB remediation waste at the cleanup site, or must be the same kind of material as that waste....

  4. Analysis of monofluoroacetic acid in urine by liquid chromatography-triple quadrupole mass spectrometry and preparation of the positive sample by the bioconversion from monofluoroacetamide to monofluoroacetic acid in vitro.

    PubMed

    Xu, Xiao-Min; Cai, Zeng-Xuan; Zhang, Jing-Shun; Ren, Yiping; Han, Jian-Long

    2016-08-01

    Whether as a rodenticide or as a natural product, monofluoroacetic acid (FAcOH) may cause poisoning to humans or animals for its high acute toxicity. Urine is one of the most typical specimens for forensic diagnosis when poisoning case about FAcOH happens. The positive sample containing FAcOH plays a key role for the development of an accurate and reliable analytical method. The bioconversion from monofluoroacetamide (FAcNH2) to FAcOH in urine in vitro was studied for the preparation of positive urine sample containing FAcOH without standard spiking or animal experiment. The average bioconversion rates were 0%, 18.6% and 41.3% when incubated the FAcNH2 spiked urine in vitro for 21days at -20°C, room temperature (RT) and 37°C, respectively. Afterwards, a fast and sensitive analytical method was developed for determination of FAcOH in urine. Samples were diluted with water containing formic acid and cleaned with polymeric anion exchange (PAX) cartridge. The acid eluate was neutralized with ammonium hydroxide and directly measured by hydrophilic interaction liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) using basic mobile phase condition. The limit of detection and limit of quantification of FAcOH in urine were 2 and 5ngmL(-1), respectively. The linear range was 5-1000ngmL(-1) with a correlation coefficient of r=0.9993 in urine calibrated with internal standard. The recoveries at four spiking levels (5, 10, 50 and 500ngmL(-1) in urine) were 87.2%-107% with relative standard deviations ranged between 4.3%-8.8%. PMID:27284971

  5. Innovative methods for inorganic sample preparation

    SciTech Connect

    Essling, A.M.; Huff, E.A.; Graczyk, D.G.

    1992-04-01

    Procedures and guidelines are given for the dissolution of a variety of selected materials using fusion, microwave, and Parr bomb techniques. These materials include germanium glass, corium-concrete mixtures, and zeolites. Emphasis is placed on sample-preparation approaches that produce a single master solution suitable for complete multielement characterization of the sample. In addition, data are presented on the soil microwave digestion method approved by the Environmental Protection Agency (EPA). Advantages and disadvantages of each sample-preparation technique are summarized.

  6. Sample preparation for single molecule localization microscopy.

    PubMed

    Allen, John R; Ross, Stephen T; Davidson, Michael W

    2013-11-21

    Single molecule localization-based optical nanoscopy was introduced in 2006, surpassing traditional diffraction-limited resolutions by an order of magnitude. Seven years later, this superresolution technique is continuing to follow a trend of increasing popularity and pervasiveness, with the proof-of-concept work long finished and commercial implementations now available. However one important aspect that tends to become lost in translation is the importance of proper sample preparation, with very few resources addressing the considerations that must be made when preparing samples for imaging with single molecule level sensitivity. Presented here is a an in-depth analysis of all aspects of sample preparation for single molecule superresolution, including both live and fixed cell preparation, choice of fluorophore, fixation and staining techniques, and imaging buffer considerations. PMID:24084850

  7. Glass sample preparation and performance investigations

    NASA Astrophysics Data System (ADS)

    Johnson, R. Barry

    1992-04-01

    This final report details the work performed under this delivery order from April 1991 through April 1992. The currently available capabilities for integrated optical performance modeling at MSFC for large and complex systems such as AXAF were investigated. The Integrated Structural Modeling (ISM) program developed by Boeing for the U.S. Air Force was obtained and installed on two DECstations 5000 at MSFC. The structural, thermal and optical analysis programs available in ISM were evaluated. As part of the optomechanical engineering activities, technical support was provided in the design of support structure, mirror assembly, filter wheel assembly and material selection for the Solar X-ray Imager (SXI) program. As part of the fabrication activities, a large number of zerodur glass samples were prepared in different sizes and shapes for acid etching, coating and polishing experiments to characterize the subsurface damage and stresses produced by the grinding and polishing operations. Various optical components for AXAF video microscope and the x-ray test facility were also fabricated. A number of glass fabrication and test instruments such as a scatter plate interferometer, a gravity feed saw and some phenolic cutting blades were fabricated, integrated and tested.

  8. Comparative clinical sample preparation of DNA and RNA viral nucleic acids for a commercial deep sequencing system (Illumina MiSeq(®)).

    PubMed

    Ullmann, Leila Sabrina; de Camargo Tozato, Claudia; Malossi, Camila Dantas; da Cruz, Tais Fukuta; Cavalcante, Raíssa Vasconcelos; Kurissio, Jacqueline Kazue; Cagnini, Didier Quevedo; Rodrigues, Marianna Vaz; Biondo, Alexander Welker; Araujo, João Pessoa

    2015-08-01

    Sequence-independent methods for viral discovery have been widely used for whole genome sequencing of viruses. Different protocols for viral enrichment, library preparation and sequencing have increasingly been more available and at lower costs. However, no study to date has focused on optimization of viral sample preparation for commercial deep sequencing. Accordingly, the aim of the present study was to evaluate an In-House enzymatic protocol for double-stranded DNA (dsDNA) synthesis and also compare the use of a commercially available kit protocol (Nextera XT, Illumina Inc, San Diego, CA, USA) and its combination with a library quantitation kit (Kapa, Kapa Biosystems, Wilmington, MA, USA) for deep sequencing (Illumina Miseq). Two RNA viruses (canine distemper virus and dengue virus) and one ssDNA virus (porcine circovirus type 2) were tested with the optimized protocols. The tested method for dsDNA synthesis has shown satisfactory results and may be used in laboratory setting, particularly when enzymes are already available. Library preparation combining commercial kits (Nextera XT and Kapa) has yielded more reads and genome coverage, probably due to a lack of small fragment recovering at the normalization step of Nextera XT. In addition, libraries may be diluted or concentrated to provide increase on genome coverage with Kapa quantitation. PMID:25901649

  9. Microfluidic Sample Preparation for Diagnostic Cytopathology

    PubMed Central

    Mach, Albert J.; Adeyiga, Oladunni B.; Di Carlo, Dino

    2014-01-01

    The cellular components of body fluids are routinely analyzed to identify disease and treatment approaches. While significant focus has been placed on developing cell analysis technologies, tools to automate the preparation of cellular specimens have been more limited, especially for body fluids beyond blood. Preparation steps include separating, concentrating, and exposing cells to reagents. Sample preparation continues to be routinely performed off-chip by technicians, preventing cell-based point-of-care diagnostics, increasing the cost of tests, and reducing the consistency of the final analysis following multiple manually-performed steps. Here, we review the assortment of biofluids for which suspended cells are analyzed, along with their characteristics and diagnostic value. We present an overview of the conventional sample preparation processes for cytological diagnosis. We finally discuss the challenges and opportunities in developing microfluidic devices for the purpose of automating or miniaturizing these processes, with particular emphases on preparing large or small volume samples, working with samples of high cellularity, automating multi-step processes, and obtaining high purity subpopulations of cells. We hope to convey the importance of and help identify new research directions addressing the vast biological and clinical applications in preparing and analyzing the array of available biological fluids. Successfully addressing the challenges described in this review can lead to inexpensive systems to improve diagnostic accuracy while simultaneously reducing overall systemic healthcare costs. PMID:23380972

  10. Precise and automated microfluidic sample preparation.

    SciTech Connect

    Crocker, Robert W.; Patel, Kamlesh D.; Mosier, Bruce P.; Harnett, Cindy K.

    2004-07-01

    Autonomous bio-chemical agent detectors require sample preparation involving multiplex fluid control. We have developed a portable microfluidic pump array for metering sub-microliter volumes at flowrates of 1-100 {micro}L/min. Each pump is composed of an electrokinetic (EK) pump and high-voltage power supply with 15-Hz feedback from flow sensors. The combination of high pump fluid impedance and active control results in precise fluid metering with nanoliter accuracy. Automated sample preparation will be demonstrated by labeling proteins with fluorescamine and subsequent injection to a capillary gel electrophoresis (CGE) chip.

  11. [Progress in sample preparation and analytical methods for trace polar small molecules in complex samples].

    PubMed

    Zhang, Qianchun; Luo, Xialin; Li, Gongke; Xiao, Xiaohua

    2015-09-01

    Small polar molecules such as nucleosides, amines, amino acids are important analytes in biological, food, environmental, and other fields. It is necessary to develop efficient sample preparation and sensitive analytical methods for rapid analysis of these polar small molecules in complex matrices. Some typical materials in sample preparation, including silica, polymer, carbon, boric acid and so on, are introduced in this paper. Meanwhile, the applications and developments of analytical methods of polar small molecules, such as reversed-phase liquid chromatography, hydrophilic interaction chromatography, etc., are also reviewed. PMID:26753274

  12. Application of hydrocyanic acid vapor generation via focused microwave radiation to the preparation of industrial effluent samples prior to free and total cyanide determinations by spectrophotometric flow injection analysis.

    PubMed

    Quaresma, Maria Cristina Baptista; de Carvalho, Maria de Fátima Batista; Meirelles, Francis Assis; Santiago, Vânia Maria Junqueira; Santelli, Ricardo Erthal

    2007-02-01

    A sample preparation procedure for the quantitative determination of free and total cyanides in industrial effluents has been developed that involves hydrocyanic acid vapor generation via focused microwave radiation. Hydrocyanic acid vapor was generated from free cyanides using only 5 min of irradiation time (90 W power) and a purge time of 5 min. The HCN generated was absorbed into an accepting NaOH solution using very simple glassware apparatus that was appropriate for the microwave oven cavity. After that, the cyanide concentration was determined within 90 s using a well-known spectrophotometric flow injection analysis system. Total cyanide analysis required 15 min irradiation time (90 W power), as well as chemical conditions such as the presence of EDTA-acetate buffer solution or ascorbic acid, depending on the effluent to be analyzed (petroleum refinery or electroplating effluents, respectively). The detection limit was 0.018 mg CN l(-1) (quantification limit of 0.05 mg CN l(-1)), and the measured RSD was better than 8% for ten independent analyses of effluent samples (1.4 mg l(-1) cyanide). The accuracy of the procedure was assessed via analyte spiking (with free and complex cyanides) and by performing an independent sample analysis based on the standard methodology recommended by the APHA for comparison. The sample preparation procedure takes only 10 min for free and 20 min for total cyanide, making this procedure much faster than traditional methodologies (conventional heating and distillation), which are time-consuming (they require at least 1 h). Samples from oil (sour and stripping tower bottom waters) and electroplating effluents were analyzed successfully. PMID:17143595

  13. Amino acid analyses of Apollo 14 samples.

    NASA Technical Reports Server (NTRS)

    Gehrke, C. W.; Zumwalt, R. W.; Kuo, K.; Aue, W. A.; Stalling, D. L.; Kvenvolden, K. A.; Ponnamperuma, C.

    1972-01-01

    Detection limits were between 300 pg and 1 ng for different amino acids, in an analysis by gas-liquid chromatography of water extracts from Apollo 14 lunar fines in which amino acids were converted to their N-trifluoro-acetyl-n-butyl esters. Initial analyses of water and HCl extracts of sample 14240 and 14298 samples showed no amino acids above background levels.

  14. A rapid and specific HPLC-electrochemical method for the determination of endogenous 5-methyltetrahydrofolic acid in plasma using solid phase sample preparation with internal standardization.

    PubMed

    Lucock, M D; Hartley, R; Smithells, R W

    1989-03-01

    A rapid and specific HPLC-electrochemical method for determining endogenous 5-methyltetrahydrofolic acid (5MeTHF) in plasma is described. Quantitative solid phase extraction of 5MeTHF and internal standard, beta-hydroxyethyltheophylline, was carried out using proprietary phenyl bonded-silica columns (Bond Elut Phenyl cartridges, 1.0 mL capacity). Chromatographic separation was achieved using a mobile phase consisting of 15% (v/v) methanol in 0.05 M KH2PO4, pH 3.5 at a flow rate of 2.0 mL/min in conjunction with a Waters Assoc. radially compressed Nova-Pak phenyl column (10 cm x 8 mm, 4 microns bonded silica). The internal standard was measured by UV detection at 254 nm. A Bioanalytical Systems Inc. LC-17 glassy carbon oxidative flow cell with a potential held at +0.35 V vs Ag/AgCl using the LC-4A amperometric controller allowed levels of 1-2 ng/mL 5MeTHF to be measured in 500 microL of plasma. Daily appraisal of the ratio produced by authentic materials clearly demonstrated that quantitation using dual detection was not subject to problems of differential response. Inter-day variation of the differential detector response is cited. Comparison of the Lactobacillus casei bioassay with HPLC demonstrates good agreement between methods but at the same time highlights the drawback of using such non-specific methods to measure samples where more than one folylmonoglutamate may be present. Antoxidant free storage for three months at -70 degrees C in darkness resulted in no deterioration of 5MeTHF. A comparison of the means and range of values for plasma folate obtained using HPLC, L. casei bioassay and the radiometric binding assay is reported. PMID:2736319

  15. Chapter A1. Preparations for Water Sampling

    USGS Publications Warehouse

    Wilde, Franceska D.; Radtke, Dean B.; Gibs, Jacob; Iwatsubo, Rick T.

    1998-01-01

    The National Field Manual for the Collection of Water-Quality Data (National Field Manual) provides guidelines and standard procedures for U.S. Geological Survey (USGS) personnel who collect data used to assess the quality of the Nation's surface-water and ground-water resources. This chapter addresses field-trip preparations, including selection of sample-collection sites for studies of surface-water quality, site reconnaissance and well selection for studies of groundwater quality, and the establishment of electronic files and field files and folders for a sampling site. Each chapter of the National Field Manual is published separately and revised periodically. Newly published and revised chapters are posted on the World Wide Web on the USGS page 'National Field Manual for the Collection of Water-Quality Data.' The URL for this page is http://pubs.water.usgs.gov/twri9A/ (accessed Jan. 31, 2005).

  16. Study on Dicarboxylic Acids in Aerosol Samples with Capillary Electrophoresis

    PubMed Central

    Adler, Heidi; Sirén, Heli

    2014-01-01

    The research was performed to study the simultaneous detection of a homologous series of α, ω-dicarboxylic acids (C2–C10), oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, and sebacic acids, with capillary electrophoresis using indirect UV detection. Good separation efficiency in 2,6-pyridinedicarboxylic acid as background electrolyte modified with myristyl trimethyl ammonium bromide was obtained. The dicarboxylic acids were ionised and separated within five minutes. For the study, authentic samples were collected onto dry cellulose membrane filters of a cascade impactor (12 stages) from outdoor spring aerosols in an urban area. Hot water and ultrasonication extraction methods were used to isolate the acids from membrane filters. Due to the low concentrations of acids in the aerosols, the extracts were concentrated with solid-phase extraction (SPE) before determination. The enrichment of the carboxylic acids was between 86 and 134% with sample pretreatment followed by 100-time increase by preparation of the sample to 50 μL. Inaccuracy was optimised for all the sample processing steps. The aerosols contained dicarboxylic acids C2–C10. Then, mostly they contained C2, C5, and C10. Only one sample contained succinic acid. In the study, the concentrations of the acids in aerosols were lower than 10 ng/m3. PMID:24729915

  17. 7 CFR 27.21 - Preparation of samples of cotton.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Preparation of samples of cotton. 27.21 Section 27.21... REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Inspection and Samples § 27.21 Preparation of samples of cotton. The samples from each bale shall be prepared as specified in this...

  18. 7 CFR 27.21 - Preparation of samples of cotton.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Preparation of samples of cotton. 27.21 Section 27.21... REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Inspection and Samples § 27.21 Preparation of samples of cotton. The samples from each bale shall be prepared as specified in this...

  19. 7 CFR 27.21 - Preparation of samples of cotton.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Preparation of samples of cotton. 27.21 Section 27.21... REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Inspection and Samples § 27.21 Preparation of samples of cotton. The samples from each bale shall be prepared as specified in this...

  20. Preparation of graphene thin films for radioactive samples.

    PubMed

    Roteta, Miguel; Fernández-Martínez, Rodolfo; Mejuto, Marcos; Rucandio, Isabel

    2016-03-01

    A new method for the preparation of conductive thin films is presented. The metallization of VYNS films guarantees the electrical conductivity but it results in the breaking of a high proportion of them. Graphene, a two-dimensional nanostructure of monolayer or few layers graphite has attracted a great deal of attention because of its excellent properties such as a good chemical stability, mechanical resistance and extraordinary electronic transport properties. In this work, the possibilities of graphene have been explored as a way to produce electrical conductive thin films without an extra metallization process. The procedure starts with preparing homogenous suspensions of reduced graphene oxide (rGO) in conventional VYNS solutions. Ultra-sonication is used to ensure a good dispersibility of rGO. Graphene oxide (GO) is prepared via oxidation of graphite and subsequent exfoliation by sonication. Different chemically rGO were obtained by reaction with hydrazine sulfate, sodium borohydride, ascorbic acid and hydroiodic acid as reducing agents. The preparation of the thin graphene films is done in a similar way as the conventional VYNS foil preparation procedure. Drops of the solution are deposited onto water. The graphene films have been used to prepare sources containing some electron capture radionuclides ((109)Cd, (55)Fe, (139)Ce) with an activity in the order of 3kBq. The samples have been measured to test the attainable low energy electron efficiency and the energy resolution of Auger and conversion electrons by 4π (electron capture)-γ coincidence measurements. The 4π (electron capture)-γ coincidence setup includes a pressurized proportional counter and a NaI(Tl) detector. Tests with different pressures up to 1000kPa were carried out. All these tests show similar values in both parameters (efficiency and resolution) as those obtained by using the conventional metallized films without the drawback of the high percentage of broken films. PMID:26651168

  1. DICARBOXYLIC ACID CONCENTRATION TRENDS AND SAMPLING ARTIFACTS

    EPA Science Inventory

    This abstract describes a slide presentation on results of dicarboxylic acid concentration trends and sampling artifacts to be presented at the 2006 International Aerosol Conference sponsored by the American Association for Aerosol Research in St. Paul, Minnesota on September 10-...

  2. Microfluidic DNA sample preparation method and device

    DOEpatents

    Krulevitch, Peter A.; Miles, Robin R.; Wang, Xiao-Bo; Mariella, Raymond P.; Gascoyne, Peter R. C.; Balch, Joseph W.

    2002-01-01

    Manipulation of DNA molecules in solution has become an essential aspect of genetic analyses used for biomedical assays, the identification of hazardous bacterial agents, and in decoding the human genome. Currently, most of the steps involved in preparing a DNA sample for analysis are performed manually and are time, labor, and equipment intensive. These steps include extraction of the DNA from spores or cells, separation of the DNA from other particles and molecules in the solution (e.g. dust, smoke, cell/spore debris, and proteins), and separation of the DNA itself into strands of specific lengths. Dielectrophoresis (DEP), a phenomenon whereby polarizable particles move in response to a gradient in electric field, can be used to manipulate and separate DNA in an automated fashion, considerably reducing the time and expense involved in DNA analyses, as well as allowing for the miniaturization of DNA analysis instruments. These applications include direct transport of DNA, trapping of DNA to allow for its separation from other particles or molecules in the solution, and the separation of DNA into strands of varying lengths.

  3. Research for amino acids in lunar samples.

    NASA Technical Reports Server (NTRS)

    Gehrke, C. W.; Zumwalt, R. W.; Kuo, K.; Rash, J. J.; Aue , W. A.; Stalling, D. L.; Kvenvolden, K. A.; Ponnamperuma, C.

    1972-01-01

    The study was primarily directed toward the examination of Apollo 14 lunar fines for indigenous amino acids or materials which could be converted to amino acids on hydrolysis with 6 N hydrochloric acid. Initial experiments were conducted to confirm the integrity of the derivatization reactions and reagents, and to optimize the gas-liquid chromatographic (GLC) instrumental and chromatographic system for the separation and flame ionization detection of the amino acid derivatives. In studies on the recovery of amino acids added to lunar fines, low recoveries were obtained when 10 ng of each amino acid were added to 50 mg of virgin fines, but the subsequent addition of 50 ng of each to the previously extracted sample resulted in much higher recoveries.

  4. Spectral Reproducibility and Quantification of Peptides in MALDI of Samples Prepared by Micro-Spotting

    NASA Astrophysics Data System (ADS)

    Bae, Yong Jin; Park, Kyung Man; Ahn, Sung Hee; Moon, Jeong Hee; Kim, Myung Soo

    2014-08-01

    Previously, we reported that MALDI spectra of peptides became reproducible when temperature was kept constant. Linear calibration curves derived from such spectral data could be used for quantification. Homogeneity of samples was one of the requirements. Among the three popular matrices used in peptide MALDI [i.e., α-cyano-4-hydroxycinnamic acid (CHCA), 2,5-dihydroxybenzoic acid (DHB), and sinapinic acid (SA)], homogeneous samples could be prepared by conventional means only for CHCA. In this work, we showed that sample preparation by micro-spotting improved the homogeneity for all three cases.

  5. Sample preparation for actinide solid state research

    NASA Astrophysics Data System (ADS)

    Spirlet, J. C.

    1982-09-01

    The actinide elements (5f elements) and their compounds constitute a very interesting group for solid state research. The electronic properties of the 5f elements show intermediate behavior between the well-understood, completely localized 4f system (lanthanides) and the 3d system (transition elements). The possibility of understanding some unexplained properties of the 3d elements through a systematic investigation of the electronic structures of the actinides considerably increased interest in samples with well-defined composition and structure and with well-known purity. In some cases, single crystals of low defect densities and high purity levels are needed to allow sophisticated investigations of physical properties. Actinide compounds are easily obtained at a high purity level by direct synthesis from pure elements using noncontaminating techniques. Examples of these techniques are the reaction of the actinide metal powder with the vapor of an oxidant in a sealed quartz ampoule, leviation melting on a water-cooled pedestal or melting in a Huking crucible. Actinide metals are produced by metallothermic reduction of commercially available oxides or carbides or by the van Arkel purification process. The metals are refined to the desired purity level by evaporation in vacuum for the more volatile elements (Ac, Pu, Am, Cm, Bk) and by the van Arkel process for the metals with low vapor pressure. Single crystals of actinide compounds have been grown by chemical vapor transport methods (oxides, chalcogenides), high temperature solution growth techniques (oxides), and pulling from the melt by the Czochralski method (oxides, intermetallics). Thin solid films have been prepared by vacuum evaporation or by focused ion-beam sputtering. The materials are analyzed for trace-level impurity content by inductively-coupled plasma spectroscopy, by spark source mass spectroscopy and by secondary-ion mass spectroscopy. The chemical composition of the compounds is determined by

  6. Novel sample preparation method for molecular detection of Mollicutes in cell culture samples.

    PubMed

    Lehmann, David; Jouette, Sébastien; Olivieri, Frédéric; Laborde, Sandra; Rofel, Céline; Simon, Emmanuelle; Metz, Didier; Felden, Luc; Ribault, Sébastien

    2010-02-01

    Research laboratories, raw materials and media suppliers as well as the biopharmaceutical industry face recurrent contamination with Mollicutes. Culture-based detection methods are very slow (28 days) and could ideally be replaced by nucleic acid testing (NAT) for rapid result. These methods are nonetheless hampered by their companion sample preparation methods. They are limited by the volume tested (0.1 to 5 mL), the protein/nucleic acid content they can accommodate and are generally performed in an open environment. The processing of low volumes of complex matrices is associated to several issues such as poor representativeness, low sensitivity, inhibition and false positives. The novel sample preparation method described in this study has been developed to overcome these limitations and to process 20-mL samples containing high loads of eukaryotic cells. A dual-membrane device is coupled to magnetic bead purification. In one single and closed device, eukaryotic cells and microorganisms are separated, contaminants are concentrated, lysed and corresponding nucleic acids are collected. This novel sample preparation method has been tested with 9 different Mollicutes. The ability to detect the contaminants down to 0.6 CFU/mL by real-time PCR among hundreds of millions of CHO-S cells (Chinese hamster ovary cells, adapted to serum-free suspension culture), without biological pre-enrichment, has been demonstrated. The novel device has been compared to manual silica spin columns, which remain the gold standard in most laboratories. These columns failed to yield the same limit of detection and reproducible results without separating mammalian cells from contaminants. Co-culture experiments have shown that the novel method allows detection of Mollicutes grown for days in presence of mammalian cells, despite the fact that these microorganisms can adhere to eukaryotic cells or invade them. The co-culture data also suggest that the novel sample preparation device might improve

  7. Waste minimization in analytical chemistry through innovative sample preparation techniques.

    SciTech Connect

    Smith, L. L.

    1998-05-28

    Because toxic solvents and other hazardous materials are commonly used in analytical methods, characterization procedures result in significant and costly amount of waste. We are developing alternative analytical methods in the radiological and organic areas to reduce the volume or form of the hazardous waste produced during sample analysis. For the radiological area, we have examined high-pressure, closed-vessel microwave digestion as a way to minimize waste from sample preparation operations. Heated solutions of strong mineral acids can be avoided for sample digestion by using the microwave approach. Because reactivity increases with pressure, we examined the use of less hazardous solvents to leach selected contaminants from soil for subsequent analysis. We demonstrated the feasibility of this approach by extracting plutonium from a NET reference material using citric and tartaric acids with microwave digestion. Analytical results were comparable to traditional digestion methods, while hazardous waste was reduced by a factor often. We also evaluated the suitability of other natural acids, determined the extraction performance on a wider variety of soil types, and examined the extraction efficiency of other contaminants. For the organic area, we examined ways to minimize the wastes associated with the determination of polychlorinated biphenyls (PCBs) in environmental samples. Conventional methods for analyzing semivolatile organic compounds are labor intensive and require copious amounts of hazardous solvents. For soil and sediment samples, we have a method to analyze PCBs that is based on microscale extraction using benign solvents (e.g., water or hexane). The extraction is performed at elevated temperatures in stainless steel cells containing the sample and solvent. Gas chromatography-mass spectrometry (GC/MS) was used to quantitate the analytes in the isolated extract. More recently, we developed a method utilizing solid-phase microextraction (SPME) for natural

  8. PREPARATION OF SOIL SAMPLING PROTOCOLS: SAMPLING TECHNIQUES AND STRATEGIES

    EPA Science Inventory

    The document serves as a companion document to the Soil Sampling Quality Assurance User's Guide, Second Edition. he two documents together provide methods, techniques, and procedures for designing a variety of soil measurement programs and associated Quality Assurance Program Pla...

  9. 40 CFR 761.323 - Sample preparation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... PROHIBITIONS Self-Implementing Alternative Extraction and Chemical Analysis Procedures for Non-liquid PCB... minimum of 10 samples weighing at least 300 grams each. Samples of PCB remediation waste used in the... PCB remediation waste at the cleanup site, or must be the same kind of material as that waste....

  10. 40 CFR 761.323 - Sample preparation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PROHIBITIONS Self-Implementing Alternative Extraction and Chemical Analysis Procedures for Non-liquid PCB... minimum of 10 samples weighing at least 300 grams each. Samples of PCB remediation waste used in the... PCB remediation waste at the cleanup site, or must be the same kind of material as that waste....

  11. 40 CFR 761.323 - Sample preparation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PROHIBITIONS Self-Implementing Alternative Extraction and Chemical Analysis Procedures for Non-liquid PCB... minimum of 10 samples weighing at least 300 grams each. Samples of PCB remediation waste used in the... PCB remediation waste at the cleanup site, or must be the same kind of material as that waste....

  12. 40 CFR 761.323 - Sample preparation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... PROHIBITIONS Self-Implementing Alternative Extraction and Chemical Analysis Procedures for Non-liquid PCB... minimum of 10 samples weighing at least 300 grams each. Samples of PCB remediation waste used in the... PCB remediation waste at the cleanup site, or must be the same kind of material as that waste....

  13. DICARBOXYLIC ACID CONCENTRATION TRENDS AND SAMPLING ARTIFACTS

    EPA Science Inventory

    Dicarboxylic acids associated with airborne particulate matter were measured during a summer period in Philadelphia that included multiple air pollution episodes. Samples were collected for two ten hour periods each day using a high volume sampler with two quartz fiber filters in...

  14. Components for automated microfluidics sample preparation and analysis

    NASA Astrophysics Data System (ADS)

    Archer, M.; Erickson, J. S.; Hilliard, L. R.; Howell, P. B., Jr.; Stenger, D. A.; Ligler, F. S.; Lin, B.

    2008-02-01

    The increasing demand for portable devices to detect and identify pathogens represents an interdisciplinary effort between engineering, materials science, and molecular biology. Automation of both sample preparation and analysis is critical for performing multiplexed analyses on real world samples. This paper selects two possible components for such automated portable analyzers: modified silicon structures for use in the isolation of nucleic acids and a sheath flow system suitable for automated microflow cytometry. Any detection platform that relies on the genetic content (RNA and DNA) present in complex matrices requires careful extraction and isolation of the nucleic acids in order to ensure their integrity throughout the process. This sample pre-treatment step is commonly performed using commercially available solid phases along with various molecular biology techniques that require multiple manual steps and dedicated laboratory space. Regardless of the detection scheme, a major challenge in the integration of total analysis systems is the development of platforms compatible with current isolation techniques that will ensure the same quality of nucleic acids. Silicon is an ideal candidate for solid phase separations since it can be tailored structurally and chemically to mimic the conditions used in the laboratory. For analytical purposes, we have developed passive structures that can be used to fully ensheath one flow stream with another. As opposed to traditional flow focusing methods, our sheath flow profile is truly two dimensional, making it an ideal candidate for integration into a microfluidic flow cytometer. Such a microflow cytometer could be used to measure targets captured on either antibody- or DNA-coated beads.

  15. Fluidics platform and method for sample preparation

    DOEpatents

    Benner, Henry W.; Dzenitis, John M.

    2016-06-21

    Provided herein are fluidics platforms and related methods for performing integrated sample collection and solid-phase extraction of a target component of the sample all in one tube. The fluidics platform comprises a pump, particles for solid-phase extraction and a particle-holding means. The method comprises contacting the sample with one or more reagents in a pump, coupling a particle-holding means to the pump and expelling the waste out of the pump while the particle-holding means retains the particles inside the pump. The fluidics platform and methods herein described allow solid-phase extraction without pipetting and centrifugation.

  16. Rapid Automated Sample Preparation for Biological Assays

    SciTech Connect

    Shusteff, M

    2011-03-04

    Our technology utilizes acoustic, thermal, and electric fields to separate out contaminants such as debris or pollen from environmental samples, lyse open cells, and extract the DNA from the lysate. The objective of the project is to optimize the system described for a forensic sample, and demonstrate its performance for integration with downstream assay platforms (e.g. MIT-LL's ANDE). We intend to increase the quantity of DNA recovered from the sample beyond the current {approx}80% achieved using solid phase extraction methods. Task 1: Develop and test an acoustic filter for cell extraction. Task 2: Develop and test lysis chip. Task 3: Develop and test DNA extraction chip. All chips have been fabricated based on the designs laid out in last month's report.

  17. Application of pressurized sample preparation methods for the analysis of steels and copper alloys.

    PubMed

    Borszéki, J; Halmos, P; Gegus, E; Kárpáti, P

    1994-07-01

    Pressurized sample preparation devices (High Pressure Asher, Pressurized Microwave Digestion system, compared with a PTFE decomposition vessel) were used to dissolve certified metal alloy samples (steel, copper) for ICP analysis. Based on the results of the analysis it was established that both up-to-date devices can be advantageously applied to quickly and quantitatively dissolve metal alloy samples. To dissolve the samples, two different kinds of acid mixtures (A: nitric and hydrochloric acid; B: nitric and hydrochloric and sulphuric and phosphoric acid) were used. The sample preparation is simpler and less time-consuming than the earlier commonly used methods, sample loss and degree of contamination are also reduced. Steel samples containing tungsten, titanium and niobium (less than 0.5%) can only be analyzed using a mixture of the four acids. By dissolving steel samples in the nitric and hydrochloric acid mixture, the concentration of their most common elements (Cr, Ni, Mn, V, Cu) as well as their S and P content can be determined. Copper alloy samples can be dissolved quickly by the pressurized microwave decomposition device using hydrochloric acid and diluted (1:1) nitric acid. PMID:18966041

  18. 7 CFR 61.34 - Drawing and preparation of sample.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Drawing and preparation of sample. 61.34 Section 61.34 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Cottonseed Samplers § 61.34 Drawing and preparation of sample. Each licensed cottonseed sampler shall...

  19. 7 CFR 61.34 - Drawing and preparation of sample.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Drawing and preparation of sample. 61.34 Section 61.34 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Cottonseed Samplers § 61.34 Drawing and preparation of sample. Each licensed cottonseed sampler shall...

  20. 7 CFR 61.34 - Drawing and preparation of sample.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Drawing and preparation of sample. 61.34 Section 61.34 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Cottonseed Samplers § 61.34 Drawing and preparation of sample. Each licensed cottonseed sampler shall...

  1. 7 CFR 61.34 - Drawing and preparation of sample.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Drawing and preparation of sample. 61.34 Section 61.34 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Cottonseed Samplers § 61.34 Drawing and preparation of sample. Each licensed cottonseed sampler shall...

  2. Ultra-Fast Sample Preparation for High-Throughput Proteomics

    SciTech Connect

    Lopez-Ferrer, Daniel; Hixson, Kim K.; Belov, Mikhail E.; Smith, Richard D.

    2011-06-21

    Sample preparation oftentimes can be the Achilles Heel of any analytical process and in the field of proteomics, preparing samples for mass spectrometric analysis is no exception. Current goals, concerning proteomic sample preparation on a large scale, include efforts toward improving reproducibility, reducing the time of processing and ultimately the automation of the entire workflow. This chapter reviews an array of recent approaches applied to bottom-up proteomics sample preparation to reduce the processing time down from hours to minutes. The current state-of-the-art in the field uses different energy inputs like microwave, ultrasound or pressure to perform the four basic steps in sample preparation: protein extraction, denaturation, reduction and alkylation, and digestion. No single energy input for enhancement of proteome sample preparation has become the universal gold standard. Instead, a combination of different energy inputs tend to produce the best results. This chapter further describes the future trends in the field such as the hyphenation of sample preparation with downstream detection and analysis systems. Finally, a detailed protocol describing the combined use of both pressure cycling technology and ultrasonic energy inputs to hasten proteomic sample preparation is presented.

  3. 40 CFR 761.392 - Preparing validation study samples.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Preparing validation study samples... Under § 761.79(d)(4) § 761.392 Preparing validation study samples. (a)(1) To validate a procedure to... surface to be used in the validation study as follows: (i) Use a spiking solution made of PCBs mixed...

  4. Preparation of Botanical Samples for Biomedical Research

    PubMed Central

    Liu, Zhijun

    2014-01-01

    Plants are chemical storehouses, a fact which has driven countless multidisciplinary quests for bioactive compounds. As the very first step of botanical research, the whole desire is to find “hit” plants with specific bioactivities. It is logical to use some strategies that can maximize the chances of finding these “hits” with limited time and resources. In addition to selecting the right plants for screening, how the plant extracts are prepared can also influence the bioactivity screening outcomes. An extract from the same plant material can be quite different in chemical composition having different preparations. Because of the complex mixture nature of plant extracts, it is possible artifact activities may be observed. Thus confirmatory activity tests are often necessary to warrant the next laborious isolation step. A bioassay directed isolation approach may be the most efficient in identifying the bioactive compounds because of the narrowed focus at each isolation step, but a phytochemistry isolation approach is appropriate to characterize a purified bioactive extract. In fact, these two approaches can be taken intermittently whenever efficiency can be improved. Finally, use of the identified active compounds is now broader. In addition to determining a lead compound to continue a drug development path, there is an increasing interest in support for the use of botanical extracts as botanical drugs. Instead of dropping the extract after extracting the lead compound, the natural analogues representing the purified extract now have a chance to become leading compounds in the pursuit of novel therapies for metabolic syndrome and other diseases. PMID:18537697

  5. Amino acid precursors in lunar samples.

    NASA Technical Reports Server (NTRS)

    Fox, S. W.; Harada, K.; Hare, P. E.

    1972-01-01

    The use of hot water to extract lunar samples, followed by the hydrolysis of the aqueous extract, appears to be the method of choice for identification and quantitation of amino acid precursors in extraterrestrial sources. The net inferences from the analyses to date are (1) that amino acid precursors are verifiably present in lunar dust, and (2) that they are quite certainly not the consequence of contamination by terrestrial organisms, including man. It is suggested that prebiotic evolutionary pathways such as have been traversed on the earth were terminated on the moon for lack of sufficient water. Although some or all of the amino acid precursors may be indigenous, the low level observed suggests that they may also result from onfall of organic compounds from interstellar matter, comets, tails, solar wind, or meteorites.

  6. Snow White Trench Prepared for Sample Collection

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The informally named 'Snow White' trench is the source for the next sample to be acquired by NASA's Phoenix Mars Lander for analysis by the wet chemistry lab.

    The Surface Stereo Imager on Phoenix took this shadow-enhanced image of the trench, on the eastern end of Phoenix's work area, on Sol 103, or the 103rd day of the mission, Sept. 8, 2008. The trench is about 23 centimeters (9 inches) wide.

    The wet chemistry lab is part of Phoenix's Microscopy, Electrochemistry and Conductivity suite of instruments.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  7. Simplified sample preparation method for triclosan and methyltriclosan determination in biota and foodstuff samples.

    PubMed

    Canosa, P; Rodríguez, I; Rubí, E; Ramil, M; Cela, R

    2008-04-25

    An improved method for the determination of triclosan (TCS) and methyltriclosan (MTCS) in fish and foodstuff samples is presented. Analytes were simultaneously extracted and purified using the matrix solid-phase dispersion (MSPD) technique, and then selectively determined by gas chromatography with tandem mass spectrometry (GC-MS/MS). Several combinations of dispersants, clean-up co-sorbents and extraction solvents were tested in order to obtain lipid-free extracts and quantitative recoveries for TCS and MTCS. Under optimised conditions, 0.5 g samples were dispersed using 1.5 g of neutral silica in a mortar with a pestle, and transferred to a polypropylene cartridge containing 3 g of silica impregnated with 10% of sulphuric acid (SiO2-H2SO4, 10%, w/w). Analytes were recovered with 10 mL of dichloromethane whereas lipids were oxidized in the layer of acidic silica. The extract was concentrated to dryness and re-constituted with 1 mL of ethyl acetate. Then, a fraction of 0.5 mL was mixed with 50 microL of N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) and injected in the GC-MS/MS system. The developed method provided absolute recoveries between 77 and 120% for different samples spiked at the low ng g(-1) level, quantification limits in the range of 1-2 ng g(-1) and a considerable simplicity in comparison with previously developed sample preparation approaches. Experiments carried out placing sliced food samples in direct contact with TCS-treated kitchenware surfaces showed the capability of the biocide to migrate into foodstuffs. PMID:18329035

  8. Alumina microstructural sample preparation using a borate glaze

    SciTech Connect

    Scott, C.; Hill, S.; Hosmer, K.

    1986-03-01

    A method was developed for preparing alumina surfaces for microstructural analysis. Samples were polished using a sodium borate glaze, which produced a smooth surface with the grain boundaries accented.

  9. Sampling and preparation of samples of peanut butter for aflatoxin analysis.

    PubMed

    Waltking, A E

    1980-01-01

    Procedures are discussed for sampling peanut butter and preparing those samples for alatoxin analysis. Special emphasis is placed on sampling the product from shipping pallets and comminuting chunk stype peanut butter in order to reduce the variability in the analysis associated with the nonuniform distribution of aflatoxin in the product. The slurry method of preparation is a convenient means of obtaining a sample which is representative of a nonhomogeneous product. PMID:7380779

  10. Novel Sample-handling Approach for XRD Analysis with Minimal Sample Preparation

    NASA Technical Reports Server (NTRS)

    Sarrazin, P.; Chipera, S.; Bish, D.; Blake, D.; Feldman, S.; Vaniman, D.; Bryson, C.

    2004-01-01

    Sample preparation and sample handling are among the most critical operations associated with X-ray diffraction (XRD) analysis. These operations require attention in a laboratory environment, but they become a major constraint in the deployment of XRD instruments for robotic planetary exploration. We are developing a novel sample handling system that dramatically relaxes the constraints on sample preparation by allowing characterization of coarse-grained material that would normally be impossible to analyze with conventional powder-XRD techniques.

  11. Analytical Chemistry Laboratory (ACL) procedure compendium. Volume 2, Sample preparation methods

    SciTech Connect

    Not Available

    1993-08-01

    This volume contains the interim change notice for sample preparation methods. Covered are: acid digestion for metals analysis, fusion of Hanford tank waste solids, water leach of sludges/soils/other solids, extraction procedure toxicity (simulate leach in landfill), sample preparation for gamma spectroscopy, acid digestion for radiochemical analysis, leach preparation of solids for free cyanide analysis, aqueous leach of solids for anion analysis, microwave digestion of glasses and slurries for ICP/MS, toxicity characteristic leaching extraction for inorganics, leach/dissolution of activated metal for radiochemical analysis, extraction of single-shell tank (SST) samples for semi-VOC analysis, preparation and cleanup of hydrocarbon- containing samples for VOC and semi-VOC analysis, receiving of waste tank samples in onsite transfer cask, receipt and inspection of SST samples, receipt and extrusion of core samples at 325A shielded facility, cleaning and shipping of waste tank samplers, homogenization of solutions/slurries/sludges, and test sample preparation for bioassay quality control program.

  12. Sample Preparation for Electron Probe Microanalysis—Pushing the Limits

    PubMed Central

    Geller, Joseph D.; Engle, Paul D.

    2002-01-01

    There are two fundamental considerations in preparing samples for electron probe microanalysis (EPMA). The first one may seem obvious, but we often find it is overlooked. That is, the sample analyzed should be representative of the population from which it comes. The second is a direct result of the assumptions in the calculations used to convert x-ray intensity ratios, between the sample and standard, to concentrations. Samples originate from a wide range of sources. During their journey to being excited under the electron beam for the production of x rays there are many possibilities for sample alteration. Handling can contaminate samples by adding extraneous matter. In preparation, the various abrasives used in sizing the sample by sawing, grinding and polishing can embed themselves. The most accurate composition of a contaminated sample is, at best, not representative of the original sample; it is misleading. Our laboratory performs EPMA analysis on customer submitted samples and prepares over 250 different calibration standards including pure elements, compounds, alloys, glasses and minerals. This large variety of samples does not lend itself to mass production techniques, including automatic polishing. Our manual preparation techniques are designed individually for each sample. The use of automated preparation equipment does not lend itself to this environment, and is not included in this manuscript. The final step in quantitative electron probe microanalysis is the conversion of x-ray intensities ratios, known as the “k-ratios,” to composition (in mass fraction or atomic percent) and/or film thickness. Of the many assumptions made in the ZAF (where these letters stand for atomic number, absorption and fluorescence) corrections the localized geometry between the sample and electron beam, or takeoff angle, must be accurately known. Small angular errors can lead to significant errors in the final results. The sample preparation technique then becomes very

  13. Process for the preparation of lactic acid and glyceric acid

    DOEpatents

    Jackson, James E [Haslett, MI; Miller, Dennis J [Okemos, MI; Marincean, Simona [Dewitt, MI

    2008-12-02

    Hexose and pentose monosaccharides are degraded to lactic acid and glyceric acid in an aqueous solution in the presence of an excess of a strongly anionic exchange resin, such as AMBERLITE IRN78 and AMBERLITE IRA400. The glyceric acid and lactic acid can be separated from the aqueous solution. Lactic acid and glyceric acid are staple articles of commerce.

  14. Efficient Sample Preparation from Complex Biological Samples Using a Sliding Lid for Immobilized Droplet Extractions

    PubMed Central

    2015-01-01

    Sample preparation is a major bottleneck in many biological processes. Paramagnetic particles (PMPs) are a ubiquitous method for isolating analytes of interest from biological samples and are used for their ability to thoroughly sample a solution and be easily collected with a magnet. There are three main methods by which PMPs are used for sample preparation: (1) removal of fluid from the analyte-bound PMPs, (2) removal of analyte-bound PMPs from the solution, and (3) removal of the substrate (with immobilized analyte-bound PMPs). In this paper, we explore the third and least studied method for PMP-based sample preparation using a platform termed Sliding Lid for Immobilized Droplet Extractions (SLIDE). SLIDE leverages principles of surface tension and patterned hydrophobicity to create a simple-to-operate platform for sample isolation (cells, DNA, RNA, protein) and preparation (cell staining) without the need for time-intensive wash steps, use of immiscible fluids, or precise pinning geometries. Compared to other standard isolation protocols using PMPs, SLIDE is able to perform rapid sample preparation with low (0.6%) carryover of contaminants from the original sample. The natural recirculation occurring within the pinned droplets of SLIDE make possible the performance of multistep cell staining protocols within the SLIDE by simply resting the lid over the various sample droplets. SLIDE demonstrates a simple easy to use platform for sample preparation on a range of complex biological samples. PMID:24927449

  15. Preparation of privatization samples for envelopes `A` and `C`

    SciTech Connect

    Winters, W.I., Westinghouse Hanford

    1996-07-17

    As part of the TWRS Privatization process, the DOE has committed to provide each of the two contractors who submitted successful bids with ten 125 mL samples of Hanford tank waste meeting chemical and radionuclide criteria specified as Waste Envelope A, B, and C. This test plan describes how the samples will be prepared before shipment.

  16. Automation of preparation of nonmetallic samples for analysis by atomic absorption and inductively coupled plasma spectrometry

    NASA Technical Reports Server (NTRS)

    Wittmann, A.; Willay, G.

    1986-01-01

    For a rapid preparation of solutions intended for analysis by inductively coupled plasma emission spectrometry or atomic absorption spectrometry, an automatic device called Plasmasol was developed. This apparatus used the property of nonwettability of glassy C to fuse the sample in an appropriate flux. The sample-flux mixture is placed in a composite crucible, then heated at high temperature, swirled until full dissolution is achieved, and then poured into a water-filled beaker. After acid addition, dissolution of the melt, and filling to the mark, the solution is ready for analysis. The analytical results obtained, either for oxide samples or for prereduced iron ores show that the solutions prepared with this device are undistinguished from those obtained by manual dissolutions done by acid digestion or by high temperature fusion. Preparation reproducibility and analytical tests illustrate the performance of Plasmasol.

  17. Method and apparatus for the preparation of liquid samples for determination of boron

    DOEpatents

    Siemer, Darryl D.

    1986-03-04

    A method and apparatus for the preparation of a liquid sample for the quantitative determination of boron by flame photometry. The sample is combined in a vessel with sulfuric acid, and an excess of methanol is added thereto. The methanol reacts with any boron present in the sample to form trimethyl borate which is volatilized by the heat of reaction between the excess methanol and sulfuric acid. The volatilized trimethyl borate is withdrawn from the vessel by either a partial vacuum or a positive pressure and is rapidly transferred to a standard flame photometer. The method is free of interference from typical boron concomitants.

  18. Method and apparatus for the preparation of liquid samples for determination of boron

    DOEpatents

    Siemer, D.D.

    A method and apparatus are described for the preparation of a liquid sample for the quantitative determination of boron by flame photometry. The sample is combined in a vessel with sulfuric acid, and an excess of methanol is added thereto. The methanol reacts with any boron present in the sample to form trimethyl borate which is volatilized by the heat of reaction between the excess methanol and sulfuric acid. The volatilized trimethyl borate is withdrawn from the vessel by either a partial vacuum or a positive pressure and is rapidly transferred to a standard flame photometer. The method is free of interference from typical boron concomitants.

  19. Method and apparatus for the preparation of liquid samples for determination of boron

    DOEpatents

    Siemer, Darryl D.

    1986-01-01

    A method and apparatus for the preparation of a liquid sample for the quantitative determination of boron by flame photometry. The sample is combined in a vessel with sulfuric acid, and an excess of methanol is added thereto. The methanol reacts with any boron present in the sample to form trimethyl borate which is volatilized by the heat of reaction between the excess methanol and sulfuric acid. The volatilized trimethyl borate is withdrawn from the vessel by either a partial vacuum or a positive pressure and is rapidly transferred to a standard flame photometer. The method is free of interference from typical boron concomitants.

  20. Fluidics platform and method for sample preparation and analysis

    SciTech Connect

    Benner, W. Henry; Dzenitis, John M.; Bennet, William J.; Baker, Brian R.

    2014-08-19

    Herein provided are fluidics platform and method for sample preparation and analysis. The fluidics platform is capable of analyzing DNA from blood samples using amplification assays such as polymerase-chain-reaction assays and loop-mediated-isothermal-amplification assays. The fluidics platform can also be used for other types of assays and analyzes. In some embodiments, a sample in a sealed tube can be inserted directly. The following isolation, detection, and analyzes can be performed without a user's intervention. The disclosed platform may also comprises a sample preparation system with a magnetic actuator, a heater, and an air-drying mechanism, and fluid manipulation processes for extraction, washing, elution, assay assembly, assay detection, and cleaning after reactions and between samples.

  1. Sample preparation prior to molecular amplification: complexities and opportunities.

    PubMed

    Butot, Sophie; Zuber, Sophie; Baert, Leen

    2014-02-01

    Molecular amplification using Reverse Transcription quantitative Polymerase Chain Reaction (RT-qPCR) is currently considered as the gold standard to detect enteric human pathogenic viruses such as norovirus and hepatitis A virus in food and water. However, the molecular-based detection requires an adequate sampling strategy and a sample preparation specific for viruses. Sampling for enteric human viruses in water and food should not necessarily follow bacterial sampling plans. The development of a reference detection method including sample preparation as proposed in ISO/TS 15216 represents a milestone to facilitate the evaluation of the performance and eventually validation of future virus detection methods. The potential viral infectivity linked to a positive PCR result is a remaining issue and pretreatments allowing the differentiation of infectious viruses would be useful for future risk assessments. PMID:24441295

  2. Surfactant roles in modern sample preparation techniques: a review.

    PubMed

    Moradi, Morteza; Yamini, Yadollah

    2012-09-01

    The pressure to decrease organic solvent usage in laboratories is increasing. Thus miniaturization and improvement of sample handling using alternatives is a challenge that has been discussed by several researchers. From this perspective, surfactant-based sample preparations were an educated choice. Since the introduction of cloud point extraction by Watanabe, considerable studies have been focused on the chemical properties of surfactants in the extraction methods. The unique properties of surfactants make them flexible agents for different miniaturized sample preparation techniques based on solid- or liquid-phase extraction. As a result, the use of surfactants with different roles in sample-preparation methodologies (such as surfactant as an emulsifier, surfactant rich phase as an extraction medium, ion pair-based extraction, hemimicelle/admicelle extraction, surfactant-coated magnetic nanoparticle, solid-phase microextraction with micellar desorption) is an important contribution to minimizing the problems arising from preliminary operations, which are the weakest step in analytical measurement. This paper reviews the literature dealing with the application of surfactant-based sample preparations to the separation and the preconcentration of organic and inorganic species. PMID:22887709

  3. Global metabolite analysis of yeast: evaluation of sample preparation methods.

    PubMed

    Villas-Bôas, Silas G; Højer-Pedersen, Jesper; Akesson, Mats; Smedsgaard, Jørn; Nielsen, Jens

    2005-10-30

    Sample preparation is considered one of the limiting steps in microbial metabolome analysis. Eukaryotes and prokaryotes behave very differently during the several steps of classical sample preparation methods for analysis of metabolites. Even within the eukaryote kingdom there is a vast diversity of cell structures that make it imprudent to blindly adopt protocols that were designed for a specific group of microorganisms. We have therefore reviewed and evaluated the whole sample preparation procedures for analysis of yeast metabolites. Our focus has been on the current needs in metabolome analysis, which is the analysis of a large number of metabolites with very diverse chemical and physical properties. This work reports the leakage of intracellular metabolites observed during quenching yeast cells with cold methanol solution, the efficacy of six different methods for the extraction of intracellular metabolites, and the losses noticed during sample concentration by lyophilization and solvent evaporation. A more reliable procedure is suggested for quenching yeast cells with cold methanol solution, followed by extraction of intracellular metabolites by pure methanol. The method can be combined with reduced pressure solvent evaporation and therefore represents an attractive sample preparation procedure for high-throughput metabolome analysis of yeasts. PMID:16240456

  4. Sample preparation for quantitation of tritium by accelerator mass spectrometry.

    PubMed

    Chiarappa-Zucca, Marina L; Dingley, Karen H; Roberts, Mark L; Velsko, Carol A; Love, Adam H

    2002-12-15

    The capability to prepare samples accurately and reproducibly for analysis of tritium (3H) content by accelerator mass spectrometry (AMS) greatly facilitates isotopic tracer studies in which attomole levels of 3H can be measured in milligram-sized samples. A method has been developed to convert the hydrogen of organic samples to a solid, titanium hydride, which can be analyzed by AMS. Using a two-step process, the sample is first oxidized to carbon dioxide and water. In the second step, the water is transferred within a heated manifold into a quartz tube, reduced to hydrogen gas using zinc, and reacted with titanium powder. The 3H/1H ratio of the titanium hydride is measured by AMS and normalized to standards whose ratios were determined by decay counting to calculate the amount of 3H in the original sample. Water, organic compounds, and biological samples with 3H activities measured by liquid scintillation counting were utilized to develop and validate the method. The 3H/1H ratios were quantified in samples that spanned 5 orders of magnitude, from 10(-10) to 10(-15), with a detection limit of 3.0 x 10(-15), which is equivalent to 0.02 dpm tritium/mg of material. Samples smaller than 2 mg were analyzed following addition of 2 mg of a tritium-free-hydrogen carrier. Preparation of organic standards containing both 14C and 3H in 2-mg organic samples demonstrated that this sample preparation methodology can also be applied to quantify both of these isotopes from a single sample. PMID:12510750

  5. ANALYTICAL VARIATION IN THE DETERMINATION OF THE FATTY ACID COMPOSITION OF STANDARD PREPARATIONS OF BRINE SHRIMP ARTEMIA: AN INTERLABORATORY EXERCISE

    EPA Science Inventory

    An international interlaboratory exercise was conducted to investigate the variability associated with the preparation and analysis of samples and the reporting of fatty acid composition data for tvo samples of Artemia supplied to the laboratories by the Artemia Reference Center ...

  6. Properties of Copolymers of Aspartic Acid and Aliphatic Dicarboxylic Acids Prepared by Reactive Extrusion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspartic acid may be prepared chemically or by the fermentation of carbohydrates. Currently, low molecular weight polyaspartic acids are prepared commercially by heating aspartic acid at high temperatures (greater than 220 degrees C) for several hours in the solid state. In an effort to develop a ...

  7. Analytical characterization of high-level mixed wastes using multiple sample preparation treatments

    SciTech Connect

    King, A.G.; Baldwin, D.L.; Urie, M.W.; McKinley, S.G.

    1994-09-01

    The Analytical Chemistry Laboratory at the Pacific Northwest Laboratory in Richland, Washington, is actively involved in performing analytical characterization of high-level mixed waste from Hanford`s single shell and double shell tank characterization programs. A full suite of analyses is typically performed on homogenized tank core samples. These analytical techniques include inductively-coupled plasma-atomic emission spectroscopy, total organic carbon methods and radiochemistry methods, as well as many others, all requiring some type of remote sample-preparation treatment to solubilize the tank sludge material for analysis. Most of these analytical methods typically use a single sample-preparation treatment, inherently providing elemental information only. To better understand and interpret tank chemistry and assist in identifying chemical compounds, selected analytical methods are performed using multiple sample-preparation treatments. The sample preparation treatments used at Pacific Northwest Laboratory for this work with high-level mixed waste include caustic fusion, acid digestion, and water leach. The type of information available by comparing results from different sample-prep treatments includes evidence for the presence of refractory compounds, acid-soluble compounds, or water-soluble compounds. Problems unique to the analysis of Hanford tank wastes are discussed. Selected results from the Hanford single shell ferrocyanide tank, 241-C-109, are presented, and the resulting conclusions are discussed.

  8. New Methods of Sample Preparation for Atom Probe Specimens

    NASA Technical Reports Server (NTRS)

    Kuhlman, Kimberly, R.; Kowalczyk, Robert S.; Ward, Jennifer R.; Wishard, James L.; Martens, Richard L.; Kelly, Thomas F.

    2003-01-01

    Magnetite is a common conductive mineral found on Earth and Mars. Disk-shaped precipitates approximately 40 nm in diameter have been shown to have manganese and aluminum concentrations. Atom-probe field-ion microscopy (APFIM) is the only technique that can potentially quantify the composition of these precipitates. APFIM will be used to characterize geological and planetary materials, analyze samples of interest for geomicrobiology; and, for the metrology of nanoscale instrumentation. Prior to APFIM sample preparation was conducted by electropolishing, the method of sharp shards (MSS), or Bosch process (deep reactive ion etching) with focused ion beam (FIB) milling as a final step. However, new methods are required for difficult samples. Many materials are not easily fabricated using electropolishing, MSS, or the Bosch process, FIB milling is slow and expensive, and wet chemistry and the reactive ion etching are typically limited to Si and other semiconductors. APFIM sample preparation using the dicing saw is commonly used to section semiconductor wafers into individual devices following manufacture. The dicing saw is a time-effective method for preparing high aspect ratio posts of poorly conducting materials. Femtosecond laser micromachining is also suitable for preparation of posts. FIB time required is reduced by about a factor of 10 and multi-tip specimens can easily be fabricated using the dicing saw.

  9. Comparison of different sample and target preparation procedures for PIXE analysis of biological materials

    NASA Astrophysics Data System (ADS)

    Maenhaut, W.; De Reu, L.; Vandenhaute, J.

    1984-04-01

    Four different methods for preparing PIXE targets from biological samples were compared. All methods involved doping with an internal standard and preparing target deposits of 1-4 mg/cm 2 on a thin substrate. In method A targets were prepared using powdered freeze-dried material. Methods B and C both included a low temperature ashing preconcentration step and method D involved an acid digestion in a teflon bomb. The procedures were applied to reference materials (e.g. NBS standards) and to "real" samples such as human kidneys and a liver, which had been analyzed by neutron activation analysis (NAA). For most elements good agreement was observed between the results of the four target preparation methods and the reference values or the NAA results. Exceptions, however, were Br, Se and Cd, which were lost in some methods. The detection limits in the different methods are compared.

  10. Target preparation for milligram sized 14C samples and data evaluation for AMS measurements

    NASA Astrophysics Data System (ADS)

    Andree, Michael; Beer, Jürg; Oeschger, Hans; Bonani, G.; Hofmann, H. J.; Morenzoni, E.; Nessi, M.; Suter, M.; Wölfli, W.

    1984-11-01

    Our preparation technique produces in a glow-discharge an amorphous carbon deposit on a copper substrate. The process starts with 1.6 cm 3 CO 2 STP (900 μg carbon) which is reduced over hot zinc to CO and subsequently cracked in the discharge. The yield of the process is typically 80%. With these targets in the Zürich ion source ion currents up to 20 μA are obtained. The background of samples prepared with this technique is presently around 30 ka (2.5% MODERN). The precision after half an hour measuring time for a modern sample is 0.7% and 2.7% for a three half-lives old sample, including the errors of the background and the NBS oxalic acid measurement. The method we use to correct for the background of the preparation and the accelerator as well as for the fractionation in the accelerator is presented.

  11. Investigation into alternative sample preparation techniques for the determination of heavy metals in stationary source emission samples collected on quartz filters.

    PubMed

    Goddard, Sharon L; Brown, Richard J C

    2014-01-01

    Monitoring stationary source emissions for heavy metals generally requires the use of quartz filters to collect samples because of the high temperature and high moisture sampling environment. The documentary standard method sample preparation technique in Europe, EN 14385, uses digestion in hydrofluoric acid and nitric acid (HF/HNO3) followed by complexing with boric acid (H3BO3) prior to analysis. However, the use of this method presents a number of problems, including significant instrumental drift during analysis caused by the matrix components, often leading to instrument breakdown and downtime for repairs, as well as posing significant health and safety risks. The aim of this work was to develop an alternative sample preparation technique for emissions samples on quartz filters. The alternative techniques considered were: (i) acid digestion in a fluoroboric acid (HBF4) and HNO3 mixture and (ii) acid extraction in an aqua regia (AR) mixture (HCl and HNO3). Assessment of the effectiveness of these options included determination of interferences and signal drift, as well as validating the different methods by measurement of matrix certified reference materials (CRMs), and comparing the results obtained from real test samples and sample blanks to determine limits of detection. The results showed that the HBF4/HNO3 mixture provides the most viable alternative to the documentary standard preparation technique. PMID:25407906

  12. Investigation into Alternative Sample Preparation Techniques for the Determination of Heavy Metals in Stationary Source Emission Samples Collected on Quartz Filters

    PubMed Central

    Goddard, Sharon L.; Brown, Richard J. C.

    2014-01-01

    Monitoring stationary source emissions for heavy metals generally requires the use of quartz filters to collect samples because of the high temperature and high moisture sampling environment. The documentary standard method sample preparation technique in Europe, EN 14385, uses digestion in hydrofluoric acid and nitric acid (HF/HNO3) followed by complexing with boric acid (H3BO3) prior to analysis. However, the use of this method presents a number of problems, including significant instrumental drift during analysis caused by the matrix components, often leading to instrument breakdown and downtime for repairs, as well as posing significant health and safety risks. The aim of this work was to develop an alternative sample preparation technique for emissions samples on quartz filters. The alternative techniques considered were: (i) acid digestion in a fluoroboric acid (HBF4) and HNO3 mixture and (ii) acid extraction in an aqua regia (AR) mixture (HCl and HNO3). Assessment of the effectiveness of these options included determination of interferences and signal drift, as well as validating the different methods by measurement of matrix certified reference materials (CRMs), and comparing the results obtained from real test samples and sample blanks to determine limits of detection. The results showed that the HBF4/HNO3 mixture provides the most viable alternative to the documentary standard preparation technique. PMID:25407906

  13. Sample preparation and electron microscopy of hydrocracking catalysts

    NASA Astrophysics Data System (ADS)

    Husain, S.; McComb, D. W.; Perkins, J. M.; Haswell, R.

    2008-08-01

    This work focuses on the preparation of zeolite and alumina hydrocracking catalysts for investigation by electron energy-loss spectroscopy (EELS). EELS can potentially give new insights into the location and structure of coke which can result in catalyst deactivation. Three sample preparation techniques have been used - microtoming, focussed ion beam milling (LIB) and conventional ion beam milling. Crushing and grinding the catalyst pellets has been discounted as a preparation technique as the spatial relationship between the coke and the catalyst is lost using this method. Microtomed sections show some mechanical damage while sections milled in a single beam LIB microscope show gallium decoration in pores and were too thick for EELS. Conventional ion beam milling has proved to be most successful as it results in extensive thin regions and maintains the spatial distribution of the zeolite and alumina phases.

  14. Comparison of leach results from field and laboratory prepared samples

    SciTech Connect

    Oblath, S.B.; Langton, C.A.

    1985-03-25

    The leach behavior of saltstone prepared in the laboratory agrees well with that from samples mixed in the field using the Littleford mixer. Leach rates of nitrates and cesium from the current reference formulation saltstone were compared. The laboratory samples were prepared using simulated salt solution; those in the field used Tank 50 decontaminated supernate. For both nitrate and cesium, the field and laboratory samples showed nearly identical leach rates for the first 30 to 50 days. For the remaining period of the test, the field samples showed higher leach rates with the maximum difference being less than a factor of three. Ruthenium and antimony were present in the Tank 50 supernate in known amounts. Antimony-125 was observed in the leachate and a fractional leach rate was calculated to be at least a factor of ten less than that of /sup 137/Cs. No /sup 106/Ru was observed in the leachate, and the release rate was not calculated. However, based on the detection limits for the analysis, the ruthenium leach rate must also be at least a factor of ten less than cesium. These data are the first measurements of the leach rates of Ru and Sb from saltstone. The nitrate leach rates for these samples were 5 x 10/sup -5/ grams of nitrate per square cm per day after 100 days for the laboratory samples and after 200 days for the field samples. These values are consistent with the previously measured leach rates for reference formulation saltstone. The relative standard deviation in the leach rate is about 15% for the field samples, which all were produced from one batch of saltstone, and about 35% for the laboratory samples, which came from different batches. These are the first recorded estimates of the error in leach rates for saltstone.

  15. Leaching of metals from steel samples in peracetic acid

    NASA Astrophysics Data System (ADS)

    Yabutani, Tomoki; Nakamura, Takamasa; Takayabagi, Toshio

    2015-03-01

    In this paper, leaching behavior of metallic species from steel samples in peracetic acid was investigated. We compared the leaching efficiency between peracetic acid and acetic acid to estimate the role of peroxo functional group for the leaching. As a result, peracetic acid enhanced the leaching ability of metallic species from the high speed steel and the alloy steel samples. MoO3, Mo, MO2C, W, WO3, VC and MnO2 were effectively leached by peracetic acid, while the stainless steel had a high resistance against corrosion by peracetic acid.

  16. Preparation of SELEX Samples for Next-Generation Sequencing.

    PubMed

    Tolle, Fabian; Mayer, Günter

    2016-01-01

    Fuelled by massive whole genome sequencing projects such as the human genome project, enormous technological advancements and therefore tremendous price drops could be achieved, rendering next-generation sequencing very attractive for deep sequencing of SELEX libraries. Herein we describe the preparation of SELEX samples for Illumina sequencing, based on the already established whole genome sequencing workflow. We describe the addition of barcode sequences for multiplexing and the adapter ligation, avoiding associated pitfalls. PMID:26552817

  17. Magnetically driven solid sample preparation for centrifugal microfluidic devices.

    PubMed

    Duford, David A; Peng, Dan D; Salin, Eric D

    2009-06-01

    A prototype for solid sample preparation on centrifugal microfluidic devices has been designed and characterized. The system uses NdFeB magnets in both the centrifugal device and a fixed base. As the centrifugal device rotates, the magnets move and spin in their chambers creating a pulverizing mechanical motion. This technique was successfully applied to the dissolution of potassium ferricyanide (K(3)[Fe(CN)(6)]), a hard colored crystal. A 0.10 g sample was completely dissolved in 3 s in 1.0 mL of water while rotating at 1000 rpm. This is a 300-fold improvement over static dissolution. PMID:19422186

  18. Sample preparation and detection device for infectious agents

    DOEpatents

    Miles, Robin R.; Wang, Amy W.; Fuller, Christopher K.; Lemoff, Asuncion V.; Bettencourt, Kerry A.; Yu, June

    2003-06-10

    A sample preparation and analysis device which incorporates both immunoassays and PCR assays in one compact, field-portable microchip. The device provides new capabilities in fluid and particle control which allows the building of a fluidic chip with no moving parts, thus decreasing fabrication cost and increasing the robustness of the device. The device can operate in a true continuous (not batch) mode. The device incorporates magnetohydrodynamic (MHD) pumps to move the fluid through the system, acoustic mixing and fractionation, dielectropheretic (DEP) sample concentration and purification, and on-chip optical detection capabilities.

  19. Preparation of TEM samples for hard ceramic powders.

    PubMed

    Xu, Qiang; Kumar, Vikas; de Kruijff, Tom; Jansen, Jacob; Zandbergen, Henny W

    2008-12-01

    It is challenging to prepare a good sample for high-resolution electron microscopy of polycrystalline ceramic powders containing hard particles or particles with a strong preferential cleavage. Here we demonstrate that embedding the particles in a Cu matrix in a pressed pellet allows for straightforward conventional ion milling. The method is applied to powders of Mg10Ir19B16 and Na0.5CoO2 to show its feasibility, whereby transmission electron microscopy (TEM) samples with crystalline areas thinner than 10 nm can be obtained easily. PMID:18722061

  20. Apparatus for preparing a sample for mass spectrometry

    DOEpatents

    Villa-Aleman, Eliel

    1994-01-01

    An apparatus for preparing a sample for analysis by a mass spectrometer system. The apparatus has an entry chamber and an ionization chamber separated by a skimmer. A capacitor having two space-apart electrodes followed by one or more ion-imaging lenses is disposed in the ionization chamber. The chamber is evacuated and the capacitor is charged. A valve injects a sample gas in the form of sample pulses into the entry chamber. The pulse is collimated by the skimmer and enters the ionization chamber. When the sample pulse passes through the gap between the electrodes, it discharges the capacitor and is thereby ionized. The ions are focused by the imaging lenses and enter the mass analyzer, where their mass and charge are analyzed.

  1. Apparatus for preparing a sample for mass spectrometry

    DOEpatents

    Villa-Aleman, E.

    1994-05-10

    An apparatus is described for preparing a sample for analysis by a mass spectrometer system. The apparatus has an entry chamber and an ionization chamber separated by a skimmer. A capacitor having two space-apart electrodes followed by one or more ion-imaging lenses is disposed in the ionization chamber. The chamber is evacuated and the capacitor is charged. A valve injects a sample gas in the form of sample pulses into the entry chamber. The pulse is collimated by the skimmer and enters the ionization chamber. When the sample pulse passes through the gap between the electrodes, it discharges the capacitor and is thereby ionized. The ions are focused by the imaging lenses and enter the mass analyzer, where their mass and charge are analyzed. 1 figures.

  2. Sample preparation methods for determination of drugs of abuse in hair samples: A review.

    PubMed

    Vogliardi, Susanna; Tucci, Marianna; Stocchero, Giulia; Ferrara, Santo Davide; Favretto, Donata

    2015-02-01

    Hair analysis has assumed increasing importance in the determination of substances of abuse, both in clinical and forensic toxicology investigations. Hair analysis offers particular advantages over other biological matrices (blood and urine), including a larger window of detection, ease of collection and sample stability. In the present work, an overview of sample preparation techniques for the determination of substances of abuse in hair is provided, specifically regarding the principal steps in hair sample treatment-decontamination, extraction and purification. For this purpose, a survey of publications found in the MEDLINE database from 2000 to date was conducted. The most widely consumed substances of abuse and psychotropic drugs were considered. Trends in simplification of hair sample preparation, washing procedures and cleanup methods are discussed. Alternative sample extraction techniques, such as head-space solid phase microextraction (HS-SPDE), supercritical fluid extraction (SFE) and molecularly imprinted polymers (MIP) are also reported. PMID:25604816

  3. Recent advances in sample preparation techniques for effective bioanalytical methods.

    PubMed

    Kole, Prashant Laxman; Venkatesh, Gantala; Kotecha, Jignesh; Sheshala, Ravi

    2011-01-01

    This paper reviews the recent developments in bioanalysis sample preparation techniques and gives an update on basic principles, theory, applications and possibilities for automation, and a comparative discussion on the advantages and limitation of each technique. Conventional liquid-liquid extraction (LLE), protein precipitation (PP) and solid-phase extraction (SPE) techniques are now been considered as methods of the past. The last decade has witnessed a rapid development of novel sample preparation techniques in bioanalysis. Developments in SPE techniques such as selective sorbents and in the overall approach to SPE, such as hybrid SPE and molecularly imprinted polymer SPE, have been addressed. Considerable literature has been published in the area of solid-phase micro-extraction and its different versions, e.g. stir bar sorptive extraction, and their application in the development of selective and sensitive bioanalytical methods. Techniques such as dispersive solid-phase extraction, disposable pipette extraction and micro-extraction by packed sorbent offer a variety of extraction phases and provide unique advantages to bioanalytical methods. On-line SPE utilizing column-switching techniques is rapidly gaining acceptance in bioanalytical applications. PP sample preparation techniques such as PP filter plates/tubes offer many advantages like removal of phospholipids and proteins in plasma/serum. Newer approaches to conventional LLE techniques (salting-out LLE) are also covered in this review article. PMID:21154887

  4. Preparation of .alpha.,.beta.-unsaturated carboxylic acids and esters

    DOEpatents

    Gogate, Makarand Ratnakar; Spivey, James Jerry; Zoeller, Joseph Robert

    1998-01-01

    Disclosed is a process for the preparation of .alpha.,.beta.-unsaturated carboxylic acids and esters thereof which comprises contacting formaldehyde or a source of formaldehyde with a carboxylic acid, ester or anhydride in the presence of a catalyst comprising an oxide of niobium.

  5. Preparation of {alpha},{beta}-unsaturated carboxylic acids and esters

    DOEpatents

    Gogate, M.R.; Spivey, J.J.; Zoeller, J.R.

    1998-09-15

    Disclosed is a process for the preparation of {alpha},{beta}-unsaturated carboxylic acids and esters thereof which comprises contacting formaldehyde or a source of formaldehyde with a carboxylic acid, ester or anhydride in the presence of a catalyst comprising an oxide of niobium.

  6. Optimization for Peptide Sample Preparation for Urine Peptidomics

    SciTech Connect

    Sigdel, Tara K.; Nicora, Carrie D.; Hsieh, Szu-Chuan; Dai, Hong; Qian, Weijun; Camp, David G.; Sarwal, Minnie M.

    2014-02-25

    Analysis of native or endogenous peptides in biofluids can provide valuable insights into disease mechanisms. Furthermore, the detected peptides may also have utility as potential biomarkers for non-invasive monitoring of human diseases. The non-invasive nature of urine collection and the abundance of peptides in the urine makes analysis by high-throughput ‘peptidomics’ methods , an attractive approach for investigating the pathogenesis of renal disease. However, urine peptidomics methodologies can be problematic with regards to difficulties associated with sample preparation. The urine matrix can provide significant background interference in making the analytical measurements that it hampers both the identification of peptides and the depth of the peptidomics read when utilizing LC-MS based peptidome analysis. We report on a novel adaptation of the standard solid phase extraction (SPE) method to a modified SPE (mSPE) approach for improved peptide yield and analysis sensitivity with LC-MS based peptidomics in terms of time, cost, clogging of the LC-MS column, peptide yield, peptide quality, and number of peptides identified by each method. Expense and time requirements were comparable for both SPE and mSPE, but more interfering contaminants from the urine matrix were evident in the SPE preparations (e.g., clogging of the LC-MS columns, yellowish background coloration of prepared samples due to retained urobilin, lower peptide yields) when compared to the mSPE method. When we compared data from technical replicates of 4 runs, the mSPE method provided significantly improved efficiencies for the preparation of samples from urine (e.g., mSPE peptide identification 82% versus 18% with SPE; p = 8.92E-05). Additionally, peptide identifications, when applying the mSPE method, highlighted the biology of differential activation of urine peptidases during acute renal transplant rejection with distinct laddering of specific peptides, which was obscured for most proteins

  7. Distribution and Origin of Amino Acids in Lunar Regolith Samples

    NASA Technical Reports Server (NTRS)

    Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Dworkin, J. P.; McLain, H. L.; Noble, S. K.; Gibson, E. K., Jr.

    2015-01-01

    The existence of organic compounds on the lunar surface has been a question of interest from the Apollo era to the present. Investigations of amino acids immediately after collection of lunar samples yielded inconclusive identifications, in part due to analytical limitations including insensitivity to certain compounds, an inability to separate enantiomers, and lack of compound-specific isotopic measurements. It was not possible to determine if the detected amino acids were indigenous to the lunar samples or the result of terrestrial contamination. Recently, we presented initial data from the analysis of amino acid abundances in 12 lunar regolith samples and discussed those results in the context of four potential amino acid sources [5]. Here, we expand on our previous work, focusing on amino acid abundances and distributions in seven regolith samples and presenting the first compound-specific carbon isotopic ratios measured for amino acids in a lunar sample.

  8. TCLP Preparation and Analysis of K East Basin Composite Sludge Samples

    SciTech Connect

    KL Silvers; JJ Wagner; RT Steele

    2000-08-15

    Sludge samples from the Hanford K East Basin were analyzed by the Toxicity Characterization Leaching Procedure (TCLP) to assist in the appropriate Resource Conservation and Recovery Act (RCIL4) designation of this material. Sludge samples were collected by Fluor Hanford, Inc. using the consolidated sludge sampling system (system that allows collection of a single sample from multiple sample locations). These samples were shipped to the Postirradiation Testing Laboratory (PTL, 327 Building) and then transferred to the Pacific Northwest National Laboratory (PNNL) Radiochemical Processing Laboratory (RPL, 325 Building) for recovery and testing. Two sludge composites were prepared, using the consolidated sludge samples, to represent K East canister sludge (sample KC Can Comp) and K East floor sludge (sample KC Floor Comp). Each composite was extracted in duplicate and analyzed in duplicate following pre-approved(a) TCLP extraction and analyses procedures. In addition, these samples and duplicates were analyzed for total RCRA metals (via acid digestion preparation). The work was conducted in accordance with the requirements of the Hanford Analytical Quality Assurance Requirements Document (HASQARD). A PNNL Quality Assurance Program compliant with J HASQARD was implemented for this effort. The results from the TCLP analyses showed that all RCRA metal concentrations were less than the TCLP limits for both the canister and floor composite samples and their respective duplicates.

  9. Fatty acid biosynthesis by a particulate preparation from germinating pea

    PubMed Central

    Bolton, Paul; Harwood, John L.

    1977-01-01

    1. Fatty acid synthesis was studied in microsomal preparations from germinating pea (Pisum sativum). 2. The preparations synthesized a mixture of saturated fatty acids up to a chain length of C24 from [14C]malonyl-CoA. 3. Whereas hexadecanoic acid was made de novo, octadecanoic acid and icosanoic acid were synthesized by elongation. 4. The products formed during [14C]malonyl-CoA incubation were analysed, and unesterified fatty acids and polar lipids were found to be major products. [14C]Palmitic acid represented a high percentage of the acyl-carrier protein esters, whereas 14C-labelled very-long-chain fatty acids were mainly present as unesterified fatty acids. CoA esters were minor products. 5. The addition of exogenous lipids to the incubation system usually resulted in stimulation of [14C]malonyl-CoA incorporation into fatty acids. The greatest stimulation was obtained with dipalmitoyl phosphatidylcholine. Both exogenous palmitic acid and dipalmitoyl phosphatidylcholine increased the amount of [14C]-stearic acid synthesized, relative to [14C]palmitic acid. Addition of stearic acid increased the amount of [14C]icosanoic acid formed. 6. [14C]Stearic acid was elongated more effectively to icosanoic acid than [14C]stearoyl-CoA, and its conversion was not decreased by addition of unlabelled stearoyl-CoA. 7. Incorporation of [14C]malonyl-CoA into fatty acids was markedly decreased by iodoacetamide and 5,5′-dithiobis-(2-nitrobenzoic acid). Palmitate elongation was sensitive to arsenite addition, and stearate elongation to the presence of Triton X-100 or fluoride. The action of fluoride was not, apparently, due to chelation. 8. The microsomal preparations differed from soluble fractions from germinating pea in (a) synthesizing very-long-chain fatty acids, (b) not utilizing exogenous palmitate–acyl-carrier protein as a substrate for palmitate elongation and (c) having fatty acid synthesis stimulated by the addition of certain complex lipids. PMID:579600

  10. Preparation and characterization Al3+-bentonite Turen Malang for esterification fatty acid (palmitic acid, oleic acid and linoleic acid)

    NASA Astrophysics Data System (ADS)

    Abdulloh, Abdulloh; Aminah, Nanik Siti; Triyono, Mudasir, Trisunaryanti, Wega

    2016-03-01

    Catalyst preparation and characterization of Al3+-bentonite for esterification of palmitic acid, oleic acid and linoleic acid has been done. Al3+-bentonite catalyst was prepared from natural bentonite of Turen Malang through cation exchange reaction using AlCl3 solution. The catalysts obtained were characterized by XRD, XRF, pyridine-FTIR and surface area analyser using the BET method. Catalyst activity test of Al3+-bentonite for esterification reaction was done at 65°C using molar ratio of metanol-fatty acid of 30:1 and 0.25 g of Al3+-bentonite catalyst for the period of ½, 1, 2, 3, 4 and 5 hours. Based on the characterization results, the Al3+-bentonite Turen Malang catalyst has a d-spacing of 15.63 Ǻ, acid sites of Brönsted and Lewis respectively of 230.79 µmol/g and 99.39 µmol/g, surface area of 507.3 m2/g and the average of radius pore of 20.09 Å. GC-MS analysis results of the oil phase after esterification reaction showed the formation of biodiesel (FAME: Fatty acid methyl ester), namely methyl palmitate, methyl oleate and methyl linoleate. The number of conversions resulted in esterification reaction using Al3+-bentonite Turen Malang catalyst was 74.61%, 37.75%, and 20, 93% for the esterification of palmitic acid, oleic acid and linoleic acid respectively.

  11. Combining electrochemical sensors with miniaturized sample preparation for rapid detection in clinical samples.

    PubMed

    Bunyakul, Natinan; Baeumner, Antje J

    2015-01-01

    Clinical analyses benefit world-wide from rapid and reliable diagnostics tests. New tests are sought with greatest demand not only for new analytes, but also to reduce costs, complexity and lengthy analysis times of current techniques. Among the myriad of possibilities available today to develop new test systems, amperometric biosensors are prominent players-best represented by the ubiquitous amperometric-based glucose sensors. Electrochemical approaches in general require little and often enough only simple hardware components, are rugged and yet provide low limits of detection. They thus offer many of the desirable attributes for point-of-care/point-of-need tests. This review focuses on investigating the important integration of sample preparation with (primarily electrochemical) biosensors. Sample clean up requirements, miniaturized sample preparation strategies, and their potential integration with sensors will be discussed, focusing on clinical sample analyses. PMID:25558994

  12. Combining Electrochemical Sensors with Miniaturized Sample Preparation for Rapid Detection in Clinical Samples

    PubMed Central

    Bunyakul, Natinan; Baeumner, Antje J.

    2015-01-01

    Clinical analyses benefit world-wide from rapid and reliable diagnostics tests. New tests are sought with greatest demand not only for new analytes, but also to reduce costs, complexity and lengthy analysis times of current techniques. Among the myriad of possibilities available today to develop new test systems, amperometric biosensors are prominent players—best represented by the ubiquitous amperometric-based glucose sensors. Electrochemical approaches in general require little and often enough only simple hardware components, are rugged and yet provide low limits of detection. They thus offer many of the desirable attributes for point-of-care/point-of-need tests. This review focuses on investigating the important integration of sample preparation with (primarily electrochemical) biosensors. Sample clean up requirements, miniaturized sample preparation strategies, and their potential integration with sensors will be discussed, focusing on clinical sample analyses. PMID:25558994

  13. Comparison of methods for the preparation of sewage sludge samples prior to the spectrophotometric determination of phosphorus

    SciTech Connect

    Katz, S.A.; Jenniss, S.W.; Ciuffo, M.; Alberts, R.

    1986-01-01

    Three procedures for the preparation of sewage sludge samples prior to the colorimetric determination of phosphorus as molybdenum blue were evaluated. Using samples of the US EPA's municipal digested sludge as a reference material, sulfuric acid/ammonium persulfate digestion, muffle furnace ignition followed by extraction of the ash with hydrochloric acid, and direct extraction of the sewage sludge with sodium bicarbonate solution were compared in terms of phosphorus recovery as determined by colorimetric measurements. On the basis of phosphorus recovery, the samples prepared by muffle furnace ignition/hydrochloric acid extraction of the ash showed the best accuracy and precision. This procedure was also superior in terms of the time and effort expended in the preparation of the sewage sludge samples.

  14. The Origin of Amino Acids in Lunar Regolith Samples

    NASA Technical Reports Server (NTRS)

    Cook, Jamie E.; Callahan, Michael P.; Dworkin, Jason P.; Glavin, Daniel P.; McLain, Hannah L.; Noble, Sarah K.; Gibson, Everett K., Jr.

    2016-01-01

    We analyzed the amino acid content of seven lunar regolith samples returned by the Apollo 16 and Apollo 17 missions and stored under NASA curation since collection using ultrahigh-performance liquid chromatography with fluorescence detection and time-of-flight mass spectrometry. Consistent with results from initial analyses shortly after collection in the 1970s, we observed amino acids at low concentrations in all of the curated samples, ranging from 0.2 parts-per-billion (ppb) to 42.7 ppb in hot-water extracts and 14.5 ppb to 651.1 ppb in 6M HCl acid-vapor-hydrolyzed, hot-water extracts. Amino acids identified in the Apollo soil extracts include glycine, D- and L-alanine, D- and L-aspartic acid, D- and L-glutamic acid, D- and L-serine, L-threonine, and L-valine, all of which had previously been detected in lunar samples, as well as several compounds not previously identified in lunar regoliths: -aminoisobutyric acid (AIB), D-and L-amino-n-butyric acid (-ABA), DL-amino-n-butyric acid, -amino-n-butyric acid, -alanine, and -amino-n-caproic acid. We observed an excess of the L enantiomer in most of the detected proteinogenic amino acids, but racemic alanine and racemic -ABA were present in some samples.

  15. Mixing apparatus for preparing NMR samples under pressure

    NASA Astrophysics Data System (ADS)

    Wu, Wen-Jin; Vidugiris, Gediminas; Mooberry, Ed S.; Westler, William M.; Markley, John L.

    2003-09-01

    The size limit for protein NMR spectroscopy in solution arises in large part from line broadening caused by slow molecular tumbling. One way to alleviate this problem is to increase the effective tumbling rate by reducing the viscosity of the solvent. Because proteins generally require an aqueous environment to remain folded, one approach has been to encapsulate hydrated proteins in reverse micelles formed by a detergent and to dissolve the encapsulated protein in a low-viscosity fluid. The high volatility of suitable low-viscosity fluids requires that the samples be prepared and maintained under pressure. We describe a novel apparatus used for the preparation of such samples. The apparatus includes a chamber for mixing the detergent with the low-viscosity solvent, a second chamber for mixing this with hydrated protein, and a 5-mm (o.d.) zirconium oxide NMR sample tube with shut-off valves designed to contain pressures on the order of 10 bar, sufficient for liquid propane. Liquids are moved from one location to another by introducing minor pressure differentials between two pressurization vessels. We discuss the operation of this apparatus and illustrate this with data on a 30-kDa protein complex (chymotrypsin:turkey ovomucoid third domain) encapsulated in reverse micelles of the detergent, sodium bis (2-ethylhexyl) sulfosuccinate, aerosol-ot (AOT), dissolved in liquid propane.

  16. Establishment and maintenance of a coal sample bank and data base. [Including sample preparation without oxidation

    SciTech Connect

    Davis, A.

    1990-01-19

    Retrieval of 5-lb splits of -1/4 inch coal from designated 30-gallon drums was completed. Preparation and analysis of these samples for the second yearly quality evaluation is in progress. After consultation with the DOE Project Manager, two replacement samples were collected. These are the first of the series which will be stored in foil laminate bags. Both of these samples were placed in 30 gallon steel drums lined with polyethylene bags at the mine site. They were equipped with lid gaskets made from Tygon tubing, and 1/4 in. metal tubing fittings to purge and pressurize the drum with argon.

  17. Use of compressed fluids for sample preparation: food applications.

    PubMed

    Mendiola, José A; Herrero, Miguel; Cifuentes, Alejandro; Ibañez, Elena

    2007-06-01

    This review attempts to provide an updated overview (including works published till June 2006) on the latest applications of compressed fluids as sample preparation techniques for food analysis. After a general review of the principles of supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE; also called accelerated solvent extraction, ASE or subcritical water extraction, SWE, when water is employed as extraction solvent), the principal applications of such techniques in the mentioned fields of food and natural products are described, discussing their main advantages and drawbacks. PMID:17353022

  18. Sample preparation and EFTEM of Meat Samples for Nanoparticle Analysis in Food

    NASA Astrophysics Data System (ADS)

    Lari, L.; Dudkiewicz, A.

    2014-06-01

    Nanoparticles are used in industry for personal care products and the preparation of food. In the latter application, their functions include the prevention of microbes' growth, increase of the foods nutritional value and sensory quality. EU regulations require a risk assessment of the nanoparticles used in foods and food contact materials before the products can reach the market. However, availability of validated analytical methodologies for detection and characterisation of the nanoparticles in food hampers appropriate risk assessment. As part of a research on the evaluation of the methods for screening and quantification of Ag nanoparticles in meat we have tested a new TEM sample preparation alternative to resin embedding and cryo-sectioning. Energy filtered TEM analysis was applied to evaluate thickness and the uniformity of thin meat layers acquired at increasing input of the sample demonstrating that the protocols used ensured good stability under the electron beam, reliable sample concentration and reproducibility.

  19. An apparatus for preparing benthic samples aboard ship

    USGS Publications Warehouse

    Pepper, Phillip N.; Girard, Thomas L.; Stapanian, Martin A.

    2001-01-01

    We describe a safe and effective apparatus for washing and reducing the volume of benthic samples collected by grab samplers aboard ship. The sample is transferred directly from the dredge to the apparatus and then washed with water pumped through pipes in the apparatus and from onboard hoses. Wastewater and materials smaller than 0.541 mm in diameter are washed overboard. Larger materials, including benthic organisms, collect on an upper 0.64-cm screen and on a lower 30-mm-mesh stainless steel bolt cloth. A collection jar is screwed into the bottom of the apparatus. Therefore, transfer of sample material from the apparatus to the jar is quick and easy. This apparatus has several advantages for use aboard ship over others described in the literature, especially in rough seas, in cold weather, and at night. The apparatus provides a safe and convenient platform for washing and reducing samples, and samples can be prepared while the vessel is traveling at full speed.

  20. Three sample preparation protocols for polymerase chain reaction based detection of Cryptosporidium parvum in environmental samples.

    PubMed

    Kostrzynska, M; Sankey, M; Haack, E; Power, C; Aldom, J E; Chagla, A H; Unger, S; Palmateer, G; Lee, H; Trevors, J T; De Grandis, S A

    1999-02-01

    Cryptosporidium parvum is a protozoan parasite responsible for an increasing number of outbreaks of gastrointestinal illness worldwide. In this report, we describe development of sample preparation protocols for polymerase chain reaction (PCR)-based detection of C. parvum in fecal material and environmental water samples. Two of these methods were found adequate for isolation of Cryptosporidium DNA from filtered water pellet suspensions. The first involved several filtration steps, immunomagnetic separation and freeze-thaw cycles. The second method involved filtration, addition of EnviroAmp lysis reagent, freeze-thaw cycles and precipitation of the DNA with isopropanol. Using nested PCR, we detected 100 oocysts/ml of filtered water pellet suspension, with either of the above sample preparation procedures. Nested PCR increased sensitivity of the assay by two to three orders of magnitude as compared to the primary PCR. The detection limit for seeded fecal samples was 10-fold higher than for filtered environmental water pellet suspension. Nested PCR results showed 62.4 and 91.1% correlation with immunofluorescence assay (IFA) for fecal samples and filtered environmental water pellet suspensions, respectively. This correlation decreased to 47.2% and 44.4%, respectively, when only IFA positive samples were analyzed. However, in fecal samples contaminated with a high number (> 10(5)/g) of C. parvum oocysts, this correlation was 100%. PMID:10076632

  1. INFECTIVITY OF HISTONE-POLIOVIRUS RIBONUCLEIC ACID PREPARATIONS.

    PubMed

    LUDWIG, E H; SMULL, C E

    1963-06-01

    Ludwig, Ernest H. (The Pennsylvania State University, University Park) and Christine E. Smull. Infectivity of histone-poliovirus ribonucleic acid preparations. J. Bacteriol. 85:1334-1338. 1963.-Some properties of histone-poliovirus ribonucleic acid (RNA) preparations, as relate to infectivity for HeLa cell monolayers, were investigated. The histone-RNA preparations were found to lose their infectivity rapidly at room temperature. They were considerably more stable at ice-bath temperature. Dilution of a histone-RNA preparation in a diluent containing an appropriate amount of histone yielded a plaque count which was proportional to the dilution factor, and which regressed linearly through the point of origin. Dilution of a histone-RNA preparation in a diluent containing no histone resulted in a rapidly decreasing plaque count which was not proportional to the dilution factor. The ability of histone to enhance the infectivity of poliovirus RNA was found to be dependent upon the presence of a low concentration of a monovalent salt in the histone-RNA preparations. Histone-RNA preparations containing approximately isotonic levels of NaCl exhibited a high degree of infectivity. When concentrations of NaCl outside this range were used, a great loss in infectivity of the histone-RNA preparations occurred. The NaCl could be replaced by KCl but not by CaCl(2), MgCl(2), or MgSO(4). PMID:14047226

  2. Sample preparation of metal alloys by electric discharge machining

    NASA Technical Reports Server (NTRS)

    Chapman, G. B., II; Gordon, W. A.

    1976-01-01

    Electric discharge machining was investigated as a noncontaminating method of comminuting alloys for subsequent chemical analysis. Particulate dispersions in water were produced from bulk alloys at a rate of about 5 mg/min by using a commercially available machining instrument. The utility of this approach was demonstrated by results obtained when acidified dispersions were substituted for true acid solutions in an established spectrochemical method. The analysis results were not significantly different for the two sample forms. Particle size measurements and preliminary results from other spectrochemical methods which require direct aspiration of liquid into flame or plasma sources are reported.

  3. HPLC study of the impurities present in different ursodeoxycholic acid preparations: comparative evaluation of four detectors.

    PubMed

    Roda, A; Gatti, R; Cavrini, V; Cerrè, C; Simoni, P

    1993-08-01

    The use of HPLC with different detectors has been investigated for the analysis of bile acid impurities present in four different commercially available ursodeoxycholic acid preparations. The bile acids were efficiently separated by C18 reversed-phase HPLC using methanol-water (3:2, v/v) as the mobile phase. The detectors used for bile acid detection were: UV at 200 nm refractive index (RI) and an evaporative light scattering mass detector (ELSD II). A prederivatization method with the formation of a fluorescent naphthacyl ester has also been used. GC-MS analysis of Me-TMS bile acid derivatives was included as a reference method. The four ursodeoxycholic acid samples were 98-99% pure. The main impurities present in the samples were chenodeoxycholic acid and to a lesser extent lithocholic acid. Only one sample was found to be almost 100% pure using all the detectors. Significant agreement of the data was found between RI, ELSD II detectors and the fluorescent method; the UV detector was unsuitable for use in this method. The analytical performances of the four detectors for bile acid analysis are reported and discussed. When the four-detector data were compared with the GC-MS method, reasonable agreement resulted. Discordant results were found in the quantitation of trace impurities like lithocholic acid and/or other minor bile acids present in amounts less than 0.1%. PMID:8257741

  4. S- to N-Palmitoyl Transfer During Proteomic Sample Preparation

    NASA Astrophysics Data System (ADS)

    Ji, Yuhuan; Bachschmid, Markus M.; Costello, Catherine E.; Lin, Cheng

    2016-04-01

    N-palmitoylation has been reported in a number of proteins and suggested to play an important role in protein localization and functions. However, it remains unclear whether N-palmitoylation is a direct enzyme-catalyzed process, or results from intramolecular S- to N-palmitoyl transfer. Here, using the S-palmitoyl peptide standard, GCpalmLGNAK, as the model system, we observed palmitoyl migration from the cysteine residue to either the peptide N-terminus or the lysine side chain during incubation in both neutral and slightly basic buffers commonly used in proteomic sample preparation. Palmitoyl transfer can take place either intra- or inter-molecularly, with the peptide N-terminus being the preferred migration site, presumably because of its lower basicity. The extent of intramolecular palmitoyl migration was low in the system studied, as it required the formation of an entropically unfavored macrocycle intermediate. Intermolecular palmitoyl transfer, however, remained a tangible problem, and may lead to erroneous reporting of in vivo N-palmitoylation. It was found that addition of the MS-compatible detergent RapiGest could significantly inhibit intermolecular palmitoyl transfer, as well as thioester hydrolysis and DTT-induced thioester cleavage. Finally, palmitoyl transfer from the cysteine residue to the peptide N-terminus can also occur in the gas phase, during collision-induced dissociation, and result in false identification of N-palmitoylation. Therefore, one must be careful with both sample preparation and interpretation of tandem mass spectra in the study of N-palmitoylation.

  5. Preparation of Soybean Seed Samples for FT-IR Microspectroscopy

    SciTech Connect

    Miller,S.; Pietrzak, L.

    2005-01-01

    Typical preparation of seed samples for infrared (IR) microspectroscopy involves imbibition of the seed for varying time periods followed by cryosectioning. Imbibition, however, may initiate germination even at 4 C with associated changes in the chemistry of the sample. We have found that it is possible to section seeds that are sufficiently hard, such as soybeans, on a standard laboratory microtome without imbibition. The use of dry sectioning of unimbibed seeds is reported here, as well as a comparison of different mounting media and modes of analysis. Glycerol, Tissue-Tek, and ethanol were used as mounting media, and the quality of the resulting spectra was assessed. Ethanol was the preferred mountant, because it dried quickly with no residue and thus did not interfere with the spectrum of interest. Analysis in transmission mode using barium fluoride windows to hold the samples was compared with transmission-reflection analysis with sections mounted on special infrared-reflecting slides. The two modes of analysis performed well in different regions of the spectrum. The mode of analysis (transmission vs. transmission-reflection) should be based on the components of greatest interest in the sample.

  6. Preparation of tissue samples for X-ray fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Chwiej, Joanna; Szczerbowska-Boruchowska, Magdalena; Lankosz, Marek; Wojcik, Slawomir; Falkenberg, Gerald; Stegowski, Zdzislaw; Setkowicz, Zuzanna

    2005-12-01

    As is well-known, trace elements, especially metals, play an important role in the pathogenesis of many disorders. The topographic and quantitative elemental analysis of pathologically changed tissues may shed some new light on processes leading to the degeneration of cells in the case of selected diseases. An ideal and powerful tool for such purpose is the Synchrotron Microbeam X-ray Fluorescence technique. It enables the carrying out of investigations of the elemental composition of tissues even at the single cell level. The tissue samples for histopathological investigations are routinely fixed and embedded in paraffin. The authors try to verify the usefulness of such prepared tissue sections for elemental analysis with the use of X-ray fluorescence microscopy. Studies were performed on rat brain samples. Changes in elemental composition caused by fixation in formalin or paraformaldehyde and embedding in paraffin were examined. Measurements were carried out at the bending magnet beamline L of the Hamburger Synchrotronstrahlungslabor HASYLAB in Hamburg. The decrease in mass per unit area of K, Br and the increase in P, S, Fe, Cu and Zn in the tissue were observed as a result of the fixation. For the samples embedded in paraffin, a lower level of most elements was observed. Additionally, for these samples, changes in the composition of some elements were not uniform for different analyzed areas of rat brain.

  7. Sulfonic acid catalysts prepared by radiation-induced graft polymerization

    SciTech Connect

    Mizota, Tomotoshi; Tsuneda, Satoshi; Saito, Kyoichi, Saito

    1994-09-01

    In this study, the authors prepared two variations of graft-type acid catalysts with different adjacent groups by radiation-induced graft polymerization (RIGP), and compared the hydrolytic activity of the resultant acid catalysts for methyl acetate with that of commercially available SO{sub 3}H-type ion-exchange beads with different degrees of cross-linking. 8 refs., 3 figs.

  8. LC-MS analysis of the plasma metabolome--a novel sample preparation strategy.

    PubMed

    Skov, Kasper; Hadrup, Niels; Smedsgaard, Jørn; Frandsen, Henrik

    2015-01-26

    Blood plasma is a well-known body fluid often analyzed in studies on the effects of toxic compounds as physiological or chemical induced changes in the mammalian body are reflected in the plasma metabolome. Sample preparation prior to LC-MS based analysis of the plasma metabolome is a challenge as plasma contains compounds with very different properties. Besides, proteins, which usually are precipitated with organic solvent, phospholipids, are known to cause ion suppression in electrospray mass spectrometry. We have compared two different sample preparation techniques prior to LC-qTOF analysis of plasma samples: the first is protein precipitation; the second is protein precipitation followed by solid phase extraction with sub-fractionation into three sub-samples: a phospholipid, a lipid and a polar sub-fraction. Molecular feature extraction of the data files from LC-qTOF analysis of the samples revealed 1792 molecular features from the protein precipitation procedure. The protein precipitation followed by solid phase extraction procedure with three sub-samples gave a total of 4234 molecular features. This suggests that sub-sampling into polar, lipid and phospholipid fractions enables extraction of more metabolomic information as compared to protein precipitation alone. Chromatography showed good separation of the metabolites with little retention time drift (<1s) and a mass accuracy below 3 ppm was observed. The performance of the method was investigated using plasma samples from rats administered the environmental pollutant perfluorononanoic acid. PMID:25531874

  9. A self-contained polymeric cartridge for automated biological sample preparation.

    PubMed

    Xu, Guolin; Lee, Daniel Yoke San; Xie, Hong; Chiew, Deon; Hsieh, Tseng-Ming; Ali, Emril Mohamed; Lun Looi, Xing; Li, Mo-Huang; Ying, Jackie Y

    2011-09-01

    Sample preparation is one of the most crucial processes for nucleic acids based disease diagnosis. Several steps are required for nucleic acids extraction, impurity washes, and DNA/RNA elution. Careful sample preparation is vital to the obtaining of reliable diagnosis, especially with low copies of pathogens and cells. This paper describes a low-cost, disposable lab cartridge for automatic sample preparation, which is capable of handling flexible sample volumes of 10 μl to 1 ml. This plastic cartridge contains all the necessary reagents for pathogen and cell lysis, DNA/RNA extraction, impurity washes, DNA/RNA elution and waste processing in a completely sealed cartridge. The entire sample preparation processes are automatically conducted within the cartridge on a desktop unit using a pneumatic fluid manipulation approach. Reagents transportation is achieved with a combination of push and pull forces (with compressed air and vacuum, respectively), which are connected to the pneumatic inlets at the bottom of the cartridge. These pneumatic forces are regulated by pinch valve manifold and two pneumatic syringe pumps within the desktop unit. The performance of this pneumatic reagent delivery method was examined. We have demonstrated the capability of the on-cartridge RNA extraction and cancer-specific gene amplification from 10 copies of MCF-7 breast cancer cells. The on-cartridge DNA recovery efficiency was 54-63%, which was comparable to or better than the conventional manual approach using silica spin column. The lab cartridge would be suitable for integration with lab-chip real-time polymerase chain reaction devices in providing a portable system for decentralized disease diagnosis. PMID:22662036

  10. Rapid Filtration Separation-Based Sample Preparation Method for Bacillus Spores in Powdery and Environmental Matrices

    PubMed Central

    Isabel, Sandra; Boissinot, Maurice; Charlebois, Isabelle; Fauvel, Chantal M.; Shi, Lu-E; Lévesque, Julie-Christine; Paquin, Amélie T.; Bastien, Martine; Stewart, Gale; Leblanc, Éric; Sato, Sachiko

    2012-01-01

    Authorities frequently need to analyze suspicious powders and other samples for biothreat agents in order to assess environmental safety. Numerous nucleic acid detection technologies have been developed to detect and identify biowarfare agents in a timely fashion. The extraction of microbial nucleic acids from a wide variety of powdery and environmental samples to obtain a quality level adequate for these technologies still remains a technical challenge. We aimed to develop a rapid and versatile method of separating bacteria from these samples and then extracting their microbial DNA. Bacillus atrophaeus subsp. globigii was used as a simulant of Bacillus anthracis. We studied the effects of a broad variety of powdery and environmental samples on PCR detection and the steps required to alleviate their interference. With a benchmark DNA extraction procedure, 17 of the 23 samples investigated interfered with bacterial lysis and/or PCR-based detection. Therefore, we developed the dual-filter method for applied recovery of microbial particles from environmental and powdery samples (DARE). The DARE procedure allows the separation of bacteria from contaminating matrices that interfere with PCR detection. This procedure required only 2 min, while the DNA extraction process lasted 7 min, for a total of <10 min. This sample preparation procedure allowed the recovery of cleaned bacterial spores and relieved detection interference caused by a wide variety of samples. Our procedure was easily completed in a laboratory facility and is amenable to field application and automation. PMID:22210204

  11. Evaluation of biological sample preparation for immunosignature-based diagnostics.

    PubMed

    Chase, Brian Andrew; Johnston, Stephen Albert; Legutki, Joseph Barten

    2012-03-01

    To address the need for a universal system to assess health status, we previously described a method termed "immunosignaturing" which splays the entire humoral antibody repertoire across a peptide microarray. Two important issues relative to the potential broad use of immunosignatures are sample preparation and stability. In the present study, we compared the immunosignatures developed from serum, plasma, saliva, and antibodies eluted from blood dried onto filter paper. We found that serum and plasma provide identical immunosignatures. Immunosignatures derived from dried blood also correlated well with those from nondried serum from the same individual. Immunosignatures derived from dried blood were capable of distinguishing naïve mice from those infected with influenza virus. Saliva was applied to the arrays, and the IgA immunosignature correlated strongly with that from dried blood. Finally, we demonstrate that dried blood retains immunosignature information even when exposed to high temperature. This work expands the potential diagnostic uses for immunosignatures. These features suggest that different forms of archival samples can be used for diagnosis development and that in prospective studies samples can be easily procured. PMID:22237890

  12. Method for preparing 6-.beta.-halopenicillanic acids

    DOEpatents

    Hansen, Erik I.; Kran-Nielsen, Mogens P.; Von Daehne, Welf

    1989-01-01

    The present invention relates to a new and improved method for the preparation of a compound of the formula I ##STR1## in which R stands for halogen, giving rise to high yields of substantially pure 6.beta.-halopenicillanic acids, obtained in one step.

  13. Preparation of {alpha}, {beta}-unsaturated carboxylic acids and anhydrides

    DOEpatents

    Spivey, J.J.; Gogate, M.R.; Zoeller, J.R.; Tustin, G.C.

    1998-01-20

    Disclosed is a process for the preparation of {alpha},{beta}-unsaturated carboxylic acids and anhydrides thereof which comprises contacting formaldehyde or a source of formaldehyde with a carboxylic anhydride in the presence of a catalyst comprising mixed oxides of vanadium, phosphorus and, optionally, a third component selected from titanium, aluminum or, preferably silicon.

  14. Preparation of .alpha., .beta.-unsaturated carboxylic acids and anhydrides

    DOEpatents

    Spivey, James Jerry; Gogate, Makarand Ratnakav; Zoeller, Joseph Robert; Tustin, Gerald Charles

    1998-01-01

    Disclosed is a process for the preparation of .alpha.,.beta.-unsaturated carboxylic acids and anhydrides thereof which comprises contacting formaldehyde or a source of formaldehyde with a carboxylic anhydride in the presence of a catalyst comprising mixed oxides of vanadium, phosphorus and, optionally, a third component selected from titanium, aluminum or, preferably silicon.

  15. The role of sample preparation in interpretation of trace element concentration variability in moss bioindication studies

    USGS Publications Warehouse

    Migaszewski, Z.M.; Lamothe, P.J.; Crock, J.G.; Galuszka, A.; Dolegowska, S.

    2011-01-01

    Trace element concentrations in plant bioindicators are often determined to assess the quality of the environment. Instrumental methods used for trace element determination require digestion of samples. There are different methods of sample preparation for trace element analysis, and the selection of the best method should be fitted for the purpose of a study. Our hypothesis is that the method of sample preparation is important for interpretation of the results. Here we compare the results of 36 element determinations performed by ICP-MS on ashed and on acid-digested (HNO3, H2O2) samples of two moss species (Hylocomium splendens and Pleurozium schreberi) collected in Alaska and in south-central Poland. We found that dry ashing of the moss samples prior to analysis resulted in considerably lower detection limits of all the elements examined. We also show that this sample preparation technique facilitated the determination of interregional and interspecies differences in the chemistry of trace elements. Compared to the Polish mosses, the Alaskan mosses displayed more positive correlations of the major rock-forming elements with ash content, reflecting those elements' geogenic origin. Of the two moss species, P. schreberi from both Alaska and Poland was also highlighted by a larger number of positive element pair correlations. The cluster analysis suggests that the more uniform element distribution pattern of the Polish mosses primarily reflects regional air pollution sources. Our study has shown that the method of sample preparation is an important factor in statistical interpretation of the results of trace element determinations. ?? 2010 Springer-Verlag.

  16. Optimal sampling and sample preparation for NIR-based prediction of field scale soil properties

    NASA Astrophysics Data System (ADS)

    Knadel, Maria; Peng, Yi; Schelde, Kirsten; Thomsen, Anton; Deng, Fan; Humlekrog Greve, Mogens

    2013-04-01

    The representation of local soil variability with acceptable accuracy and precision is dependent on the spatial sampling strategy and can vary with a soil property. Therefore, soil mapping can be expensive when conventional soil analyses are involved. Visible near infrared spectroscopy (vis-NIR) is considered a cost-effective method due to labour savings and relative accuracy. However, savings may be offset by the costs associated with number of samples and sample preparation. The objective of this study was to find the most optimal way to predict field scale total organic carbon (TOC) and texture. To optimize the vis-NIR calibrations the effects of sample preparation and number of samples on the predictive ability of models with regard to the spatial distribution of TOC and texture were investigated. Conditioned Latin hypercube sampling (cLHs) method was used to select 125 sampling locations from an agricultural field in Denmark, using electromagnetic induction (EMI) and digital elevation model (DEM) data. The soil samples were scanned in three states (field moist, air dried and sieved to 2 mm) with a vis-NIR spectrophotometer (LabSpec 5100, ASD Inc., USA). The Kennard-Stone algorithm was applied to select 50 representative soil spectra for the laboratory analysis of TOC and texture. In order to investigate how to minimize the costs of reference analysis, additional smaller subsets (15, 30 and 40) of samples were selected for calibration. The performance of field calibrations using spectra of soils at the three states as well as using different numbers of calibration samples was compared. Final models were then used to predict the remaining 75 samples. Maps of predicted soil properties where generated with Empirical Bayesian Kriging. The results demonstrated that regardless the state of the scanned soil, the regression models and the final prediction maps were similar for most of the soil properties. Nevertheless, as expected, models based on spectra from field

  17. Use of robotic systems for radiochemical sample changing and for analytical sample preparation

    SciTech Connect

    Delmastro, J.R.; Hartenstein, S.D.; Wade, M.A.

    1989-05-15

    Two uses of the Perkin-Elmer (PE) robotic system will be presented. In the first, a PE robot functions as an automatic sample changer for up to five low energy photon spectrometry (LEPS) detectors operated with a Nuclear Data ND 6700 system. The entire system, including the robot, is controlled by an IBM PC-AT using software written in compiled BASIC. Problems associated with the development of the system and modifications to the robot will be presented. In the second, an evaluation study was performed to assess the abilities of the PE robotic system for performing complex analytical sample preparation procedures. For this study, a robotic system based upon the PE robot and auxiliary devices was constructed and programmed to perform the preparation of final product samples (UO{sub 3}) for accountability and impurity specification analyses. These procedures require sample dissolution, dilution, and liquid-liquid extraction steps. The results of an in-depth evaluation of all system components will be presented.

  18. Preparation, characterization and catalytic properties of MCM-48 supported tungstophosphoric acid mesoporous materials for green synthesis of benzoic acid

    SciTech Connect

    Wu, Hai-Yan; Zhang, Xiao-Li; Chen, Xi; Chen, Ya; Zheng, Xiu-Cheng

    2014-03-15

    MCM-48 and tungstophosphoric acid (HPW) were prepared and applied for the synthesis of HPW/MCM-48 mesoporous materials. The characterization results showed that HPW/MCM-48 obtained retained the typical mesopore structure of MCM-48, and the textural parameters decreased with the increase loading of HPW. The catalytic oxidation results of benzyl alcohol and benzaldehyde with 30% H{sub 2}O{sub 2} indicated that HPW/MCM-48 was an efficient catalyst for the green synthesis of benzoic acid. Furthermore, 35 wt% HPW/MCM-48 sample showed the highest activity under the reaction conditions. Highlights: • 5–45 wt% HPW/MCM-48 mesoporous catalysts were prepared and characterized. • Their catalytic activities for the green synthesis of benzoic acid were investigated. • HPW/MCM-48 was approved to be an efficient catalyst. • 5 wt% HPW/MCM-48 exhibited the highest catalytic activity.

  19. Analysis of Carbohydrate and Fatty Acid Marker Abundance in Ricin Toxin Preparations for Forensic Information

    SciTech Connect

    Colburn, Heather A.; Wunschel, David S.; Kreuzer-Martin, Helen W.; Moran, James J.; Antolick, Kathryn C.; Melville, Angela M.

    2010-07-15

    One challenge in the forensic analysis of ricin samples is determining the method and extent of sample preparation. Ricin purification from the source castor seeds is essentially a protein purification through removal of the non-protein fractions of the seed. Two major, non-protein constituents in the seed are the castor oil and carbohydrates. Ricinoleic acid is a relatively unique fatty acid in nature and is the most abundant component of castor oil, which comprises roughly half the seed weight. The carbohydrate component comprises roughly half of the remaining “mash” left after oil and hull removal. We used derivatization of carbohydrate and fatty acid markers followed by identification and quantification using gas chromatography/mass spectrometry (GC/MS) to assess compositional changes in ricin samples purified by different methods. The loss of ricinoleic acid indicated steps for oil removal had occurred. Changes to the carbohydrate content of the sample were also observed following protein precipitation. The differential loss of arabinose relative to mannose indicated removal of the major carbohydrate fraction of the seed and enrichment of the protein content. Taken together, these changes in fatty acid and carbohydrate abundance are indicative of the preparation method used for each sample.

  20. Surfactant-Induced Artifacts during Proteomic Sample Preparation.

    PubMed

    Ji, Yuhuan; Liu, Minjing; Bachschmid, Markus M; Costello, Catherine E; Lin, Cheng

    2015-06-01

    Bottom-up proteomics is a powerful tool for characterization of protein post-translational modifications (PTMs), where PTMs are identified at the peptide level by mass spectrometry (MS) following protein digestion. However, enzymatic digestion is associated with additional sample processing steps that may potentially introduce artifactual modifications. Here, during an MS study of the PTMs of the regulator of G-protein signaling 4, we discovered that the use of ProteaseMAX, which is an acid-labile surfactant commonly used to improve protein solubilization and digestion efficiency, can lead to in vitro modifications on cysteine residues. These hydrophobic modifications resemble S-palmitoylation and hydroxyfarnesylation, thus discouraging the use of ProteaseMAX in studies of lipid modifications of proteins. Furthermore, since they target the cysteine thiol group, the presence of these artifacts will inevitably lead to inaccuracies in quantitative analysis of cysteine modifications. PMID:25945600

  1. Portable system for microbial sample preparation and oligonucleotide microarray analysis.

    PubMed

    Bavykin, S G; Akowski, J P; Zakhariev, V M; Barsky, V E; Perov, A N; Mirzabekov, A D

    2001-02-01

    We have developed a three-component system for microbial identification that consists of (i) a universal syringe-operated silica minicolumn for successive DNA and RNA isolation, fractionation, fragmentation, fluorescent labeling, and removal of excess free label and short oligonucleotides; (ii) microarrays of immobilized oligonucleotide probes for 16S rRNA identification; and (iii) a portable battery-powered device for imaging the hybridization of fluorescently labeled RNA fragments with the arrays. The minicolumn combines a guanidine thiocyanate method of nucleic acid isolation with a newly developed hydroxyl radical-based technique for DNA and RNA labeling and fragmentation. DNA and RNA can also be fractionated through differential binding of double- and single-stranded forms of nucleic acids to the silica. The procedure involves sequential washing of the column with different solutions. No vacuum filtration steps, phenol extraction, or centrifugation is required. After hybridization, the overall fluorescence pattern is captured as a digital image or as a Polaroid photo. This three-component system was used to discriminate Escherichia coli, Bacillus subtilis, Bacillus thuringiensis, and human HL60 cells. The procedure is rapid: beginning with whole cells, it takes approximately 25 min to obtain labeled DNA and RNA samples and an additional 25 min to hybridize and acquire the microarray image using a stationary image analysis system or the portable imager. PMID:11157263

  2. Portable system for microbial sample preparation and oligonucleotide microarray analysis.

    SciTech Connect

    Bavykin, S. G.; Akowski, J. P.; Zakhariev, V. M.; Barsky, V. E.; Mirzabekov, A. D.; Perov, A. N.; Biochip Technology Center; Engelhardt Inst. of Molecular Biology

    2001-02-01

    We have developed a three-component system for microbial identification that consists of (i) a universal syringe-operated silica minicolumn for successive DNA and RNA isolation, fractionation, fragmentation, fluorescent labeling, and removal of excess free label and short oligonucleotides; (ii) microarrays of immobilized oligonucleotide probes for 16S rRNA identification; and (iii) a portable battery-powered device for imaging the hybridization of fluorescently labeled RNA fragments with the arrays. The minicolumn combines a guanidine thiocyanate method of nucleic acid isolation with a newly developed hydroxyl radical-based technique for DNA and RNA labeling and fragmentation. DNA and RNA can also be fractionated through differential binding of double- and single-stranded forms of nucleic acids to the silica. The procedure involves sequential washing of the column with different solutions. No vacuum filtration steps, phenol extraction, or centrifugation is required. After hybridization, the overall fluorescence pattern is captured as a digital image or as a Polaroid photo. This three-component system was used to discriminate Escherichia coli, Bacillus subtilis, Bacillus thuringiensis, and human HL60 cells. The procedure is rapid: beginning with whole cells, it takes approximately 25 min to obtain labeled DNA and RNA samples and an additional 25 min to hybridize and acquire the microarray image using a stationary image analysis system or the portable imager.

  3. The origin of amino acids in lunar regolith samples

    NASA Astrophysics Data System (ADS)

    Elsila, Jamie E.; Callahan, Michael P.; Dworkin, Jason P.; Glavin, Daniel P.; McLain, Hannah L.; Noble, Sarah K.; Gibson, Everett K.

    2016-01-01

    We analyzed the amino acid content of seven lunar regolith samples returned by the Apollo 16 and Apollo 17 missions and stored under NASA curation since collection using ultrahigh-performance liquid chromatography with fluorescence detection and time-of-flight mass spectrometry. Consistent with results from initial analyses shortly after collection in the 1970s, we observed amino acids at low concentrations in all of the curated samples, ranging from 0.2 parts-per-billion (ppb) to 42.7 ppb in hot-water extracts and 14.5-651.1 ppb in 6 M HCl acid-vapor-hydrolyzed, hot-water extracts. Amino acids identified in the Apollo soil extracts include glycine, D- and L-alanine, D- and L-aspartic acid, D- and L-glutamic acid, D- and L-serine, L-threonine, and L-valine, all of which had previously been detected in lunar samples, as well as several compounds not previously identified in lunar regoliths: α-aminoisobutyric acid (AIB), D- and L-β-amino-n-butyric acid (β-ABA), DL-α-amino-n-butyric acid, γ-amino-n-butyric acid, β-alanine, and ε-amino-n-caproic acid. We observed an excess of the L enantiomer in most of the detected proteinogenic amino acids, but racemic alanine and racemic β-ABA were present in some samples. We also examined seven samples from Apollo 15, 16, and 17 that had been previously allocated to a non-curation laboratory, as well as two samples of terrestrial dunite from studies of lunar module engine exhaust that had been stored in the same laboratory. The amino acid content of these samples suggested that contamination had occurred during non-curatorial storage. We measured the compound-specific carbon isotopic ratios of glycine, β-alanine, and L-alanine in Apollo regolith sample 70011 and found values of -21‰ to -33‰. These values are consistent with those seen in terrestrial biology and, together with the enantiomeric compositions of the proteinogenic amino acids, suggest that terrestrial biological contamination is a primary source of the

  4. Novel sample preparation for operando TEM of catalysts.

    PubMed

    Miller, Benjamin K; Barker, Trevor M; Crozier, Peter A

    2015-09-01

    A new TEM sample preparation method is developed to facilitate operando TEM of gas phase catalysis. A porous Pyrex-fiber pellet TEM sample was produced, allowing a comparatively large amount of catalyst to be loaded into a standard Gatan furnace-type tantalum heating holder. The increased amount of catalyst present inside the environmental TEM allows quantitative determination of the gas phase products of a catalytic reaction performed in-situ at elevated temperatures. The product gas concentration was monitored using both electron energy loss spectroscopy (EELS) and residual gas analysis (RGA). Imaging of catalyst particles dispersed over the pellet at atomic resolution is challenging, due to charging of the insulating glass fibers. To overcome this limitation, a metal grid is placed into the holder in addition to the pellet, allowing catalyst particles dispersed over the grid to be imaged, while particles in the pellet, which are assumed to experience identical conditions, contribute to the overall catalytic conversion inside the environmental TEM cell. The gas within the cell is determined to be well-mixed, making this assumption reasonable. PMID:25974880

  5. Automated acoustic matrix deposition for MALDI sample preparation.

    PubMed

    Aerni, Hans-Rudolf; Cornett, Dale S; Caprioli, Richard M

    2006-02-01

    Novel high-throughput sample preparation strategies for MALDI imaging mass spectrometry (IMS) and profiling are presented. An acoustic reagent multispotter was developed to provide improved reproducibility for depositing matrix onto a sample surface, for example, such as a tissue section. The unique design of the acoustic droplet ejector and its optimization for depositing matrix solution are discussed. Since it does not contain a capillary or nozzle for fluid ejection, issues with clogging of these orifices are avoided. Automated matrix deposition provides better control of conditions affecting protein extraction and matrix crystallization with the ability to deposit matrix accurately onto small surface features. For tissue sections, matrix spots of 180-200 microm in diameter were obtained and a procedure is described for generating coordinate files readable by a mass spectrometer to permit automated profile acquisition. Mass spectral quality and reproducibility was found to be better than that obtained with manual pipet spotting. The instrument can also deposit matrix spots in a dense array pattern so that, after analysis in a mass spectrometer, two-dimensional ion images may be constructed. Example ion images from a mouse brain are presented. PMID:16448057

  6. Ultrasound: a subexploited tool for sample preparation in metabolomics.

    PubMed

    Luque de Castro, M D; Delgado-Povedano, M M

    2014-01-01

    Metabolomics, one of the most recently emerged "omics", has taken advantage of ultrasound (US) to improve sample preparation (SP) steps. The metabolomics-US assisted SP step binomial has experienced a dissimilar development that has depended on the area (vegetal or animal) and the SP step. Thus, vegetal metabolomics and US assisted leaching has received the greater attention (encompassing subdisciplines such as metallomics, xenometabolomics and, mainly, lipidomics), but also liquid-liquid extraction and (bio)chemical reactions in metabolomics have taken advantage of US energy. Also clinical and animal samples have benefited from US assisted SP in metabolomics studies but in a lesser extension. The main effects of US have been shortening of the time required for the given step, and/or increase of its efficiency or availability for automation; nevertheless, attention paid to potential degradation caused by US has been scant or nil. Achievements and weak points of the metabolomics-US assisted SP step binomial are discussed and possible solutions to the present shortcomings are exposed. PMID:24331041

  7. Acid digestion of geological and environmental samples using open-vessel focused microwave digestion.

    PubMed

    Taylor, Vivien F; Toms, Andrew; Longerich, Henry P

    2002-01-01

    The application of open vessel focused microwave acid digestion is described for the preparation of geological and environmental samples for analysis using inductively coupled plasma-mass spectrometry (ICP-MS). The method is compared to conventional closed-vessel high pressure methods which are limited in the use of HF to break down silicates. Open-vessel acid digestion more conveniently enables the use of HF to remove Si from geological and plant samples as volatile SiF4, as well as evaporation-to-dryness and sequential acid addition during the procedure. Rock reference materials (G-2 granite, MRG-1 gabbros, SY-2 syenite, JA-1 andesite, and JB-2 and SRM-688 basalts) and plant reference materials (BCR and IAEA lichens, peach leaves, apple leaves, Durham wheat flour, and pine needles) were digested with results comparable to conventional hotplate digestion. The microwave digestion method gave poor results for granitic samples containing refractory minerals, however fusion was the preferred method of preparation for these samples. Sample preparation time was reduced from several days, using conventional hotplate digestion method, to one hour per sample using our microwave method. PMID:11936112

  8. Surface and catalytic properties of acid metal carbons prepared by the sol gel method

    NASA Astrophysics Data System (ADS)

    Aguado-Serrano, J.; Rojas-Cervantes, M. L.; Martín-Aranda, R. M.; López-Peinado, A. J.; Gómez-Serrano, V.

    2006-06-01

    The sol-gel method has been applied for the synthesis of a series of acid metal-carbon xerogels (with M = V, Cr, Mo and Ni) by polymerisation of resorcinol with formaldehyde in the presence of metallic precursors. A blank sample was also prepared without any metal addition. The xerogels were heated in nitrogen at 1000 °C to obtain the pyrolysed products. The samples were characterised by different techniques such as thermal-mass spectrometry analysis, gas physisorption, and mercury porosimetry. In addition, the acid character of the pyrolysed products was tested by the Claisen-Schmidt condensation between benzaldehyde and acetophenone for the formation of chalcones.

  9. Determination of the presence of hyaluronic acid in preparations containing amino acids: the molecular weight characterization.

    PubMed

    Bellomaria, A; Nepravishta, R; Mazzanti, U; Marchetti, M; Piccioli, P; Paci, M

    2014-10-15

    Several pharmaceutical preparations contain hyaluronic acid in the presence of a large variety of low molecular weight charged molecules like amino acids. In these mixtures, it is particularly difficult to determine the concentration and the molecular weight of the hyaluronic acid fragments. In fact zwitterionic compounds in high concentration behave by masking the hyaluronic acid due to the electrostatic interactions between amino acids and hyaluronic acid. In such conditions the common colorimetric test of the hyaluronic acid determination appears ineffective and in the (1)H NMR spectra the peaks of the polymer disappear completely. By a simple separation procedure the presence of hyaluronic acid was revealed by the DMAB test and (1)H NMR while its average molecular weight in the final product was determined by DOSY NMR spectroscopy alone. The latter determination is very important due to the healthy effects of some sizes of this polymer's fragments. PMID:25078662

  10. Flow Injection Potentiometric Assay of Hexoprenaline in Its Pure State, Pharmaceutical Preparations, and Biological Samples

    PubMed Central

    El-Nashar, Rasha M.

    2008-01-01

    Different hexoprenaline (Hx2SO4) conventional and coated wire electrodes were constructed and evaluated. Membranes were based on hexoprenalinium phosphotungstate (Hx-PTA) and hexporenalinium phosphomolybdate (Hx-PMA). The electrodes were fully characterized in terms of their composition, response time, life span, pH, and temperature and then were applied to the potentiometric determination of the hexoprenalinium ion in its pure state, pharmaceutical preparations, and biological samples, urine and plasma, under batch and flow injection conditions. The selectivity of the electrodes towards many inorganic cations, sugars, amino acids, and some other brochodilatures of close chemical composition was also tested. PMID:18483573

  11. Infrared biospectroscopy for a fast qualitative evaluation of sample preparation in metabolomics.

    PubMed

    Kuligowski, Julia; Pérez-Guaita, David; Escobar, Javier; Lliso, Isabel; de la Guardia, Miguel; Lendl, Bernhard; Vento, Máximo; Quintás, Guillermo

    2014-09-01

    Liquid chromatography-mass spectrometry (LC-MS) has been increasingly used in biomedicine to study the dynamic metabolomic responses of biological systems under different physiological or pathological conditions. To obtain an integrated snapshot of the system, metabolomic methods in biomedicine typically analyze biofluids (e.g. plasma) that require clean-up before being injected into LC-MS systems. However, high resolution LC-MS is costly in terms of resources required for sample and data analysis and care must be taken to prevent chemical (e.g. ion suppression) or statistical artifacts. Because of that, the effect of sample preparation on the metabolomic profile during metabolomic method development is often overlooked. This work combines an Attenuated Total Reflectance-Fourier transform infrared (ATR-FTIR) and a multivariate exploratory data analysis for a cost-effective qualitative evaluation of major changes in sample composition during sample preparation. ATR-FTIR and LC-time of flight mass spectrometry (TOFMS) data from the analysis of a set of plasma samples precipitated using acetonitrile, methanol and acetone performed in parallel were used as a model example. Biochemical information obtained from the analysis of the ATR-FTIR and LC-TOFMS data was thoroughly compared to evaluate the strengths and shortcomings of FTIR biospectroscopy for assessing sample preparation in metabolomics studies. Results obtained show the feasibility of ATR-FTIR for the evaluation of major trends in the plasma composition changes among different sample pretreatments, providing information in terms of e.g., amino acids, proteins, lipids and carbohydrates overall contents comparable to those found by LC-TOFMS. PMID:24913874

  12. Quantitative microanalysis of bile acids in biological samples. Collaborative study.

    PubMed

    Nakayama, F

    1988-10-28

    The analysis of bile acids in biological samples has always presented a problem because of their complex nature and low concentration. Recently, newer analytical procedures for bile acids have become available, including enzymatic analysis, radioimmunoassay, thin-layer chromatography (TLC), gas chromatography, high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring (SIM). However, they differ greatly with respect to specificity, sensitivity, accuracy and simplicity. On the other hand, the choice of analytical procedure differs according to the specific aims and the nature of biological samples to be analysed. These newer procedures have been compared in a double-blind fashion by distributing bile, plasma and urine samples to seven participating laboratories. GC-MS-SIM was found to be the most sensitive and reliable, but it requires other procedures for preliminary clean-up and fractionation steps. Enzymatic analysis is simple and gives small analytical errors but tends to over-estimate plasma bile acids. Radioimmunoassay gives variable results but is useful as a screening procedure for large numbers of plasma samples. TLC gives reliable results for biliary bile acids in experienced hands, except for differentiation between conjugated dihydroxycholanoic acids. HPLC, whether using derivatization or with fixed 3 alpha-hydroxy steroid dehydrogenase detection, is suitable for the analysis of major bile acids in normal human serum but not for the identification of unknown minor peaks. PMID:3243854

  13. Sample Preparation Report of the Fourth OPCW Confidence Building Exercise on Biomedical Sample Analysis

    SciTech Connect

    Udey, R. N.; Corzett, T. H.; Alcaraz, A.

    2014-07-03

    Following the successful completion of the 3rd biomedical confidence building exercise (February 2013 – March 2013), which included the analysis of plasma and urine samples spiked at low ppb levels as part of the exercise scenario, another confidence building exercise was targeted to be conducted in 2014. In this 4th exercise, it was desired to focus specifically on the analysis of plasma samples. The scenario was designed as an investigation of an alleged use of chemical weapons where plasma samples were collected, as plasma has been reported to contain CWA adducts which remain present in the human body for several weeks (Solano et al. 2008). In the 3rd exercise most participants used the fluoride regeneration method to analyze for the presence of nerve agents in plasma samples. For the 4th biomedical exercise it was decided to evaluate the analysis of human plasma samples for the presence/absence of the VX adducts and aged adducts to blood proteins (e.g., VX-butyrylcholinesterase (BuChE) and aged BuChE adducts using a pepsin digest technique to yield nonapeptides; or equivalent). As the aging of VX-BuChE adducts is relatively slow (t1/2 = 77 hr at 37 °C [Aurbek et al. 2009]), soman (GD), which ages much more quickly (t1/2 = 9 min at 37 °C [Masson et al. 2010]), was used to simulate an aged VX sample. Additional objectives of this exercise included having laboratories assess novel OP-adducted plasma sample preparation techniques and analytical instrumentation methodologies, as well as refining/designating the reporting formats for these new techniques.

  14. Preparative yield and properties of humic acids obtained by sequential alkaline extractions

    NASA Astrophysics Data System (ADS)

    Kholodov, V. A.; Yaroslavtseva, N. V.; Konstantinov, A. I.; Perminova, I. V.

    2015-10-01

    The preparative yield, composition, and structure of humic acids obtained by sequential alkaline extractions from two soils (a soddy-podzolic soil under forest and a typical chernozem in treatment with permanent black fallow of a long-term experiment since 1964) have been studied. The preparative yield of humic acids from the first extraction is 0.40 and 0.94% for the soddy-podzolic soil (Retisols) and the chernozem, respectively. The preparative yield from the second extraction is lower by several times, and the yield from the third extraction is lower by an order of magnitude. The study of the obtained preparations by elemental analysis, gel-permeation chromatography, and 13C NMR spectroscopy has shown insignificant changes in the elemental, molecular-weight, and structural-group composition of humic acids among the extractions. It has been supposed that this is related to the soil features: typical climatic factors for the formation of soil subtype in the case of soddy-podzolic soil and the land use in the long-term experiment in the case of typical chernozem. It has been concluded that that a single extraction is sufficient for the separation of humic acids and the preparation of a representative sample.

  15. An Efficient Protocol for Preparation of Gallic Acid from Terminalia bellirica (Gaertn.) Roxb by Combination of Macroporous Resin and Preparative High-Performance Liquid Chromatography.

    PubMed

    Zou, Denglang; Chen, Tao; Chen, Chen; Li, Hongmei; Liu, Yongling; Li, Yulin

    2016-08-01

    In this article, macroporous resin column chromatography and preparative high-performance liquid chromatography were applied for preparation of gallic acid from Terminalia bellirica (Gaertn.) Roxb. In the first step, six kinds of resins were investigated by adsorption and desorption tests and AB-8 macroporous resin was selected for the enrichment of gallic acid. As a result, 20 g of gallic acid at a purity of 71% could be separated from 100 g of crude extract in which the content of gallic acid was 16.7% and the recovery of gallic acid reached 85.0%. In the second step, preparative high-performance liquid chromatography was selected to purify gallic acid. As a result, 640 mg of gallic acid at a purity of 99.1% was obtained from 1 g of sample in 35 min. The results demonstrated that macroporous resin coupled with preparative high-performance liquid chromatography was suitable for preparation of gallic acid from T. bellirica (Gaertn.) Roxb. PMID:27076561

  16. CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING LIQUID FOOD SAMPLES FOR ANALYSIS OF POLAR ORGANIC POLLUTANTS (SOP-5.29)

    EPA Science Inventory

    This SOP describes the extraction and preparation of a liquid food sample for analysis of acidic persistent organic pollutants such as acid herbicides, pentachlorphenol, and 3,5,6-trichloro-2-phenol. It covers the extraction, concentration and derivatization of samples that are t...

  17. CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING SOLID FOOD SAMPLES FOR ANALYSIS OF POLAR ORGANIC POLLUTANTS (SOP-5.28)

    EPA Science Inventory

    This SOP describes the extraction and preparation of a solid food sample for analysis of acidic persistent organic pollutants such as acid herbicides, pentachlorphenol, and 3,5,6-trichloro-2-phenol. It covers the extraction, concentration and derivatization of samples that are to...

  18. Preparation and evaluation of sauces from lactic acid fermented vegetables.

    PubMed

    Joshi, V K; Somesh, Sharma

    2010-03-01

    Different combinations of fermented vegetables like carrot, radish and cucumber with pear and mango pulps were made separately and were processed. All the sauces prepared were having a constant TSS of 18°B using different combinations of fermented pulp viz., 25, 50, 75 and 100% with fruit pulps of mango and pear. The titratable acidity of carrot, radish and cucumber based sauces ranged from 1.22 to 1.39%. The blending ratio influenced the titratable acidity, Brix-acid ratio, pH and colour of the various sauces. In general, physico-chemical and sensory characteristics of all sauces prepared met the FPO specifications. Carrot with pear pulp based sauce had the highest overall acceptability. Product prepared with 25% radish + 75% pear and sauce with blend of 50% cucumber + 50% pear were preferred to others. Fermented carrot based sauce having blend of 75% fermented carrot + 25% pear was adjudged sensorily as the best. The cost of production of fermented vegetable based sauces (200 ml bottle) ranged between Rs 15.54 and 24.14 and the lowest (Rs 15.54) cost was for radish based fermented sauce. PMID:23572627

  19. Hydrophobic starch nanocrystals preparations through crosslinking modification using citric acid.

    PubMed

    Zhou, Jiang; Tong, Jin; Su, Xingguang; Ren, Lili

    2016-10-01

    Biodegradable starch nanocrystals prepared by an acid treatment process were modified through crosslinking modification using citric acid as reactant by a dry reaction method. The occurrence of crosslinking modification was evaluated by Fourier transform infrared spectroscopy and swelling degree. X-ray diffraction, wettability tests and contact angle measurements were used to characterize the modified starch nanocrystals. It was found that the crosslinked starch nanocrystals displayed a higher affinity for low polar solvents such as dichloromethane. The surface of starch nanocrystals became more roughness after crosslinking modification with citric acid and the size decreased as revealed by scanning electron microscopy and dynamic light scattering results. XRD analysis showed that the crystalline structure of starch nanocrystals was basically not changed after the crosslinking modification with shorter heating time. The resulting hydrophobic starch nanocrystals are versatile precursors to the development of nanocomposites. PMID:27365120

  20. IMPROVED SAMPLE PREPARATION METHOD FOR GLYCAN ANALYSIS OF GLYCOPROTEINS BY CE-LIF AND CE-MS

    PubMed Central

    Szabo, Zoltan; Guttman, András; Rejtar, Tomas; Karger, Barry L.

    2010-01-01

    Capillary electrophoresis (CE) is a high resolution separation technique broadly used in the biotechnology industry for carbohydrate analysis. The standard sample preparation protocol for CE analysis of glycans released from glycoproteins generally requires derivatization times of overnight at 37°C, using ≥100 fold excess of fluorophore reagent, 8-aminopyrene-1,3,6-trisulfonic-acid (APTS), if the sample is unknown, or it is a regulated biotherapeutic product, possibly containing terminal sialic acid(s). In this paper, we report on significant improvements for the standard CE sample preparation method of glycan analysis. By replacing the conventionally used acetic acid catalyst with citric acid, as low as 1 : 10 glycan to fluorophore molar ratio (vs the typical 1 : ≥100 ratio) maintained the >95% derivatization yield at 55°C with only 50 minutes reaction time. Terminal sialic acid loss was negligible at 55°C during the derivatization process, and thus the kinetics of labeling at 55°C was faster than the loss of sialic acid from the glycan. The reduced relative level of APTS simplified the removal of excess reagent, important in both CE-LIF (electrokinetic injection bias) and CE-MS (ion suppression). Coupling capillary electrophoresis to electrospray ionization mass spectrometry confirmed that the individual peaks separated by CE corresponded to single glycans and increased the confidence of structural assignment based on glucose unit values. PMID:20309892

  1. Back-etch method for plan view transmission electron microscopy sample preparation of optically opaque films.

    PubMed

    Yao, Bo; Coffey, Kevin R

    2008-04-01

    Back-etch methods have been widely used to prepare plan view transmission electron microscopy (TEM) samples of thin films on membranes by removal of the Si substrate below the membrane by backside etching. The conventional means to determine when to stop the etch process is to observe the color of the light transmitted through the sample, which is sensitive to the remaining Si thickness. However, most metallic films thicker than 75 nm are opaque, and there is no detectable color change prior to film perforation. In this paper, a back-etch method based on the observation of an abrupt change of optical reflection contrast is introduced as a means to determine the etch endpoint to prepare TEM samples for these films. As the acid etchant removes the Si substrate material a rough interface is generated. This interface becomes a relatively smooth and featureless region when the etchant reaches the membrane (film/SiO2). This featureless region is caused by the mirror reflection of the film plane (film/SiO2 interface) through the optically transparent SiO2 layer. The lower etch rate of SiO2 (compared with Si) gives the operator enough time to stop the etching without perforating the film. A clear view of the morphology and control of Si roughness during etching are critical to this method, which are discussed in detail. The procedures of mounting wax removal and sample rinsing are also described in detail, as during these steps damage to the membrane may easily occur without appropriate consideration. As examples, the preparation of 100-nm-thick Fe-based amorphous alloy thin film and 160-nm-thick Cu-thin film samples for TEM imaging is described. PMID:18227137

  2. Nucleic acid isolation from ecological samples--fungal associations, lichens.

    PubMed

    Grube, Martin

    2005-01-01

    Ecological samples of fungal associations pose particular challenges for nucleic acid extraction due to the presence of several genomes. Thorough examination of the samples prior to extraction is important to assess the risks of contamination. If manual separation of symbionts or their axenic cultivation is not feasible, symbiont-specific primers can be applied in PCR experiments. A basic protocol is suggested here which can be optimized for specific applications. PMID:15865960

  3. Aquatic hazard assessment of a commercial sample of naphthenic acids.

    PubMed

    Swigert, James P; Lee, Carol; Wong, Diana C L; White, Russell; Scarlett, Alan G; West, Charles E; Rowland, Steven J

    2015-04-01

    This paper presents chemical composition and aquatic toxicity characteristics of a commercial sample of naphthenic acids (NAs). Naphthenic acids are derived from the refining of petroleum middle distillates and can contribute to refinery effluent toxicity. NAs are also present in oil sands process-affected water (OSPW), but differences in the NAs compositions from these sources precludes using a common aquatic toxicity dataset to represent the aquatic hazards of NAs from both origins. Our chemical characterization of a commercial sample of NAs showed it to contain in order of abundance, 1-ring>2-ring>acyclic>3-ring acids (∼84%). Also present were monoaromatic acids (7%) and non-acids (9%, polyaromatic hydrocarbons and sulfur heterocyclic compounds). While the acyclic acids were only the third most abundant group, the five most abundant individual compounds were identified as C(10-14) n-acids (n-decanoic acid to n-tetradecanoic acid). Aquatic toxicity testing of fish (Pimephales promelas), invertebrate (Daphnia magna), algae (Pseudokirchneriella subcapitata), and bacteria (Vibrio fischeri) showed P. promelas to be the most sensitive species with 96-h LL50=9.0 mg L(-1) (LC50=5.6 mg L(-1)). Acute EL50 values for the other species ranged 24-46 mg L(-1) (EC50 values ranged 20-30 mg L(-1)). Biomimetic extraction via solid-phase-microextraction (BE-SPME) suggested a nonpolar narcosis mode of toxic action for D. magna, P. subcapitata, and V. fischeri. The BE analysis under-predicted fish toxicity, which indicates that a specific mode of action, besides narcosis, may be a factor for fishes. PMID:25434270

  4. Total airborne mold particle sampling: evaluation of sample collection, preparation and counting procedures, and collection devices.

    PubMed

    Godish, Diana; Godish, Thad

    2008-02-01

    This study was conducted to evaluate (i) procedures used to collect, prepare, and count total airborne mold spore/particle concentrations, and (ii) the relative field performance of three commercially available total airborne mold spore/particle sampling devices. Differences between factory and laboratory airflow calibration values of axial fan-driven sampling instruments (used in the study) indicated a need for laboratory calibration using a mass flow meter to ensure that sample results were accurately calculated. An aniline blue-amended Calberla's solution adjusted to a pH of 4.2-4.4 provided good sample mounting/counting results using Dow Corning high vacuum grease, Dow Corning 280A adhesive, and Dow Corning 316 silicone release spray for samples collected using mini-Burkard and Allergenco samplers. Count variability among analysts was most pronounced in 5% counts of relatively low mold particle deposition density samples and trended downward with increased count percentage and particle deposition density. No significant differences were observed among means of 5, 10, and 20% counts and among analysts; a significant interaction effect was observed between analysts' counts and particle deposition densities. Significantly higher mini-Burkard and Air-O-Cell total mold spore/particle counts for 600x vs. 400x (1.9 and 2.3 x higher, respectively), 1000x vs. 600x (1.9 and 2.2 x higher, respectively) and 1000x vs. 400x (3.6 and 4.6 x higher, respectively) comparisons indicated that 1000x magnification counts best quantified total airborne mold spore/particles using light microscopy, and that lower magnification counts may result in unacceptable underreporting of airborne mold spore/particle concentrations. Modest but significantly higher (1.2x) total mold spore concentrations were observed with Allergenco vs. mini-Burkard samples collected in co-located, concurrently operated sampler studies; moderate but significantly higher mini-Burkard count values (1.4x) were

  5. Laser-assisted microdissection for real-time PCR sample preparation.

    PubMed

    Pinzani, P; Orlando, C; Pazzagli, M

    2006-01-01

    Laser-assisted microdissection (LMD) has been developed to procure precisely the cells of interest in a tissue specimen, in a rapid and practical manner. Together with real-time PCR and RT-PCR techniques, it is now feasible to study genetic alterations, gene expression features and proteins in defined cell populations from complex normal and diseased tissues. The process that brings from sample collection to the final quantitative results is articulated in several steps, each of which requires optimal choices in order to end up with high-quality nucleic acid or protein that allows successful application of the final quantitative assays. This review will describe shortly the development of LMD technologies and the principles they are based on. Trying to highlight the advantages and disadvantages of LMD, the main problems related to specimens collection and processing, section preparation and extraction of bio-molecules from microdissected tissue samples have been analysed. PMID:16480765

  6. Preparation and physical properties of chitin fatty acids esters.

    PubMed

    Yang, Byung Y; Ding, Qiong; Montgomery, Rex

    2009-02-17

    Trifluoroacetic anhydride is an effective promoter for the preparation of chitin single- and mixed-acid esters. Complete dissolution is achieved within 30 min when powdered chitin is heated at 70 degrees C in a mixed solution of carboxylic acid(s) and trifluoroacetic anhydride. Chitin esters prepared are chitin acetate, chitin butyrate, chitin hexanoate and chitin octanoate, chitin co-acetate/butyrate, chitin co-acetate/hexanoate, chitin co-acetate/octanoate, chitin co-acetate/palmitate, each from a solution of the respective reactants. The products have degrees of O-acyl substitution in a range of DS 1-2 depending on the nature of acyl group, as analyzed by gas-liquid and high-pressure liquid chromatography. Acetic acid as a mutual component for the mixed-acid esters increases the total degree of substitution, and the acetyl substitution is close to the relative distribution in the reaction mixture for chitin co-acetate/butyrate. It is favored over hexanoate, octanoate, and palmitate. The parent molecules, as calculated by the composition of the chitin esters and their molecular weights by light-scattering spectroscopy, are 30 kDa for the smallest and 150-151 kDa for the largest. Films of these chitin derivatives when cast from solution are strong and flexible with limited extensibility. By dynamic mechanical analysis of the ester film, it was found that both the glass transition temperature (T(g)) and the tensile modulus (E' at 25 degrees C) are highest for chitin acetate (218 degrees C and 5.8 GPa), and lowest for chitin octanoate (182 degrees C and 1.5 GPa). For the other esters, these values lie between the above-cited values, where the T(g) and the E' decrease with an increase in the chain length of the acyl constituent. PMID:19091309

  7. Amphiphilic mediated sample preparation for micro-flow cytometry

    DOEpatents

    Clague, David S.; Wheeler, Elizabeth K.; Lee, Abraham P.

    2009-03-17

    A flow cytometer includes a flow cell for detecting the sample, an oil phase in the flow cell, a water phase in the flow cell, an oil-water interface between the oil phase and the water phase, a detector for detecting the sample at the oil-water interface, and a hydrophobic unit operatively connected to the sample. The hydrophobic unit is attached to the sample. The sample and the hydrophobic unit are placed in an oil and water combination. The sample is detected at the interface between the oil phase and the water phase.

  8. Amphiphilic mediated sample preparation for micro-flow cytometry

    DOEpatents

    Clague, David S.; Wheeler, Elizabeth K.; Lee, Abraham P.

    2006-07-25

    A flow cytometer includes a flow cell for detecting the sample, an oil phase in the flow cell, a water phase in the flow cell, an oil-water interface between the oil phase and the water phase, a detector for detecting the sample at the oil-water interface, and a hydrophobic unit operatively connected to the sample. The hydrophobic unit is attached to the sample. The sample and the hydrophobic unit are placed in an oil and water combination. The sample is detected at the interface between the oil phase and the water phase.

  9. Quality analysis of salmon calcitonin in a polymeric bioadhesive pharmaceutical formulation: sample preparation optimization by DOE.

    PubMed

    D'Hondt, Matthias; Van Dorpe, Sylvia; Mehuys, Els; Deforce, Dieter; DeSpiegeleer, Bart

    2010-12-01

    A sensitive and selective HPLC method for the assay and degradation of salmon calcitonin, a 32-amino acid peptide drug, formulated at low concentrations (400 ppm m/m) in a bioadhesive nasal powder containing polymers, was developed and validated. The sample preparation step was optimized using Plackett-Burman and Onion experimental designs. The response functions evaluated were calcitonin recovery and analytical stability. The best results were obtained by treating the sample with 0.45% (v/v) trifluoroacetic acid at 60 degrees C for 40 min. These extraction conditions did not yield any observable degradation, while a maximum recovery for salmon calcitonin of 99.6% was obtained. The HPLC-UV/MS methods used a reversed-phase C(18) Vydac Everest column, with a gradient system based on aqueous acid and acetonitrile. UV detection, using trifluoroacetic acid in the mobile phase, was used for the assay of calcitonin and related degradants. Electrospray ionization (ESI) ion trap mass spectrometry, using formic acid in the mobile phase, was implemented for the confirmatory identification of degradation products. Validation results showed that the methodology was fit for the intended use, with accuracy of 97.4+/-4.3% for the assay and detection limits for degradants ranging between 0.5 and 2.4%. Pilot stability tests of the bioadhesive powder under different storage conditions showed a temperature-dependent decrease in salmon calcitonin assay value, with no equivalent increase in degradation products, explained by the chemical interaction between salmon calcitonin and the carbomer polymer. PMID:20655159

  10. Lipoxygenation of arachidonic acid by subcellular preparations from murine keratinocytes

    SciTech Connect

    Ziboh, V.A.; Casebolt, T.L.; Marcelo, C.L.; Voorhees, J.J.

    1984-10-01

    In these studies, we examined the possibility that cell-free preparations from murine keratinocytes possess 5-lipoxygenase activity in addition to the well-established cyclooxygenase pathway of arachidonic acid (AA) in these cells. Our data demonstrated that the high-speed (105,000 g) supernatant preparations of the murine keratinocytes metabolized (14C)AA into labeled lipoxygenase products. Portions of these radioactive metabolites cochromatographed and comigrated with 12-HETE (a marker for 12-lipoxygenase pathway) and with authentic LTB4 (a marker for 5-lipoxygenase pathway) on silicic acid column chromatography and by thin-layer chromatography (TLC) in two solvent systems respectively. Identity of the novel 14C which comigrated with LTB4 on both TLC and column chromatography was verified further by cochromatography of the free acid with authentic LTB4 on a reverse phase (RP) and the methyl esters on a straight phase high-pressure liquid chromatography. Incubation of the cell-free preparations with (14C)AA in the presence of ETYA, NDGA (inhibitors of cyclooxygenase and lipoxygenase pathways) as well as with 15-HETE (an inhibitor of lipoxygenase pathway) resulted in decreased formation of (14C) 12-HETE and the (14C)LTB4-like metabolite. On the contrary, incubations of the cell-free extracts with (14C) AA in the presence of indomethacin (a cyclooxygenase inhibitor) resulted in increased biosynthesis of the labeled lipoxygenase metabolites. These data indicate the existence of enzymes in soluble fraction of murine keratinocyte which can catalyze the transformation of (14C) AA into products of both the 12- and 5-lipoxygenase pathways.

  11. Final LDRD report : development of sample preparation methods for ChIPMA-based imaging mass spectrometry of tissue samples.

    SciTech Connect

    Maharrey, Sean P.; Highley, Aaron M.; Behrens, Richard, Jr.; Wiese-Smith, Deneille

    2007-12-01

    The objective of this short-term LDRD project was to acquire the tools needed to use our chemical imaging precision mass analyzer (ChIPMA) instrument to analyze tissue samples. This effort was an outgrowth of discussions with oncologists on the need to find the cellular origin of signals in mass spectra of serum samples, which provide biomarkers for ovarian cancer. The ultimate goal would be to collect chemical images of biopsy samples allowing the chemical images of diseased and nondiseased sections of a sample to be compared. The equipment needed to prepare tissue samples have been acquired and built. This equipment includes an cyro-ultramicrotome for preparing thin sections of samples and a coating unit. The coating unit uses an electrospray system to deposit small droplets of a UV-photo absorbing compound on the surface of the tissue samples. Both units are operational. The tissue sample must be coated with the organic compound to enable matrix assisted laser desorption/ionization (MALDI) and matrix enhanced secondary ion mass spectrometry (ME-SIMS) measurements with the ChIPMA instrument Initial plans to test the sample preparation using human tissue samples required development of administrative procedures beyond the scope of this LDRD. Hence, it was decided to make two types of measurements: (1) Testing the spatial resolution of ME-SIMS by preparing a substrate coated with a mixture of an organic matrix and a bio standard and etching a defined pattern in the coating using a liquid metal ion beam, and (2) preparing and imaging C. elegans worms. Difficulties arose in sectioning the C. elegans for analysis and funds and time to overcome these difficulties were not available in this project. The facilities are now available for preparing biological samples for analysis with the ChIPMA instrument. Some further investment of time and resources in sample preparation should make this a useful tool for chemical imaging applications.

  12. Hydroxyapatite-phosphonoformic acid hybrid compounds prepared by hydrothermal method

    NASA Astrophysics Data System (ADS)

    Turki, Thouraya; Othmani, Masseoud; Bantignies, Jean-Louis; Bouzouita, Khaled

    2014-01-01

    Hydroxyapatites were prepared in the presence of different amounts of phosphonoformic acid (PFA) via the hydrothermal method. The obtained powders were characterized through chemical analysis, XRD, IR, 31P MAS-NMR, TEM, and TG-TDA. The XRD showed that the PFA did not affect the apatite composition. Indeed, only a reduction of the crystallite size was noted. After grafting of PFA, the IR spectroscopy revealed the appearance of new bands belonging to HPO42- and carboxylate groups of the apatite and organic moiety, respectively. Moreover, the 31P MAS-NMR spectra exhibited a peak with a low intensity assigned to the terminal phosphonate group of the organic moiety in addition to that of the apatite. Based on these results, a reaction mechanism involving the surface hydroxyl groups (tbnd Casbnd OH) of the apatite and the carboxyl group of the acid was proposed.

  13. 21 CFR 201.304 - Tannic acid and barium enema preparations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 4 2011-04-01 2011-04-01 false Tannic acid and barium enema preparations. 201.304... Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished...

  14. 21 CFR 201.304 - Tannic acid and barium enema preparations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 4 2012-04-01 2012-04-01 false Tannic acid and barium enema preparations. 201.304... Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished...

  15. 21 CFR 201.304 - Tannic acid and barium enema preparations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 4 2014-04-01 2014-04-01 false Tannic acid and barium enema preparations. 201.304... Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished...

  16. 21 CFR 201.304 - Tannic acid and barium enema preparations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 4 2013-04-01 2013-04-01 false Tannic acid and barium enema preparations. 201.304... Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished...

  17. 21 CFR 201.304 - Tannic acid and barium enema preparations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Tannic acid and barium enema preparations. 201.304... Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished...

  18. Preparation of Samples for Single-Worm Tracking

    PubMed Central

    Yemini, Eviatar; Kerr, Rex A.; Schafer, William R.

    2016-01-01

    Neurobiological research in genetically tractable organisms relies heavily on robust assays for behavioral phenotypes. The simple body plan of the nematode Caenorhabditis elegans makes it particularly amenable to the use of automated microscopy and image analysis to describe behavioral patterns quantitatively. This protocol first describes the preparation and use of media for growing and maintaining worms for tracking. The second part of the protocol describes how to prepare a single young adult worm for recording during video analysis. Although the protocol was developed for use in a single-worm tracker, it addresses factors important for the generation of reproducible, standardized images in all systems. PMID:22135667

  19. Cations in mammalian cells and chromosomes: Sample preparation protocols affect elemental abundances by SIMS

    NASA Astrophysics Data System (ADS)

    Levi-Setti, R.; Gavrilov, K. L.; Neilly, M. E.

    2006-07-01

    The focus of our current research aims at detailing and quantifying the presence of cations, primarily Ca and Mg, in mammalian cells and chromosomes throughout the different stages of the cell cycle, using our high resolution scanning ion microprobe, the UC-SIM. The 45 keV Ga + probe of this instrument, typically ˜40 nm in diameter, carries a current of 30-40 pA, appropriate for surface SIMS studies, but limited in sample erosion rate for dynamic SIMS mapping over cell-size areas, of order 100 μm × 100 μm. Practical and reliable use of this probe toward the above SIMS goals requires a careful matching of the latter factors with the physical and chemical consequences of sample preparation protocols. We examine here how the preferred sample cryo-preservation methodologies such as freeze-fracture and lyophilization affect high resolution SIMS analysis, and, from this standpoint, develop and evaluate the advantages and disadvantages of fast alternate approaches to drying frozen samples. The latter include the use of methanol, ethanol, and methanol/acetic acid fixative. Methanol-dried freeze-fractured samples preserve histological morphology and yield Ca and Mg distributions containing reliable differential dynamical information, when compared with those following lyophilization.

  20. A rapid sample preparation method for the HPLC determination of the opioid antagonist naltrexone in serum.

    PubMed

    Hurst, W J; Zagon, I S; Aboul-Enein, H Y

    1999-08-01

    HPLC with UV and electrochemical detection has routinely been employed for the determination of the opioid antagonist naltrexone in serum. Sample preparation protocols range from liquid/liquid to solid phase extraction. The sample preparation described in this communication uses ultrafiltration as the mode of sample preparation prior to HPLC analysis. The method is accurate, precise and saves considerable time compared to previously published techniques. PMID:10483613

  1. Controlled environment vitrification system: an improved sample preparation technique.

    PubMed

    Bellare, J R; Davis, H T; Scriven, L E; Talmon, Y

    1988-09-01

    The controlled environment vitrification system (CEVS) permits cryofixation of hydrated biological and colloidal dispersions and aggregates from a temperature- and saturation-controlled environment. Otherwise, specimens prepared in an uncontrolled laboratory atmosphere are subject to evaporation and heat transfer, which may introduce artifacts caused by concentration, pH, ionic strength, and temperature changes. Moreover, it is difficult to fix and examine the microstructure of systems at temperatures other than ambient (e.g., biological systems at in vivo conditions and colloidal systems above room temperature). A system has been developed that ensures that a liquid or partially liquid specimen is maintained in its original state while it is being prepared before vitrification and, once prepared, is vitrified with little alteration of its microstructure. A controlled environment is provided within a chamber where temperature and chemical activity of volatile components can be controlled while the specimen is being prepared. The specimen grid is mounted on a plunger, and a synchronous shutter is opened almost simultaneously with the release of the plunger, so that the specimen is propelled abruptly through the shutter opening into a cryogenic bath. We describe the system and its use and illustrate the value of the technique with TEM micrographs of surfactant microstructures in which specimen preparation artifacts were avoided. We also discuss applications to other instruments like SEM, to other techniques like freeze-fracture, and to novel "on the grid" experiments that make it possible to freeze successive instants of dynamic processes such as membrane fusion, chemical reactions, and phase transitions. PMID:3193246

  2. PREPARATION OF SOIL SAMPLING PROTOCOL: TECHNIQUES AND STRATEGIES

    EPA Science Inventory

    This report sets out a system for developing soil sampling protocols that can be used to meet the needs of the environmental scientist working under a number of situations. The body of the report discusses the factors that influence the selection of a particular sampling design a...

  3. EVALUATION OF ARG-1 SAMPLES PREPARED BY CESIUM CARBONATE DISSOLUTION DURING THE ISOLOK SME ACCEPTABILITY TESTING

    SciTech Connect

    Edwards, T.; Hera, K.; Coleman, C.

    2011-12-05

    Evaluation of Defense Waste Processing Facility (DWPF) Chemical Process Cell (CPC) cycle time identified several opportunities to improve the CPC processing time. The Mechanical Systems & Custom Equipment Development (MS&CED) Section of the Savannah River National Laboratory (SRNL) recently completed the evaluation of one of these opportunities - the possibility of using an Isolok sampling valve as an alternative to the Hydragard valve for taking DWPF process samples at the Slurry Mix Evaporator (SME). The use of an Isolok for SME sampling has the potential to improve operability, reduce maintenance time, and decrease CPC cycle time. The SME acceptability testing for the Isolok was requested in Task Technical Request (TTR) HLW-DWPF-TTR-2010-0036 and was conducted as outlined in Task Technical and Quality Assurance Plan (TTQAP) SRNLRP-2011-00145. RW-0333P QA requirements applied to the task, and the results from the investigation were documented in SRNL-STI-2011-00693. Measurement of the chemical composition of study samples was a critical component of the SME acceptability testing of the Isolok. A sampling and analytical plan supported the investigation with the analytical plan directing that the study samples be prepared by a cesium carbonate (Cs{sub 2}CO{sub 3}) fusion dissolution method and analyzed by Inductively Coupled Plasma - Optical Emission Spectroscopy (ICP-OES). The use of the cesium carbonate preparation method for the Isolok testing provided an opportunity for an additional assessment of this dissolution method, which is being investigated as a potential replacement for the two methods (i.e., sodium peroxide fusion and mixed acid dissolution) that have been used at the DWPF for the analysis of SME samples. Earlier testing of the Cs{sub 2}CO{sub 3} method yielded promising results which led to a TTR from Savannah River Remediation, LLC (SRR) to SRNL for additional support and an associated TTQAP to direct the SRNL efforts. A technical report resulting

  4. Multi-element determination of Cu, Fe, Ni and Zn content in vegetable oils samples by high-resolution continuum source atomic absorption spectrometry and microemulsion sample preparation.

    PubMed

    Nunes, Luana S; Barbosa, José T P; Fernandes, Andréa P; Lemos, Valfredo A; Santos, Walter N L Dos; Korn, Maria Graças A; Teixeira, Leonardo S G

    2011-07-15

    The aim of this work was to evaluate the microemulsification as sample preparation procedure for determination of Cu, Fe, Ni and Zn in vegetable oils samples by High-Resolution Continuum Source Flame Atomic Absorption Spectrometry (HR-CS FAAS). Microemulsions were prepared by mixing samples with propan-1-ol and aqueous acid solution, which allowed the use of inorganic aqueous standards for the calibration. To a sample mass of 0.5g, 100μL of hydrochloric acid and propan-1-ol were added and the resulting mixture diluted to a final volume of 10mL. The sample was manually shaken resulting in a visually homogeneous system. The main lines were selected for all studied metals and the detection limits (3σ, n=10) were 0.12, 0.62, 0.58 and 0.12mgkg(-1) for Cu, Fe, Ni and Zn, respectively. The relative standard deviation (RSD) ranged from 5% to 11 % in samples spiked with 0.25 and 1.5μgmL(-1) of each metal, respectively. Recoveries varied from 89% to 102%. The proposed method was applied to the determination of Cu, Fe, Ni and Zn in soybean, olive and sunflower oils. PMID:23140735

  5. Preparation of polyaniline nanostructures doped with different dicarboxylic acids through template-free method

    NASA Astrophysics Data System (ADS)

    Sun, Chuanyu; Wang, Yu

    2014-09-01

    In this article nanoscaled polyanilines (PANI) were prepared based on template-free method in the presence of dicarboxylic acid dopants (e.g. D-tartaric acid, succinic acid, maleic acid and fumaric acid). The trans-cis isomerization of butenedioic acid played an important role in the formation of nanostructures from the plane-like to nanofibers, and the PANI doped with maleic acid (MA) had larger diameter, higher crystallinity and conductivity than PANI doped with fumaric acid (FA).

  6. Sulfuric Acid Intercalated Graphite Oxide for Graphene Preparation

    NASA Astrophysics Data System (ADS)

    Hong, Yanzhong; Wang, Zhiyong; Jin, Xianbo

    2013-12-01

    Graphene has shown enormous potential for innovation in various research fields. The current chemical approaches based on exfoliation of graphite via graphite oxide (GO) are potential for large-scale synthesis of graphene but suffer from high cost, great operation difficulties, and serious waste discharge. We report a facile preparation of graphene by rapid reduction and expansion exfoliation of sulfuric acid intercalated graphite oxide (SIGO) at temperature just above 100°C in ambient atmosphere, noting that SIGO is easily available as the immediate oxidation descendent of graphite in sulfuric acid. The oxygenic and hydric groups in SIGO are mainly removed through dehydration as catalyzed by the intercalated sulfuric acid (ISA). The resultant consists of mostly single layer graphene sheets with a mean diameter of 1.07 μm after dispersion in DMF. This SIGO process is reductant free, easy operation, low-energy, environmental friendly and generates graphene with low oxygen content, less defect and high conductivity. The provided synthesis route from graphite to graphene via SIGO is compact and readily scalable.

  7. Sulfuric Acid Intercalated Graphite Oxide for Graphene Preparation

    PubMed Central

    Hong, Yanzhong; Wang, Zhiyong; Jin, Xianbo

    2013-01-01

    Graphene has shown enormous potential for innovation in various research fields. The current chemical approaches based on exfoliation of graphite via graphite oxide (GO) are potential for large-scale synthesis of graphene but suffer from high cost, great operation difficulties, and serious waste discharge. We report a facile preparation of graphene by rapid reduction and expansion exfoliation of sulfuric acid intercalated graphite oxide (SIGO) at temperature just above 100°C in ambient atmosphere, noting that SIGO is easily available as the immediate oxidation descendent of graphite in sulfuric acid. The oxygenic and hydric groups in SIGO are mainly removed through dehydration as catalyzed by the intercalated sulfuric acid (ISA). The resultant consists of mostly single layer graphene sheets with a mean diameter of 1.07 μm after dispersion in DMF. This SIGO process is reductant free, easy operation, low-energy, environmental friendly and generates graphene with low oxygen content, less defect and high conductivity. The provided synthesis route from graphite to graphene via SIGO is compact and readily scalable. PMID:24310650

  8. Preview of the NASA NNWG NDE Sample Preparation Handbook

    NASA Technical Reports Server (NTRS)

    2010-01-01

    This viewgraph presents a step-by-step how-to fabrication documentation of every kind of sample that is fabricated for MSFC by UA Huntsville, including photos and illustrations. The tabulation of what kind of samples are being fabricated for what NDE method, detailed instructions/documentation of the inclusion/creation of defects, detailed specifications for materials, processes, and equipment, case histories and/or experiences with the different fabrication methods and defect inclusion techniques, discussion of pitfalls and difficulties associated with sample fabrication and defect inclusion techniques, and a discussion of why certain fabrication techniques are needed as related to the specific NDE methods are included in this presentation.

  9. Preparation of fatty acid methyl esters for gas-liquid chromatography[S

    PubMed Central

    Ichihara, Ken'ichi; Fukubayashi, Yumeto

    2010-01-01

    A convenient method using commercial aqueous concentrated HCl (conc. HCl; 35%, w/w) as an acid catalyst was developed for preparation of fatty acid methyl esters (FAMEs) from sterol esters, triacylglycerols, phospholipids, and FFAs for gas-liquid chromatography (GC). An 8% (w/v) solution of HCl in methanol/water (85:15, v/v) was prepared by diluting 9.7 ml of conc. HCl with 41.5 ml of methanol. Toluene (0.2 ml), methanol (1.5 ml), and the 8% HCl solution (0.3 ml) were added sequentially to the lipid sample. The final HCl concentration was 1.2% (w/v). This solution (2 ml) was incubated at 45°C overnight or heated at 100°C for 1–1.5 h. The amount of FFA formed in the presence of water derived from conc. HCl was estimated to be <1.4%. The yields of FAMEs were >96% for the above lipid classes and were the same as or better than those obtained by saponification/methylation or by acid-catalyzed methanolysis/methylation using commercial anhydrous HCl/methanol. The method developed here could be successfully applied to fatty acid analysis of various lipid samples, including fish oils, vegetable oils, and blood lipids by GC. PMID:19759389

  10. FTIR studies on the acidity of sulfated zirconia prepared by thermolysis of zirconium sulfate

    SciTech Connect

    Platero, E.E.; Mentruit, M.P.; Arean, C.O.; Zecchina, A.

    1996-09-01

    Sulfated zirconia having a BET surface area of 90 m{sup 2}g{sup -1} and a temperature-resistant mesoporous texture was prepared by thermolysis (at 1000 K) of zirconium sulfate. Infrared studies of surface sulfates, CO adsorption at 77 K, and room temperature adsorption of pyridine showed close similarity to sulfated zirconias prepared by impregnation of doping from the gas phase. Four main families of Lewis acid centers were found, which gave CO adducts characterized by stretching frequencies of 2212, 2202, 2196, and 2188 cm{sup -1}. Interaction of CO (at liquid nitrogen temperature) with surface hydroxyls (in partially hydroxylated samples) was found to shift the O-H stretching frequency from 3650 to 3510 cm{sup -1}, due to formation of hydrogen-bonded OH{center_dot}{center_dot}CO complexes. This downward shift, {Delta}{nu}{sub OH} = 140 cm{sup -1}, is significantly larger than the corresponding value for pure zirconia ({Delta}{nu}{sub OH} = 90 cm{sup -1}), which strongly suggests enhancement of the Bronsted acidity. Samples showing the acidic OH group at 3650 cm{sup -1} were found to contain also disulfate groups and traces of molecular water. Surface hydroxyls is sulfated zirconia still appear, however, to be weaker Bronsted acid sites than are bridging OH groups in zeolites. 49 refs., 7 figs., 2 tabs.

  11. Intelligent front-end sample preparation tool using acoustic streaming.

    SciTech Connect

    Cooley, Erika J.; McClain, Jaime L.; Murton, Jaclyn K.; Edwards, Thayne L.; Achyuthan, Komandoor E.; Branch, Darren W.; Clem, Paul Gilbert; Anderson, John Mueller; James, Conrad D.; Smith, Gennifer; Kotulski, Joseph Daniel

    2009-09-01

    We have successfully developed a nucleic acid extraction system based on a microacoustic lysis array coupled to an integrated nucleic acid extraction system all on a single cartridge. The microacoustic lysing array is based on 36{sup o} Y cut lithium niobate, which couples bulk acoustic waves (BAW) into the microchannels. The microchannels were fabricated using Mylar laminates and fused silica to form acoustic-fluidic interface cartridges. The transducer array consists of four active elements directed for cell lysis and one optional BAW element for mixing on the cartridge. The lysis system was modeled using one dimensional (1D) transmission line and two dimensional (2D) FEM models. For input powers required to lyse cells, the flow rate dictated the temperature change across the lysing region. From the computational models, a flow rate of 10 {micro}L/min produced a temperature rise of 23.2 C and only 6.7 C when flowing at 60 {micro}L/min. The measured temperature changes were 5 C less than the model. The computational models also permitted optimization of the acoustic coupling to the microchannel region and revealed the potential impact of thermal effects if not controlled. Using E. coli, we achieved a lysing efficacy of 49.9 {+-} 29.92 % based on a cell viability assay with a 757.2 % increase in ATP release within 20 seconds of acoustic exposure. A bench-top lysing system required 15-20 minutes operating up to 58 Watts to achieve the same level of cell lysis. We demonstrate that active mixing on the cartridge was critical to maximize binding and release of nucleic acid to the magnetic beads. Using a sol-gel silica bead matrix filled microchannel the extraction efficacy was 40%. The cartridge based magnetic bead system had an extraction efficiency of 19.2%. For an electric field based method that used Nafion films, a nucleic acid extraction efficiency of 66.3 % was achieved at 6 volts DC. For the flow rates we tested (10-50 {micro}L/min), the nucleic acid extraction

  12. 7 CFR 61.34 - Drawing and preparation of sample.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... forwarding to a licensed cottonseed chemist for analysis and grading. The duplicate shall be sealed and retained by the sampler until the original official sample shall have been analyzed by a licensed...

  13. Influence of sample preparation on the assay of isoflavones

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The complexity of sample matrices, coexistence of multiple forms of bioactive phytochemicals, and their interaction of with other cellular components pose a significant challenge for optimize extraction and accurate estimation of bioactive phytochemicals in foods and dietary supplements. This artic...

  14. Fast and accurate preparation fatty acid methyl esters by microwave-assisted derivatization in the yeast Saccharomyces cerevisiae.

    PubMed

    Khoomrung, Sakda; Chumnanpuen, Pramote; Jansa-ard, Suwanee; Nookaew, Intawat; Nielsen, Jens

    2012-06-01

    We present a fast and accurate method for preparation of fatty acid methyl esters (FAMEs) using microwave-assisted derivatization of fatty acids present in yeast samples. The esterification of free/bound fatty acids to FAMEs was completed within 5 min, which is 24 times faster than with conventional heating methods. The developed method was validated in two ways: (1) through comparison with a conventional method (hot plate) and (2) through validation with the standard reference material (SRM) 3275-2 omega-3 and omega-6 fatty acids in fish oil (from the Nation Institute of Standards and Technology, USA). There were no significant differences (P>0.05) in yields of FAMEs with both validations. By performing a simple modification of closed-vessel microwave heating, it was possible to carry out the esterification in Pyrex glass tubes kept inside the closed vessel. Hereby, we are able to increase the number of sample preparations to several hundred samples per day as the time for preparation of reused vessels was eliminated. Pretreated cell disruption steps are not required, since the direct FAME preparation provides equally quantitative results. The new microwave-assisted derivatization method facilitates the preparation of FAMEs directly from yeast cells, but the method is likely to also be applicable for other biological samples. PMID:22569641

  15. Sample preparation for arsenic speciation in terrestrial plants--a review.

    PubMed

    Amaral, Clarice D B; Nóbrega, Joaquim A; Nogueira, Ana R A

    2013-10-15

    Arsenic is an element widely present in nature. Additionally, it may be found as different species in several matrices and therefore it is one of the target elements in chemical speciation. Although the number of studies in terrestrial plants is low, compared to matrices such as fish or urine, this number is raising due to the fact that this type of matrix are closely related to the human food chain. In speciation analysis, sample preparation is a critical step and several extraction procedures present drawbacks. In this review, papers dealing with extraction procedures, analytical methods, and studies of species conservation in plants cultivated in terrestrial environment are critically discussed. Analytical procedures based on extractions using water or diluted acid solutions associated with HPLC-ICP-MS are good alternatives, owing to their versatility and sensitivity, even though less expensive strategies are shown as feasible choices. PMID:24054594

  16. Preparation and Application of Novel Magnetic Molecularly Imprinted Composites for Recognition of Sulfadimethoxine in Feed Samples.

    PubMed

    Feng, Min; Li, Hengye; Zhang, Lin; Zhang, Jingyou; Dai, Jianping; Wang, Xiaojin; Zhang, Lingli; Wei, Yunji

    2016-01-01

    Novel magnetic molecularly imprinted composites were prepared through a facile method using sulfadimethoxine (SDM) as template. The inorganic magnetic nanoparticles were linked with the organic molecularly imprinted polymer (MIP) through irreversibly covalent bond. So, the resulted composites showed excellent stability and reusability under acidic elution conditions. The magnetic MIP composites showed good selectivity, high binding capacity and excellent kinetics toward SDM. Adopting the magnetic MIP composites as extraction material, an off-line magnetic solid-phase extraction (SPE)/high performance liquid chromatography (HPLC) method was established. The calibration curve was linear in the range of 0.05 - 15 mg kg(-1) (r(2) = 0.9976). The LOD and LOQ were 0.016 and 0.052 mg kg(-1), respectively, while the recoveries were in the range of 89.3 - 107.0%. These novel magnetic MIP composites may become a powerful tool for the extraction of template from complex samples with good efficiency. PMID:27169650

  17. Sample preparation of solid samples for metal determination by atomic spectroscopy - An overview and selected recent applications

    SciTech Connect

    Sneddon, J.; Hardaway, C.; Bobbadi, K.; Reddy, A.

    2006-07-01

    Classical methods involving dry dissolution, wet decomposition, and microwave methods for digestion/dissolution of solid samples for metal determination by various atomic spectroscopic techniques are discussed. Recent applications of solid sample preparation are presented including soils, sediments, food, cosmetics, oils, and coal.

  18. Enhanced spot preparation for liquid extractive sampling and analysis

    SciTech Connect

    Van Berkel, Gary J.; King, Richard C.

    2015-09-22

    A method for performing surface sampling of an analyte, includes the step of placing the analyte on a stage with a material in molar excess to the analyte, such that analyte-analyte interactions are prevented and the analyte can be solubilized for further analysis. The material can be a matrix material that is mixed with the analyte. The material can be provided on a sample support. The analyte can then be contacted with a solvent to extract the analyte for further processing, such as by electrospray mass spectrometry.

  19. Preparation of Amperometric Glucose Biosensor Based on 4-Mercaptobenzoic Acid

    NASA Astrophysics Data System (ADS)

    Wang, Huihui; Ohnuki, Hitoshi; Endo, Hideaki; Izumi, Mitsuru

    A novel glucose biosensor was fabricated by a combination of a self-assembled monolayer (SAM) of 4-mercaptobenzoic acid and the Langmuir-Blodgett (LB) technique. Because of the catalysis of Prussian Blue contained in the LB film layers, the prepared amperometric biosensor worked at a very low potential range around 0.0 V vs. Ag/AgCl. The optimum operating conditions for glucose biosensor were investigated by varying the glucose oxidase immobilization time, the applied potential and the pH of buffer solution. The steady-state current responses of the glucose biosensor showed a good linear relationship to glucose concentrations from 0.1 mM to 154 mM.

  20. Microsystem strategies for sample preparation in biological detection.

    SciTech Connect

    James, Conrad D.; Galambos, Paul C.; Bennett, Dawn Jonita; Manginell, Monica; Okandan, Murat; Acrivos, Andreas; Brozik, Susan Marie; Khusid, Boris

    2005-03-01

    The objective of this LDRD was to develop microdevice strategies for dealing with samples to be examined in biological detection systems. This includes three sub-components: namely, microdevice fabrication, sample delivery to the microdevice, and sample processing within the microdevice. The first component of this work focused on utilizing Sandia's surface micromachining technology to fabricate small volume (nanoliter) fluidic systems for processing small quantities of biological samples. The next component was to develop interfaces for the surface-micromachined silicon devices. We partnered with Micronics, a commercial company, to produce fluidic manifolds for sample delivery to our silicon devices. Pressure testing was completed to examine the strength of the bond between the pressure-sensitive adhesive layer and the silicon chip. We are also pursuing several other methods, both in house and external, to develop polymer-based fluidic manifolds for packaging silicon-based microfluidic devices. The second component, sample processing, is divided into two sub-tasks: cell collection and cell lysis. Cell collection was achieved using dielectrophoresis, which employs AC fields to collect cells at energized microelectrodes, while rejecting non-cellular particles. Both live and dead Staph. aureus bacteria have been collected using RF frequency dielectrophoresis. Bacteria have been separated from polystyrene microspheres using frequency-shifting dielectrophoresis. Computational modeling was performed to optimize device separation performance, and to predict particle response to the dielectrophoretic traps. Cell lysis is continuing to be pursued using microactuators to mechanically disrupt cell membranes. Novel thermal actuators, which can generate larger forces than previously tested electrostatic actuators, have been incorporated with and tested with cell lysis devices. Significant cell membrane distortion has been observed, but more experiments need to be conducted to

  1. Effects of Sample Preparation on the Infrared Reflectance Spectra of Powders

    SciTech Connect

    Brauer, Carolyn S.; Johnson, Timothy J.; Myers, Tanya L.; Su, Yin-Fong; Blake, Thomas A.; Forland, Brenda M.

    2015-05-22

    While reflectance spectroscopy is a useful tool in identifying molecular compounds, laboratory measurement of solid (particularly powder) samples often is confounded by sample preparation methods. For example, both the packing density and surface roughness can have an effect on the quantitative reflectance spectra of powdered samples. Recent efforts in our group have focused on developing standard methods for measuring reflectance spectra that accounts for sample preparation, as well as other factors such as particle size and provenance. In this work, the effect of preparation method on sample reflectivity was investigated by measuring the directional-hemispherical spectra of samples that were hand-packed as well as pressed into pellets using an integrating sphere attached to a Fourier transform infrared spectrometer. The results show that the methods used to prepare the sample have a substantial effect on the measured reflectance spectra, as do other factors such as particle size.

  2. Flavonoids and Phenolic Acids in Methanolic Extracts, Infusions and Tinctures from Commercial Samples of Lemon Balm.

    PubMed

    Arceusz, Agnieszka; Wesolowski, Marek; Ulewicz-Magulska, Beata

    2015-06-01

    The aim of this study was to quantify the levels of flavonoids (rutin, myricetin, quercetin, kaempferol) and phenolic acids (gallic, p-coumaric, rosmarinic, syringic, caffeic, chlorogenic, ellagic, ferulic) in lemon balm (Melissa officinalis L.) commonly used as a culinary, aromatic and medicinal herb. A rapid and reliable HPLC procedure was developed to determine the phenolic compounds in methanolic extracts, infusions and tinctures prepared from lemon balm. Except for myricetin and quercetin, as well as ellagic, gallic and rosmarinic acids, higher levels of the analytes under study were determined in the methanolic extracts (up to 22 mg/g of dry weight, DW), than in infusions (up to 5 mg/g DW). Tinctures were the poorest in flavonoids and phenolic acids (below 550 μg/g DW), except for ellagic and rosmarinic acids, which were quantified in tinctures at higher levels (mg/g DW). To sum up, the flavonoids were extracted more effectively in the infusions and tinctures than the phenolic acids. Statistically significant correlations were found between phenolic acids, possibly owing to similar biochemical pathways of the compounds. The hierarchical cluster and principal component analyses have also shown that the samples of lemon balm could be differentiated based on the levels of flavonoids and phenolic acids. PMID:26197530

  3. Nanoparticle preparation of Mefenamic acid by electrospray drying

    SciTech Connect

    Zolkepali, Nurul Karimah Bakar, Noor Fitrah Abu Anuar, Nornizar; Naim, M. Nazli; Bakar, Mohd Rushdi Abu

    2014-02-24

    Nanoparticles preparation of Mefenamic acid (MA) by using an electrospray drying method was conducted in this study. Electrospray drying is a process that uses electrostatic force to disperse a conductive liquid stream into fine charged droplets through the coulomb fission of charges in the liquid and finally dry into fine particles. Electrospray drying modes operation usually in Taylor cone jet, and it was formed by controlling applied voltage and liquid flow rate. A conductive liquid (2.77–8.55μScm{sup −1}) which is MA solution was prepared by using acetone with concentration 0.041 and 0.055 M before pumping at a flow rate of 3–6ml/h. By applying the applied voltage at 1.3–1.5 kV, Taylor cone jet mode was formed prior to the electrospray. During electrospray drying process, solvent evaporation from the droplet was occurring that leads to coulomb disruption and may generate to nanoparticles. The dried nanoparticles were collected on a grounded substrate that was placed at varying distance from the electrospray. MA particle with size range of 100–400 nm were produced by electrospray drying process. Characterization of particles by using X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) show that particles formed into polymorph I.

  4. Preparation and evaluation of microemulsion systems containing salicylic acid.

    PubMed

    Badawi, Alia A; Nour, Samia A; Sakran, Wedad S; El-Mancy, Shereen Mohamed Sameh

    2009-01-01

    Microemulsions (MEs) are clear, thermodynamically stable systems. They were used to solubilize drugs and to improve topical drug availability. Salicylic acid (SA) is a keratolytic agent used in topical products with antimicrobial actions. The objective of this work was to prepare and evaluate SA ME systems. Different concentrations of SA were incorporated in an ME base composed of isopropyl myristate, water, and Tween 80: propylene glycol in the ratio of 15:1. Three ME systems were prepared: S2%, S5%, and S10% which contain 2%, 5%, and 10% of SA, respectively. Evaluation by examination under cross-polarizing microscope, measuring of percent transmittance, pH measurement, determination of the specific gravity, assessment of rheological properties, and accelerated stability study were carried out. The data showed that the addition of SA markedly affected the physical properties of the base. All systems were not affected by accelerated stability tests. Stability study for 6 months under ambient conditions was carried out for S10%. No remarkable changes were recorded except a decrease in the viscosity value after 1 month. The results suggested that ME could be a suitable vehicle for topical application of different concentrations of SA. PMID:19757081

  5. Functional hyaluronic acid hydrogels prepared by a novel method.

    PubMed

    Cui, Ning; Qian, Junmin; Zhao, Na; Wang, Hongjie

    2014-12-01

    In this study, a novel simple method was developed to prepare functional hyaluronic acid (HA) hydrogels simultaneously containing hydrazone and disulfide bonds in their crossbridges. The HA hydrogels were formed by directly reacting 2,5-hexanedione and 3,3'-dithiodipropionate hydrazide-modified HA, and were characterized by FT-IR, SEM, TGA and mechanical tests. The results showed that the formation of HA hydrogels was a result of the reaction between ketone and hydrazide groups. The resultant HA hydrogels exhibited a porous morphology with a pore size range of 50 μm to 400 μm, and their compressive modulus and G″/G' ratio were 18.8±0.6 kPa and 0.002, respectively. Both swelling and degradation ratios gradually decreased with the increasing degree of crosslinking. However, the degree of crosslinking had a slight effect on the decomposition temperature of the HA hydrogels. It can be concluded that the simple method presented in this study is feasible to prepare HA hydrogels through hydrazone bond crosslinking by reacting diketone molecules and hydrazide-modified HA, and the HA hydrogels have potential in biomedical applications. PMID:25491866

  6. Sample preparation and assay refinements for pathogen detection platforms

    NASA Astrophysics Data System (ADS)

    Lim, Daniel V.; Kearns, Elizabeth A.; Leskinen, Stephaney D.; Magaña, Sonia; Stroot, Joyce M.; Hunter, Dawn M.; Schlemmer, Sarah M.

    2009-02-01

    Food-borne and waterborne microbial pathogens are a potential problem in biowarfare and public health. Such pathogens can affect the health, combat readiness, and effectiveness of the warfighter in a battlefield environment and present potential threats to the civilian population through intentional or natural contamination of food and water. Conventional procedures to detect and identify microbial pathogens in food, water, and other materials can take days to perform and may provide inconclusive information. Research at the University of South Florida's Advanced Biosensors Laboratory (ABL) focuses on development of sample processing procedures and biosensor-based assays for rapid detection of biothreat agents. Rapid processing methods, including use of an automated concentrator of microorganisms in water, have been developed for complex matrix samples including ground beef, apple juice, produce, potable water and recreational water, enabling such samples to be directly tested by biosensor assays for target analytes. Bacillus atrophaeus spores and other bacteria can be concentrated from potable and recreational water at low levels with a dead-end hollow-fiber ultrafiltration concentration system. Target bacteria recovered by these processing procedures can be identified by evanescent wave, fiber optic biosensors or other detection platforms. Fiber optic biosensor assays have been improved to include subsequent PCR analysis and viability determination of captured target bacteria using broth enrichment and/or ATP luminescence.

  7. Preparation of an acid butanol standard from fresh apples.

    PubMed

    Li, Chunmei; Trombley, John D; Schmidt, Michael A; Hagerman, Ann E

    2010-05-01

    We have developed a simple method for preparing and verifying suitable standards for the acid butanol assay from a readily available source. Phenolics were extracted from fresh apples with methanol, and sugars were removed from the crude extract by treatment with Amberlite resin before fractionating the proanthocyanidins into ethyl acetate. The ethyl acetate fraction was chromatographed on Toyopearl TSK HW-50F to yield about 50 mg of procyanidin dimer and 35 mg of trimer from 1 kg fresh apple fruit. The purity and identity of the standards was easily confirmed by using ESI-MS. In the acid butanol assay, the pure dimer, trimer and purified Sorghum procyanidin had similar color yields on a mass basis, and produced about three times more color than purified quebracho tannin. This new standard overcomes problems associated with overestimation of tannin due to use of the unreactive quebracho tannin standard. Use of the new standard will enable accurate comparisons of tannin levels between laboratories and will standardize comparisons between species, thus promoting our understanding of the role of condensed tannins in plants. PMID:20379766

  8. Accurate analysis of taurine, anserine, carnosine and free amino acids in a cattle muscle biopsy sample.

    PubMed

    Imanari, Mai; Higuchi, Mikito; Shiba, Nobuya; Watanabe, Akira

    2010-06-01

    We have established an analysis method for some free amino acids (FAAs), as well as taurine (Tau), anserine (Ans) and carnosine (Car), in a fresh biopsy sample from cattle muscle. A series of model biopsy samples, corresponding to the mixtures of lean meat, fat and connective tissue, was prepared and showed high correlation coefficients between the compound concentration and the 3-methylhistidine (3-MeHis) content derived from hydrolysis of the biopsy sample (r = 0.74-0.95, P < 0.01). Interference from blood contamination could not be neglected, because the concentration of some FAAs in blood was comparable to that in muscle. However, it was possible to control the contamination of Tau, Ans, Car, glutamic acid, glutamine, asparatic acid and alanine to less than 5.0% when the blood contamination was controlled to less than 23%.These results suggest the necessity of measuring 3-MeHis as an index of lean meat and hemoglobin as an index of blood contamination when compounds in muscle biopsy samples are evaluated. We have carried out a series of these analyses using one biopsy sample and reveal differences in Tau, Ans, Car and some FAAs in beef muscle after different feeding regimes. PMID:20597895

  9. Two Dimensional Polyamides Prepared From Unsaturated Carboxylic Acids And Amines.

    DOEpatents

    McDonald, William F.; Huang, Zhi Heng; Wright, Stacy C.; Danzig, Morris; Taylor, Andrew C.

    2002-07-17

    A polyamide and a process for preparing the polyamide are disclosed. The process comprises reacting in a reaction mixture a monomer selected from unsaturated carboxylic acids, esters of unsaturated carboxylic acids, anhydrides of unsaturated carboxylic acids, and mixtures thereof, and a first amine to form an intermediate reaction product in the reaction mixture, wherein the first amine is selected from RR.sub.1 NH, RNH.sub.2, RR.sub.1 NH.sub.2.sup.+, RNH.sub.3.sup.+ and mixtures thereof, wherein R and R.sub.1 can be the same or different and each contain between about 1 and 50 carbon atoms and are optionally substituted with heteroatoms oxygen, nitrogen, sulfur, and phosphorus and combinations thereof, and reacting the intermediate reaction product and a second amine to form a polyamide, wherein the second amine is selected from R.sub.2 R.sub.3 NH, R.sub.2 NH.sub.2, R.sub.2 R.sub.3 NH.sub.2.sup.+, R.sub.2 NH.sub.3.sup.+ and mixtures thereof wherein R.sub.2 and R.sub.3 can be the same or different and each contain between about 1 and 50 carbon atoms and are optionally substituted with heteroatoms oxygen, nitrogen, sulfur, and phosphorus and combinations thereof, wherein multiple of the R, R.sub.1, R.sub.2, and R.sub.3 are in vertically aligned spaced relationship along a backbone formed by the polyamide. In one version of the invention, the monomer is selected from maleic anhydride, maleic acid esters, and mixtures thereof. In another version of the invention, the first amine is an alkylamine, such as tetradecylamine, and the second amine is a polyalkylene polyamine, such as pentaethylenehexamine. In yet another version of the invention, the first amine and the second amine are olefinic or acetylenic amines, such as the reaction products of an alkyldiamine and an acetylenic carboxylic acid. The first amine and the second amine may be the same or different depending on the desired polyamide polymer structure.

  10. Optimisation of a sample preparation method for the determination of fumonisin B(1) in rice.

    PubMed

    Petrarca, Mateus Henrique; Rodrigues, Maria Isabel; Rossi, Elizeu Antonio; de Sylos, Célia Maria

    2014-09-01

    A simple, rapid and cost-effective sample preparation method for the determination of fumonisin B1 in rice was optimised using a strategy of sequential experimental designs. Initially, a Plackett-Burman design was applied to select the statistically significant variables for the determination of fumonisin B1, and then, a central composite rotatable design was used to define the optimal conditions of these variables. The method involves extraction with a 50% acetonitrile aqueous solution and glacial acetic acid, liquid-liquid partitioning with addition of anhydrous sodium sulphate and sodium chloride, followed by dispersive SPE clean-up with diatomaceous earth. The final extract was analysed by HPLC-FLD after precolumn derivatisation with ortho-phthaldialdehyde. The optimised method was validated for selectivity, linearity, matrix effect, limits of detection and quantification, trueness, and precision, and then applied to commercial samples of polished rice. This is the first report of the occurrence of fumonisin B1 in commercial samples of polished rice from the Southeast region of Brazil. PMID:24731341

  11. Comparison of acid leaching and fusion techniques to determine uranium in soil samples by alpha spectrometry.

    PubMed

    Dirican, Abdullah; Şahin, Mihriban

    2016-03-01

    Dissolution of radionuclides of interest is an indispensable first step in the alpha spectrometric analysis of soil samples. In this study a uranium recovery method for the analysis of uranium isotopes in soil samples is presented. Two different soil sample dissolution techniques were used: digestion in open beaker and fusion. The results of these techniques were compared. Two proficiency test samples and one reference material prepared by the IAEA were analyzed. Better results were obtained by fusion dissolution technique but impurities were higher than with acid leaching. Results of two techniques were more or less similar within the uncertainty limits. The detection limit (a(#)) was evaluated as part of the quality control. PMID:26651172

  12. Organic compounds in lunar samples: pyrolysis products, hydrocarbons, amino acids.

    PubMed

    Nagy, B; Drew, D M; Hamilton, P B; Modzeleski, V E; Murphy, M E; Scott, W M; Urey, H C; Young, M

    1970-01-30

    Lunar fines and a chip from inside a rock pyrolyzed in helium at 700 degrees C gave methane, other gases, and aromatic hydrocarbons. Benzene/methanol extracts of fines yielded traces of high molecular weight alkanes and sulfur. Traces of glycine, alanine, ethanolamine, and urea were found in aqueous extracts. Biological controls and a terrestrial rock, dunite, subjected to exhaust from the lunar module descent engine showed a different amino acid distribution. Interpretation of the origin of the carbon compounds requires extreme care, because of possible contamination acquired during initial sample processing. PMID:5410553

  13. Current advances and strategies towards fully automated sample preparation for regulated LC-MS/MS bioanalysis.

    PubMed

    Zheng, Naiyu; Jiang, Hao; Zeng, Jianing

    2014-09-01

    Robotic liquid handlers (RLHs) have been widely used in automated sample preparation for liquid chromatography-tandem mass spectrometry (LC-MS/MS) bioanalysis. Automated sample preparation for regulated bioanalysis offers significantly higher assay efficiency, better data quality and potential bioanalytical cost-savings. For RLHs that are used for regulated bioanalysis, there are additional requirements, including 21 CFR Part 11 compliance, software validation, system qualification, calibration verification and proper maintenance. This article reviews recent advances in automated sample preparation for regulated bioanalysis in the last 5 years. Specifically, it covers the following aspects: regulated bioanalysis requirements, recent advances in automation hardware and software development, sample extraction workflow simplification, strategies towards fully automated sample extraction, and best practices in automated sample preparation for regulated bioanalysis. PMID:25384595

  14. Sample Preparation for Mass Spectrometry Imaging of Plant Tissues: A Review

    PubMed Central

    Dong, Yonghui; Li, Bin; Malitsky, Sergey; Rogachev, Ilana; Aharoni, Asaph; Kaftan, Filip; Svatoš, Aleš; Franceschi, Pietro

    2016-01-01

    Mass spectrometry imaging (MSI) is a mass spectrometry based molecular ion imaging technique. It provides the means for ascertaining the spatial distribution of a large variety of analytes directly on tissue sample surfaces without any labeling or staining agents. These advantages make it an attractive molecular histology tool in medical, pharmaceutical, and biological research. Likewise, MSI has started gaining popularity in plant sciences; yet, information regarding sample preparation methods for plant tissues is still limited. Sample preparation is a crucial step that is directly associated with the quality and authenticity of the imaging results, it therefore demands in-depth studies based on the characteristics of plant samples. In this review, a sample preparation pipeline is discussed in detail and illustrated through selected practical examples. In particular, special concerns regarding sample preparation for plant imaging are critically evaluated. Finally, the applications of MSI techniques in plants are reviewed according to different classes of plant metabolites. PMID:26904042

  15. CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING DERMAL WIPE AND SURFACE WIPE SAMPLES FOR ANALYSIS OF POLAR ORGANIC POLLUTANTS (SOP-5.27)

    EPA Science Inventory

    The method for extracting and preparing a dermal or surface wipe sample for analysis of acidic persistent organic pollutants is summarized in this standard operating procedure. It covers the extraction and concentration of samples that are to be analyzed by gas chromatography/mas...

  16. Preparation of a K(+) -imprinted polymer for the selective recognition of K(+) in food samples.

    PubMed

    Hashemi, Beshare; Shamsipur, Mojtaba; Seyedzadeh, Zahra

    2016-05-01

    An analytical method is reported for the preparation of K(+) -imprinted nanoparticles using cryptand 222 as the complexing agent, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the crosslinker and 2,2'-azobisisobutyronitrile as the radical initiator. The prepared particles have a diameter of 200-250 nm. The maximum adsorption capacity of potassium ion-imprinted polymer particles was 120 μmol/g. The optimum pH for quantitative extraction was 9.0. The nature of the eluent, eluent concentration, adsorption and desorption times, weight of the polymer material, aqueous phase, and desorption volumes were also studied. The relative selectivity coefficients of K(+) /Li(+) , K(+) /Na(+) , K(+) /Rb(+) and K(+) /Cs(+) were 48.10, 4.80, 29.70, and 43.4, respectively. The relative standard deviation and limit of detection of the method were obtained 1.61% and 4.62 ng/L, respectively. Finally, the method was applied for the determination of potassium ions from different samples using flame photometry. PMID:27005866

  17. ANALYSIS OF RICIN TOXIN PREPARATIONS FOR CARBOHYDRATE AND FATTY ACID ABUNDANCE AND ISOTOPE RATIO INFORMATION

    SciTech Connect

    Wunschel, David S.; Kreuzer-Martin, Helen W.; Antolick, Kathryn C.; Colburn, Heather A.; Moran, James J.; Melville, Angela M.

    2009-12-01

    This report describes method development and preliminary evaluation for analyzing castor samples for signatures of purifying ricin. Ricin purification from the source castor seeds is essentially a problem of protein purification using common biochemical methods. Indications of protein purification will likely manifest themselves as removal of the non-protein fractions of the seed. Two major, non-protein, types of biochemical constituents in the seed are the castor oil and various carbohydrates. The oil comprises roughly half the seed weight while the carbohydrate component comprises roughly half of the remaining “mash” left after oil and hull removal. Different castor oil and carbohydrate components can serve as indicators of specific toxin processing steps. Ricinoleic acid is a relatively unique fatty acid in nature and is the most abundant component of castor oil. The loss of ricinoleic acid indicates a step to remove oil from the seeds. The relative amounts of carbohydrates and carbohydrate-like compounds, including arabinose, xylose, myo-inositol fucose, rhamnose, glucosamine and mannose detected in the sample can also indicate specific processing steps. For instance, the differential loss of arabinose relative to mannose and N-acetyl glucosamine indicates enrichment for the protein fraction of the seed using protein precipitation. The methods developed in this project center on fatty acid and carbohydrate extraction from castor samples followed by derivatization to permit analysis by gas chromatography-mass spectrometry (GC-MS). Method descriptions herein include: the source and preparation of castor materials used for method evaluation, the equipment and description of procedure required for chemical derivatization, and the instrument parameters used in the analysis. Two types of derivatization methods describe analysis of carbohydrates and one procedure for analysis of fatty acids. Two types of GC-MS analysis is included in the method development, one

  18. Recent developments in sample preparation and data pre-treatment in metabonomics research.

    PubMed

    Li, Ning; Song, Yi peng; Tang, Huiru; Wang, Yulan

    2016-01-01

    Metabonomics is a powerful approach for biomarker discovery and an effective tool for pinpointing endpoint metabolic effects of external stimuli, such as pathogens and disease development. Due to its wide applications, metabonomics is required to deal with various biological samples of different properties. Hence sample preparation and corresponding data pre-treatment become important factors in ensuring validity of an investigation. In this review, we summarize some recent developments in metabonomics sample preparation and data-pretreatment procedures. PMID:26342458

  19. The preparation of zaragozic acid A analogues by directed biosynthesis.

    PubMed

    Chen, T S; Petuch, B; MacConnell, J; White, R; Dezeny, G; Arison, B; Bergstrom, J D; Colwell, L; Huang, L; Monaghan, R L

    1994-11-01

    Zaragozic acid A analogues are produced by an unidentified sterile fungus when it is exogenously supplied with 2-thiophenecarboxylic acid, 3-thiophenecarboxylic acid, 2-furoic acid, 2-fluorobenzoic acid, 3-fluorobenzoic acid, or 4-fluorobenzoic acid. The analogues carry 2-thiophenyl, 3-thiophenyl, 2-furyl, o-fluorophenyl, m-fluorophenyl, or p-fluorophenyl group, respectively, at C-6' of the C-1 alkyl side chain replacing the phenyl group of natural zaragozic acid A. All the new analogues of zaragozic acid A possess picomolar inhibitory activity against squalene synthase in vitro. PMID:8002393

  20. The Effect of Sample Preparation on the Release Measurements of Manganin Gauges.

    NASA Astrophysics Data System (ADS)

    Thomas, Dan; Chapman, David; Proud, William

    2007-06-01

    Sample preparation and alignment are recognized as essential parts of good experimental practice. As well as close attention to these factors it is also important to recognize that all measurement devices have an inherent resolution time. Depending on the parameter of interest the appropriate degree of sample preparation can be applied. In a previous paper [SCCM 2005] the effect of front surface roughness was compared, in this paper the effect of rear face preparation is addressed. Plate impact experiments on a PMMA sample are described and the stress history measured using Manganin gauges reported.

  1. Preparation of alginate beads containing a prodrug of diethylenetriaminepentaacetic acid

    PubMed Central

    Yang, Yu-Tsai; Di Pasqua, Anthony J.; He, Weiling; Tsai, Tsuimin; Sueda, Katsuhiko; Zhang, Yong; Jay, Michael

    2012-01-01

    A penta-ethyl ester prodrug of the radionuclide decorporation agent diethylenetriaminepentaacetic acid (DTPA), which exists as an oily liquid, was encapsulated in alginate beads by the ionotropic gelation method. An optimal formulation was found by varying initial concentrations of DTPA pentaethyl ester, alginate polymer, Tween 80 surfactant and calcium chloride. All prepared alginate beads were ~1.6 mm in diameter, and the optimal formulation had loading and encapsulation efficiencies of 91.0 ± 1.1 and 72.6 ± 2.2%, respectively, and only 3.2 ± 0.8% water absorption after storage at room temperature in ~80% relative humidity. Moreover, Fourier transform infrared spectroscopy showed that DTPA penta-ethyl ester did not react with excipients during formation of the DTPA penta-ethyl ester-containing alginate beads. Release of prodrug from alginate beads was via anomalous transport, and its stability enhanced by encapsulation. Collectively, these data suggest that this solid dosage form may be suitable for oral administration after radionuclide contamination. PMID:23399237

  2. Nanoprodrugs of NSAIDs: Preparation and Characterization of Flufenamic Acid Nanoprodrugs

    PubMed Central

    Lee, Bong-Seop; Yoon, Chi Woo; Osipov, Arsen; Moghavem, Nuriel; Nwachokor, Daniel; Amatya, Rina; Na, Rebekah; Pantoja, Joe L.; Pham, Michael D.; Black, Keith L.; Yu, John S.

    2011-01-01

    We demonstrated that hydrophobic derivatives of the nonsteroidal anti-inflammatory drug (NSAID)flufenamic acid (FA), can be formed into stable nanometer-sized prodrugs (nanoprodrugs) that inhibit the growth of glioma cells, suggesting their potential application as anticancer agent. We synthesized highly hydrophobic monomeric and dimeric prodrugs of FA via esterification and prepared nanoprodrugs using spontaneous emulsification mechanism. The nanoprodrugs were in the size range of 120 to 140 nm and physicochemically stable upon long-term storage as aqueous suspension, which is attributed to the strong hydrophobic interaction between prodrug molecules. Importantly, despite the highly hydrophobic nature and water insolubility, nanoprodrugs could be readily activated into the parent drug by porcine liver esterase, presenting a potential new strategy for novel NSAID prodrug design. The nanoprodrug inhibited the growth of U87-MG glioma cells with IC50 of 20 μM, whereas FA showed IC50 of 100 μM, suggesting that more efficient drug delivery was achieved with nanoprodrugs. PMID:21603162

  3. Solar-thermal complex sample processing for nucleic acid based diagnostics in limited resource settings

    PubMed Central

    Gumus, Abdurrahman; Ahsan, Syed; Dogan, Belgin; Jiang, Li; Snodgrass, Ryan; Gardner, Andrea; Lu, Zhengda; Simpson, Kenneth; Erickson, David

    2016-01-01

    The use of point-of-care (POC) devices in limited resource settings where access to commonly used infrastructure, such as water and electricity, can be restricted represents simultaneously one of the best application fits for POC systems as well as one of the most challenging places to deploy them. Of the many challenges involved in these systems, the preparation and processing of complex samples like stool, vomit, and biopsies are particularly difficult due to the high number and varied nature of mechanical and chemical interferents present in the sample. Previously we have demonstrated the ability to use solar-thermal energy to perform PCR based nucleic acid amplifications. In this work demonstrate how the technique, using similar infrastructure, can also be used to perform solar-thermal based sample processing system for extracting and isolating Vibrio Cholerae nucleic acids from fecal samples. The use of opto-thermal energy enables the use of sunlight to drive thermal lysing reactions in large volumes without the need for external electrical power. Using the system demonstrate the ability to reach a 95°C threshold in less than 5 minutes and maintain a stable sample temperature of +/− 2°C following the ramp up. The system is demonstrated to provide linear results between 104 and 108 CFU/mL when the released nucleic acids were quantified via traditional means. Additionally, we couple the sample processing unit with our previously demonstrated solar-thermal PCR and tablet based detection system to demonstrate very low power sample-in-answer-out detection. PMID:27231636

  4. Interlaboratory evaluation of cellulosic acid-soluble internal air sampling capsules for multi-element analysis.

    PubMed

    Andrews, Ronnee N; Feng, H Amy; Ashley, Kevin

    2016-01-01

    An interlaboratory study was carried out to evaluate the use of acid-soluble cellulosic air sampling capsules for their suitability in the measurement of trace elements in workplace atmospheric samples. These capsules are used as inserts to perform closed-face cassette sample collection for occupational exposure monitoring. The interlaboratory study was performed in accordance with NIOSH guidelines that describe statistical procedures for evaluating measurement accuracy of air monitoring methods. The performance evaluation materials used consisted of cellulose acetate capsules melded to mixed-cellulose ester filters that were dosed with multiple elements from commercial standard aqueous solutions. The cellulosic capsules were spiked with the following 33 elements of interest in workplace air monitoring: Ag, Al, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, In, K, La, Li, Mg, Mn, Mo, Ni, P, Pb, Sb, Se, Sn, Sr, Te, Ti, Tl, V, W, Y, Zn, Zr. The elemental loading levels were certified by an accredited provider of certified reference materials. Triplicates of media blanks and multielement-spiked capsules at three different elemental loadings were sent to each participating laboratory; the elemental loading levels were not revealed to the laboratories. The volunteer participating laboratories were asked to prepare the samples by acid dissolution and to analyze aliquots of extracted samples by inductively coupled plasma atomic emission spectrometry in accordance with NIOSH methods. It was requested that the study participants report their analytical results in units of μg of each target element per internal capsule sample. For the majority of the elements investigated (30 out of 33), the study accuracy estimates obtained satisfied the NIOSH accuracy criterion (A < 25%). This investigation demonstrates the utility of acid-soluble internal sampling capsules for multielement analysis by atomic spectrometry. PMID:26308974

  5. Solar-thermal complex sample processing for nucleic acid based diagnostics in limited resource settings.

    PubMed

    Gumus, Abdurrahman; Ahsan, Syed; Dogan, Belgin; Jiang, Li; Snodgrass, Ryan; Gardner, Andrea; Lu, Zhengda; Simpson, Kenneth; Erickson, David

    2016-05-01

    The use of point-of-care (POC) devices in limited resource settings where access to commonly used infrastructure, such as water and electricity, can be restricted represents simultaneously one of the best application fits for POC systems as well as one of the most challenging places to deploy them. Of the many challenges involved in these systems, the preparation and processing of complex samples like stool, vomit, and biopsies are particularly difficult due to the high number and varied nature of mechanical and chemical interferents present in the sample. Previously we have demonstrated the ability to use solar-thermal energy to perform PCR based nucleic acid amplifications. In this work demonstrate how the technique, using similar infrastructure, can also be used to perform solar-thermal based sample processing system for extracting and isolating Vibrio Cholerae nucleic acids from fecal samples. The use of opto-thermal energy enables the use of sunlight to drive thermal lysing reactions in large volumes without the need for external electrical power. Using the system demonstrate the ability to reach a 95°C threshold in less than 5 minutes and maintain a stable sample temperature of +/- 2°C following the ramp up. The system is demonstrated to provide linear results between 10(4) and 10(8) CFU/mL when the released nucleic acids were quantified via traditional means. Additionally, we couple the sample processing unit with our previously demonstrated solar-thermal PCR and tablet based detection system to demonstrate very low power sample-in-answer-out detection. PMID:27231636

  6. Electrodeposition as an alternate method for preparation of environmental samples for iodide by AMS

    SciTech Connect

    Adamic, M. L.; Lister, T. E.; Dufek, E. J.; Jenson, D. D.; Olson, J. E.; Vockenhuber, C.; Watrous, M. G.

    2015-03-25

    This paper presents an evaluation of an alternate method for preparing environmental samples for 129I analysis by accelerator mass spectrometry (AMS) at Idaho National Laboratory. The optimal sample preparation method is characterized by ease of preparation, capability of processing very small quantities of iodide, and ease of loading into a cathode. Electrodeposition of iodide on a silver wire was evaluated using these criteria. This study indicates that the electrochemically-formed silver iodide deposits produce ion currents similar to those from precipitated silver iodide for the same sample mass. Furthermore, precipitated silver iodide samples are usually mixed with niobium or silver powder prior to loading in a cathode. Using electrodeposition, the silver is already mixed with the sample and can simply be picked up with tweezers, placed in the sample die, and pressed into a cathode. The major advantage of this method is that the silver wire/electrodeposited silver iodide is much easier to load into a cathode.

  7. Electrodeposition as an alternate method for preparation of environmental samples for iodide by AMS

    NASA Astrophysics Data System (ADS)

    Adamic, M. L.; Lister, T. E.; Dufek, E. J.; Jenson, D. D.; Olson, J. E.; Vockenhuber, C.; Watrous, M. G.

    2015-10-01

    This paper presents an evaluation of an alternate method for preparing environmental samples for 129I analysis by accelerator mass spectrometry (AMS) at Idaho National Laboratory. The optimal sample preparation method is characterized by ease of preparation, capability of processing very small quantities of iodide, and ease of loading into a cathode. Electrodeposition of iodide on a silver wire was evaluated using these criteria. This study indicates that the electrochemically-formed silver iodide deposits produce ion currents similar to those from precipitated silver iodide for the same sample mass. Precipitated silver iodide samples are usually mixed with niobium or silver powder prior to loading in a cathode. Using electrodeposition, the silver is already mixed with the sample and can simply be picked up with tweezers, placed in the sample die, and pressed into a cathode. The major advantage of this method is that the silver wire/electrodeposited silver iodide is much easier to load into a cathode.

  8. Solventless and solvent-minimized sample preparation techniques for determining currently used pesticides in water samples: a review.

    PubMed

    Tankiewicz, Maciej; Fenik, Jolanta; Biziuk, Marek

    2011-10-30

    The intensification of agriculture means that increasing amounts of toxic organic and inorganic compounds are entering the environment. The pesticides generally applied nowadays are regarded as some of the most dangerous contaminants of the environment. Their presence in the environment, especially in water, is hazardous because they cause human beings to become more susceptible to disease. For these reasons, it is essential to monitor pesticide residues in the environment with the aid of all accessible analytical methods. The analysis of samples for the presence of pesticides is problematic, because of the laborious and time-consuming operations involved in preparing samples for analysis, which themselves may be a source of additional contaminations and errors. To date, it has been standard practice to use large quantities of organic solvents in the sample preparation process; but as these solvents are themselves hazardous, solventless and solvent-minimized techniques are coming into use. This paper discusses the most commonly used over the last 15 years sample preparation techniques for monitoring organophosphorus and organonitrogen pesticides residue in water samples. Furthermore, a significant trend in sample preparation, in accordance with the principles of 'Green Chemistry' is the simplification, miniaturization and automation of analytical techniques. In view of this aspect, several novel techniques are being developed in order to reduce the analysis step, increase the sample throughput and to improve the quality and the sensitivity of analytical methods. The paper describes extraction techniques requiring the use of solvents - liquid-liquid extraction (LLE) and its modifications, membrane extraction techniques, hollow fibre-protected two-phase solvent microextraction, liquid phase microextraction based on the solidification of a floating organic drop (LPME-SFO), solid-phase extraction (SPE) and single-drop microextraction (SDME) - as well as solvent

  9. Preparation of poly (styrene)-b-poly (acrylic acid)/γ-Fe 2O 3 composites

    NASA Astrophysics Data System (ADS)

    Zhang, L. D.; Liu, W. L.; Xiao, C. L.; Yao, J. S.; Fan, Z. P.; Sun, X. L.; Zhang, X.; Wang, L.; Wang, X. Q.

    2011-12-01

    The use of a block copolymer, poly (styrene)-b-poly (acrylic acid) (PS-b-PAA) to prepare a magnetic nanocomposite was investigated. Poly (styrene)-poly (t-butyl acrylate) block copolymer, being synthesized by atom transfer radical polymerization, was hydrolyzed with hydrochloric acid for obtaining PS-b-PAA. The obtained PS-b-PAA was then compounded with the modified γ-Fe2O3, and subsequently the magnetic nanocomposite was achieved. The products were characterized by 1H NMR, FTIR, gel permeation chromatography, thermogravimetric analysis, transmission electron microscopy and vibrating sample magnetometer. The results showed that the nanocomposites exhibited soft magnetism, with the mean diameter of 100 nm approximately.

  10. 9 CFR 147.8 - Procedures for preparing egg yolk samples for diagnostic tests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Procedures for preparing egg yolk... IMPROVEMENT PLAN Blood Testing Procedures § 147.8 Procedures for preparing egg yolk samples for diagnostic... chapter. (a) Under the supervision of an Authorized Agent or State Inspector, the eggs which are used...

  11. 9 CFR 147.8 - Procedures for preparing egg yolk samples for diagnostic tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Procedures for preparing egg yolk... IMPROVEMENT PLAN Blood Testing Procedures § 147.8 Procedures for preparing egg yolk samples for diagnostic... chapter. (a) Under the supervision of an Authorized Agent or State Inspector, the eggs which are used...

  12. 9 CFR 147.8 - Procedures for preparing egg yolk samples for diagnostic tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Procedures for preparing egg yolk... IMPROVEMENT PLAN Blood Testing Procedures § 147.8 Procedures for preparing egg yolk samples for diagnostic... chapter. (a) Under the supervision of an Authorized Agent or State Inspector, the eggs which are used...

  13. Microwave-assisted sample preparation of coal and coal fly ash for subsequent metal determination

    SciTech Connect

    Srogi, K.

    2007-01-15

    The aim of this paper is to review microwave-assisted digestion of coal and coal fly ash. A brief description of microwave heating principles is presented. Microwave-assisted digestion appears currently to be the most popular preparation technique, possibly due to the comparatively rapid sample preparation and the reduction of contamination, compared to the conventional hot-plate digestion methods.

  14. Preparation of pure microbiological samples for pyrolysis gas-liquid chromatography studies

    NASA Technical Reports Server (NTRS)

    Oxborrow, G. S.; Fields, N. D.; Puleo, J. R.

    1976-01-01

    Bacterial samples were prepared for pyrolysis gas-liquid chromatography using cells grown on membrane filters. Pyrochromatograms were reproducible when cells harvested from the filters were pyrolyzed without being washed.

  15. TCLP Preparation and Analysis of K East Basin Composite Sludge Samples

    SciTech Connect

    Silvers, Kurt L.

    2000-08-15

    This report contains results from TCLP preparation and analysis of K East Basin floor and canister composite sludge samples. Analyses were performed in the Radiochemical Processing Laboratory (PNNL, 325 Building).

  16. SIGNIFICANCE OF SAMPLE PREPARATION IN ACCURATE ESTIMATION OF PHENOLIC PHYTOCHEMICALS IN FOODS AND FOOD PRODUCTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The extractability of the phenolic compounds is influenced by their chemical structure, degree of polymerization, and interaction with other components in the matrix. This talk describes the influence of sample preparation parameters (extraction techniques, extraction solvents, temperature, pressu...

  17. Electrical conduction in macroscopically oriented deoxyribonucleic and hyaluronic acid samples

    NASA Astrophysics Data System (ADS)

    Kutnjak, Zdravko; Lahajnar, Gojmir; Filipič, Cene; Podgornik, Rudolf; Nordenskiöld, Lars; Korolev, Nikolay; Rupprecht, Allan

    2005-04-01

    Measurements of the quasistatic and frequency dependent electrical conductivity below 1 MHz were carried out on wet-spun, macroscopically oriented, calf thymus deoxyribonucleic (DNA) and umbilical cord hyaluronic acid (HA) bulk samples. The frequency dependence of the electrical conductivity in the frequency range of approximately 10-3-106Hz of both materials is surprisingly rather similar. Temperature dependence of the quasistatic electrical conductivity above the low temperature saturation plateau can be well described by the activated Arrhenius law with the activation energy of ≈0.8eV for both DNA and HA. We discuss the meaning of these findings for the possible conduction mechanism in these particular charged polyelectrolytes.

  18. Searching for Amino Acids in Meteorites and Comet Samples

    NASA Technical Reports Server (NTRS)

    Cook, Jamie Elsila

    2010-01-01

    Chemistry plays an important role in the interdisciplinary field of astrobiology, which strives to understand the origin, distribution, and evolution of life throughout the universe. Chemical techniques are used to search for and characterize the basic ingredients for life, from the elements through simple molecules and up to the more complex compounds that may serve as the ingredients for life. The Astrobiology Analytical Laboratory at NASA Goddard uses state-of-the-art laboratory analytical instrumentation in unconventional ways to examine extraterrestrial materials and tackle some of the big questions in astrobiology. This talk will discuss some of the instrumentation and techniques used for these unique samples, as well as some of our most interesting results. The talk will present two areas of particular interest in our laboratory: (1) the search for chiral excesses in meteoritic amino acids, which may help to explain the origin of homochirality in life on Earth; and (2) the detection of amino acids and amines in material returned by NASA's Stardust mission, which rendevouzed with a cornet and brought back cometary particles to the Earth.

  19. Preparation of fatty acid methyl esters for gas-chromatographic analysis of marine lipids: insight studies.

    PubMed

    Carvalho, Ana P; Malcata, F Xavier

    2005-06-29

    Assays for fatty acid composition in biological materials are commonly carried out by gas chromatography, after conversion of the lipid material into the corresponding methyl esters (FAME) via suitable derivatization reactions. Quantitative derivatization depends on the type of catalyst and processing conditions employed, as well as the solubility of said sample in the reaction medium. Most literature pertinent to derivatization has focused on differential comparison between alternative methods; although useful to find out the best method for a particular sample, additional studies on factors that may affect each step of FAME preparation are urged. In this work, the influence of various parameters in each step of derivatization reactions was studied, using both cod liver oil and microalgal biomass as model systems. The accuracies of said methodologies were tested via comparison with the AOCS standard method, whereas their reproducibility was assessed by analysis of variance of (replicated) data. Alkaline catalysts generated lower levels of long-chain unsaturated FAME than acidic ones. Among these, acetyl chloride and BF(3) were statistically equivalent to each other. The standard method, which involves alkaline treatment of samples before acidic methylation with BF(3), provided equivalent results when compared with acidic methylation with BF(3) alone. Polarity of the reaction medium was found to be of the utmost importance in the process: intermediate values of polarity [e.g., obtained by a 1:1 (v/v) mixture of methanol with diethyl ether or toluene] provided amounts of extracted polyunsaturated fatty acids statistically higher than those obtained via the standard method. PMID:15969474

  20. Sample preparation method for glass welding by ultrashort laser pulses yields higher seam strength

    SciTech Connect

    Cvecek, K.; Miyamoto, I.; Strauss, J.; Wolf, M.; Frick, T.; Schmidt, M.

    2011-05-01

    Glass welding by ultrashort laser pulses allows joining without the need of an absorber or a preheating and postheating process. However, cracks generated during the welding process substantially impair the joining strength of the welding seams. In this paper a sample preparation method is described that prevents the formation of cracks. The measured joining strength of samples prepared by this method is substantially higher than previously reported values.

  1. Defining a sample preparation workflow for advanced virus detection and understanding sensitivity by next-generation sequencing.

    PubMed

    Wang, Christopher J; Feng, Szi Fei; Duncan, Paul

    2014-01-01

    The application of next-generation sequencing (also known as deep sequencing or massively parallel sequencing) for adventitious agent detection is an evolving field that is steadily gaining acceptance in the biopharmaceutical industry. In order for this technology to be successfully applied, a robust method that can isolate viral nucleic acids from a variety of biological samples (such as host cell substrates, cell-free culture fluids, viral vaccine harvests, and animal-derived raw materials) must be established by demonstrating recovery of model virus spikes. In this report, we implement the sample preparation workflow developed by Feng et. al. and assess the sensitivity of virus detection in a next-generation sequencing readout using the Illumina MiSeq platform. We describe a theoretical model to estimate the detection of a target virus in a cell lysate or viral vaccine harvest sample. We show that nuclease treatment can be used for samples that contain a high background of non-relevant nucleic acids (e.g., host cell DNA) in order to effectively increase the sensitivity of sequencing target viruses and reduce the complexity of data analysis. Finally, we demonstrate that at defined spike levels, nucleic acids from a panel of model viruses spiked into representative cell lysate and viral vaccine harvest samples can be confidently recovered by next-generation sequencing. PMID:25475632

  2. Proteomic Challenges: Sample Preparation Techniques for Microgram-Quantity Protein Analysis from Biological Samples

    PubMed Central

    Feist, Peter; Hummon, Amanda B.

    2015-01-01

    Proteins regulate many cellular functions and analyzing the presence and abundance of proteins in biological samples are central focuses in proteomics. The discovery and validation of biomarkers, pathways, and drug targets for various diseases can be accomplished using mass spectrometry-based proteomics. However, with mass-limited samples like tumor biopsies, it can be challenging to obtain sufficient amounts of proteins to generate high-quality mass spectrometric data. Techniques developed for macroscale quantities recover sufficient amounts of protein from milligram quantities of starting material, but sample losses become crippling with these techniques when only microgram amounts of material are available. To combat this challenge, proteomicists have developed micro-scale techniques that are compatible with decreased sample size (100 μg or lower) and still enable excellent proteome coverage. Extraction, contaminant removal, protein quantitation, and sample handling techniques for the microgram protein range are reviewed here, with an emphasis on liquid chromatography and bottom-up mass spectrometry-compatible techniques. Also, a range of biological specimens, including mammalian tissues and model cell culture systems, are discussed. PMID:25664860

  3. Optimisation Of Preparation And Measurement Protocols For Luminescence Dating Of Small Samples From A Suite Of Porcelains And Faiences

    NASA Astrophysics Data System (ADS)

    Burbridge, C. I.; Rodrigues, A. L.; Dias, M. I.; Prudencio, M. I.; Cardoso, G.

    Experiments designed to evaluate protocols for preparation and luminescence measurement of small samples (<100 mg) from high fired ceramics are described. These include: additive TL of untreatedmaterial; multiple stimulation (Predose TL, OSL, TL) of hydrofluoric washed fragments; Simplified Predose and SAR OSL of silicate powders from hydrochloric and fluorosilicic acid treatment. The 110°C TL signal in the Simplified Predose technique minimised required sample size, but growth with cumulative predose was sub-linear. For exponential extrapolations 11/26 faience samples yielded results within 1σ of typological expectations, but substantial scatter was interpreted as relating to radiation quenching effects. Extrapolation errors were investigated by deactivating samples and regenerating their predose responses. Acid treatment of cores drilled from sherds enabled preparation of mineral and grain-size fractions while avoiding crushing effects, and damage to or contamination by the glaze and decoration. Results of luminescence measurements indicate that future work should focus on the use of open detection filter combinations to increase signal levels, to enable quenching corrections in predose measurements and the use of high temperature TL signals.

  4. Different sample preparation and detection methods for normal and lung cancer urinary proteome analysis.

    PubMed

    Sinchaikul, Supachok; Tantipaiboonwong, Payungsak; Sriyam, Supawadee; Tzao, Ching; Phutrakul, Suree; Chen, Shui-Tein

    2010-01-01

    The urinary proteome is known to be a valuable field of study related to human physiological functions because many components in urine provide an alternative to blood plasma as a potential source of disease biomarkers useful in clinical diagnosis and therapeutic application. Due to the variability and complexity of urine, sample preparation is very important for decreasing the dynamic range of components and isolating specific urinary proteins prior to analysis. We discuss many useful sample preparation methods in this chapter, including those of lung cancer urine samples. In addition, protein detection methods are also crucial in visualizing protein profiles and for quantification of protein content in urine samples from both normal donor and lung cancer patients. This chapter also provides alternative choices of urine sample preparation and detection methods for selective use in urinary proteome analysis and for identifying urinary protein markers in lung cancer and other diseases. PMID:20407942

  5. On radiation damage in FIB-prepared softwood samples measured by scanning X-ray diffraction.

    PubMed

    Storm, Selina; Ogurreck, Malte; Laipple, Daniel; Krywka, Christina; Burghammer, Manfred; Di Cola, Emanuela; Müller, Martin

    2015-03-01

    The high flux density encountered in scanning X-ray nanodiffraction experiments can lead to severe radiation damage to biological samples. However, this technique is a suitable tool for investigating samples to high spatial resolution. The layered cell wall structure of softwood tracheids is an interesting system which has been extensively studied using this method. The tracheid cell has a complex geometry, which requires the sample to be prepared by cutting it perpendicularly to the cell wall axis. Focused ion beam (FIB) milling in combination with scanning electron microscopy allows precise alignment and cutting without splintering. Here, results of a scanning X-ray diffraction experiment performed on a biological sample prepared with a focused ion beam of gallium atoms are reported for the first time. It is shown that samples prepared and measured in this way suffer from the incorporation of gallium atoms up to a surprisingly large depth of 1 µm. PMID:25723928

  6. Elimination of the artefact peaks in capillary electrophoresis determination of glutamate by using organic solvents in sample preparation.

    PubMed

    Campos, Camila Dalben Madeira; de Campos Braga, Patricia Aparecida; Reyes, Felix Guillermo Reyes; da Silva, José Alberto Fracassi

    2015-11-01

    Focusing on the demand from the food industry for fast and reliable alternative methods to control the quality of food products, we present in this paper a method for amino acid separation and glutamic acid quantification in complex matrices employing capillary electrophoresis with capacitively coupled contactless conductivity detection. We demonstrate by simulation and experimentally the use of organic solvents in sample preparation to prevent peak splitting and increase stacking in capillary electrophoretic separations of amino acids. Additionally, we obtained results for glutamic acid quantification comparable to those obtained via traditional methods used at industrial sites. We tested premium and low-cost samples with large variations in their glutamic acid content, which demonstrated the wide range of applicability of the method presented herein. The results of the proposed capacitively coupled contactless conductivity detection based capillary electrophoresis method agreed with those obtained by an enzymatic detector and ultra high performance liquid chromatography coupled to tandem mass spectrometry, considering a confidence level of 95%. PMID:26332708

  7. Critical comparison of sample preparation strategies for shotgun proteomic analysis of formalin-fixed, paraffin-embedded samples: insights from liver tissue

    PubMed Central

    2014-01-01

    Background The growing field of formalin-fixed paraffin-embedded (FFPE) tissue proteomics holds promise for improving translational research. Direct tissue trypsinization (DT) and protein extraction followed by in solution digestion (ISD) or filter-aided sample preparation (FASP) are the most common workflows for shotgun analysis of FFPE samples, but a critical comparison of the different methods is currently lacking. Experimental design DT, FASP and ISD workflows were compared by subjecting to the same label-free quantitative approach three independent technical replicates of each method applied to FFPE liver tissue. Data were evaluated in terms of method reproducibility and protein/peptide distribution according to localization, MW, pI and hydrophobicity. Results DT showed lower reproducibility, good preservation of high-MW proteins, a general bias towards hydrophilic and acidic proteins, much lower keratin contamination, as well as higher abundance of non-tryptic peptides. Conversely, FASP and ISD proteomes were depleted in high-MW proteins and enriched in hydrophobic and membrane proteins; FASP provided higher identification yields, while ISD exhibited higher reproducibility. Conclusions These results highlight that diverse sample preparation strategies provide significantly different proteomic information, and present typical biases that should be taken into account when dealing with FFPE samples. When a sufficient amount of tissue is available, the complementary use of different methods is suggested to increase proteome coverage and depth. PMID:25097466

  8. Sample preparation for thermo-gravimetric determination and thermo-gravimetric characterization of refuse derived fuel.

    PubMed

    Robinson, T; Bronson, B; Gogolek, P; Mehrani, P

    2016-02-01

    Thermo-gravimetric analysis (TGA) is a useful method for characterizing fuels. In the past it has been applied to the study of refuse derived fuel (RDF) and related materials. However, the heterogeneity of RDF makes the preparation of small representative samples very difficult and this difficulty has limited the effectiveness of TGA for characterization of RDF. A TGA method was applied to a variety of materials prepared from a commercially available RDF using a variety of procedures. Applicability of TGA method to the determination of the renewable content of RDF was considered. Cryogenic ball milling was found to be an effective means of preparing RDF samples for TGA. When combined with an effective sample preparation, TGA could be used as an alternative method for assessing the renewable content of RDF. PMID:26611398

  9. Process for the preparation of 3,4-dihydroxybutanoic acid and salts thereof

    DOEpatents

    Hollingsworth, Rawle I.

    1994-01-01

    A process for the preparation of 3,4-dihydroxybutanoic acid (1) and salts thereof from a glucose source containing 1,4-linked glucose as a substituent is described. The process uses an alkali metal hdyroxide and hydrogen peroxide to convert the glucose source to (1). The compound (1) is useful as a chemical intermediate to naturally occurring fatty acids and is used to prepare 3,4-dihydroxybutanoic acid-gamma-lactone (2) and furanone (3), particularly stereoisomers of these compounds.

  10. Process For The Preparation Of 3,4-Dihyd Roxybutanoic Acid And Salts Thereof

    DOEpatents

    Hollingsworth, Rawle I.

    1994-06-07

    A process for the preparation of 3,4-dihydroxybutanoic acid (1) and salts thereof from a glucose source containing 1,4-linked glucose as a substituent is described. The process uses an alkali metal hdyroxide and hydrogen peroxide to convert the glucose source to (1). The compound (1) is useful as a chemical intermediate to naturally occurring fatty acids and is used to prepare 3,4-dihydroxybutanoic acid-gamma-lactone (2) and furanone (3), particularly stereoisomers of these compounds.

  11. Modeling of the acid-leaching process in the preparation of chemical ultraclean coal

    SciTech Connect

    Wang, H.; Wang, Z.

    1995-12-31

    The paper is continued from ``Modeling of the Preparation of Chemical Ultraclean Coal`` presented at 11th Pittsburgh Coal Conference. As to acid-alkali deashing process, acid-leaching is a post-processing for the preparation of ultraclean coal, which can be used to remove chemical products caused by alkali-leaching processing. A soluble model is developed to establish an acid-leaching rate equation, which indicates that model result is compatible well with the experimental data.

  12. Preparation and characterization of SPION functionalized via caffeic acid

    NASA Astrophysics Data System (ADS)

    Baykal, A.; Amir, Md.; Günerb, S.; Sözeri, H.

    2015-12-01

    Caffeic acid coated superparamagnetic iron oxide nanoparticles (SPION-CFA) was synthesized by reflux method. The structural, spectroscopic and magnetic properties were studied by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), and Vibrating sample magnetometer (VSM) techniques. Thermal gravimetric analysis (TG) and Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of CA on the surface of SPION. The theoretical analyzes performed on recorded room temperature VSM spectrum confirmed the formation of superparamagnetic nature of SPION-CFA. The particle size dependent Langevin function was applied to determine the average magnetic particle dimension (Dmag) around 11.93 nm. In accordance, the average crystallite and particle sizes were obtained as 11.40 nm and ~12.00 nm from XRD and TEM measurements. The extrapolated specific saturation magnetization (σs) is 44.11 emu/g and measured magnetic moment is 1.83 μB. These parameters assign small order of magnetization for NPs with respect to bulk Fe3O4. Magnetic anisotropy was offered as uniaxial and calculated effective anisotropy constant (Keff) is 34.82×104 Erg/g. The size-dependent saturation magnetization suggests the existence of a magnetically inactive layer as 1.035 nm for SPION-CFA.

  13. Glass sample preparation and performance investigations. [solar x-ray imager

    NASA Technical Reports Server (NTRS)

    Johnson, R. Barry

    1992-01-01

    This final report details the work performed under this delivery order from April 1991 through April 1992. The currently available capabilities for integrated optical performance modeling at MSFC for large and complex systems such as AXAF were investigated. The Integrated Structural Modeling (ISM) program developed by Boeing for the U.S. Air Force was obtained and installed on two DECstations 5000 at MSFC. The structural, thermal and optical analysis programs available in ISM were evaluated. As part of the optomechanical engineering activities, technical support was provided in the design of support structure, mirror assembly, filter wheel assembly and material selection for the Solar X-ray Imager (SXI) program. As part of the fabrication activities, a large number of zerodur glass samples were prepared in different sizes and shapes for acid etching, coating and polishing experiments to characterize the subsurface damage and stresses produced by the grinding and polishing operations. Various optical components for AXAF video microscope and the x-ray test facility were also fabricated. A number of glass fabrication and test instruments such as a scatter plate interferometer, a gravity feed saw and some phenolic cutting blades were fabricated, integrated and tested.

  14. Preparation and analysis of standardized waste samples for Controlled Ecological Life Support Systems (CELSS)

    NASA Technical Reports Server (NTRS)

    Carden, J. L.; Browner, R.

    1982-01-01

    The preparation and analysis of standardized waste samples for controlled ecological life support systems (CELSS) are considered. Analysis of samples from wet oxidation experiments, the development of ion chromatographic techniques utilizing conventional high pressure liquid chromatography (HPLC) equipment, and an investigation of techniques for interfacing an ion chromatograph (IC) with an inductively coupled plasma optical emission spectrometer (ICPOES) are discussed.

  15. Accumulated analyses of amino acid precursors in returned lunar samples

    NASA Technical Reports Server (NTRS)

    Fox, S. W.; Harada, K.; Hare, P. E.

    1973-01-01

    Six amino acids (glycine, alanine, aspartic acid, glutamic acid, serine, and threonine) obtained by hydrolysis of extracts have been quantitatively determined in ten collections of fines from five Apollo missions. Although the amounts found, 7-45 ng/g, are small, the lunar amino acid/carbon ratios are comparable to those of the carbonaceous chondrites, Murchison and Murray, as analyzed by the same procedures. Since both the ratios of amino acid to carbon, and the four or five most common types of proteinous amino acid found, are comparable for the two extraterrestrial sources despite different cosmophysical histories of the moon and meteorites, common cosmochemical processes are suggested.

  16. Pilot study of a rapid and minimally instrumented sputum sample preparation method for molecular diagnosis of tuberculosis

    PubMed Central

    Ferguson, Tanya M.; Weigel, Kris M.; Lakey Becker, Annie; Ontengco, Delia; Narita, Masahiro; Tolstorukov, Ilya; Doebler, Robert; Cangelosi, Gerard A.; Niemz, Angelika

    2016-01-01

    Nucleic acid amplification testing (NAAT) enables rapid and sensitive diagnosis of tuberculosis (TB), which facilitates treatment and mitigates transmission. Nucleic acid extraction from sputum constitutes the greatest technical challenge in TB NAAT for near-patient settings. This report presents preliminary data for a semi-automated sample processing method, wherein sputum is disinfected and liquefied, followed by PureLyse® mechanical lysis and solid-phase nucleic acid extraction in a miniaturized, battery-operated bead blender. Sputum liquefaction and disinfection enabled a >104 fold reduction in viable load of cultured Mycobacterium tuberculosis (M.tb) spiked into human sputum, which mitigates biohazard concerns. Sample preparation via the PureLyse® method and a clinically validated manual method enabled positive PCR-based detection for sputum spiked with 104 and 105 colony forming units (cfu)/mL M.tb. At 103 cfu/mL sputum, four of six and two of six samples amplified using the comparator and PureLyse® method, respectively. For clinical specimens from TB cases and controls, the two methods provided 100% concordant results for samples with 1 mL input volume (N = 41). The semi-automated PureLyse® method therefore performed similarly to a validated manual comparator method, but is faster, minimally instrumented, and can be integrated into TB molecular diagnostic platforms designed for near-patient low-resource settings. PMID:26785769

  17. Pilot study of a rapid and minimally instrumented sputum sample preparation method for molecular diagnosis of tuberculosis.

    PubMed

    Ferguson, Tanya M; Weigel, Kris M; Lakey Becker, Annie; Ontengco, Delia; Narita, Masahiro; Tolstorukov, Ilya; Doebler, Robert; Cangelosi, Gerard A; Niemz, Angelika

    2016-01-01

    Nucleic acid amplification testing (NAAT) enables rapid and sensitive diagnosis of tuberculosis (TB), which facilitates treatment and mitigates transmission. Nucleic acid extraction from sputum constitutes the greatest technical challenge in TB NAAT for near-patient settings. This report presents preliminary data for a semi-automated sample processing method, wherein sputum is disinfected and liquefied, followed by PureLyse(®) mechanical lysis and solid-phase nucleic acid extraction in a miniaturized, battery-operated bead blender. Sputum liquefaction and disinfection enabled a >10(4) fold reduction in viable load of cultured Mycobacterium tuberculosis (M.tb) spiked into human sputum, which mitigates biohazard concerns. Sample preparation via the PureLyse(®) method and a clinically validated manual method enabled positive PCR-based detection for sputum spiked with 10(4) and 10(5) colony forming units (cfu)/mL M.tb. At 10(3) cfu/mL sputum, four of six and two of six samples amplified using the comparator and PureLyse(®) method, respectively. For clinical specimens from TB cases and controls, the two methods provided 100% concordant results for samples with 1 mL input volume (N = 41). The semi-automated PureLyse(®) method therefore performed similarly to a validated manual comparator method, but is faster, minimally instrumented, and can be integrated into TB molecular diagnostic platforms designed for near-patient low-resource settings. PMID:26785769

  18. Fast derivatization of fatty acids in different meat samples for gas chromatography analysis.

    PubMed

    Figueiredo, Ingrid Lima; Claus, Thiago; Oliveira Santos Júnior, Oscar; Almeida, Vitor Cinque; Magon, Thiago; Visentainer, Jesuí Vergilio

    2016-07-22

    In order to analyze the composition of fatty acids employing gas chromatography as the separation method, a derivatization of lipids using esterification and transesterification reactions is needed. The methodologies currently available are time consuming and use large amounts of sample and reagents. Thus, this work proposes a new procedure to carry out the derivatization of fatty acids without the need for prior extraction of lipids. The use of small amounts of sample (100mg) allows the analysis to be performed in specific parts of animals, in most cases without having them slaughtered. Another benefit is the use of small amounts of reagents (only 2mL of NaOH/Methanol and H2SO4/Methanol). The use of an experimental design procedure (Design Expert software) allows the optimization of the alkaline and acid reaction times. The procedure was validated for five minutes in both steps. The method was validated for bovine fat, beef, chicken, pork, fish and shrimp meats. The results for the merit figures of accuracy (from 101.07% to 109.18%), precision (RSDintra-day (from 0.65 to 3.93%), RSDinter-day (from 1.57 to 5.22%)), linearity (R(2)=0.9864) and robustness confirmed that the new method is satisfactory within the linear range of 2-30% of lipids in the sample. Besides the benefits of minimizing the amount of samples and reagents, the procedure enables gas chromatography sample preparation in a very short time compared with traditional procedures. PMID:27320376

  19. Before the injection--modern methods of sample preparation for separation techniques.

    PubMed

    Smith, Roger M

    2003-06-01

    The importance of sample preparation methods as the first stage in an analytical procedure is emphasised and examined. Examples are given of the extraction and concentration of analytes from solid, liquid and gas phase matrices, including solvent phase extractions, such as supercritical fluids and superheated water extraction, solid-phase extraction and solid-phase microextraction, headspace analysis and vapour trapping. The potential role of selective extraction methods, including molecular imprinted phases and affinity columns, are considered. For problem samples alternative approaches, such as derivatisation are discussed, and potential new approaches minimising sample preparation are noted. PMID:12877164

  20. Reducing Spatial Heterogeneity of MALDI Samples with Marangoni Flows During Sample Preparation.

    PubMed

    Lai, Yin-Hung; Cai, Yi-Hong; Lee, Hsun; Ou, Yu-Meng; Hsiao, Chih-Hao; Tsao, Chien-Wei; Chang, Huan-Tsung; Wang, Yi-Sheng

    2016-08-01

    This work demonstrates a method to prepare homogeneous distributions of analytes to improve data reproducibility in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). Natural-air drying processes normally result in unwanted heterogeneous spatial distributions of analytes in MALDI crystals and make quantitative analysis difficult. This study demonstrates that inducing Marangoni flows within drying droplets can significantly reduce the heterogeneity problem. The Marangoni flows are accelerated by changing substrate temperatures to create temperature gradients across droplets. Such hydrodynamic flows are analyzed semi-empirically. Using imaging mass spectrometry, changes of heterogeneity of molecules with the change of substrate temperature during drying processes are demonstrated. The observed heterogeneities of the biomolecules reduce as predicted Marangoni velocities increase. In comparison to conventional methods, drying droplets on a 5 °C substrate while keeping the surroundings at ambient conditions typically reduces the heterogeneity of biomolecular ions by 65%-80%. The observation suggests that decreasing substrate temperature during droplet drying processes is a simple and effective means to reduce analyte heterogeneity for quantitative applications. Graphical Abstract ᅟ. PMID:27126469

  1. Reducing Spatial Heterogeneity of MALDI Samples with Marangoni Flows During Sample Preparation

    NASA Astrophysics Data System (ADS)

    Lai, Yin-Hung; Cai, Yi-Hong; Lee, Hsun; Ou, Yu-Meng; Hsiao, Chih-Hao; Tsao, Chien-Wei; Chang, Huan-Tsung; Wang, Yi-Sheng

    2016-04-01

    This work demonstrates a method to prepare homogeneous distributions of analytes to improve data reproducibility in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). Natural-air drying processes normally result in unwanted heterogeneous spatial distributions of analytes in MALDI crystals and make quantitative analysis difficult. This study demonstrates that inducing Marangoni flows within drying droplets can significantly reduce the heterogeneity problem. The Marangoni flows are accelerated by changing substrate temperatures to create temperature gradients across droplets. Such hydrodynamic flows are analyzed semi-empirically. Using imaging mass spectrometry, changes of heterogeneity of molecules with the change of substrate temperature during drying processes are demonstrated. The observed heterogeneities of the biomolecules reduce as predicted Marangoni velocities increase. In comparison to conventional methods, drying droplets on a 5 °C substrate while keeping the surroundings at ambient conditions typically reduces the heterogeneity of biomolecular ions by 65%-80%. The observation suggests that decreasing substrate temperature during droplet drying processes is a simple and effective means to reduce analyte heterogeneity for quantitative applications.

  2. Reducing Spatial Heterogeneity of MALDI Samples with Marangoni Flows During Sample Preparation

    NASA Astrophysics Data System (ADS)

    Lai, Yin-Hung; Cai, Yi-Hong; Lee, Hsun; Ou, Yu-Meng; Hsiao, Chih-Hao; Tsao, Chien-Wei; Chang, Huan-Tsung; Wang, Yi-Sheng

    2016-08-01

    This work demonstrates a method to prepare homogeneous distributions of analytes to improve data reproducibility in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). Natural-air drying processes normally result in unwanted heterogeneous spatial distributions of analytes in MALDI crystals and make quantitative analysis difficult. This study demonstrates that inducing Marangoni flows within drying droplets can significantly reduce the heterogeneity problem. The Marangoni flows are accelerated by changing substrate temperatures to create temperature gradients across droplets. Such hydrodynamic flows are analyzed semi-empirically. Using imaging mass spectrometry, changes of heterogeneity of molecules with the change of substrate temperature during drying processes are demonstrated. The observed heterogeneities of the biomolecules reduce as predicted Marangoni velocities increase. In comparison to conventional methods, drying droplets on a 5 °C substrate while keeping the surroundings at ambient conditions typically reduces the heterogeneity of biomolecular ions by 65%-80%. The observation suggests that decreasing substrate temperature during droplet drying processes is a simple and effective means to reduce analyte heterogeneity for quantitative applications.

  3. Development of a high vacuum sample preparation system for helium mass spectrometer

    NASA Astrophysics Data System (ADS)

    Kumar, P.; Das, N. K.; Mallik, C.; Bhandari, R. K.

    2012-11-01

    A high vacuum sample preparation system for the 3He/4He ratio mass spectrometer (Helix SFT) has been developed to remove all the gaseous constituents excluding helium from the field gases. The sample preparation system comprises of turbo molecular pump, ion pump, zirconium getter, pipettes and vacuum gauges with controller. All these are fitted with cylindrical SS chamber using all metal valves. The field samples are initially treated with activated charcoal trap immersed in liquid nitrogen to cutoff major impurities and moisture present in the sample gas. A sample of 5 ml is collected out of this stage at a pressure of 10-2 mbar. This sample is subsequently purified at a reduced pressure of 10-7 mbar before it is injected into the ion source of the mass spectrometer. The sample pressure was maintained below 10-7 mbar with turbo molecular vacuum pumps and ion pumps. The sample gas passes through several getter elements and a cold finger with the help of manual high vacuum valves before it is fed to the mass spectrometer. Thus the high vacuum sample preparation system introduces completely clean, dry and refined helium sample to the mass spectrometer for best possible analysis of isotopic ratio of helium.

  4. Repeating cytological preparations on liquid-based cytology samples: A methodological advantage?

    PubMed

    Pinto, Alvaro P; Maia, Henrique Felde; di Loretto, Celso; Krunn, Patrícia; Túlio, Siumara; Collaço, Luis Martins

    2007-10-01

    This study investigates the rule that repeating cytological preparations on liquid-based cytology improves sample adequacy, diagnosis, microbiological, and hormonal evaluations. We reviewed 156 cases of pap-stained preparations of exfoliated cervical cells in two slides processed by DNA-Cytoliq System. After sample repeat/dilution, limiting factors affecting sample adequacy were removed in nine cases and three unsatisfactory cases were reclassified as satisfactory. Diagnosis was altered in 24 cases. Of these, the original diagnosis in 15 was atypical squamous cells of undetermined significance; after the second slide examination, diagnosis in 5 of the 15 cases changed to low-grade squamous intraepithelial lesion, 3 to high-grade squamous intraepithelial lesion, and 7 to absence of lesion. Microbiological evaluation was altered, with Candida sp. detected in two repeated slides. Repeat slide preparation or dilution of residual samples enhances cytological diagnosis and decreases effects of limiting factors in manually processed DIGENE DCS LBC. PMID:17854084

  5. Sample preparation protocols for realization of reproducible characterization of single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Decker, J. E.; Hight Walker, A. R.; Bosnick, K.; Clifford, C. A.; Dai, L.; Fagan, J.; Hooker, S.; Jakubek, Z. J.; Kingston, C.; Makar, J.; Mansfield, E.; Postek, M. T.; Simard, B.; Sturgeon, R.; Wise, S.; Vladar, A. E.; Yang, L.; Zeisler, R.

    2009-12-01

    Harmonized sample pre-treatment is an essential first step in ensuring quality of measurements as regards repeatability, interlaboratory reproducibility and commutability. The development of standard preparation methods for single-wall carbon nanotube (SWCNT) samples is therefore essential to progress in their investigation and eventual commercialization. Here, descriptions of sample preparation and pre-treatment for the physicochemical characterization of SWCNTs are provided. Analytical methods of these protocols include scanning electron microscopy (dry, wet), transmission electron microscopy (dry, wet), atomic force microscopy, inductively coupled plasma mass spectrometry, neutron activation analysis, Raman spectroscopy (dry, wet), UV-Vis-NIR absorption and photoluminescence spectroscopy, manometric isothermal gas adsorption and thermogravimetric analysis. Although sample preparation refers to these specific methods, application to other methods for measurement and characterization of SWCNTs can be envisioned.

  6. Preparation of fatty acid methyl esters from Osage orange (Maclura pomifera) oil and evaluation as biodiesel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fatty acid methyl esters were prepared in high yield by transesterification of Osage orange (Maclura pomifera) oil. Extracted using supercritical CO2, the crude oil was initially treated with mineral acid and methanol to lower its content of free fatty acids, thus rendering it amenable to homogeneou...

  7. Thermophysical properties of starch and whey protein composite prepared in presence of organic acid and esters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previously, we prepared starch and protein composite by reactive mixing in presence of various organic acids and found that use of these acid esters resulted in composites with good mechanical properties. In this study, concentration (% w/w) of acid citrates in the starch-protein composites were var...

  8. Design and construction of a sample preparation chamber for atomic beam scattering

    SciTech Connect

    Nielsen, C.

    1992-05-18

    A new type of atomic beam scattering spectrometer was built to advance the usefulness of the atomic beam scattering technique as a surface dynamics probe. The facility was not only built to investigate the typical alkali halide samples such as NaCl, NaF, and LiF, but also to investigate metallic surfaces. Metal samples are more complicated to study, due to their reactive surfaces and the sample preparation process. A surface analysis chamber was constructed as an attachment to the scattering facility to treat samples under ultra high vacuum (UHV) and then transfer these samples into the scattering facility. This surface analysis chamber is referred to as the sample preparation chamber and is the basis for this thesis.

  9. Impact of sample preparation on mineralogical analysis of zero-valent iron reactive barrier materials

    SciTech Connect

    Phillips, Debra Helen; Gu, Baohua; Watson, David B; Roh, Yul

    2003-03-01

    Permeable reactive barriers (PRBs) of zero-valent iron (Fe{sup 0}) are increasingly being used to remediate contaminated ground water. Corrosion of Fe{sup 0} filings and the formation of precipitates can occur when the PRB material comes in contact with ground water and may reduce the lifespan and effectiveness of the barrier. At present, there are no routine procedures for preparing and analyzing the mineral precipitates from Fe{sup 0} PRB material. These procedures are needed because mineralogical composition of corrosion products used to interpret the barrier processes can change with iron oxidation and sample preparation. The objectives of this study were (i) to investigate a method of preparing Fe{sup 0} reactive barrier material for mineralogical analysis by X-ray diffraction (XRD), and (ii) to identify Fe mineral phases and rates of transformations induced by different mineralogical preparation techniques. Materials from an in situ Fe{sup 0} PRB were collected by undisturbed coring and processed for XRD analysis after different times since sampling for three size fractions and by various drying treatments. We found that whole-sample preparation for analysis was necessary because mineral precipitates occurred within the PRB material in different size fractions of the samples. Green rusts quickly disappeared from acetone-dried samples and were not present in air-dried and oven-dried samples. Maghemite/magnetite content increased over time and in oven-dried samples, especially after heating to 105 C. We conclude that care must be taken during sample preparation of Fe{sup 0} PRB material, especially for detection of green rusts, to ensure accurate identification of minerals present within the barrier system.

  10. Coagulant properties of Moringa oleifera protein preparations: application to humic acid removal.

    PubMed

    Santos, Andréa F S; Paiva, Patrícia M G; Teixeira, José A C; Brito, António G; Coelho, Luana C B B; Nogueira, Regina

    2012-01-01

    This work aimed to characterize the coagulant properties of protein preparations from Moringa oleifera seeds in the removal of humic acids from water. Three distinct preparations were assayed, namely extract (seeds homogenized with 0.15 M NaCl), fraction (extract precipitated with 60% w/v ammonium sulphate) and cMoL (protein purified with guar gel column chromatography). The extract showed the highest coagulant activity in a protein concentration between 1 mg/L and 180 mg/L at pH 7.0. The zeta potential of the extract (-10 mV to -15 mV) was less negative than that of the humic acid (-41 mV to -42 mV) in a pH range between 5.0 and 8.0; thus, the mechanism that might be involved in this coagulation activity is adsorption and neutralization of charges. Reduction of total organic carbon (TOC) and dissolved organic carbon (DOC) was observed in water samples containing 9 mg/L carbon as humic acid when treated with 1 mg/L of the extract. A decrease in colour and in the aromatic content of the treated water was also observed. These results suggested that the extract from M. oleifera seeds in a low concentration (1 mg/L) can be an interesting natural alternative for removing humic acid from water in developing countries. The extract dose determined in the present study does not impart odour or colour to the treated water. PMID:22519089

  11. Study of inlet materials for sampling atmospheric nitric acid

    SciTech Connect

    Neuman, J.A.; Huey, L.G.; Ryerson, T.B.; Fahey, D.W. |

    1999-04-01

    The adsorption of nitric acid (HNO{sub 3}) from a flowing gas stream is studied for a variety of wall materials to determine their suitability for use in atmospheric sampling instruments. Parts per billion level mixtures of HNO{sub 3} in synthetic air flow through tubes of different materials such that >80% of the molecules interact with the walls. A chemical ionization mass spectrometer with a fast time response and high sensitivity detects HNO{sub 3} that is not adsorbed on the tube walls. Less than 5% of available HNO{sub 3} is adsorbed on Teflon fluoropolymer tubing after 1 min of HNO{sub 3} exposure, whereas >70% is lost on walls made of stainless steel, glass, fused silica, aluminum, nylon, silica-steel, and silane-coated glass. Glass tubes exposed to HNO{sub 3} on the order of hours passivate with HNO{sub 3} adsorption dropping to zero. The adsorption of HNO{sub 3} on PFA Teflon tubing (PFA) is nearly temperature-independent from 10 to 80 C, but below {minus}10 C nearly all HNO{sub 3} that interacts with PFA is reversibly adsorbed. In ambient and synthetic air, humidity increases HNO{sub 3} adsorption. The results suggest that Teflon at temperatures above 10 C is an optimal choice for inlet surfaces used for in situ measurements of HNO{sub 3} in the ambient atmosphere.

  12. Surface Cleaning Techniques: Ultra-Trace ICP-MS Sample Preparation and Assay of HDPE

    SciTech Connect

    Overman, Nicole R.; Hoppe, Eric W.; Addleman, Raymond S.

    2013-06-01

    The world’s most sensitive radiation detection and assay systems depend upon ultra-low background (ULB) materials to reduce unwanted radiological backgrounds. Herein, we evaluate methods to clean HDPE, a material of interest to ULB systems and the means to provide rapid assay of surface and bulk contamination. ULB level material and ultra-trace level detection of actinide elements is difficult to attain, due to the introduction of contamination from sample preparation equipment such as pipette tips, sample vials, forceps, etc. and airborne particulate. To date, literature available on the cleaning of such polymeric materials and equipment for ULB applications and ultra-trace analyses is limited. For these reasons, a study has been performed to identify an effective way to remove surface contamination from polymers in an effort to provide improved instrumental detection limits. Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) was utilized to assess the effectiveness of a variety of leachate solutions for removal of inorganic uranium and thorium surface contamination from polymers, specifically high density polyethylene (HDPE). HDPE leaching procedures were tested to optimize contaminant removal of thorium and uranium. Calibration curves for thorium and uranium ranged from 15 ppq (fg/mL) to 1 ppt (pg/mL). Detection limits were calculated at 6 ppq for uranium and 7 ppq for thorium. Results showed the most effective leaching reagent to be clean 6 M nitric acid for 72 hour exposures. Contamination levels for uranium and thorium found in the leachate solutions were significant for ultralow level radiation detection applications.

  13. TruSeq Stranded mRNA and Total RNA Sample Preparation Kits

    Cancer.gov

    Total RNA-Seq enabled by ribosomal RNA (rRNA) reduction is compatible with formalin-fixed paraffin embedded (FFPE) samples, which contain potentially critical biological information. The family of TruSeq Stranded Total RNA sample preparation kits provides a unique combination of unmatched data quality for both mRNA and whole-transcriptome analyses, robust interrogation of both standard and low-quality samples and workflows compatible with a wide range of study designs.

  14. Preparation of Highly Purified Stearidonic Acid from Echium Oil via an Enzymatic Method Combined with Preparative High Performance Liquid Chromatography.

    PubMed

    Baik, Ji Yeon; Kim, Nam Ho; Oh, Se-Wook; Kim, In-Hwan

    2015-01-01

    Stearidonic acid (SDA), an n-3 polyunsaturated fatty acid (PUFA), can be obtained from plant origin oils and it can be a good source of PUFA for vegetarians. SDA can be easily converted to longer PUFA such as docosahexaenoic acid and eicosapentaenoic acid. Highly purified stearidonic acid (SDA) was prepared successfully from echium oil via an enzymatic method combined with preparative high performance liquid chromatography. In the 1(st) step, SDA enrichment was accomplished using Candida rugosa lipase and 39.5% of SDA was obtained in the fatty acid fraction. Subsequently, the 1(st) reaction mixture was used for the 2(nd) enzymatic esterification without any separation process. The 2(nd) esterification was conducted for further SDA enrichment in a packed-bed reactor using Lipozyme RM IM from Rhizomucor miehei and the SDA content increased in a very short residence time. Ethanol was selected as an appropriate alcohol to react as an acyl receptor, and the other conditions for SDA enrichment were optimized at 20°C of temperature, and 1:4 of molar ratio (i.e., fatty acid to ethanol). Under these conditions, 51.6% of SDA was obtained in the fatty acid fraction after a residence time of 15 min. Finally, highly purified SDA (purity, >99%) was obtained by prep-HPLC using the SDA-rich fraction obtained from the two-step lipase-catalyzed esterification. PMID:25994555

  15. An efficient and cost-effective method for preparing transmission electron microscopy samples from powders

    SciTech Connect

    Wen, Haiming; Lin, Yaojun; Seidman, David N.; Schoenung, Julie M.; van Rooyen, Isabella J.; Lavernia, Enrique J.

    2015-09-09

    The preparation of transmission electron microcopy (TEM) samples from powders with particle sizes larger than ~100 nm poses a challenge. The existing methods are complicated and expensive, or have a low probability of success. Herein, we report a modified methodology for preparation of TEM samples from powders, which is efficient, cost-effective, and easy to perform. This method involves mixing powders with an epoxy on a piece of weighing paper, curing the powder–epoxy mixture to form a bulk material, grinding the bulk to obtain a thin foil, punching TEM discs from the foil, dimpling the discs, and ion milling the dimpled discs to electron transparency. Compared with the well established and robust grinding–dimpling–ion-milling method for TEM sample preparation for bulk materials, our modified approach for preparing TEM samples from powders only requires two additional simple steps. In this article, step-by-step procedures for our methodology are described in detail, and important strategies to ensure success are elucidated. Furthermore, our methodology has been applied successfully for preparing TEM samples with large thin areas and high quality for many different mechanically milled metallic powders.

  16. An efficient and cost-effective method for preparing transmission electron microscopy samples from powders

    DOE PAGESBeta

    Wen, Haiming; Lin, Yaojun; Seidman, David N.; Schoenung, Julie M.; van Rooyen, Isabella J.; Lavernia, Enrique J.

    2015-09-09

    The preparation of transmission electron microcopy (TEM) samples from powders with particle sizes larger than ~100 nm poses a challenge. The existing methods are complicated and expensive, or have a low probability of success. Herein, we report a modified methodology for preparation of TEM samples from powders, which is efficient, cost-effective, and easy to perform. This method involves mixing powders with an epoxy on a piece of weighing paper, curing the powder–epoxy mixture to form a bulk material, grinding the bulk to obtain a thin foil, punching TEM discs from the foil, dimpling the discs, and ion milling the dimpledmore » discs to electron transparency. Compared with the well established and robust grinding–dimpling–ion-milling method for TEM sample preparation for bulk materials, our modified approach for preparing TEM samples from powders only requires two additional simple steps. In this article, step-by-step procedures for our methodology are described in detail, and important strategies to ensure success are elucidated. Furthermore, our methodology has been applied successfully for preparing TEM samples with large thin areas and high quality for many different mechanically milled metallic powders.« less

  17. [Combined action of nitrofuran preparations and bile acids on staphylococci].

    PubMed

    Tkachuk, N I

    1984-03-01

    The effect of cholic, glycocholic and deoxycholic bile acids on the antimicrobial activity of furacin, furadonin, furagin and furoxone was studied with the use of collection strains and fresh isolates of staphylococci. The method of dilutions in liquid media was used. Cholic and glycocholic acids lowered the MIC of furacin, furadonin, furoxone and furagin with respect to the collection strains by 4-16, 5, 4-6 and 22-37 times, respectively. The potentiating effect of deoxycholic acid on the nitrofuran drugs was even more pronounced. Thus, when the nitrofurans were used in combination with deoxycholic acid, their MIC dropped by 16-114 times. A significant increase in the antimicrobial activity of the nitrofurans under the effect of the bile acids was also observed with respect to the fresh isolates of Staphylococcus, while it was somewhat lower. The subbacteriostatic doses of cholic, glycocholic and deoxycholic bile acids also increased the bactericidal effect of the nitrofuran drugs. The minimum bactericidal concentrations (MBC) of furacin, furoxone, furadonin and furagin decreased from 12.5, 2.08, 25.0 and 1.82 to 0.78, 0.26, 2.34 and 0.032 micrograms/ml, respectively. The most pronounced decrease in the MBC was observed under the effect of deoxycholic acid. Therefore, the bile acids potentiated the nitrofuran antistaphylococcal activity. The combinations of deoxycholic acid with furagin or furoxone were the most effective. PMID:6732204

  18. Practical preparation procedures for docetaxel-loaded nanoparticles using polylactic acid-co-glycolic acid

    PubMed Central

    Keum, Chang-Gu; Noh, Young-Wook; Baek, Jong-Suep; Lim, Ji-Ho; Hwang, Chan-Ju; Na, Young-Guk; Shin, Sang-Chul; Cho, Cheong-Weon

    2011-01-01

    Background Nanoparticles fabricated from the biodegradable and biocompatible polymer, polylactic-co-glycolic acid (PLGA), are the most intensively investigated polymers for drug delivery systems. The objective of this study was to explore fully the development of a PLGA nanoparticle drug delivery system for alternative preparation of a commercial formulation. In our nanoparticle fabrication, our purpose was to compare various preparation parameters. Methods Docetaxel-loaded PLGA nanoparticles were prepared by a single emulsion technique and solvent evaporation. The nanoparticles were characterized by various techniques, including scanning electron microscopy for surface morphology, dynamic light scattering for size and zeta potential, x-ray photoelectron spectroscopy for surface chemistry, and high-performance liquid chromatography for in vitro drug release kinetics. To obtain a smaller particle, 0.2% polyvinyl alcohol, 0.03% D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS), 2% Poloxamer 188, a five-minute sonication time, 130 W sonication power, evaporation with magnetic stirring, and centrifugation at 8000 rpm were selected. To increase encapsulation efficiency in the nanoparticles, certain factors were varied, ie, 2–5 minutes of sonication time, 70–130 W sonication power, and 5–25 mg drug loading. Results A five-minute sonication time, 130 W sonication power, and a 10 mg drug loading amount were selected. Under these conditions, the nanoparticles reached over 90% encapsulation efficiency. Release kinetics showed that 20.83%, 40.07%, and 51.5% of the docetaxel was released in 28 days from nanoparticles containing Poloxamer 188, TPGS, or polyvinyl alcohol, respectively. TPGS and Poloxamer 188 had slower release kinetics than polyvinyl alcohol. It was predicted that there was residual drug remaining on the surface from x-ray photoelectron spectroscopy. Conclusion Our research shows that the choice of surfactant is important for controlled release of

  19. Simultaneous determination of B-vitamins and ascorbic acid in multi-vitamin preparations by reversed-phase HPLC.

    PubMed

    Tee, E S; Khor, S

    1996-09-01

    The tedious and time consuming methods employed for the analysis of individual B-vitamins can now be replaced by ion-pair reversed-phase high-performance liquid chromatographic (HPLC) methods. This laboratory has previously reported the simultaneous determination of eight water-soluble vitamin standards that is, B1, B2, B6, B12, C, niacin, niacinamide and folic acid. The proposed isocratic HPLC method, employing 3 channels of detection, adequately separated all eight vitamins in less than 20 minutes. This study reports another phase of the project whereby the method was employed for the analysis of pharmaceutical preparations. Different extraction procedures were first evaluated, namely acid, acid plus enzyme and alkaline hydrolysis methods, using vitamin standards, individual vitamin tablets and multivitamin preparations. The amounts obtained from the analysis were compared with the declared values. Recovery studies were also carried out. The method of acid hydrolysis with 0.1N sulphuric acid was found suitable for use and was thus adopted as the extraction procedure for the analysis of 10 multivitamin preparations obtained from various pharmaceutical outlets. For most of these preparations, the amount obtained were close to the declared values, except for folic acid and cyanocobalamin. Further trials on folic acid showed that the problem could be resolved by omitting the filtration step in the final extract after acid hydrolysis and diluting with 0.01N sodium hydroxide before processing for chromatography. Vitamin B12 was not detectable using the present chromatography system probably because of its low concentration in the samples studied. PMID:22692140

  20. Field enhancement sample stacking for analysis of organic acids in traditional Chinese medicine by capillary electrophoresis.

    PubMed

    Zhu, Qianqian; Xu, Xueqin; Huang, Yuanyuan; Xu, Liangjun; Chen, Guonan

    2012-07-13

    A technique known as field enhancement sample stacking (FESS) and capillary electrophoresis (CE) separation has been developed to analyze and detect organic acids in the three traditional Chinese medicines (such as Portulaca oleracea L., Crataegus pinnatifida and Aloe vera L.). In FESS, a reverse electrode polarity-stacking mode (REPSM) was applied as on-line preconcentration strategy. Under the optimized condition, the baseline separation of eight organic acids (linolenic acid, lauric acid, p-coumaric acid, ascorbic acid, benzoic acid, caffeic acid, succinic acid and fumaric acid) could be achieved within 20 min. Validation parameters of this method (such as detection limits, linearity and precision) were also evaluated. The detection limits ranged from 0.4 to 60 ng/mL. The results indicated that the proposed method was effective for the separation of mixtures of organic acids. Satisfactory recoveries were also obtained in the analysis of these organic acids in the above traditional Chinese medicine samples. PMID:22381886

  1. Preparation of molecularly imprinted polymers based on magnetic nanoparticles for the selective extraction of protocatechuic acid from plant extracts.

    PubMed

    Xie, Xiaoyu; Wei, Fen; Chen, Liang; Wang, Sicen

    2015-03-01

    In this study, highly selective core-shell molecularly imprinted polymers on the surface of magnetic nanoparticles were prepared using protocatechuic acid as the template molecule. The resulting magnetic molecularly imprinted polymers were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and vibrating sample magnetometry. The binding performances of the prepared materials were evaluated by static and selective adsorption. The binding isotherms were obtained for protocatechuic acid and fitted by the Langmuir isotherm model and Freundlich isotherm model. Furthermore, the resulting materials were used as the solid-phase extraction materials coupled to high-performance liquid chromatography for the selective extraction and detection of protocatechuic acid from the extracts of Homalomena occulta and Cynomorium songaricum with the recoveries in the range 86.3-102.2%. PMID:25641806

  2. Optimizing Frozen Sample Preparation for Laser Microdissection: Assessment of CryoJane Tape-Transfer System®.

    PubMed

    Golubeva, Yelena G; Smith, Roberta M; Sternberg, Lawrence R

    2013-01-01

    Laser microdissection is an invaluable tool in medical research that facilitates collecting specific cell populations for molecular analysis. Diversity of research targets (e.g., cancerous and precancerous lesions in clinical and animal research, cell pellets, rodent embryos, etc.) and varied scientific objectives, however, present challenges toward establishing standard laser microdissection protocols. Sample preparation is crucial for quality RNA, DNA and protein retrieval, where it often determines the feasibility of a laser microdissection project. The majority of microdissection studies in clinical and animal model research are conducted on frozen tissues containing native nucleic acids, unmodified by fixation. However, the variable morphological quality of frozen sections from tissues containing fat, collagen or delicate cell structures can limit or prevent successful harvest of the desired cell population via laser dissection. The CryoJane Tape-Transfer System®, a commercial device that improves cryosectioning outcomes on glass slides has been reported superior for slide preparation and isolation of high quality osteocyte RNA (frozen bone) during laser dissection. Considering the reported advantages of CryoJane for laser dissection on glass slides, we asked whether the system could also work with the plastic membrane slides used by UV laser based microdissection instruments, as these are better suited for collection of larger target areas. In an attempt to optimize laser microdissection slide preparation for tissues of different RNA stability and cryosectioning difficulty, we evaluated the CryoJane system for use with both glass (laser capture microdissection) and membrane (laser cutting microdissection) slides. We have established a sample preparation protocol for glass and membrane slides including manual coating of membrane slides with CryoJane solutions, cryosectioning, slide staining and dissection procedure, lysis and RNA extraction that facilitated

  3. Two-in-one sample preparation for plan-view TEM.

    PubMed

    Sáfrán, György; Szász, Noémi; Sáfrán, Eszter

    2015-07-01

    Transmission electron microscopy (TEM) sample preparation requires special skills, it is time consuming and costly, hence, an increase of the efficiency is of primary importance. This article describes a method that duplicates the yield of the conventional mechanical and ion beam preparation of plan-view TEM samples. As a modification of the usual procedures, instead of one two different samples are comprised in a single specimen. The two pre-cut slabs, one from each samples, are embedded side by side in the window of a 3 mm dia Ti disk and the specimen is thinned mechanically and by ion milling until perforation that occurs at the interface of the two different slabs. That, with proper implementation, provides acceptable size thin area for the TEM study of both samples. The suitability of the two-in-one method has been confirmed through examples. PMID:25989619

  4. Stereochemistry of amino acids in surface samples of a marine sediment

    USGS Publications Warehouse

    Pollock, G.E.; Kvenvolden, K.A.

    1978-01-01

    In two surface samples of marine sediment, the percentages of d-alanine and d-aspartic acid are significantly higher than the other d-amino acids and are similar to the range found in soils. The percentage of d-glutamic acid is also higher than the other amino acids but less than d-alanine and d-aspartic acid. These d-amino acids may come mainly from bacteria. ?? 1978.

  5. Total Sample Conditioning and Preparation of Nanoliter Volumes for Electron Microscopy.

    PubMed

    Arnold, Stefan A; Albiez, Stefan; Opara, Nadia; Chami, Mohamed; Schmidli, Claudio; Bieri, Andrej; Padeste, Celestino; Stahlberg, Henning; Braun, Thomas

    2016-05-24

    Electron microscopy (EM) entered a new era with the emergence of direct electron detectors and new nanocrystal electron diffraction methods. However, sample preparation techniques have not progressed and still suffer from extensive blotting steps leading to a massive loss of sample. Here, we present a simple but versatile method for the almost lossless sample conditioning and preparation of nanoliter volumes of biological samples for EM, keeping the sample under close to physiological condition. A microcapillary is used to aspirate 3-5 nL of sample. The microcapillary tip is immersed into a reservoir of negative stain or trehalose, where the sample becomes conditioned by diffusive exchange of salt and heavy metal ions or sugar molecules, respectively, before it is deposited as a small spot onto an EM grid. We demonstrate the use of the method to prepare protein particles for imaging by transmission EM and nanocrystals for analysis by electron diffraction. Furthermore, the minute sample volume required for this method enables alternative strategies for biological experiments, such as the analysis of the content of a single cell by visual proteomics, fully exploiting the single molecule detection limit of EM. PMID:27074622

  6. Electric transport measurements on bulk, polycrystalline MgB2 samples prepared at various reaction temperatures

    NASA Astrophysics Data System (ADS)

    Wiederhold, A.; Koblischka, M. R.; Inoue, K.; Muralidhar, M.; Murakami, M.; Hartmann, U.

    2016-03-01

    A series of disk-shaped, bulk MgB2 superconductors (sample diameter up to 4 cm) was prepared in order to improve the performance for superconducting super-magnets. Several samples were fabricated using a solid state reaction in pure Ar atmosphere from 750 to 950oC in order to determine the optimum processing parameters to obtain the highest critical current density as well as large trapped field values. Additional samples were prepared with added silver (up to 10 wt.-%) to the Mg and B powder. Magneto-resistance data and I/V-characteristics were recorded using an Oxford Instruments Teslatron system. From Arrhenius plots, we determine the TAFF pinning potential, U 0. The I/V-characteristics yield detailed information on the current flow through the polycrystalline samples. The current flow is influenced by the presence of pores in the samples. Our analysis of the achieved critical currents together with a thorough microstructure investigation reveals that the samples prepared at temperatures between 775°C and 805°C exhibit the smallest grains and the best connectivity between them, while the samples fabricated at higher reaction temperatures show a reduced connectivity and lower pinning potential. Doping the samples with silver leads to a considerable increase of the pinning potential and hence, the critical current densities.

  7. A Proteomics Sample Preparation Method for Mature, Recalcitrant Leaves of Perennial Plants

    PubMed Central

    Na, Zhang; Chengying, Lao; Bo, Wang; Dingxiang, Peng; Lijun, Liu

    2014-01-01

    Sample preparation is key to the success of proteomics studies. In the present study, two sample preparation methods were tested for their suitability on the mature, recalcitrant leaves of six representative perennial plants (grape, plum, pear, peach, orange, and ramie). An improved sample preparation method was obtained: Tris and Triton X-100 were added together instead of CHAPS to the lysis buffer, and a 20% TCA-water solution and 100% precooled acetone were added after the protein extraction for the further purification of protein. This method effectively eliminates nonprotein impurities and obtains a clear two-dimensional gel electrophoresis array. The method facilitates the separation of high-molecular-weight proteins and increases the resolution of low-abundance proteins. This method provides a widely applicable and economically feasible technology for the proteomic study of the mature, recalcitrant leaves of perennial plants. PMID:25028960

  8. Optimal sample preparation to characterize corrosion in historical photographs with analytical TEM.

    PubMed

    Grieten, Eva; Caen, Joost; Schryvers, Dominique

    2014-10-01

    An alternative focused ion beam preparation method is used for sampling historical photographs containing metallic nanoparticles in a polymer matrix. We use the preparation steps of classical ultra-microtomy with an alternative final sectioning with a focused ion beam. Transmission electron microscopy techniques show that the lamella has a uniform thickness, which is an important factor for analytical transmission electron microscopy. Furthermore, the method maintains the spatial distribution of nanoparticles in the soft matrix. The results are compared with traditional preparation techniques such as ultra-microtomy and classical focused ion beam milling. PMID:25256650

  9. Methodological aspects of sample preparation for the determination of carbamate residues: a review.

    PubMed

    Santaladchaiyakit, Yanawath; Srijaranai, Supalax; Burakham, Rodjana

    2012-09-01

    This review covers recent developments in sample preparations and analytical techniques for determination of residues of carbamate pesticides. Special attention is paid to the newly established microextraction techniques, including cloud-point extraction, dispersive liquid-liquid microextraction, and ultrasound-assisted surfactant-enhanced emulsification microextraction. In addition, extractions using a variety of solvents, as well as miniaturized and on-line sample preparation systems, are discussed. Applications of the different methods for the determination of carbamate pesticide residues in food and environmental matrices are included. PMID:22997028

  10. Preparation and tribological properties of stearic acid-modified hierarchical anatase TiO 2 microcrystals

    NASA Astrophysics Data System (ADS)

    Qian, Jianhua; Yin, Xiangyu; Wang, Ning; Liu, Lin; Xing, Jinjuan

    2012-01-01

    Hierarchical TiO2 microcrystals were synthesized through a facile solvothermal method. X-ray diffraction (XRD) and scanning electron microscope (SEM) measurements were used to characterize the structure of the as-prepared samples. The results indicated that the synthesized hierarchical titania (TiO2) microspheres were composed of numerous anatase phase TiO2 particles. The as-prepared samples were chemically modified with stearic acid to improve their dispersion in oil. Fourier transmission infrared spectroscopy (FT-IR) and thermogravimetry analysis (TGA) were carried out to evaluate the characteristics of the modified TiO2 microcrystals. The tribological properties of the modified TiO2 microcrystals as additives of liquid paraffin were studied by a four-ball tester, and the results showed that they could significantly improve anti-wear performance, friction-reduction property and load-carrying capacity of liquid paraffin. These advantages make the modified TiO2 microcrystals promising for green lubricating oil additives.

  11. Rapid Quantification of Hepatitis B Virus DNA by Automated Sample Preparation and Real-Time PCR

    PubMed Central

    Stelzl, Evelyn; Muller, Zsofia; Marth, Egon; Kessler, Harald H.

    2004-01-01

    Monitoring of hepatitis B virus (HBV) DNA in serum by molecular methods has become the standard for assessment of the replicative activity of HBV. Several molecular assays for the detection and quantification of HBV DNA have been described. However, they usually lack automated sample preparation. Moreover, those assays, which are based on PCR, are limited by a short dynamic range (2 to 3 log units). In the present study, the use of RealArt HBV LC PCR Reagents in conjunction with automated extraction on the COBAS AMPLIPREP analyzer was evaluated. Members of an HBV proficiency program panel were tested; linearity, interassay, and intra-assay variations were determined. The performance of the assay in a routine clinical laboratory was evaluated with a total of 117 clinical specimens. When members of the HBV proficiency program panel were tested by the new molecular assay, the results were found to be within ±0.5 log unit of the results obtained by reference laboratories. Determination of linearity resulted in a quasilinear curve over more than 6 log units. The interassay variation of the RealArt HBV LC PCR Reagents by use of the automated sample preparation protocol ranged from 16 to 73%, and the intra-assay variation ranged from 9 to 40%. When clinical samples were tested by the new assay with the automated sample preparation protocol and the results were compared with those obtained by the COBAS AMPLICOR HBV MONITOR Test with manual sample preparation, the results for 76% of all samples with positive results by both tests were found to be within ±0.5 log unit and the results for another 18% were found to be within between 0.5 and 1.0 log unit. In conclusion, the real-time PCR assay with automated sample preparation proved to be suitable for the routine molecular laboratory and required less hands-on time. PMID:15184417

  12. Low-Cost 3D Printers Enable High-Quality and Automated Sample Preparation and Molecular Detection

    PubMed Central

    Chan, Kamfai; Coen, Mauricio; Hardick, Justin; Gaydos, Charlotte A.; Wong, Kah-Yat; Smith, Clayton; Wilson, Scott A.; Vayugundla, Siva Praneeth; Wong, Season

    2016-01-01

    Most molecular diagnostic assays require upfront sample preparation steps to isolate the target’s nucleic acids, followed by its amplification and detection using various nucleic acid amplification techniques. Because molecular diagnostic methods are generally rather difficult to perform manually without highly trained users, automated and integrated systems are highly desirable but too costly for use at point-of-care or low-resource settings. Here, we showcase the development of a low-cost and rapid nucleic acid isolation and amplification platform by modifying entry-level 3D printers that cost between $400 and $750. Our modifications consisted of replacing the extruder with a tip-comb attachment that houses magnets to conduct magnetic particle-based nucleic acid extraction. We then programmed the 3D printer to conduct motions that can perform high-quality extraction protocols. Up to 12 samples can be processed simultaneously in under 13 minutes and the efficiency of nucleic acid isolation matches well against gold-standard spin-column-based extraction technology. Additionally, we used the 3D printer’s heated bed to supply heat to perform water bath-based polymerase chain reactions (PCRs). Using another attachment to hold PCR tubes, the 3D printer was programmed to automate the process of shuttling PCR tubes between water baths. By eliminating the temperature ramping needed in most commercial thermal cyclers, the run time of a 35-cycle PCR protocol was shortened by 33%. This article demonstrates that for applications in resource-limited settings, expensive nucleic acid extraction devices and thermal cyclers that are used in many central laboratories can be potentially replaced by a device modified from inexpensive entry-level 3D printers. PMID:27362424

  13. Low-Cost 3D Printers Enable High-Quality and Automated Sample Preparation and Molecular Detection.

    PubMed

    Chan, Kamfai; Coen, Mauricio; Hardick, Justin; Gaydos, Charlotte A; Wong, Kah-Yat; Smith, Clayton; Wilson, Scott A; Vayugundla, Siva Praneeth; Wong, Season

    2016-01-01

    Most molecular diagnostic assays require upfront sample preparation steps to isolate the target's nucleic acids, followed by its amplification and detection using various nucleic acid amplification techniques. Because molecular diagnostic methods are generally rather difficult to perform manually without highly trained users, automated and integrated systems are highly desirable but too costly for use at point-of-care or low-resource settings. Here, we showcase the development of a low-cost and rapid nucleic acid isolation and amplification platform by modifying entry-level 3D printers that cost between $400 and $750. Our modifications consisted of replacing the extruder with a tip-comb attachment that houses magnets to conduct magnetic particle-based nucleic acid extraction. We then programmed the 3D printer to conduct motions that can perform high-quality extraction protocols. Up to 12 samples can be processed simultaneously in under 13 minutes and the efficiency of nucleic acid isolation matches well against gold-standard spin-column-based extraction technology. Additionally, we used the 3D printer's heated bed to supply heat to perform water bath-based polymerase chain reactions (PCRs). Using another attachment to hold PCR tubes, the 3D printer was programmed to automate the process of shuttling PCR tubes between water baths. By eliminating the temperature ramping needed in most commercial thermal cyclers, the run time of a 35-cycle PCR protocol was shortened by 33%. This article demonstrates that for applications in resource-limited settings, expensive nucleic acid extraction devices and thermal cyclers that are used in many central laboratories can be potentially replaced by a device modified from inexpensive entry-level 3D printers. PMID:27362424

  14. Instrument and method for X-ray diffraction, fluorescence, and crystal texture analysis without sample preparation

    NASA Technical Reports Server (NTRS)

    Gendreau, Keith (Inventor); Martins, Jose Vanderlei (Inventor); Arzoumanian, Zaven (Inventor)

    2010-01-01

    An X-ray diffraction and X-ray fluorescence instrument for analyzing samples having no sample preparation includes a X-ray source configured to output a collimated X-ray beam comprising a continuum spectrum of X-rays to a predetermined coordinate and a photon-counting X-ray imaging spectrometer disposed to receive X-rays output from an unprepared sample disposed at the predetermined coordinate upon exposure of the unprepared sample to the collimated X-ray beam. The X-ray source and the photon-counting X-ray imaging spectrometer are arranged in a reflection geometry relative to the predetermined coordinate.

  15. Evolution of the phase content of zirconia powders prepared by sol-gel acid hydrolysis

    SciTech Connect

    Rivas, P.C.; Martinez, J.A.; Caracoche, M.C.; Rodriguez, A.M.; Lopez Garcia, A.R.; Pavlik, R.S. Jr.; Klein, L.C.

    1998-01-01

    The evolution of the phase content in zirconia powders that have been prepared by sol-gel acid hydrolysis has been investigated using the perturbed-angular-correlation (PAC) technique and X-ray diffractometry. As a consequence of performing annealing treatments at increasing temperatures between room temperature and 1,000 C, the amorphous starting material transforms to the tetragonal form and then to the monoclinic form. The metastable tetragonal phase exhibits two hyperfine components, one of which describes very defective zirconium surroundings. The evolution of PAC relative fractions is in agreement with the diffraction results. The durability of the samples in sodium hydroxide seems to increase as the relative amount of the most-defective zirconium surroundings of the tetragonal form increases.

  16. Porous texture of activated carbons prepared by phosphoric acid activation of woods

    NASA Astrophysics Data System (ADS)

    Díaz-Díez, M. A.; Gómez-Serrano, V.; Fernández González, C.; Cuerda-Correa, E. M.; Macías-García, A.

    2004-11-01

    Activated carbons (ACs) have been prepared using chestnut, cedar and walnut wood shavings from furniture industries located in the Comunidad Autónoma de Extremadura (SW Spain). Phosphoric acid (H3PO4) at different concentrations (i.e. 36 and 85 wt.%) has been used as activating agent. ACs have been characterized from the results obtained by N2 adsorption at 77 K. Moreover, the fractal dimension (D) has been calculated in order to determine the AC surface roughness degree. Optimal textural properties of ACs have been obtained by chemical activation with H3PO4 36 wt.%. This is corroborated by the slightly lower values of D for samples treated with H3PO4 85 wt.%.

  17. Open focused microwave-assisted sample preparation for rapid total and mercury species determination in environmental solid samples.

    PubMed

    Tseng, C M; Garraud, H; Amouroux, D; Donard, O F; de Diego, A

    1998-01-01

    This paper describes rapid, simple microwave-assisted leaching/ digestion procedures for total and mercury species determination in sediment samples and biomaterials. An open focused microwave system allowed the sample preparation time to be dramatically reduced to only 24 min when a power of 40-80 W was applied. Quantitative leaching of methylmercury from sediments by HNO(3) solution and complete dissolution of biomaterials by an alkaline solution, such as 25% TMAH solution, were obtained. Methylmercury compounds were kept intact without decomposition or losses by evaporation. Quantitative recoveries of total mercury were achieved with a two-step microwave attack using a combination of HNO(3) and H(2)0(2) solutions as extractant. The whole pretreatment procedure only takes 15 min, which can be further shortened by an automated robust operation with an open focused system. These analytical procedures were validated by the analysis of environmental certified reference materials. The results confirm that the open focused microwave technique is a promising tool for solid sample preparation in analytical and environmental chemistry. PMID:18924826

  18. Fuel properties of heptadecene isomers prepared via tandem isomerization-decarboxylation of oleic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heptadecene isomers were prepared via tandem isomerization-decarboxylation of oleic acid using catalytic triruthenium dodecacarbonyl [Ru3(CO)12]. Chromatographic and spectroscopic characterization of the isolated heptadecene mixture indicated that it consisted of 96% internal isomers and 4% aromatic...

  19. Amino acid preservation in saline halite core samples: Analogs for Martian dry evaporitic regions

    NASA Astrophysics Data System (ADS)

    Bada, J.; Aubrey, A.; Lowenstein, T.; Timofeeff, M.

    2008-12-01

    in the deepest core section. This may indicate some recent amino acid contribution to the pool of certain amino acids. Racemization rates can be calculated from the equation: ln[(1+D/L)/(1-D/L)] - ln [(1+D/L)/(1-D/L)]t=0 = 2ki(time) where ki is the first-order rate constant for the interconversion of the enantiomers. Using the D/L ratios at the top of the core for the t = 0 term gives kasp = 3.5x10exp-5 y-1 and 1.3x10exp-5 y-1 for the 18 and 70 ka samples, respectively. For valine, the values are kval = 5.6x10exp-6 y-1 and 7.3x10exp-6 y-1. Extrapolating these values to the average surface temperatures on Mars indicates that the chirality of these amino acids would be preserved for billions of years. Thus, closed basin lacustrine and dry desert valley regions with evaporite-rich deposits are suitable environments in the search for preserved biosignatures on Mars. References [1] Bibring, J.P., et al., Science 307, 1576 (2005) [2] Klinghofer, G., et al., Science 306, 1740 (2004) [3] Osterloo, M.M., et al., Science 319, 1651 (2008) [4] Squyres, S.W., et al., Nature 443, E1 (2006) [5] Lowenstein, T.K., et al., Geology 27, 3 (1999) [6] Glavin, D., et al., Earth Planet. Sci. Lett. 185,1 (2001) [7] Aubrey, A. D., et al., in preparation, Nature Geo. Sci.

  20. SRAT CHEMISTRY AND ACID CONSUMPTION DURING SIMULATED DWPF MELTER FEED PREPARATION

    SciTech Connect

    Koopman, D; David Best, D; Bradley Pickenheim, B

    2008-12-03

    Due to higher than expected hydrogen generation during the Tank 51-Sludge Batch 4 (SB4) qualification run, DWPF engineering requested the Savannah River National Laboratory (SRNL) to expand the ongoing catalytic hydrogen generation program. The work presented in this Technical Report was identified as part of SRNL/Liquid Waste Organization (LWO) meetings to define potential causes of catalytic hydrogen generation as well as from an external technical review panel commissioned to evaluate SRNL hydrogen related data and programs. New scope included improving the understanding of SRAT/SME process chemistry, particularly as it related to acid consumption and hydrogen generation. The expanded hydrogen program scope was covered under the technical task request (TTR): HLW-DWPF-TTR-2007-0016. A task technical and quality assurance plan (TT&QAP) was issued to cover focus areas raised in meetings with LWO plus a portion of the recommendations made by the review panel. A supporting analytical study plan was issued. It was also noted in the review of catalytic hydrogen generation that control of the DWPF acid stoichiometry was an important element in controlling hydrogen generation. A separate TTR was issued to investigate ways of improving the determination of the acid requirement during processing: HLWDWPF-TTR-0015. A separate TT&QAP was prepared for this task request. This report discusses some progress on this task related to developing alternative acid equations and to performing experimental work to supplement the existing database. Simulant preparation and preliminary flowsheet studies were already documented. The prior work produced a sufficient quantity of simulant for the hydrogen program and melter feed rheology testing. It also defined a suitable acid addition stoichiometry. The results presented in this report come from samples and process data obtained during sixteen 22-L SRAT/SME simulations that were performed in the second half of 2007 to produce eight SME

  1. Development and Evaluation of a Micro- and Nanoscale Proteomic Sample Preparation Method

    SciTech Connect

    Wang, Haixing H.; Qian, Weijun; Mottaz, Heather M.; Clauss, Therese R.W.; Anderson, David J.; Moore, Ronald J.; Camp, David G.; Khan, Arshad H.; Sforza, Daniel M.; Pallavicini, Maria; Smith, Desmond J.; Smith, Richard D.

    2005-10-05

    Efficient and effective sample preparation of micro- and nano-scale (micro- and nano-gram) clinical specimens for proteomic applications is often difficult due to losses during the processing steps. Herein we describe a simple “single-tube” preparation protocol appropriate for small proteomic samples using the organic co-solvent, trifluoroethanol (TFE). TFE facilitates both protein extraction and protein denaturation without requiring a separate cleanup step, thus minimizing sample loss. The performance of the TFE method was initially evaluated by comparing to traditional detergent-based methods on relatively large scale sample processing using human breast cancer cells and mouse brain tissue. The results demonstrated that the TFE protocol provided comparable results to the traditional detergent-based protocols for larger samples (milligrams), based on both sample recovery and peptide/protein identification. The effectiveness of this protocol for micro- and nano-scale sample processing was then evaluated for the extraction of proteins/peptides and shown effective for small mouse brain tissue samples (~ 20 μg total protein content) and also for samples of ~ 5 000 human breast cancer MCF-7 cells (~ 500 ng total protein content), where the detergent-based methods were ineffective due to losses during cleanup and transfer steps.

  2. Sequential injection titration method using second-order signals: determination of acidity in plant oils and biodiesel samples.

    PubMed

    del Río, Vanessa; Larrechi, M Soledad; Callao, M Pilar

    2010-06-15

    A new concept of flow titration is proposed and demonstrated for the determination of total acidity in plant oils and biodiesel. We use sequential injection analysis (SIA) with a diode array spectrophotometric detector linked to chemometric tools such as multivariate curve resolution-alternating least squares (MCR-ALS). This system is based on the evolution of the basic specie of an acid-base indicator, alizarine, when it comes into contact with a sample that contains free fatty acids. The gradual pH change in the reactor coil due to diffusion and reaction phenomenona allows the sequential appearance of both species of the indicator in the detector coil, recording a data matrix for each sample. The SIA-MCR-ALS method helps to reduce the amounts of sample, the reagents and the time consumed. Each determination consumes 0.413ml of sample, 0.250ml of indicator and 3ml of carrier (ethanol) and generates 3.333ml of waste. The frequency of the analysis is high (12 samples h(-1) including all steps, i.e., cleaning, preparing and analysing). The utilized reagents are of common use in the laboratory and it is not necessary to use the reagents of perfect known concentration. The method was applied to determine acidity in plant oil and biodiesel samples. Results obtained by the proposed method compare well with those obtained by the official European Community method that is time consuming and uses large amounts of organic solvents. PMID:20441941

  3. Electrodeposition as an alternate method for preparation of environmental samples for iodide by AMS

    DOE PAGESBeta

    Adamic, M. L.; Lister, T. E.; Dufek, E. J.; Jenson, D. D.; Olson, J. E.; Vockenhuber, C.; Watrous, M. G.

    2015-03-25

    This paper presents an evaluation of an alternate method for preparing environmental samples for 129I analysis by accelerator mass spectrometry (AMS) at Idaho National Laboratory. The optimal sample preparation method is characterized by ease of preparation, capability of processing very small quantities of iodide, and ease of loading into a cathode. Electrodeposition of iodide on a silver wire was evaluated using these criteria. This study indicates that the electrochemically-formed silver iodide deposits produce ion currents similar to those from precipitated silver iodide for the same sample mass. Furthermore, precipitated silver iodide samples are usually mixed with niobium or silver powdermore » prior to loading in a cathode. Using electrodeposition, the silver is already mixed with the sample and can simply be picked up with tweezers, placed in the sample die, and pressed into a cathode. The major advantage of this method is that the silver wire/electrodeposited silver iodide is much easier to load into a cathode.« less

  4. Sample collection and preparation methods affecting mutagenicity and cytotoxicity of coal fly ash

    SciTech Connect

    Mumford, J.; Lewtas, J.

    1983-07-01

    Reports by several investigators describing the biological activity of coal fly ash have presented a variety of results which in some cases are conflicting. The biological activity of coal fly ash may differ because of one or more of the following factors: (1) the samples studied were from different sources; (2) the samples were prepared for bioassay differently; (3) the sampling method differed, and, therefore, collected samples were different in chemical or physical properties which affect the biological activity. Several variables involved in coal fly ash studies -- source, sample collection land preparation methods, bioassay method -- are undoubtedly responsible for the diversity of biological effects observed. The objectives of this study were to examine the sample preparation and collection factors which may affect the observed biological activity caused by coal fly ash and to evaluate the mutagenicity and cytotoxicity of fluidized-bed combustion (FBC) fly ash from experimental and commercial units. The bioassays used in this study were the Ames Salmonella plate incorporation test for mutagenicity and the rabbit alveolar macrophage (RAM) system for cytotoxicity.

  5. The influence of target preparation and mode of irradiation on PIXE analysis of biological samples

    NASA Astrophysics Data System (ADS)

    Galuszka, Janusz; Jarczyk, Lucjan; Rokita, Eugeniusz; Strzalkowski, Adam; Sych, Marek

    1984-04-01

    The following methods of target preparation were examined and compared: dry ashing at high temperature, low temperature ashing in plasma asher, wet ashing, lyophilization at a temperature of 35°C, cryofixation with drying in vacuum and dehydration in alcohol with drying in vacuum. All these techniques were applied to prepare targets from five different rat organs: liver, kidney, brain, lung and muscle tissue. The dried and powdered sample material was pressed into pellets or was distributed on formvar film. The evaporation of the thin carbon layer on the investigated target and placing of the thin carbon film in front of a target were also tested. The targets were irradiated in vacuum using an external beam in the air chamber. The influence of the method of target preparation on the detection limits, time requirements and escape of elements from the sample material is discussed.

  6. QuEChERS sample preparation approach for mass spectrometric analysis of pesticide residues in foods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter describes an easy, rapid, and low-cost sample preparation approach for the determination of pesticide residues in foods using gas and/or liquid chromatographic (GC and/or LC) analytical separation and mass spectrometric (MS) detection. The approach is known as QuEChERS, which stands fo...

  7. 40 CFR 205.160-2 - Test sample selection and preparation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Test sample selection and preparation. 205.160-2 Section 205.160-2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.160-2...

  8. 40 CFR 205.160-2 - Test sample selection and preparation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Test sample selection and preparation. 205.160-2 Section 205.160-2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.160-2...

  9. 40 CFR 205.160-2 - Test sample selection and preparation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Test sample selection and preparation. 205.160-2 Section 205.160-2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.160-2...

  10. 9 CFR 147.8 - Procedures for preparing egg yolk samples for diagnostic tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Procedures for preparing egg yolk samples for diagnostic tests. 147.8 Section 147.8 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE LIVESTOCK IMPROVEMENT AUXILIARY PROVISIONS ON NATIONAL...

  11. 9 CFR 147.8 - Procedures for preparing egg yolk samples for diagnostic tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Procedures for preparing egg yolk samples for diagnostic tests. 147.8 Section 147.8 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE LIVESTOCK IMPROVEMENT AUXILIARY PROVISIONS ON NATIONAL...

  12. Standardized Sample Preparation Using a Drop-on-Demand Printing Platform

    PubMed Central

    Holthoff, Ellen L.; Farrell, Mikella E.; Pellegrino, Paul M.

    2013-01-01

    Hazard detection systems must be evaluated with appropriate test material concentrations under controlled conditions in order to accurately identify and quantify unknown residues commonly utilized in theater. The existing assortment of hazard reference sample preparation methods/techniques presents a range of variability and reproducibility concerns, making it increasingly difficult to accurately assess optically- based detection technologies. To overcome these challenges, we examined the optimization, characterization, and calibration of microdroplets from a drop-on-demand microdispenser that has a proven capability for the preparation of energetic reference materials. Research presented herein focuses on the development of a simplistic instrument calibration technique and sample preparation protocol for explosive materials testing based on drop-on-demand technology. Droplet mass and reproducibility were measured using ultraviolet-visible (UV-Vis) absorption spectroscopy. The results presented here demonstrate the operational factors that influence droplet dispensing for specific materials (e.g., energetic and interferents). Understanding these parameters permits the determination of droplet and sample uniformity and reproducibility (typical R2 values of 0.991, relative standard deviation or RSD ≤ 5%), and thus the demonstrated maturation of a successful and robust methodology for energetic sample preparation. PMID:23653050

  13. Soil and Water – What is Detectable through Microbiological Sample Preparation Techniques

    EPA Science Inventory

    The concerns of a potential terrorist’s use of biological agents in soil and ground water are articulated by comparisons to major illnesses in this Country involving contaminated drinking water sources. Objectives are focused on the importance of sample preparation in the rapid, ...

  14. SAMPLING ARTIFACT ESTIMATES FOR ALKANES, HOPANES, AND ALIPHATIC CARBOXYLIC ACIDS

    EPA Science Inventory

    Sampling artifacts for molecular markers from organic speciation of particulate matter were investigated by analyzing forty-one samples collected in Philadelphia as a part of the Northeast Oxidant and Particulate Study (NEOPS). Samples were collected using a high volume sampler ...

  15. Capillary electrophoresis analysis of organic amines and amino acids in saline and acidic samples using the Mars organic analyzer.

    PubMed

    Stockton, Amanda M; Chiesl, Thomas N; Lowenstein, Tim K; Amashukeli, Xenia; Grunthaner, Frank; Mathies, Richard A

    2009-11-01

    The Mars Organic Analyzer (MOA) has enabled the sensitive detection of amino acid and amine biomarkers in laboratory standards and in a variety of field sample tests. However, the MOA is challenged when samples are extremely acidic and saline or contain polyvalent cations. Here, we have optimized the MOA analysis, sample labeling, and sample dilution buffers to handle such challenging samples more robustly. Higher ionic strength buffer systems with pK(a) values near pH 9 were developed to provide better buffering capacity and salt tolerance. The addition of ethylaminediaminetetraacetic acid (EDTA) ameliorates the negative effects of multivalent cations. The optimized protocol utilizes a 75 mM borate buffer (pH 9.5) for Pacific Blue labeling of amines and amino acids. After labeling, 50 mM (final concentration) EDTA is added to samples containing divalent cations to ameliorate their effects. This optimized protocol was used to successfully analyze amino acids in a saturated brine sample from Saline Valley, California, and a subcritical water extract of a highly acidic sample from the Río Tinto, Spain. This work expands the analytical capabilities of the MOA and increases its sensitivity and robustness for samples from extraterrestrial environments that may exhibit pH and salt extremes as well as metal ions. PMID:19968460

  16. Preparative two-dimensional liquid chromatography/mass spectrometry for the purification of complex pharmaceutical samples.

    PubMed

    Zhang, Yinong; Zeng, Lu; Pham, Catherine; Xu, Rongda

    2014-01-10

    A new preparative two-dimensional liquid chromatography/mass spectrometry system (2D LC-LC/MS) has been designed and implemented to enhance capability and resolving power for the separation and purification of pharmaceutical samples. The system was constructed by modifications of a conventional preparative LC/MS instrument with the addition of a set of switching valves and a sample loop, as well as interfacing a custom software program with MassLynx. The system integrates two chromatographic separations from the first and second dimensions into a single automated run to perform the purification of a target compound from a complex mixture without intermediate steps of sample preparation. The chromatography in the first dimension, operated in the heart-cutting mode, separates the target compound from the impurities by mass-triggered fractionation based on its molecular weight. This purified fraction from the first dimension is stored in the sample loop, and then gets transferred to the second column by using at-column dilution. A control software program, coined Prep 2D LCMS, was designed to integrate with MassLynx to retrieve data acquisition status. All of the chromatographic hardware components used in this preparative 2D LC-LC/MS system are from the original open access preparative LC/MS system, which has high level of robustness and affords easy and user-friendly operation. The new system is very versatile and capable of collecting multiple fractions with different masses under various purification modes as configured in the methods, such as conventional one-dimensional (1D) purification and/or 2D purification. This new preparative 2D LC-LC/MS system is therefore the ideal tool for medicinal chemistry lab in drug discovery environment. PMID:24309715

  17. Preparation of 4-amino-2,4-dioxobutanoic acid

    DOEpatents

    Unkefer, Pat J.; Martinez, Rodolfo A.; Glass, David R.

    2015-06-02

    A process for synthesizing 4-amino-2,4-dioxobutanoic acid involves reacting diethyl oxalate with sodium ethoxide in ethanol to form a reaction mixture, and afterward adding ethyl cyanoacetate to the reaction mixture and allowing a reaction to proceed under conditions suitable to form a first reaction product of the formula diethyl-2-cyano-3-hydroxy-butenedioate, and then isolating the diethyl-2-cyano-3-hydroxybutenedioate, and afterward reacting the diethyl-2-cyano-3-hydroxy-butenedioate with aqueous sodium hydroxide under conditions suitable to form 4-amino-2,4-dioxobutanoic acid.

  18. Preparation of 4-amino-2,4-dioxobutanoic acid

    DOEpatents

    Unkefer, Pat J.; Martinez, Rodolfo A.; Glass, David R.

    2016-03-22

    A process for synthesizing 4-amino-2,4-dioxobutanoic acid involves reacting diethyl oxalate with an alkoxide in ethanol to form a reaction mixture, and afterward adding ethyl cyanoacetate to the reaction mixture and allowing a reaction to proceed under conditions suitable to form a first reaction product of the formula diethyl 2-cyano-3-hydroxy-butenedioate, and then isolating the diethyl 2-cyano-3-hydroxy-butenedioate, and afterward reacting the diethyl-2-cyano-3-hydroxy-butenedioate with an aqueous hydroxide under conditions suitable to form 4-amino-2,4-dioxobutanoic acid.

  19. Automated sample preparation for radiogenic and non-traditional metal isotope analysis by MC-ICP-MS

    NASA Astrophysics Data System (ADS)

    Field, M. P.; Romaniello, S. J.; Gordon, G. W.; Anbar, A. D.

    2012-12-01

    High throughput analysis is becoming increasingly important for many applications of radiogenic and non-traditional metal isotopes. While MC-ICP-MS instruments offer the potential for very high sample throughout, the requirement for labor-intensive sample preparation and purification procedures remains a substantial bottleneck. Current purification protocols require manually feeding gravity-driven separation columns, a process that is both costly and time consuming. This bottleneck is eliminated with the prepFAST-MC™, an automated, low-pressure ion exchange chromatography system that can process from 1 to 60 samples in unattended operation. The syringe-driven system allows sample loading, multiple acid washes, column conditioning and elution cycles necessary to isolate elements of interest and automatically collect up to 3 discrete eluent fractions at user-defined intervals (time, volume and flow rate). Newly developed protocols for automated purification of uranium illustrates high throughput (>30 per run), multiple samples processed per column (>30), complete (>99%) matrix removal, high recovery (> 98%, n=25), and excellent precision (2 sigma =0.03 permil, n=10). The prepFAST-MC™ maximizes sample throughput and minimizes costs associated with personnel and consumables providing an opportunity to greatly expand research horizons in fields where large isotopic data sets are required, including archeology, geochemistry, and climate/environmental science

  20. Advancement of Solidification Processing Technology Through Real Time X-Ray Transmission Microscopy: Sample Preparation

    NASA Technical Reports Server (NTRS)

    Stefanescu, D. M.; Curreri, P. A.

    1996-01-01

    Two types of samples were prepared for the real time X-ray transmission microscopy (XTM) characterization. In the first series directional solidification experiments were carried out to evaluate the critical velocity of engulfment of zirconia particles in the Al and Al-Ni eutectic matrix under ground (l-g) conditions. The particle distribution in the samples was recorded on video before and after the samples were directionally solidified. In the second series samples of the above two type of composites were prepared for directional solidification runs to be carried out on the Advanced Gradient Heating Facility (AGHF) aboard the space shuttle during the LMS mission in June 1996. X-ray microscopy proved to be an invaluable tool for characterizing the particle distribution in the metal matrix samples. This kind of analysis helped in determining accurately the critical velocity of engulfment of ceramic particles by the melt interface in the opaque metal matrix composites. The quality of the cast samples with respect to porosity and instrumented thermocouple sheath breakage or shift could be easily viewed and thus helped in selecting samples for the space shuttle experiments. Summarizing the merits of this technique it can be stated that this technique enabled the use of cast metal matrix composite samples since the particle location was known prior to the experiment.

  1. Gas-Assisted Annular Microsprayer for Sample Preparation for Time-Resolved Cryo-Electron Microscopy

    PubMed Central

    Lu, Zonghuan; Barnard, David; Shaikh, Tanvir R.; Meng, Xing; Mannella, Carmen A.; Yassin, Aymen; Agrawal, Rajendra; Wagenknecht, Terence; Lu, Toh-Ming

    2014-01-01

    Time-resolved cryo electron microscopy (TRCEM) has emerged as a powerful technique for transient structural characterization of isolated biomacromolecular complexes in their native state within the time scale of seconds to milliseconds. For TRCEM sample preparation, microfluidic device [9] has been demonstrated to be a promising approach to facilitate TRCEM biological sample preparation. It is capable of achieving rapidly aqueous sample mixing, controlled reaction incubation, and sample deposition on electron microscopy (EM) grids for rapid freezing. One of the critical challenges is to transfer samples to cryo-EM grids from the microfluidic device. By using microspraying method, the generated droplet size needs to be controlled to facilitate the thin ice film formation on the grid surface for efficient data collection, while not too thin to be dried out before freezing, i.e., optimized mean droplet size needs to be achieved. In this work, we developed a novel monolithic three dimensional (3D) annular gas-assisted microfluidic sprayer using 3D MEMS (MicroElectroMechanical System) fabrication techniques. The microsprayer demonstrated dense and consistent microsprays with average droplet size between 6-9 μm, which fulfilled the above droplet size requirement for TRCEM sample preparation. With droplet density of around 12-18 per grid window (window size is 58×58 μm), and the data collectible thin ice region of >50% total wetted area, we collected ~800-1000 high quality CCD micrographs in a 6-8 hour period of continuous effort. This level of output is comparable to what were routinely achieved using cryo-grids prepared by conventional blotting and manual data collection. In this case, weeks of data collection process with the previous device [9] has shortened to a day or two. And hundreds of microliter of valuable sample consumption can be reduced to only a small fraction. PMID:25530679

  2. Analytical electron microscopy of a crack tip extracted from a stressed Alloy 800 sample exposed to an acid sulfate environment.

    PubMed

    Persaud, S Y; Carcea, A G; Huang, J; Korinek, A; Botton, G A; Newman, R C

    2014-06-01

    Alloy 800 (Fe-21Cr-33Ni) has been found susceptible to cracking in acid sulfate environments, but the mechanism is not well understood. Alloy 800 C-ring samples were exposed to an acid sulfate environment at 315°C and cracks were found with depths in excess of 300μm after 60h. Preparation of a TEM sample containing crack tips is challenging, but the ability to perform high-resolution microscopy at the crack tip would lend insight to the mechanism of acid sulfate stress corrosion cracking (AcSCC). The lift-out technique combined with a focused ion beam sample preparation was used to extract a crack tip along the cross-section of an acid sulfate crack in an Alloy 800 C-ring. TEM elemental analysis was done using EDS and EELS which identified a duplex oxide within the crack; an inner oxide consisting of a thin 3-4nm Cr-rich oxide and an outer oxide enriched in Fe and Cr. Preliminary conclusions and hypotheses resulted with respect to the mechanism of AcSCC in Alloy 800. PMID:24792448

  3. Challenges of biological sample preparation for SIMS imaging of elements and molecules at subcellular resolution

    NASA Astrophysics Data System (ADS)

    Chandra, Subhash

    2008-12-01

    Secondary ion mass spectrometry (SIMS) based imaging techniques capable of subcellular resolution characterization of elements and molecules are becoming valuable tools in many areas of biology and medicine. Due to high vacuum requirements of SIMS, the live cells cannot be analyzed directly in the instrument. The sample preparation, therefore, plays a critical role in preserving the native chemical composition for SIMS analysis. This work focuses on the evaluation of frozen-hydrated and frozen freeze-dried sample preparations for SIMS studies of cultured cells with a CAMECA IMS-3f dynamic SIMS ion microscope instrument capable of producing SIMS images with a spatial resolution of 500 nm. The sandwich freeze-fracture method was used for fracturing the cells. The complimentary fracture planes in the plasma membrane were characterized by field-emission secondary electron microscopy (FESEM) in the frozen-hydrated state. The cells fractured at the dorsal surface were used for SIMS analysis. The frozen-hydrated SIMS analysis of individual cells under dynamic primary ion beam (O 2+) revealed local secondary ion signal enhancements correlated with the water image signals of 19(H 3O) +. A preferential removal of water from the frozen cell matrix in the Z-axis was also observed. These complications render the frozen-hydrated sample type less desirable for subcellular dynamic SIMS studies. The freeze-drying of frozen-hydrated cells, either inside the instrument or externally in a freeze-drier, allowed SIMS imaging of subcellular chemical composition. Morphological evaluations of fractured freeze-dried cells with SEM and confocal laser scanning microscopy (CLSM) revealed well-preserved mitochondria, Golgi apparatus, and stress fibers. SIMS analysis of fractured freeze-dried cells revealed well-preserved chemical composition of even the most highly diffusible ions like K + and Na + in physiologically relevant concentrations. The high K-low Na signature in individual cells

  4. Gel-aided sample preparation (GASP)--a simplified method for gel-assisted proteomic sample generation from protein extracts and intact cells.

    PubMed

    Fischer, Roman; Kessler, Benedikt M

    2015-04-01

    We describe a "gel-assisted" proteomic sample preparation method for MS analysis. Solubilized protein extracts or intact cells are copolymerized with acrylamide, facilitating denaturation, reduction, quantitative cysteine alkylation, and matrix formation. Gel-aided sample preparation has been optimized to be highly flexible, scalable, and to allow reproducible sample generation from 50 cells to milligrams of protein extracts. This methodology is fast, sensitive, easy-to-use on a wide range of sample types, and accessible to nonspecialists. PMID:25515006

  5. Community-Level Physiological Profiling of Microbial Communities in Constructed Wetlands: Effects of Sample Preparation.

    PubMed

    Button, Mark; Weber, Kela; Nivala, Jaime; Aubron, Thomas; Müller, Roland Arno

    2016-03-01

    Community-level physiological profiling (CLPP) using BIOLOG® EcoPlates™ has become a popular method for characterizing and comparing the functional diversity, functional potential, and metabolic activity of heterotrophic microbial communities. The method was originally developed for profiling soil communities; however, its usage has expanded into the fields of ecotoxicology, agronomy, and the monitoring and profiling of microbial communities in various wastewater treatment systems, including constructed wetlands for water pollution control. When performing CLPP on aqueous samples from constructed wetlands, a wide variety of sample characteristics can be encountered and challenges may arise due to excessive solids, color, or turbidity. The aim of this study was to investigate the impacts of different sample preparation methods on CLPP performed on a variety of aqueous samples covering a broad range of physical and chemical characteristics. The results show that using filter paper, centrifugation, or settling helped clarify samples for subsequent CLPP analysis, however did not do so as effectively as dilution for the darkest samples. Dilution was able to provide suitable clarity for the darkest samples; however, 100-fold dilution significantly affected the carbon source utilization patterns (CSUPs), particularly with samples that were already partially or fully clear. Ten-fold dilution also had some effect on the CSUPs of samples which were originally clear; however, the effect was minimal. Based on these findings, for this specific set of samples, a 10-fold dilution provided a good balance between ease of use, sufficient clarity (for dark samples), and limited effect on CSUPs. The process and findings outlined here can hopefully serve future studies looking to utilize CLPP for functional analysis of microbial communities and also assist in comparing data from studies where different sample preparation methods were utilized. PMID:26563413

  6. Preparation of Saturated and Unsaturated Fatty Acid Hydrazides and Long Chain C-glycoside Ketohydrazones

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method is described to prepare both saturated and unsaturated fatty acid acyl hydrazides using lipase as a catalyst. Hydrazides were generated from fatty acid methyl esters as well as directly from vegetable oils, and an organic co-solvent was not needed to maintain the integrity of the unsaturat...

  7. Preparation of Oriented, Fully Hydrated Lipid Samples for Structure Determination Using X-Ray Scattering

    PubMed Central

    Tristram-Nagle, Stephanie A.

    2009-01-01

    Summary This chapter describes a method of sample preparation called “the rock and roll method,” which is basically a solvent evaporation technique with controlled manual sample movement during evaporation of solvent from lipid/solvent mixtures that produces well-oriented thick stacks of about 2000 lipid bilayers. Many lipid types have been oriented using different solvent mixtures that balance solubilization of the lipid with uniform deposition of the lipid solution onto solid substrates. These well-oriented thick stacks are then ideal samples for collection of both X-ray diffraction data in the gel phase and X-ray diffuse scattering data in the fluid phase of lipids. The degree of orientation is determined using visual inspection, polarizing microscopy, and a mosaic spread X-ray experiment. Atomic force microscopy is used to compare samples prepared using the rock and roll method with those prepared by spin-coating, which produces well-oriented but less homogeneous lipid stacks. These samples can be fully hydrated through the vapor provided that the hydration chamber has excellent temperature and humidity control. PMID:17951727

  8. Preparation of oriented, fully hydrated lipid samples for structure determination using X-ray scattering.

    PubMed

    Tristram-Nagle, Stephanie A

    2007-01-01

    This chapter describes a method of sample preparation called "the rock and roll method," which is basically a solvent evaporation technique with controlled manual sample movement during evaporation of solvent from lipid/solvent mixtures that produces well-oriented thick stacks of about 2000 lipid bilayers. Many lipid types have been oriented using different solvent mixtures that balance solubilization of the lipid with uniform deposition of the lipid solution onto solid substrates. These well-oriented thick stacks are then ideal samples for collection of both X-ray diffraction data in the gel phase and X-ray diffuse scattering data in the fluid phase of lipids. The degree of orientation is determined using visual inspection, polarizing microscopy, and a mosaic spread X-ray experiment. Atomic force microscopy is used to compare samples prepared using the rock and roll method with those prepared by spin-coating, which produces well-oriented but less homogeneous lipid stacks. These samples can be fully hydrated through the vapor provided that the hydration chamber has excellent temperature and humidity control. PMID:17951727

  9. Applied Focused Ion Beam Techniques for Sample Preparation of Astromaterials for Integrated Nano-Analysis

    SciTech Connect

    Graham, G A; Teslich, N E; Kearsley, A T; Stadermann, F J; Stroud, R M; Dai, Z R; Ishii, H A; Hutcheon, I D; Bajt, S; Snead, C J; Weber, P K; Bradley, J P

    2007-02-20

    Sample preparation is always a critical step in study of micrometer sized astromaterials available for study in the laboratory, whether their subsequent analysis is by electron microscopy or secondary ion mass spectrometry. A focused beam of gallium ions has been used to prepare electron transparent sections from an interplanetary dust particle, as part of an integrated analysis protocol to maximize the mineralogical, elemental, isotopic and spectroscopic information extracted from one individual particle. In addition, focused ion beam techniques have been employed to extract cometary residue preserved on the rims and walls of micro-craters in 1100 series aluminum foils that were wrapped around the sample tray assembly on the Stardust cometary sample collector. Non-ideal surface geometries and inconveniently located regions of interest required creative solutions. These include support pillar construction and relocation of a significant portion of sample to access a region of interest. Serial sectioning, in a manner similar to ultramicrotomy, is a significant development and further demonstrates the unique capabilities of focused ion beam microscopy for sample preparation of astromaterials.

  10. Sample Preparation for Fungal Community Analysis by High-Throughput Sequencing of Barcode Amplicons.

    PubMed

    Clemmensen, Karina Engelbrecht; Ihrmark, Katarina; Durling, Mikael Brandström; Lindahl, Björn D

    2016-01-01

    Fungal species participate in vast numbers of processes in the landscape around us. However, their often cryptic growth, inside various substrates and in highly diverse species assemblages, has been a major obstacle to thorough analysis of fungal communities, hampering exhaustive description of the fungal kingdom. Recent technological developments allowing rapid, high-throughput sequencing of mixed communities from many samples at once are currently having a tremendous impact in fungal community ecology. Universal DNA extraction followed by amplification and sequencing of fungal species-level barcodes such as the nuclear internal transcribed spacer (ITS) region now enable identification and relative quantification of fungal community members across well-replicated experimental settings. Here, we present the sample preparation procedure presently used in our laboratory for fungal community analysis by high-throughput sequencing of amplified ITS2 markers. We focus on the procedure optimized for studies of total fungal communities in humus-rich soils, wood, and litter. However, this procedure can be applied to other sample types and markers. We focus on the laboratory-based part of sample preparation, that is, the procedure from the point where samples enter the laboratory until amplicons are submitted for sequencing. Our procedure comprises four main parts: (1) universal DNA extraction, (2) optimization of PCR conditions, (3) production of tagged ITS amplicons, and (4) preparation of the multiplexed amplicon mix to be sequenced. The presented procedure is independent of the specific high-throughput sequencing technology used, which makes it highly versatile. PMID:26791497

  11. Surface textural analysis of quartz grains by scanning electron microscopy (SEM): From sample preparation to environmental interpretation

    NASA Astrophysics Data System (ADS)

    Vos, K.; Vandenberghe, N.; Elsen, J.

    2014-01-01

    Surface microtextures on quartz grains provide an insight into the sedimentary history of clastic sediments. Not only information on the depositional environment is provided, but also in some cases, successive sedimentary cycles can be recognised. Sample preparation and SEM imaging are the initial, and therefore crucial, steps in the study of microtextures. A sample preparation procedure using 15% hydrochloric acid and 50 g/L tetrasodium pyrophosphate solutions removes most of the grain coatings and adhering particles. The study of microtextures on 1300 quartz grains from a wide variety of environments was complemented with the reference works and atlases (Krinsley and Doornkamp, 1973; Le Ribault, 1977; Higgs, 1979; Mahaney, 2002) to construct an interpretation scheme allowing to differentiate between fluvial, marine, eolian, glacial and diagenetic/alteration environments based on microtextures. In a case study, the known littoral setting of two samples was confirmed by using the interpretation scheme for quartz microtextures. Furthermore, successive reworking of the grains in eolian and intertidal environments was recognised.

  12. Sample preparation for the analysis of isoflavones from soybeans and soy foods.

    PubMed

    Rostagno, M A; Villares, A; Guillamón, E; García-Lafuente, A; Martínez, J A

    2009-01-01

    This manuscript provides a review of the actual state and the most recent advances as well as current trends and future prospects in sample preparation and analysis for the quantification of isoflavones from soybeans and soy foods. Individual steps of the procedures used in sample preparation, including sample conservation, extraction techniques and methods, and post-extraction treatment procedures are discussed. The most commonly used methods for extraction of isoflavones with both conventional and "modern" techniques are examined in detail. These modern techniques include ultrasound-assisted extraction, pressurized liquid extraction, supercritical fluid extraction and microwave-assisted extraction. Other aspects such as stability during extraction and analysis by high performance liquid chromatography are also covered. PMID:19041977

  13. Membrane biofouling characterization: effects of sample preparation procedures on biofilm structure and the microbial community.

    PubMed

    Xue, Zheng; Lu, Huijie; Liu, Wen-Tso

    2014-01-01

    Ensuring the quality and reproducibility of results from biofilm structure and microbial community analysis is essential to membrane biofouling studies. This study evaluated the impacts of three sample preparation factors (ie number of buffer rinses, storage time at 4°C, and DNA extraction method) on the downstream analysis of nitrifying biofilms grown on ultrafiltration membranes. Both rinse and storage affected biofilm structure, as suggested by their strong correlation with total biovolume, biofilm thickness, roughness and the spatial distribution of EPS. Significant variations in DNA yields and microbial community diversity were also observed among samples treated by different rinses, storage and DNA extraction methods. For the tested biofilms, two rinses, no storage and DNA extraction with both mechanical and chemical cell lysis from attached biofilm were the optimal sample preparation procedures for obtaining accurate information about biofilm structure, EPS distribution and the microbial community. PMID:25115516

  14. Automated sample preparation for ICP analysis of active pharmaceutical ingredients and intermediates.

    PubMed

    Sims, Jonathan; Smith, Andrew; Patel, Dharmista; Batchelor, Richard; Carreira, Judith

    2011-10-01

    Routine testing of active pharmaceutical ingredients (APIs) for metal residues is an expectation of regulatory bodies such as the FDA (U.S. Food and Drug Administration). Sample preparation techniques are the rate-limiting step in the testing process and can be variable depending on the specific characteristics of the API under test. Simplification and standardization of the routine preparation of inductively coupled plasma spectroscopy sample solutions of organic compounds has been developed using a commercially available robotic workstation. Contamination from the metal components of the instrument and from sample tubes used in the methodology has been studied using a Design of Experiments approach. The optimized method described can be used for the measurement of trace metals in Pharmaceuticals at levels compliant with European and U.S. regulatory requirements. PMID:21906564

  15. Oxalic-acid leaching of rock, soil, and stream-sediment samples as an anomaly-accentuated technique

    USGS Publications Warehouse

    Alminas, Henry V.; Mosier, Elwin L.

    1976-01-01

    In many instances total-rock and sieved-soil and stream-sediment samples lack the sensitivity and contrast required for reconnaissance exploration and necessary in the search for blind ore deposits. Heavy-mineral concentrates incorporate the required sensitivity and contrast but are overly expensive for two reasons: time-consuming sample preparation is required to obtain them, and they cannot be easily derived from all bulk-sample types. Trace-metal-content comparisons of the oxalic-acid-leachable portions with heavy-mineral concentrates show that the leachates are equal to the heavy-mineral concentrates in sensitivity and contrast. Simplicity of preparation and the resultant cost savings are additional advantages of this proposed method.

  16. Automatic non-metallic sample preparation for inductively coupled plasma spectrometry

    NASA Astrophysics Data System (ADS)

    Wittmann, A. A.; Willay, G. M. H.

    A device to prepare a solution for analysis by plasma spectrometry or AAS in less than 7 min has been developed. This apparatus makes use of the practical properties of a "composite crucible" allowing the total recovery of the melted product and eliminating the cleaning of the crucible. Because of high frequency heating and continuous swirling, the fusion is rapid and complete. All sequences of the fusion process are controlled by a microprocessor. Six programs allow a choice of different operation parameters for the dissolution of various kinds of either mineral or metallic products. For the latter, preoxidation can be achieved during the first fusion cycle at relatively low temperature. This apparatus is used to prepare oxide samples and pre-reduced iron ores from steel plants. Standard deviations characterizing the reproducibility of the preparation and the repeatibility of the measurements are given. ICP-AES analysis of the samples prepared by automatic fusion-dilution gave the same accuracy than those prepared manually by fusion in the muffle furnace or by wet chemical digestion.

  17. Graphite sample preparation for AMS in a high pressure and temperature press

    USGS Publications Warehouse

    Rubin, M.; Mysen, B.O.; Polach, H.

    1984-01-01

    A high pressure-high temperature press is used to make target material for accelerator mass spectrometry. Graphite was produced from typical 14C samples including oxalic acid and carbonates. Beam strength of 12C was generally adequate, but random radioactive contamination by 14C made age measurements impractical. ?? 1984.

  18. Graphite sample preparation for AMS in a high pressure and temperature press

    USGS Publications Warehouse

    Rubin, Meyer; Mysen, Bjorn O.; Polach, Henry

    1984-01-01

    A high pressure-temperature press is used to make target material for accelerator mass spectrometry. Graphite was produced from typical **1**4C samples including oxalic acid and carbonates. Beam strength of **1**2C was generally adequate, but random radioactive contamination by **1**4C made age measurements impractical.

  19. Process for the preparation of 3,4-dihydroxybutanoic acid and salts thereof

    DOEpatents

    Hollingsworth, Rawle I.

    1994-01-01

    A process for the preparation of 3,4-dihydroxybutanoic acid (1) and salts thereof from a glucose source containing 1,4-1inked glucose as a substituent is described. The process uses an alkali metal hdyroxide and hydrogen peroxide to convert the glucose source to (1). The compound (1) is useful as a chemical intermediate to naturally occurring fatty acids and is used to prepare 3,4-dihydroxybutanoic acid-gamma-lactone (2) and furanone (3), particularly stereoisomers of these compounds.

  20. Optimal sample preparation conditions for the determination of uranium in biological samples by kinetic phosphorescence analysis (KPA).

    PubMed

    Ejnik, J W; Hamilton, M M; Adams, P R; Carmichael, A J

    2000-12-15

    Kinetic phosphorescence analysis (KPA) is a proven technique for rapid, precise, and accurate determination of uranium in aqueous solutions. Uranium analysis of biological samples require dry-ashing in a muffle furnace between 400 and 600 degrees C followed by wet-ashing with concentrated nitric acid and hydrogen peroxide to digest the organic component in the sample that interferes with uranium determination by KPA. The optimal dry-ashing temperature was determined to be 450 degrees C. At dry-ashing temperatures greater than 450 degrees C, uranium loss was attributed to vaporization. High temperatures also caused increased background values that were attributed to uranium leaching from the glass vials. Dry-ashing temperatures less than 450 degrees C result in the samples needing additional wet-ashing steps. The recovery of uranium in urine samples was 99.2+/-4.02% between spiked concentrations of 1.98-1980 ng (0.198-198 microg l(-1)) uranium, whereas the recovery in whole blood was 89.9+/-7.33% between the same spiked concentrations. The limit of quantification in which uranium in urine and blood could be accurately measured above the background was determined to be 0.05 and 0.6 microg l(-1), respectively. PMID:11130202

  1. Preparation and characterization of ambazone salt with nicotinic acid

    NASA Astrophysics Data System (ADS)

    Kacsó, I.; Muresan-Pop, M.; Borodi, Gh.; Bratu, I.

    2012-02-01

    Salt formation is a good method of increasing solubility, dissolution rate and consequently the bioavailability of poor soluble acidic or basic drugs. The aim of this study was to obtain and to investigate the structural properties of the compound that was obtained by solvent drop grinding method at room temperature starting from the 1:1 molar ratios of ambazone (AMB) and nicotinic acid (NA). The obtained compound (AMB•NA) was investigated by thermal analysis (DSC, TG-DTA), X-ray powder diffraction (PXRD) and infrared spectroscopy (FTIR). The difference between the patterns of AMB•NA and of the starting compounds evidenced the formation of a salt. Using X-ray powder diffraction data, the lattice parameters were determined. The thermal and FTIR measurements on the pure compounds and on the (1:1) grinding mixture of AMB with NA confirm the salt formation.

  2. Comparison of catalysts for direct transesterification of fatty acids in freeze-dried forage samples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Preparation of fatty acid methyl esters from forages comparing BF3 in CH3OH to HCl in CH3OH as a catalyst in single-step direct transesterification has not been reported. Our objective was to compare 1.09 M methanolic HCl to 7% BF3 in CH3OH as catalysts for direct transesterification of fatty acids ...

  3. Preparation and evaluation of lignosulfonates as a dispersant for gypsum paste from acid hydrolysis lignin.

    PubMed

    Matsushita, Yasuyuki; Yasuda, Seiichi

    2005-03-01

    In order to effectively utilize a by-product of the acid saccharification process of woody materials, the chemical conversion of guaiacyl sulfuric acid lignin (SAL), one of the acid hydrolysis lignins, into water-soluble sulfonated products with high dispersibitity was investigated. At first, SAL was phenolated (P-SAL) to enhance the solubility and reactivity. Lignosulfonates were prepared from P-SAL by three methods of hydroxymethylation followed by neutral sulfonation (two-step method), sulfomethylation (one-step method) and arylsulfonation. Surprisingly, all prepared lignosulfonates possessed 30 to 70% higher dispersibility for gypsum paste than the commercial lignosulfonate. Evaluation of the preparations for gypsum paste suggested that the higher molecular weights and sulfur contents of the preparations increased their dispersibility. PMID:15491828

  4. Electrochemical biosensing platform using hydrogel prepared from ferrocene modified amino acid as highly efficient immobilization matrix.

    PubMed

    Qu, Fengli; Zhang, Yi; Rasooly, Avraham; Yang, Minghui

    2014-01-21

    To increase the loading of glucose oxidase (GOx) and simplify glucose biosensor fabrication, hydrogel prepared from ferrocene (Fc) modified amino acid phenylalanine (Phe, F) was utilized for the incorporation of GOx. The synthesized hydrogel displays good biocompatibility and contains a significant number of Fc moieties, which can be considered as an ideal matrix to immobilize enzymes for the preparation of mediator-based biosensors. The hydrogel was studied by scanning electron microscopy, which indicated that it was composed of nanofibers with a diameter of around 50-100 nm and length extended to 1 mm. With the addition of GOx into the hydrogel and by directly dropping the resulting biocomposite onto the electrode surface, a glucose biosensor, that displays good performance due to improved enzyme loading and efficient electron transfer, can be simply constructed. The favorable network structure and good biocompatibility of the hydrogel could effectively avoid enzyme leakage and maintain the bioactivity of the enzymes, which resulted in good stability of the biosensor. The biosensor was utilized for the detection of glucose in blood samples with results comparable to those obtained from the hospital. The hydrogel as a functional component of an amperometric biosensor has implications for future development of biosensors and for clinical applications. PMID:24383679

  5. [Quantitative analysis of seven phenolic acids in eight Yinqiao Jiedu serial preparations by quantitative analysis of multi-components with single-marker].

    PubMed

    Wang, Jun-jun; Zhang, Li; Guo, Qing; Kou, Jun-ping; Yu, Bo-yang; Gu, Dan-hua

    2015-04-01

    The study aims to develop a unified method to determine seven phenolic acids (neochlorogenic acid, chlorogenic acid, 4-caffeoylquinic acid, caffeic acid, isochlorogenic acid B, isochlorogenic acid A and isochlorogenic acid C) contained in honeysuckle flower that is the monarch drug of all the eight Yinqiao Jiedu serial preparations using quantitative analysis of multi-components by single-marker (QAMS). Firstly, chlorogenic acid was used as a reference to get the average relative correction factors (RCFs) of the other phenolic acids in ratios to the reference; columns and instruments from different companies were used to validate the durability of the achieved RCFs in different levels of standard solutions; and honeysuckle flower extract was used as the reference substance to fix the positions of chromatographic peaks. Secondly, the contents of seven phenolic acids in eight different Yinqiao Jiedu serial preparations samples were calculated based on the RCFs durability. Finally, the quantitative results were compared between QAMS and the external standard (ES) method. The results have showed that the durability of the achieved RCFs is good (RSD during 0.80% - 2.56%), and there are no differences between the quantitative results of QAMS and ES (the relative average deviation < 0.93%). So it can be successfully used to the quantitative control of honeysuckle flower principally prescribed in Yinqiao Jiedu serial preparations. PMID:26223132

  6. Preparation of magnetic molecularly imprinted polymer for the separation of tetracycline antibiotics from egg and tissue samples.

    PubMed

    Chen, Ligang; Liu, Jun; Zeng, Qinglei; Wang, Hui; Yu, Aimin; Zhang, Hanqi; Ding, Lan

    2009-05-01

    Magnetic molecularly imprinted polymers were prepared using hydrophobic Fe(3)O(4) magnetite as the magnetically susceptible component, oxytetracycline as template molecule, methacrylic acid as functional monomer, and styrene and divinylbenzene as polymeric matrix components. The polymers were applied to the separation of tetracycline antibiotics from egg and tissue samples. The extraction and clean-up procedures were carried out in a single step by blending and stirring the sample, extraction solvent and polymers. The analytes can be transferred from the sample matrix to the polymers directly or through the extraction solvent as medium. When the extraction was complete, the polymers adsorbing the analytes were easily separated from the sample matrix by an adscititious magnet. The analytes eluted from the polymers were determined by liquid chromatography-tandem mass spectrometry. The recoveries ranging from 72.8% to 96.5% were obtained with relative standard deviations in the range of 2.9-12.3%. The limit of detection was less than 0.2 ng g(-1). The feasibility of this method was validated by analysis of incurred egg and tissue samples, and the results were compared with those obtained by the classical method in which solvent extraction, centrifugation, and subsequent clean-up and concentration by solid-phase extraction were applied. The proposed method reduced the complicacy of classical method and improved the reliability of method. PMID:19268956

  7. A cost effective, sensitive, and environmentally friendly sample preparation method for determination of Polycyclic Aromatic Hydrocarbons in solid samples

    PubMed Central

    Yamaguchi, Chika; Lee, Wen-Yee

    2010-01-01

    A simple, cost effective, and yet sensitive sample preparation technique was investigated for determining polycyclic aromatic hydrocarbons (PAHs) in solid samples. The method comprises ultrasonic extraction, Stir Bar Sorptive Extraction (SBSE), and thermal desorption-gas chromatography-mass spectrometry (TD – GC/MS) to increase analytical capacity in laboratories. This method required no clean-up and satisfied PAHs recovery and significantly advances cost performance over conventional extraction methods, such as Soxhlet and Microwave Assisted Extraction (MAE). This study evaluated three operational parameters for ultrasonic extraction: solvent composition, extraction time, and sample load. A standard material, SRM 1649 a (urban dust), was used as the solid sample matrix, and 12 priority PAHs on the US Environmental Protection Agency (US EPA) list were analyzed. Combination of non-polar and polar solvents ameliorated extraction efficiency. Acetone/hexane mixtures of 2:3 and 1:1 (v/v) gave the most satisfactory results: recoveries ranged from 63.3 % to 122 %. Single composition solvents (methanol, hexane, and dichloromethane) showed fewer recoveries. Comparing 20 minutes with 60 minutes sonication, longer sonication diminished extraction efficiencies in general. Furthermore, sample load became a critical factor in certain solvent systems, such as MeOH. MAE was also compared to the ultrasonic extraction, and results determined that the 20-minutes ultrasonic extraction using acetone / hexane (2:3 v/v) was as potent as MAE. The SBSE method using 20 mL of 30 % alcohol-fortified solution rendered a limit of detection ranging from 1.7 to 32 ng L−1 and a limit of quantitation ranging from 5.8 to 110 ng L−1 for the 16 US EPA PAHs. PMID:20851399

  8. Compact low temperature scanning tunneling microscope with in-situ sample preparation capability

    NASA Astrophysics Data System (ADS)

    Kim, Jungdae; Nam, Hyoungdo; Qin, Shengyong; Kim, Sang-ui; Schroeder, Allan; Eom, Daejin; Shih, Chih-Kang

    2015-09-01

    We report on the design of a compact low temperature scanning tunneling microscope (STM) having in-situ sample preparation capability. The in-situ sample preparation chamber was designed to be compact allowing quick transfer of samples to the STM stage, which is ideal for preparing temperature sensitive samples such as ultra-thin metal films on semiconductor substrates. Conventional spring suspensions on the STM head often cause mechanical issues. To address this problem, we developed a simple vibration damper consisting of welded metal bellows and rubber pads. In addition, we developed a novel technique to ensure an ultra-high-vacuum (UHV) seal between the copper and stainless steel, which provides excellent reliability for cryostats operating in UHV. The performance of the STM was tested from 2 K to 77 K by using epitaxial thin Pb films on Si. Very high mechanical stability was achieved with clear atomic resolution even when using cryostats operating at 77 K. At 2 K, a clean superconducting gap was observed, and the spectrum was easily fit using the BCS density of states with negligible broadening.

  9. Minimizing technical variation during sample preparation prior to label-free quantitative mass spectrometry.

    PubMed

    Scheerlinck, E; Dhaenens, M; Van Soom, A; Peelman, L; De Sutter, P; Van Steendam, K; Deforce, D

    2015-12-01

    Sample preparation is the crucial starting point to obtain high-quality mass spectrometry data and can be divided into two main steps in a bottom-up proteomics approach: cell/tissue lysis with or without detergents and a(n) (in-solution) digest comprising denaturation, reduction, alkylation, and digesting of the proteins. Here, some important considerations, among others, are that the reagents used for sample preparation can inhibit the digestion enzyme (e.g., 0.1% sodium dodecyl sulfate [SDS] and 0.5 M guanidine HCl), give rise to ion suppression (e.g., polyethylene glycol [PEG]), be incompatible with liquid chromatography-tandem mass spectrometry (LC-MS/MS) (e.g., SDS), and can induce additional modifications (e.g., urea). Taken together, all of these irreproducible effects are gradually becoming a problem when label-free quantitation of the samples is envisioned such as during the increasingly popular high-definition mass spectrometry (HDMS(E)) and sequential window acquisition of all theoretical fragment ion spectra (SWATH) data-independent acquisition strategies. Here, we describe the detailed validation of a reproducible method with sufficient protein yield for sample preparation without any known LC-MS/MS interfering substances by using 1% sodium deoxycholate (SDC) during both cell lysis and in-solution digest. PMID:26302362

  10. Compact low temperature scanning tunneling microscope with in-situ sample preparation capability.

    PubMed

    Kim, Jungdae; Nam, Hyoungdo; Qin, Shengyong; Kim, Sang-ui; Schroeder, Allan; Eom, Daejin; Shih, Chih-Kang

    2015-09-01

    We report on the design of a compact low temperature scanning tunneling microscope (STM) having in-situ sample preparation capability. The in-situ sample preparation chamber was designed to be compact allowing quick transfer of samples to the STM stage, which is ideal for preparing temperature sensitive samples such as ultra-thin metal films on semiconductor substrates. Conventional spring suspensions on the STM head often cause mechanical issues. To address this problem, we developed a simple vibration damper consisting of welded metal bellows and rubber pads. In addition, we developed a novel technique to ensure an ultra-high-vacuum (UHV) seal between the copper and stainless steel, which provides excellent reliability for cryostats operating in UHV. The performance of the STM was tested from 2 K to 77 K by using epitaxial thin Pb films on Si. Very high mechanical stability was achieved with clear atomic resolution even when using cryostats operating at 77 K. At 2 K, a clean superconducting gap was observed, and the spectrum was easily fit using the BCS density of states with negligible broadening. PMID:26429448

  11. Compact low temperature scanning tunneling microscope with in-situ sample preparation capability

    SciTech Connect

    Kim, Jungdae; Nam, Hyoungdo; Schroeder, Allan; Shih, Chih-Kang; Qin, Shengyong; Kim, Sang-ui; Eom, Daejin

    2015-09-15

    We report on the design of a compact low temperature scanning tunneling microscope (STM) having in-situ sample preparation capability. The in-situ sample preparation chamber was designed to be compact allowing quick transfer of samples to the STM stage, which is ideal for preparing temperature sensitive samples such as ultra-thin metal films on semiconductor substrates. Conventional spring suspensions on the STM head often cause mechanical issues. To address this problem, we developed a simple vibration damper consisting of welded metal bellows and rubber pads. In addition, we developed a novel technique to ensure an ultra-high-vacuum (UHV) seal between the copper and stainless steel, which provides excellent reliability for cryostats operating in UHV. The performance of the STM was tested from 2 K to 77 K by using epitaxial thin Pb films on Si. Very high mechanical stability was achieved with clear atomic resolution even when using cryostats operating at 77 K. At 2 K, a clean superconducting gap was observed, and the spectrum was easily fit using the BCS density of states with negligible broadening.

  12. Actuation Behavior of Polylactic Acid Fiber Films Prepared by Electrospinning.

    PubMed

    Nobeshima, Taiki; Ishii, Yuya; Sakai, Heisuke; Uemura, Sei; Yoshida, Manabu

    2016-04-01

    A poly-DL-lactide (PLA) fiber film was prepared using the electrospinning method. This film consisted of randomly oriented PLA nanofibers. Consequently, it had sponge-like structure and was quite soft compared to PLA films prepared by spin coating. The average diameter of the fibers and the density of the film were 730 nm and 20%, respectively. By applying a voltage, the PLA film was subjected to electric-field-induced strain: expansion and compression in the thickness direction. When a voltage of -200 V was applied to the film, its thickness shrank from 13.5 µm to 10.0 µm (a 26% reduction). Electric-field-induced strain can occur via two different mechanisms: The first is electrostrictive behavior. That. is, in a highly electric field region, a change of film thickness occurs (compression only) from the electrostatic force between electrodes. The second mechanism is piezoelectric-like behavior that occurs in racemic PLA, wherein a PLA nanofiber is expanded and compressed by applying positive and negative voltage. Such piezoelectric-like behavior was not observed in spin-coated PLA films. PMID:27451629

  13. [PREPARATIONS OF PAMIDRONOVIC ACID IN COMPLEX TREATMENT ON OSTEOGENESIS IMPERFECTA].

    PubMed

    Zyma, A M; Guk, Yu M; Magomedov, O M; Gayko, O G; Kincha-Polishchuk, T A

    2015-07-01

    Modern view of drug therapy in the complex treatment of orthopedic manifestations of osteogenesis imperfecta (OI) was submitted. Developed and tested system of drug correction of structural and functional state of bone tissue (BT) using drugs pamidronovic acid, depending on osteoporosis severity and type of disease. Such therapy is appropriate to apply both independently and in conjunction with surgery to correct deformations of long bones of the lower extremities. Effectiveness and feasibility of the proposed methods of drug therapy was proved, most patients resume features walking and support. PMID:26591224

  14. Preparation of layered thin film samples for angle-resolved photoemission spectroscopy

    SciTech Connect

    Harrison, S. E.; Zhou, B.; Huo, Y.; Harris, J. S.; Pushp, A.; Kellock, A. J.; Parkin, S. S. P.; Chen, Y.; Hesjedal, T.

    2014-09-22

    Materials with layered van der Waals crystal structures are exciting research topics in condensed matter physics and materials science due to outstanding physical properties associated with their strong two dimensional nature. Prominent examples include bismuth tritelluride and triselenide topological insulators (TIs), which are characterized by a bulk bandgap and pairwise counter-propagating spin-polarized electronic surface states. Angle-resolved photoemission spectroscopy (ARPES) of ex-situ grown thin film samples has been limited by the lack of suitable surface preparation techniques. We demonstrate the shortcomings of previously successful conventional surface preparation techniques when applied to ternary TI systems which are susceptible to severe oxidation. We show that in-situ cleaving is a simple and effective technique for preparation of clean surfaces on ex-situ grown thin films for high quality ARPES measurements. The method presented here is universally applicable to other layered van der Waals systems as well.

  15. Preparation of polyethylene sacks for collection of precipitation samples for chemical analysis

    USGS Publications Warehouse

    Schroder, L.J.; Bricker, A.W.

    1985-01-01

    Polyethylene sacks are used to collect precipitation samples. Washing polyethylene with acetone, hexane, methanol, or nitric acid can change the adsorptive characteristics of the polyethylene. In this study, simulated precipitation at pH 4.5 was in contact with the polyethylene sacks for 21 days; subsamples were removed for chemical analysis at 7, 14, and 21 days after intitial contact. Sacks washed with acetone adsorbed iron and lithium; sacks washed with hexane adsorbed barium, iron , and lithium; sacks washed with methanol adsorbed calcium and iron; and sacks washed with 0.30 N nitric acid adsorbed iron. Leaching the plastic sacks with 0.15 N nitric acid did not result in 100-percent recovery of any of the adsorbed metals. Washing polyethylene sacks with dilute nitric acid caused the pH of the simulated precipitation to be decreased by 0.2 pH unit after 1 week of contact with the polyethylene. The specific conductance increased by 10 microsiemens per centimeter. Contamination of precipitation samples by lead was determined to be about 0.1 microgram per liter from contact with precleaned polyethylene sacks. No measurable contamination of precipitation samples by zinc occurred. (USGS)

  16. Adsorption properties of biomass-based activated carbon prepared with spent coffee grounds and pomelo skin by phosphoric acid activation

    NASA Astrophysics Data System (ADS)

    Ma, Xiaodong; Ouyang, Feng

    2013-03-01

    Activated carbon prepared from spent coffee grounds and pomelo skin by phosphoric acid activation had been employed as the adsorbent for ethylene and n-butane at room temperature. Prepared activated carbon was characterized by means of nitrogen adsorption-desorption, X-ray powder diffraction, scanning electron microscope and Fourier transform infrared spectroscope. It was confirmed that pore structure played an important role during the adsorption testes. Adsorption isotherms of ethylene and n-butane fitted well with Langmuir equation. The prepared samples owned better adsorption capacity for n-butane than commercial activated carbon. Isosteric heats of adsorptions at different coverage were calculated through Clausius-Clapeyron equation. Micropore filling effect was explained in a thermodynamic way.

  17. [Preparation of sub-standard samples and XRF analytical method of powder non-metallic minerals].

    PubMed

    Kong, Qin; Chen, Lei; Wang, Ling

    2012-05-01

    In order to solve the problem that standard samples of non-metallic minerals are not satisfactory in practical work by X-ray fluorescence spectrometer (XRF) analysis with pressed powder pellet, a method was studied how to make sub-standard samples according to standard samples of non-metallic minerals and to determine how they can adapt to analysis of mineral powder samples, taking the K-feldspar ore in Ebian-Wudu, Sichuan as an example. Based on the characteristic analysis of K-feldspar ore and the standard samples by X-ray diffraction (XRD) and chemical methods, combined with the principle of the same or similar between the sub-standard samples and unknown samples, the experiment developed the method of preparation of sub-standard samples: both of the two samples above mentioned should have the same kind of minerals and the similar chemical components, adapt mineral processing, and benefit making working curve. Under the optimum experimental conditions, a method for determination of SiO2, Al2O3, Fe2O3, TiO2, CaO, MgO, K2O and Na2O of K-feldspar ore by XRF was established. Thedetermination results are in good agreement with classical chemical methods, which indicates that this method was accurate. PMID:22827101

  18. Qualitative and quantitative determination of COPs in Cypriot meat samples using HPLC determination of the most effective sample preparation procedure.

    PubMed

    Georgiou, Christiana A; Kapnissi-Christodoulou, Constantina P

    2013-03-01

    This research work describes the development of a fast high-performance liquid chromatography method for the simultaneous determination of five important cholesterol oxidation products (COPs). The influence of various experimental parameters, such as the composition of the mobile phase, the flow rate and the column temperature, were investigated. Baseline separation was achieved by using acetonitrile-methanol-water-isopropanol (67:27:5:1) as a mobile phase with a 10°C column temperature. The developed method demonstrated good linearity and high reproducibility, with relative standard deviation values below 1.26% for all the COPs that were examined. The method was then applied, for the first time, to Cypriot smoked-meat products (lountza and hiromeri). The presence of COPs in these products suggests that the preparation of the meat products, and particularly the smoking process, possibly favors the oxidation of cholesterol. Finally, three different sample preparation procedures were evaluated and the optimum procedure was determined based on recovery, precision and simplicity. PMID:22927309

  19. imFASP: An integrated approach combining in-situ filter-aided sample pretreatment with microwave-assisted protein digestion for fast and efficient proteome sample preparation.

    PubMed

    Zhao, Qun; Fang, Fei; Wu, Ci; Wu, Qi; Liang, Yu; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2016-03-17

    An integrated sample preparation method, termed "imFASP", which combined in-situ filter-aided sample pretreatment and microwave-assisted trypsin digestion, was developed for preparation of microgram and even nanogram amounts of complex protein samples with high efficiency in 1 h. For imFASP method, proteins dissolved in 8 M urea were loaded onto a filter device with molecular weight cut off (MWCO) as 10 kDa, followed by in-situ protein preconcentration, denaturation, reduction, alkylation, and microwave-assisted tryptic digestion. Compared with traditional in-solution sample preparation method, imFASP method generated more protein and peptide identifications (IDs) from preparation of 45 μg Escherichia coli protein sample due to the higher efficiency, and the sample preparation throughput was significantly improved by 14 times (1 h vs. 15 h). More importantly, when the starting amounts of E. coli cell lysate decreased to nanogram level (50-500 ng), the protein and peptide identified by imFASP method were improved at least 30% and 44%, compared with traditional in-solution preparation method, suggesting dramatically higher peptide recovery of imFASP method for trace amounts of complex proteome samples. All these results demonstrate that the imFASP method developed here is of high potential for high efficient and high throughput preparation of trace amounts of complex proteome samples. PMID:26920773

  20. Integrated process for preparing a carboxylic acid from an alkane

    DOEpatents

    Benderly, Abraham; Chadda, Nitin; Sevon, Douglass

    2011-12-20

    The present invention relates to an integrated process for producing unsaturated carboxylic acids from the corresponding C.sub.2-C.sub.4 alkane. The process begins with performance of thermally integrated dehydrogenation reactions which convert a C.sub.2-C.sub.4 alkane to its corresponding C.sub.2-C.sub.4 alkene, and which involve exothermically converting a portion of an alkane to its corresponding alkene by oxidative dehydrogenation in an exothermic reaction zone, in the presence of oxygen and a suitable catalyst, and then feeding the products of the exothermic reaction zone to an endothermic reaction zone wherein at least a portion of the remaining unconverted alkane is endothermically dehydrogenated to form an additional quantity of the same corresponding alkene, in the presence of carbon dioxide and an other suitable catalyst. The alkene products of the thermally integrated dehydrogenation reactions are then provided to a catalytic vapor phase partial oxidation process for conversion of the alkene to the corresponding unsaturated carboxylic acid or nitrile. Unreacted alkene and carbon dioxide are recovered from the oxidation product stream and recycled back to the thermally integrated dehydrogenation reactions.

  1. Preparation of Compact Agarose Cell Blocks from the Residues of Liquid-Based Cytology Samples

    PubMed Central

    Choi, Suk Jin; Choi, Yeon Il; Kim, Lucia; Park, In Suh; Han, Jee Young; Kim, Joon Mee; Chu, Young Chae

    2014-01-01

    Background Inevitable loss of diagnostic material should be minimized during cell block preparation. We introduce a modified agarose cell block technique that enables the synthesis of compact cell blocks by using the entirety of a cell pellet without the loss of diagnostic material during cell block preparations. The feasibility of this technique is illustrated by high-throughput immunocytochemistry using high-density cell block microarray (CMA). Methods The cell pellets of Sure- Path residues were pre-embedded in ultra-low gelling temperature agarose gel and re-embedded in standard agarose gel. They were fixed, processed, and embedded in paraffin using the same method as tissue sample processing. The resulting agarose cell blocks were trimmed and represented on a CMA for high-throughput analysis using immunocytochemical staining. Results The SurePath residues were effectively and entirely incorporated into compact agarose cell buttons and embedded in paraffin. Sections of the agarose cell blocks revealed cellularities that correlated well with corresponding SurePath smears and had immunocytochemical features that were sufficient for diagnosis of difficult cases. Conclusions This agarose-based compact cell block technique enables preparation of high-quality cell blocks by using up the residual SurePath samples without loss of diagnostic material during cell block preparation. PMID:25366070

  2. Improvements in soft gelatin capsule sample preparation for USP-based simethicone FTIR analysis.

    PubMed

    Hargis, Amy D; Whittall, Linda B

    2013-02-23

    Due to the absence of a significant chromophore, Simethicone raw material and finished product analysis is achieved using a FTIR-based method that quantifies the polydimethylsiloxane (PDMS) component of the active ingredient. The method can be found in the USP monographs for several dosage forms of Simethicone-containing pharmaceutical products. For soft gelatin capsules, the PDMS assay values determined using the procedure described in the USP method were variable (%RSDs from 2 to 9%) and often lower than expected based on raw material values. After investigation, it was determined that the extraction procedure used for sample preparation was causing loss of material to the container walls due to the hydrophobic nature of PDMS. Evaluation revealed that a simple dissolution of the gelatin capsule fill in toluene provided improved assay results (%RSDs≤0.5%) as well as a simplified and rapid sample preparation. PMID:23245254

  3. Applications of Blue Light-curing Acrylic Resin to Forensic Sample Preparation and Microtomy.

    PubMed

    Groves, Ethan; Palenik, Christopher S

    2016-03-01

    This study discusses the results of an evaluation of a one-part blue light-curing acrylic resin for embedding trace evidence prior to the preparation of thin sections with a microtome. Through a comparison to several epoxy resins, the physical properties relevant to both trace evidence examination and analytical microscopy in general, including as viscosity, clarity, color, hardness, and cure speed, were explored. Finally, thin sections from paint samples embedded in this acrylic resin were evaluated to determine if, through smearing or impregnation, the resin contributed to the infrared spectra. The results of this study show that blue light-curing acrylic resins provide the desired properties of an embedding medium, generate high-quality thin sections, and can significantly simplify the preparation of paint chips, fibers and a multitude of other types of microscopic samples in the forensic trace evidence laboratory. PMID:27404623

  4. Optimization of proteomic sample preparation procedures for comprehensive protein characterization of pathogenic systems

    SciTech Connect

    Brewer, Heather M.; Norbeck, Angela D.; Adkins, Joshua N.; Manes, Nathan P.; Ansong, Charles; Shi, Liang; Rikihisa, Yasuko; Kikuchi, Takane; Wong, Scott; Estep, Ryan D.; Heffron, Fred; Pasa-Tolic, Ljiljana; Smith, Richard D.

    2008-12-19

    The elucidation of critical functional pathways employed by pathogens and hosts during an infectious cycle is both challenging and central to our understanding of infectious diseases. In recent years, mass spectrometry-based proteomics has been used as a powerful tool to identify key pathogenesis-related proteins and pathways. Despite the analytical power of mass spectrometry-based technologies, samples must be appropriately prepared to characterize the functions of interest (e.g. host-response to a pathogen or a pathogen-response to a host). The preparation of these protein samples requires multiple decisions about what aspect of infection is being studied, and it may require the isolation of either host and/or pathogen cellular material.

  5. An introduction to sample preparation and imaging by cryo-electron microscopy for structural biology.

    PubMed

    Thompson, Rebecca F; Walker, Matt; Siebert, C Alistair; Muench, Stephen P; Ranson, Neil A

    2016-05-01

    Transmission electron microscopy (EM) is a versatile technique that can be used to image biological specimens ranging from intact eukaryotic cells to individual proteins >150kDa. There are several strategies for preparing samples for imaging by EM, including negative staining and cryogenic freezing. In the last few years, cryo-EM has undergone a 'resolution revolution', owing to both advances in imaging hardware, image processing software, and improvements in sample preparation, leading to growing number of researchers using cryo-EM as a research tool. However, cryo-EM is still a rapidly growing field, with unique challenges. Here, we summarise considerations for imaging of a range of specimens from macromolecular complexes to cells using EM. PMID:26931652

  6. An introduction to sample preparation and imaging by cryo-electron microscopy for structural biology

    PubMed Central

    Thompson, Rebecca F.; Walker, Matt; Siebert, C. Alistair; Muench, Stephen P.; Ranson, Neil A.

    2016-01-01

    Transmission electron microscopy (EM) is a versatile technique that can be used to image biological specimens ranging from intact eukaryotic cells to individual proteins >150 kDa. There are several strategies for preparing samples for imaging by EM, including negative staining and cryogenic freezing. In the last few years, cryo-EM has undergone a ‘resolution revolution’, owing to both advances in imaging hardware, image processing software, and improvements in sample preparation, leading to growing number of researchers using cryo-EM as a research tool. However, cryo-EM is still a rapidly growing field, with unique challenges. Here, we summarise considerations for imaging of a range of specimens from macromolecular complexes to cells using EM. PMID:26931652

  7. Sample preparation for the analysis of flavors and off-flavors in foods.

    PubMed

    Wilkes, J G; Conte, E D; Kim, Y; Holcomb, M; Sutherland, J B; Miller, D W

    2000-06-01

    Off-flavors in foods may originate from environmental pollutants, the growth of microorganisms, oxidation of lipids, or endogenous enzymatic decomposition in the foods. The chromatographic analysis of flavors and off-flavors in foods usually requires that the samples first be processed to remove as many interfering compounds as possible. For analysis of foods by gas chromatography (GC), sample preparation may include mincing, homogenation, centrifugation, distillation, simple solvent extraction, supercritical fluid extraction, pressurized-fluid extraction, microwave-assisted extraction, Soxhlet extraction, or methylation. For high-performance liquid chromatography of amines in fish, cheese, sausage and olive oil or aldehydes in fruit juice, sample preparation may include solvent extraction and derivatization. Headspace GC analysis of orange juice, fish, dehydrated potatoes, and milk requires almost no sample preparation. Purge-and-trap GC analysis of dairy products, seafoods, and garlic may require heating, microwave-mediated distillation, purging the sample with inert gases and trapping the analytes with Tenax or C18, thermal desorption, cryofocusing, or elution with ethyl acetate. Solid-phase microextraction GC analysis of spices, milk and fish can involve microwave-mediated distillation, and usually requires adsorption on poly(dimethyl)siloxane or electrodeposition on fibers followed by thermal desorption. For short-path thermal desorption GC analysis of spices, herbs, coffee, peanuts, candy, mushrooms, beverages, olive oil, honey, and milk, samples are placed in a glass-lined stainless steel thermal desorption tube, which is purged with helium and then heated gradually to desorb the volatiles for analysis. Few of the methods that are available for analysis of food flavors and off-flavors can be described simultaneously as cheap, easy and good. PMID:10890508

  8. Electrodeposited Fe-Co films prepared from a citric-acid-based plating bath

    NASA Astrophysics Data System (ADS)

    Yanai, T.; Uto, H.; Shimokawa, T.; Nakano, M.; Fukunaga, H.; Suzuki, K.

    2013-06-01

    Electrodeposited Fe-Co films are commonly prepared in a boric-acid-based bath. In this research, we applied citric acid instead of boric acid for the plating of Fe-Co films because boron in the waste bath is restricted by environmental-protection regulations in Japan. We evaluated the effect of citric acid on the magnetic and structural properties of the films. The saturation magnetization of the Fe-Co films slightly increased while the Fe content in the Fe-Co films decreased with increasing citric acid concentration. The lowest coercivity value of 240 A/m was obtained at a citric acid concentration of 100 g/L. The plating bath with this citric acid concentration enabled us to obtain Fe-Co films with high saturation magnetizations and smooth surface morphologies.

  9. On the preparation of electron sensor using LiRbSO4 samples

    NASA Astrophysics Data System (ADS)

    El-Muraikhi, M.; Kassem, M. E.; Gaafar, M.; Abdel Gawad, M. M. H.; Ragab, I. M.

    2005-01-01

    The dielectric spectroscopy of metal-metal sulfate LiRbSO4 samples are described with particular emphasis on sensor performance to be used in the field of radiation. The obtained results as the effect of different electron energy beams at fixed dose, 0.5 Gy, showed abrupt change of the electrical properties (electrical conductivity, capacitance, and loss tangent). The results can be explained on the basis of radiation-induced defects followed by radiation quenching. The prepared samples can be used in the field of radiation dosimeter.

  10. Sample preparation and liquid chromatographic determination of vitamin D in food products.

    PubMed

    Bui, M H

    1987-01-01

    Vitamin D in different fortified foods is determined by using liquid chromatography (LC). Sample preparation is described for fortified skim milk, infant formulas, chocolate drink powder, and diet food. The procedure involves 2 main steps: saponification of the sample followed by extraction, and quantitation by LC analysis. Depending on the sample matrix, additional steps are necessary, i.e., enzymatic digestion for hydrolyzing the starch in the sample and cartridge purification before LC injection. An isocratic system consisting of 0.5% water in methanol (v/v) on two 5 microns ODS Hypersil, 12 X 0.4 cm id columns is used. Recovery of vitamin D added to unfortified skim milk is 98%. The results of vitamin D determination in homogenized skim milk, fortified milk powder, fortified milk powder with soybean, chocolate drink powder, and sports diet food are given. PMID:3680113

  11. Sample Preparation Approaches for iTRAQ Labeling and Quantitative Proteomic Analyses in Systems Biology.

    PubMed

    Spanos, Christos; Moore, J Bernadette

    2016-01-01

    Among a variety of global quantification strategies utilized in mass spectrometry (MS)-based proteomics, isobaric tags for relative and absolute quantitation (iTRAQ) are an attractive option for examining the relative amounts of proteins in different samples. The inherent complexity of mammalian proteomes and the diversity of protein physicochemical properties mean that complete proteome coverage is still unlikely from a single analytical method. Numerous options exist for reducing protein sample complexity and resolving digested peptides prior to MS analysis. Indeed, the reliability and efficiency of protein identification and quantitation from an iTRAQ workflow strongly depend on sample preparation upstream of MS. Here we describe our methods for: (1) total protein extraction from immortalized cells; (2) subcellular fractionation of murine tissue; (3) protein sample desalting, digestion, and iTRAQ labeling; (4) peptide separation by strong cation-exchange high-performance liquid chromatography; and (5) peptide separation by isoelectric focusing. PMID:26700038

  12. DNA isolation and sample preparation for quantification of adduct levels by accelerator mass spectrometry.

    PubMed

    Dingley, Karen H; Ubick, Esther A; Vogel, John S; Ognibene, Ted J; Malfatti, Michael A; Kulp, Kristen; Haack, Kurt W

    2014-01-01

    Accelerator mass spectrometry (AMS) is a highly sensitive technique used for the quantification of adducts following exposure to carbon-14- or tritium-labeled chemicals, with detection limits in the range of one adduct per 10(11)-10(12) nucleotides. The protocol described in this chapter provides an optimal method for isolating and preparing DNA samples to measure isotope-labeled DNA adducts by AMS. When preparing samples, special precautions must be taken to avoid cross-contamination of isotope among samples and produce a sample that is compatible with AMS. The DNA isolation method described is based upon digestion of tissue with proteinase K, followed by extraction of DNA using Qiagen isolation columns. The extracted DNA is precipitated with isopropanol, washed repeatedly with 70 % ethanol to remove salt, and then dissolved in water. DNA samples are then converted to graphite or titanium hydride and the isotope content measured by AMS to quantify adduct levels. This method has been used to reliably generate good yields of uncontaminated, pure DNA from animal and human tissues for analysis of adduct levels. PMID:24623226

  13. Simple Sodium Dodecyl Sulfate-Assisted Sample Preparation Method for LC-MS-based Proteomic Applications

    SciTech Connect

    Zhou, Jianying; Dann, Geoffrey P.; Shi, Tujin; Wang, Lu; Gao, Xiaoli; Su, Dian; Nicora, Carrie D.; Shukla, Anil K.; Moore, Ronald J.; Liu, Tao; Camp, David G.; Smith, Richard D.; Qian, Weijun

    2012-03-10

    Sodium dodecyl sulfate (SDS) is one of the most popular laboratory reagents used for highly efficient biological sample extraction; however, SDS presents a significant challenge to LC-MS-based proteomic analyses due to its severe interference with reversed-phase LC separations and electrospray ionization interfaces. This study reports a simple SDS-assisted proteomic sample preparation method facilitated by a novel peptide-level SDS removal protocol. After SDS-assisted protein extraction and digestion, SDS was effectively (>99.9%) removed from peptides through ion substitution-mediated DS- precipitation with potassium chloride (KCl) followed by {approx}10 min centrifugation. Excellent peptide recovery (>95%) was observed for less than 20 {mu}g of peptides. Further experiments demonstrated the compatibility of this protocol with LC-MS/MS analyses. The resulting proteome coverage from this SDS-assisted protocol was comparable to or better than those obtained from other standard proteomic preparation methods in both mammalian tissues and bacterial samples. These results suggest that this SDS-assisted protocol is a practical, simple, and broadly applicable proteomic sample processing method, which can be particularly useful when dealing with samples difficult to solubilize by other methods.

  14. Preparation of 4-amino-2,4-dioxobutanoic acid

    DOEpatents

    Unkefer, Pat J.; Martinez, Rodolfo A.; Glass, David R.

    2016-03-22

    A process for synthesizing 4-amino-2,4-dioxobutanoate involves reacting a dialkyl oxalate with an alkoxide in ethanol to form a reaction mixture, and afterward adding an alkyl cyano acetate to the reaction mixture and allowing a reaction to proceed under conditions suitable to form a first reaction product of the formula diethyl 2-cyano-3-hydroxy-butenedioate, and then isolating the diethyl 2-cyano-3-hydroxy-butenedioate, and afterward reacting the diethyl-2-cyano-3-hydroxy-butenedioate with an aqueous hydroxide under conditions suitable to form 4-amino-2,4-dioxobutanoate. The 4-amino-2,4-dioxobutanoate may be acidified into 4-amino-2,4-dioxobutanoic acid.

  15. Lab-on-a-chip modules for detection of highly pathogenic bacteria: from sample preparation to detection

    NASA Astrophysics Data System (ADS)

    Julich, S.; Kopinč, R.; Hlawatsch, N.; Moche, C.; Lapanje, A.; Gärtner, C.; Tomaso, H.

    2014-05-01

    Lab-on-a-chip systems are innovative tools for the detection and identification of microbial pathogens in human and veterinary medicine. The major advantages are small sample volume and a compact design. Several fluidic modules have been developed to transform analytical procedures into miniaturized scale including sampling, sample preparation, target enrichment, and detection procedures. We present evaluation data for single modules that will be integrated in a chip system for the detection of pathogens. A microfluidic chip for purification of nucleic acids was established for cell lysis using magnetic beads. This assay was evaluated with spiked environmental aerosol and swab samples. Bacillus thuringiensis was used as simulant for Bacillus anthracis, which is closely related but non-pathogenic for humans. Stationary PCR and a flow-through PCR chip module were investigated for specific detection of six highly pathogenic bacteria. The conventional PCR assays could be transferred into miniaturized scale using the same temperature/time profile. We could demonstrate that the microfluidic chip modules are suitable for the respective purposes and are promising tools for the detection of bacterial pathogens. Future developments will focus on the integration of these separate modules to an entire lab-on-a-chip system.

  16. Correlating Mineralogy and Amino Acid Contents of Milligram-Scale Murchison Carbonaceous Chondrite Samples

    NASA Technical Reports Server (NTRS)

    Burton, Aaron, S.; Berger, Eve L.; Locke, Darren R.; Elsila, Jamie E.; Glavin, Daniel P.; Dworkin, Jason P.

    2015-01-01

    Amino acids, the building blocks of proteins, have been found to be indigenous in most of the carbonaceous chondrite groups. The abundances of amino acids, as well as their structural, enantiomeric and isotopic compositions differ significantly among meteorites of different groups and petrologic types. This suggests that there is a link between parent-body conditions, mineralogy and the synthesis and preservation of amino acids (and likely other organic molecules). However, elucidating specific causes for the observed differences in amino acid composition has proven extremely challenging because samples analyzed for amino acids are typically much larger ((is) approximately 100 mg powders) than the scale at which meteorite heterogeneity is observed (sub mm-scale differences, (is) approximately 1-mg or smaller samples). Thus, the effects of differences in mineralogy on amino acid abundances could not be easily discerned. Recent advances in the sensitivity of instrumentation have made possible the analysis of smaller samples for amino acids, enabling a new approach to investigate the link between mineralogical con-text and amino acid compositions/abundances in meteorites. Through coordinated mineral separation, mineral characterization and highly sensitive amino acid analyses, we have performed preliminary investigations into the relationship between meteorite mineralogy and amino acid composition. By linking amino acid data to mineralogy, we have started to identify amino acid-bearing mineral phases in different carbonaceous meteorites. The methodology and results of analyses performed on the Murchison meteorite are presented here.

  17. Improved Butanol-Methanol (BUME) Method by Replacing Acetic Acid for Lipid Extraction of Biological Samples.

    PubMed

    Cruz, Mutya; Wang, Miao; Frisch-Daiello, Jessica; Han, Xianlin

    2016-07-01

    Extraction of lipids from biological samples is a critical step in lipidomics, especially for shotgun lipidomics where lipid extracts are directly infused into a mass spectrometer. The butanol-methanol (BUME) extraction method was originally developed to extract lipids from plasma samples with 1 % acetic acid. Considering some lipids are sensitive to acidic environments, we modified this protocol by replacing acetic acid with lithium chloride solution and extended the modified extraction to tissue samples. Although no significant reduction of plasmalogen levels in the acidic BUME extracts of rat heart samples was found, the modified method was established to extract various tissue samples, including rat liver, heart, and plasma. Essentially identical profiles of the majority of lipid classes were obtained from the extracts of the modified BUME and traditional Bligh-Dyer methods. However, it was found that neither the original, nor the modified BUME method was suitable for 4-hydroxyalkenal species measurement in biological samples. PMID:27245345

  18. GUIDELINES FOR PREPARING ENVIRONMENTAL AND WASTE SAMPLES FOR MUTAGENICITY (AMES) TESTING: INTERIM PROCEDURES AND PANEL MEETING PROCEEDINGS

    EPA Science Inventory

    The User's Guide presents review papers and interim protocols for the preparation of waste and environmental samples for testing with the Salmonella reverse-mutation assay (Ames test). Sample types addressed include air, drinking water (processed), environmental and wastewaters, ...

  19. Lead biomonitoring in different organs of lead intoxicated rats employing GF AAS and different sample preparations.

    PubMed

    de Sousa, Rafael Arromba; Sabarense, Céphora Maria; Prado, Gustavo L P; Metze, Konradin; Cadore, Solange

    2013-01-30

    An analytical procedure was developed for the determination of lead in different tissues from Wistar Hanover rats, previously intoxicated with lead acetate during a toxicological study. About 25 mg of dried sample (bone, liver, kidney, heart, lung and spleen) were mixed with 8.0 mL of 7.00 mol L(-1) nitric acid and digested using microwave radiation in closed vessel. Except for the bone samples, the other tissues could also be analyzed after alkaline solubilization with TMAH. All the digested or solubilized samples were analyzed by graphite furnace atomic absorption spectrometry. Good accuracy and precision were attained when analyzing reference standard materials (for bone, liver and kidney) and also from addition to recovery experiments (for heart, lung and spleen tissues). The method was applied to samples from nine animals and the results suggested that there is a profile for lead bioaccumulation in these animals, which seemed to adapt themselves to continuous lead exposure. PMID:23597893

  20. Preventing and Removing Contamination in a Natural Radiocarbon Sample Preparation Laboratory

    SciTech Connect

    Zermeno, P; Kurdyla, D K; Buchholz, B A; Heller, S J; Frantz, B R; Brown, T A; Kashgarian, M

    2002-10-25

    The introduction of elevated {sup 14}C contamination into a natural radiocarbon sample preparation laboratory can occur through many different pathways. The most difficult to control is the introduction of contaminated samples from outside labs. Laboratories can remain {sup 14}C contaminated as a result of earlier tracer based research, even if ''hot'' work has not occurred in the laboratories in decades. Prior to accepting samples from outside collaborators, it is recommended that the collaborators test their labs for {sup 14}C contamination. Any surface in a lab that has high use by multiple people has the potential to be contaminated. The standard procedure for determining whether a collaborator's lab is contaminated consists of swiping lab surfaces with small glass fiber filters wetted with alcohol and measuring them for {sup 14}C content using AMS. Volatile {sup 14}C can be detected by using aerosol monitors consisting of fine soot that is depleted in {sup 14}C. These monitors can be set out in the laboratory in question to check for volatile {sup 14}C contamination. In the event that a hot sample is introduced in the natural radiocarbon sample prep laboratory, all sample submission should be stopped until the lab is declared clean. Samples already being processed should be completed along with {sup 14}C depleted material and measured by AMS. This will help determine if the contaminated samples have affected other samples in the laboratory. After a contamination event, the laboratory and associated equipment requires cleaning or disposal. All surfaces and equipment should be wiped down with acetone or ethanol. All chemicals in use should be disposed of in the appropriate waste containers and those waste containers removed from the lab. Once the natural radiocarbon laboratory has been thoroughly ''cleaned'', several background samples consisting of {sup 14}C depleted material should be processed through the lab and measured by AMS before unknown samples are

  1. Study of an Acid-Free Technique for the Preparation of Glycyrrhetinic Acid from Ammonium Glycyrrhizinate in Subcritical Water.

    PubMed

    Lekar, Anna V; Borisenko, Sergey N; Vetrova, Elena V; Filonova, Olga V; Maksimenko, Elena V; Borisenko, Nikolai I; Minkin, Vladimir I

    2015-11-01

    The aim of this work was to study an application of a previously developed expedient acid-free technique for the preparation of glycyrrhetinic acid from ammonium glycyrrhizinate that requires no use of acids and toxic organic solvents. Subcritical water that serves as a reactant and a solvent was used in order to obtain glycyrrhetinic acid in good yields starting from ammonium glycyrrhizinate. It has been shown that variation of only one parameter of the process (temperature) allows alteration to thecomposition of the hydrolysis products. A new method was used for the synthesis of glycyrrhetinic acid (glycyrrhizic acid aglycone) and its monoglycoside. HPLC combined with mass spectrometry and NMR spectroscopy were used to determine the quantitative and qualitative compositions of the obtained products. The method developed for the production of glycyrrhetinic acid in subcritical water is environmentally friendly and faster than conventional hydrolysis methods that use acids and-expensive and toxic organic solvents. The proposed technique has a potential for the future development of inexpensive and environmentally friendly technologies for production of new pharmaceutical plant-based substances. PMID:26749800

  2. Preparation of environmental samples for the determination of polycyclic aromatic hydrocarbons by thin-layer chromatography.

    PubMed

    Poole, S K; Dean, T A; Poole, C F

    1987-07-29

    An evaluation of extraction procedures, liquid-liquid distribution systems, Sep-Pak cartridges, liquid-solid chromatography using silica, alumina and chemically modified silica packings (acid-base treated ethylammonium nitrate and picric acid impregnated), macroreticular resins and gel permeation columns for the analysis of polycyclic aromatic hydrocarbons (CPAHs) in environmental samples by thin-layer chromatography is discussed. For particulate samples solvent extraction using a Soxhlet apparatus or ultrasonication was found to be preferable to sublimation and liquid-liquid distribution between hexane and dimethyl sulfoxide followed by silica gel column chromatography was the preferred method for sample clean-up. Using this procedure enabled six PAHs (anthracene, fluoranthene, benz[a]anthracene, perylene, pyrene, and coronene) to be determined quantitatively in urban air particulate, diesel engine exhaust particulate, laboratory ventilator dust, household dust, river water, and tea samples. The PAHs were identified by coincidence of retention between the sample and standards in the same chromatographic system and by adequate agreement with standards for their normalized emission response ratios. The two-point calibration method was used for quantitation. Good agreement for the concentration of PAHs in the air particulate and diesel particulate extracts with published data using gas chromatography-mass spectrometry and high-performance liquid chromatography was found. PMID:2444609

  3. Controlled antibody release from gelatin for on-chip sample preparation.

    PubMed

    Zhang, Xichen; Wasserberg, Dorothee; Breukers, Christian; Terstappen, Leon W M M; Beck, Markus

    2016-05-10

    A practical way to realize on-chip sample preparation for point-of-care diagnostics is to store the required reagents on a microfluidic device and release them in a controlled manner upon contact with the sample. For the development of such diagnostic devices, a fundamental understanding of the release kinetics of reagents from suitable materials in microfluidic chips is therefore essential. Here, we study the release kinetics of fluorophore-conjugated antibodies from (sub-) μm thick gelatin layers and several ways to control the release time. The observed antibody release is well-described by a diffusion model. Release times ranging from ∼20 s to ∼650 s were determined for layers with thicknesses (in the dry state) between 0.25 μm and 1.5 μm, corresponding to a diffusivity of 0.65 μm(2) s(-1) (in the swollen state) for our standard layer preparation conditions. By modifying the preparation conditions, we can influence the properties of gelatin to realize faster or slower release. Faster drying at increased temperatures leads to shorter release times, whereas slower drying at increased humidity yields slower release. As expected in a diffusive process, the release time increases with the size of the antibody. Moreover, the ionic strength of the release medium has a significant impact on the release kinetics. Applying these findings to cell counting chambers with on-chip sample preparation, we can tune the release to control the antibody distribution after inflow of blood in order to achieve homogeneous cell staining. PMID:27077142

  4. ANALYSIS OF ACID PRECIPITATION SAMPLES COLLECTED BY STATE AGENCIES--SAMPLING PERIOD JAN 1988 - DEC 1988

    EPA Science Inventory

    This report presents analytical data from the 30 acid precipitation collection sites in the State-operated Network. amples are collected weekly in plastic bag liners and shipped in 500 mL polyethylene bottles to Global Geochemistry Corporation (the central laboratory for the netw...

  5. ANALYSIS OF ACID PRECIPITATION SAMPLES COLLECTED BY STATE AGENCIES SAMPLING PERIOD JANUARY 1990 - DECEMBER 1990

    EPA Science Inventory

    This report presents analytical data from the 30 acid precipitation collection sites in the State-Operated Network. amples are collected weekly in plastic bag liners and shipped in 500 mL polyethylene bottles to Global Geochemistry Corporation (the central laboratory for the netw...

  6. ANALYSIS OF ACID PRECIPITATION SAMPLES COLLECTED BY STATE AGENCIES SAMPLING PERIOD: JANUARY 1992 - DECEMBER 1992

    EPA Science Inventory

    This report presents analytical data from 30 acid precipitation collection sites in the State-Operated Network. amples are collected weekly in plastic bag bucket liners and shipped in 500 mL polyethylene bottled to Global Geochemistry Corporation, the central laboratory for the n...

  7. Sample preparation and direct electrospray ionization on a tip column for rapid mass spectrometry analysis of complex samples.

    PubMed

    Huang, Yun-Qing; You, Jin-Qing; Yuan, Bi-Feng; Feng, Yu-Qi

    2012-10-01

    A handheld pipette tip column electrospray ionization source (PTC-ESI source) was developed for rapid mass spectrometry analysis at ambient pressure. The PTC-ESI source was made up of three main component parts including a micro DC high voltage (HV) power supply, a micropipette and a disposable micropipette tip filled with a plug of adsorbent. A DC high voltage was applied to the sharp point of the micropipette tip column to induce electrospray ionization. The PTC-ESI source was successfully used for direct analysis of basic organic compounds, organic acids and peptides in a simple matrix. In the case of complex samples, micro-extraction based on the adsorbent phase filled in the pipette tip was used to remove impurities and concentrate target analytes prior to ionization. The eluting solution was not pipetted out, but directly dispersed in the form of electrospray from the pipette tip for ionization. The effectiveness of the PTC-ESI source has been further demonstrated by fast analysis of therapeutic compounds and endogenous bioactive chemicals in complex biological samples. PMID:22898704

  8. A variation of transmission electron microscope sample preparation for VLSI analysis.

    PubMed

    Madden, M C; Crafard, P

    1989-02-01

    Sample preparation for VLSI analysis is often slow due to long ion milling time and because the location of the thin area of the sample is difficult to control. By modifying the standard techniques used with a VCR Group (and perhaps other) mechanical dimpler, the ion milling time can be reduced to less than 30 min. and the location on the thinned area reasonably controlled. These modifications involve the use of a radiused edge on the dimpling tool, a rubber O-ring on the polishing tool, and not rotating the sample platen during polishing. The modifications to the dimpling and polishing tools allow more control of the geometry of the dimple, while not rotating the sample platen allows a thinner sample to be produced and permits the use of the sample translation micrometers to shift the location of the thinned area during polishing. The quality of samples produced using this modified procedure is equivalent to that obtained with the more standard methods. PMID:2709134

  9. Preserving the distribution of inorganic arsenic species in groundwater and acid mine drainage samples.

    PubMed

    Bednar, A J; Garbarino, J R; Ranville, J F; Wildeman, T R

    2002-05-15

    The distribution of inorganic arsenic species must be preserved in the field to eliminate changes caused by metal oxyhydroxide precipitation, photochemical oxidation, and redox reactions. Arsenic species sorb to iron and manganese oxyhydroxide precipitates, and arsenite can be oxidized to arsenate by photolytically produced free radicals in many sample matrices. Several preservatives were evaluated to minimize metal oxyhydroxide precipitation, such as inorganic acids and ethylenediaminetetraacetic acid (EDTA). EDTA was found to work best for all sample matrices tested. Storing samples in opaque polyethylene bottles eliminated the effects of photochemical reactions. The preservation technique was tested on 71 groundwater and six acid mine drainage samples. Concentrations in groundwater samples reached 720 microg-As/L for arsenite and 1080 microg-As/L for arsenate, and acid mine drainage samples reached 13 000 microg-As/L for arsenite and 3700 microg-As/L for arsenate. The arsenic species distribution in the samples ranged from 0 to 90% arsenite. The stability of the preservation technique was established by comparing laboratory arsenic speciation results for samples preserved in the field to results for subsamples speciated onsite. Statistical analyses indicated that the difference between arsenite and arsenate concentrations for samples preserved with EDTA in opaque bottles and field speciation results were analytically insignificant. The percentage change in arsenite:arsenate ratios for a preserved acid mine drainage sample and groundwater sample during a 3-month period was -5 and +3%, respectively. PMID:12038832

  10. Perfluoroalkyl Acid Concentrations in Blood Samples Subjected to Transportation and Processing Delay

    PubMed Central

    Bach, Cathrine Carlsen; Henriksen, Tine Brink; Bossi, Rossana; Bech, Bodil Hammer; Fuglsang, Jens; Olsen, Jørn; Nohr, Ellen Aagaard

    2015-01-01

    Background In studies of perfluoroalkyl acids, the validity and comparability of measured concentrations may be affected by differences in the handling of biospecimens. We aimed to investigate whether measured plasma levels of perfluoroalkyl acids differed between blood samples subjected to delay and transportation prior to processing and samples with immediate processing and freezing. Methods Pregnant women recruited at Aarhus University Hospital, Denmark, (n = 88) provided paired blood samples. For each pair of samples, one was immediately processed and plasma was frozen, and the other was delayed and transported as whole blood before processing and freezing of plasma (similar to the Danish National Birth Cohort). We measured 12 perfluoroalkyl acids and present results for compounds with more than 50% of samples above the lower limit of quantification. Results For samples taken in the winter, relative differences between the paired samples ranged between -77 and +38% for individual perfluoroalkyl acids. In most cases concentrations were lower in the delayed and transported samples, e.g. the relative difference was -29% (95% confidence interval -30; -27) for perfluorooctane sulfonate. For perfluorooctanoate there was no difference between the two setups [corresponding estimate 1% (0, 3)]. Differences were negligible in the summer for all compounds. Conclusions Transport of blood samples and processing delay, similar to conditions applied in some large, population-based studies, may affect measured perfluoroalkyl acid concentrations, mainly when outdoor temperatures are low. Attention to processing conditions is needed in studies of perfluoroalkyl acid exposure in humans. PMID:26356420

  11. Extraction Chromatographic Methods in the Sample Preparation Sequence for Thermal Ionization Mass Spectrometric Analysis of Plutonium Isotopes

    SciTech Connect

    Grate, Jay W.; O'Hara, Matthew J.; Farawila, Anne F.; Douglas, Matthew; Haney, Morgan M.; Peterson, Steve L.; Maiti, Tapas C.; Aardahl, Christopher L.

    2011-10-17

    A sample preparation sequence for actinide isotopic analysis by TIMS is described that includes column-based extraction chromatography as the first separation step, followed by anion exchange column separations. The sequence is designed to include a wet ashing step after the extraction chromatography to prevent any leached extractant or oxalic acid eluent reagents from interfering with subsequent separations, source preparation, or TIMS ionization. TEVA-resin and DGA-resin materials, containing extractants that consist only of C, N, O, and H atoms, were investigated for isolation of plutonium. Radiotracer level studies confirmed expected high yields from column-based separation procedures. Femtogram-level studies were carried out with TIMS detection, using multiple isotopic spikes through the separation sequence. Pu recoveries were 87% and 86% for TEVA- and DGA-resins separations respectively. The Pu recoveries from 400 {mu}L anion-exchange column separations were 89% and 93% for trial sequences incorporating TEVA and DGA-resin. Thus, a prior extraction chromatography step in the sequence did not interfere with the subsequent anion exchange separation when a simple wet ash step was carried out in between these column separations. The average measurement efficiency, for Pu, encompassing the chemical separation recoveries and the TIMS ionization efficiency, was 2.73 {+-} 0.77% (2-sigma) for the DGA-resin trials and 2.67 {+-} 0.54% for the TEVA-resin trials, compared to 3.41% and 2.37% (average 2.89%) for two spikes in the experimental set. These compare with an average measurement efficiency of 2.78 {+-} 1.70%, n = 33 from process benchmark analyses using Pu spikes processed through a sequence of oxalate precipitation, wet ash, iron hydroxide precipitation, and anion exchange column separations. We conclude that extraction chromatography can be a viable separation procedure as part of a multistep sequence for TIMS sample preparation.

  12. Studies on the oxidation of hexamethylbenzene 2: Preparation of dimethylpyromellitic acid

    NASA Technical Reports Server (NTRS)

    Chiba, K.; Tomura, S.

    1986-01-01

    Hexamethylbenzene (HMB) was difficult to be oxidized with an alkaline potassium permanganate solution, since HMB was insoluble in an aqueous alkaline solution. But, when HMB was warmed with 50% nitric acid for a short time, and then treated with aqueous potassium permanganate, the reaction occurred readily and dimethylpyromellitic acid was obtained. When HMB was warmed with 50% nitric acid for 1 to 2 minutes, a yellow material was produced, which was soluble in hot aqueous potassium hydroxide, though free from carboxylic acids. It contained a little amount of bis-(nitromethyl)prehnitene and several unknown compounds. Further, the heat stability of polyimide prepared by the reaction of tetramethyldimethylpyromellitate with 4,4 prime-diaminodiphenylmethane turned out to be nearly equal to that of polyimide prepared from tetramethylpyromellitate.

  13. Formic acid requirement for the Savannah River Site Defense Waste Processing Facility melter feed preparation

    SciTech Connect

    Hsu, C.W.

    1991-01-01

    The Westinghouse Savannah River Company (WSRC) will vitrify the high-level radioactive waste into a borosilicate glass wasteform using a slurry-fed, joule-heated melter. Formic acid is used to treat the sludge slurry for melter feed preparation. Both a minimum formate requirement and a maximum allowable formate level need to be established to adequately prepare the sludge for melter feed. The data from the Savannah River Laboratory (SRL) Scale Glass Melter (SGM), Integrated DWPF Melter System (IDMS), and research mini-melter runs were used for this purpose. The stoichiometry for major reactions during formic acid treatment was revised to reflect the more predominant chemical reactions and their yields. A minimum formic acid requirement was established according to this revised stoichiometry. Methods for determining the minimum level of formic acid were specified. An operating envelope that includes the maximum total formate level and the minimum nitrate levels, was also proposed. 5 refs., 3 figs., 4 tabs.

  14. Comparison of two sample preparation techniques for sniffing experiments with broccoli (Brassica oleracea var. italica Plenck).

    PubMed

    Ulrich, D; Krumbein, A; Schonhof, I; Hoberg, E

    1998-12-01

    The suitability of the headspace solid phase microextraction (HSSPME) for gas chromatography-olfactometry (GC-O) with aroma extract dilution analysis in comparison to the dynamic head space sampling on a Tenax trap was tested exemplarily by the aroma volatiles of fresh broccoli. A high number of odour sensations in qualitative olfactometry was registered with both sample preparation techniques. The key aroma compounds of the fresh broccoli material are represented by high flavour dilution factors with dynamic head space sampling and headspace SPME. The SPME method has found to be a convenient and fast technique suitable especially for qualitative GC-O. The adsorption selectivity of the fiber and the substance discrimination have to be taken into account for quantitative use like aroma extract dilution analysis. PMID:9881367

  15. Cryo-focused Ion Beam Sample Preparation for Imaging Vitreous Cells by Cryo-electron Tomography

    PubMed Central

    Schaffer, Miroslava; Engel, Benjamin D.; Laugks, Tim; Mahamid, Julia; Plitzko, Jürgen M.; Baumeister, Wolfgang

    2016-01-01

    Cryo-electron tomography (CET) is a well-established technique for imaging cellular and molecular structures at sub-nanometer resolution. As the method is limited to samples that are thinner than 500 nm, suitable sample preparation is required to attain CET data from larger cell volumes. Recently, cryo-focused ion beam (cryo-FIB) milling of plunge-frozen biological material has been shown to reproducibly yield large, homogeneously thin, distortion-free vitreous cross-sections for state-of-the-art CET. All eukaryotic and prokaryotic cells that can be plunge-frozen can be thinned with the cryo-FIB technique. Together with advances in low-dose microscopy, this has shifted the frontiers of in situ structural biology. In this protocol we describe the typical steps of the cryo-FIB technique, starting with fully grown cell cultures. Three recently investigated biological samples are given as examples. PMID:27294174

  16. Enhancing sample preparation capabilities for accelerator mass spectrometry radiocarbon and radiocalcium studies

    SciTech Connect

    Taylor, R.E.

    1991-08-20

    With support provided by the LLNL Accelerator Mass Spectrometry Laboratory, the UCR Radiocarbon Laboratory continued its studies involving sample pretreatment and target preparation for both AMS radiocarbon ({sup 14}C) and radiocalcium ({sup 41}Ca) involving applications to archaeologically -- and paleoanthropologically- related samples. With regard to AMS {sup 14}C-related studies, we have extended the development of a series of procedures which have, as their initial goal, the capability to combust several hundred microgram amounts of a chemically-pretreated organic sample and convert the resultant CO{sub 2} to graphitic carbon which will consistently yield relatively high {sup 13}C{sup {minus}} ion currents and blanks which will yield, on a consistent basis, {sup 14}C count rates at or below 0.20% modern, giving an 2 sigma age limit of >50,000 yr BP.

  17. A high-throughput robotic sample preparation system and HPLC-MS/MS for measuring urinary anatabine, anabasine, nicotine and major nicotine metabolites☆

    PubMed Central

    Wei, Binnian; Feng, June; Rehmani, Imran J.; Miller, Sharyn; McGuffey, James E.; Blount, Benjamin C.; Wang, Lanqing

    2015-01-01

    Background Most sample preparation methods characteristically involve intensive and repetitive labor, which is inefficient when preparing large numbers of samples from population-scale studies. Methods This study presents a robotic system designed to meet the sampling requirements for large population-scale studies. Using this robotic system, we developed and validated a method to simultaneously measure urinary anatabine, anabasine, nicotine and seven major nicotine metabolites: 4-Hydroxy-4-(3-pyridyl)butanoic acid, cotinine-N-oxide, nicotine-N-oxide, trans-3′-hydroxycotinine, norcotinine, cotinine and nornicotine. We analyzed robotically prepared samples using high-performance liquid chromatography (HPLC) coupled with triple quadrupole mass spectrometry in positive electrospray ionization mode using scheduled multiple reaction monitoring (sMRM) with a total runtime of 8.5 min. Results The optimized procedure was able to deliver linear analyte responses over a broad range of concentrations. Responses of urine-based calibrators delivered coefficients of determination (R2) of >0.995. Sample preparation recovery was generally higher than 80%. The robotic system was able to prepare four 96-well plate (384 urine samples) per day, and the overall method afforded an accuracy range of 92–115%, and an imprecision of <15.0% on average. Conclusions The validation results demonstrate that the method is accurate, precise, sensitive, robust, and most significantly labor-saving for sample preparation, making it efficient and practical for routine measurements in large population-scale studies such as the National Health and Nutrition Examination Survey (NHANES) and the Population Assessment of Tobacco and Health (PATH) study. PMID:24968308

  18. Methods of biological fluids sample preparation - biogenic amines, methylxanthines, water-soluble vitamins.

    PubMed

    Płonka, Joanna

    2015-01-01

    In recent years demands on the amount of information that can be obtained from the analysis of a single sample have increased. For time and economic reasons it is necessary to examine at the same time larger number of compounds, and compounds from different groups. This can best be seen in such areas as clinical analysis. In many diseases, the best results for patients are obtained when treatment fits the individual characteristics of the patient. Dosage monitoring is important at the beginning of therapy and in the full process of treatment. In the treatment of many diseases biogenic amines (dopamine, serotonin) and methylxanthines (theophylline, theobromine, caffeine) play an important role. They are used as drugs separately or in combination with others to support and strengthen the action of other drugs - for example, the combination of caffeine and paracetamol. Vitamin supplementation may be also an integral part of the treatment process. Specification of complete sample preparation parameters for extraction of the above compounds from biological matrices has been reviewed. Particular attention was given to the preparation stage and extraction methods. This review provides universal guidance on establishing a common procedures across laboratories to facilitate the preparation and analysis of all discussed compounds. PMID:25381720

  19. Rapid Microbial Sample Preparation from Blood Using a Novel Concentration Device

    PubMed Central

    Boardman, Anna K.; Campbell, Jennifer; Wirz, Holger; Sharon, Andre; Sauer-Budge, Alexis F.

    2015-01-01

    Appropriate care for bacteremic patients is dictated by the amount of time needed for an accurate diagnosis. However, the concentration of microbes in the blood is extremely low in these patients (1–100 CFU/mL), traditionally requiring growth (blood culture) or amplification (e.g., PCR) for detection. Current culture-based methods can take a minimum of two days, while faster methods like PCR require a sample free of inhibitors (i.e., blood components). Though commercial kits exist for the removal of blood from these samples, they typically capture only DNA, thereby necessitating the use of blood culture for antimicrobial testing. Here, we report a novel, scaled-up sample preparation protocol carried out in a new microbial concentration device. The process can efficiently lyse 10 mL of bacteremic blood while maintaining the microorganisms’ viability, giving a 30‑μL final output volume. A suite of six microorganisms (Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Haemophilus influenzae, Pseudomonas aeruginosa, and Candida albicans) at a range of clinically relevant concentrations was tested. All of the microorganisms had recoveries greater than 55% at the highest tested concentration of 100 CFU/mL, with three of them having over 70% recovery. At the lowest tested concentration of 3 CFU/mL, two microorganisms had recoveries of ca. 40–50% while the other four gave recoveries greater than 70%. Using a Taqman assay for methicillin-sensitive S. aureus (MSSA)to prove the feasibility of downstream analysis, we show that our microbial pellets are clean enough for PCR amplification. PCR testing of 56 spiked-positive and negative samples gave a specificity of 0.97 and a sensitivity of 0.96, showing that our sample preparation protocol holds great promise for the rapid diagnosis of bacteremia directly from a primary sample. PMID:25675242

  20. Automated sample preparation station for studying self-diffusion in porous solids with NMR spectroscopy

    SciTech Connect

    Hedin, Niklas; DeMartin, Gregory J.; Reyes, Sebastian C.

    2006-03-15

    In studies of gas diffusion in porous solids with nuclear magnetic resonance (NMR) spectroscopy the sample preparation procedure becomes very important. An apparatus is presented here that pretreats the sample ex situ and accurately sets the desired pressure and temperature within the NMR tube prior to its introduction in the spectrometer. The gas manifold that supplies the NMR tube is also connected to a microbalance containing another portion of the same sample, which is kept at the same temperature as the sample in the NMR tube. This arrangement permits the simultaneous measurement of the adsorption loading on the sample, which is required for the interpretation of the NMR diffusion experiments. Furthermore, to ensure a good seal of the NMR tube, a hybrid valve design composed of titanium, a Teflon registered seat, and Kalrez registered O-rings is utilized. A computer controlled algorithm ensures the accuracy and reproducibility of all the procedures, enabling the NMR diffusion experiments to be performed at well controlled conditions of pressure, temperature, and amount of gas adsorbed on the porous sample.

  1. An integrated pipeline for sample preparation and characterization at the EMBL@PETRA3 synchrotron facilities.

    PubMed

    Boivin, Stephane; Kozak, Sandra; Rasmussen, Gry; Nemtanu, Ioana Maria; Vieira, Vanessa; Meijers, Rob

    2016-02-15

    The characterization of macromolecular samples at synchrotrons has traditionally been restricted to direct exposure to X-rays, but beamline automation and diversification of the user community has led to the establishment of complementary characterization facilities off-line. The Sample Preparation and Characterization (SPC) facility at the EMBL@PETRA3 synchrotron provides synchrotron users access to a range of biophysical techniques for preliminary or parallel sample characterization, to optimize sample usage at the beamlines. Here we describe a sample pipeline from bench to beamline, to assist successful structural characterization using small angle X-ray scattering (SAXS) or macromolecular X-ray crystallography (MX). The SPC has developed a range of quality control protocols to assess incoming samples and to suggest optimization protocols. A high-throughput crystallization platform has been adapted to reach a broader user community, to include chemists and biologists that are not experts in structural biology. The SPC in combination with the beamline and computational facilities at EMBL Hamburg provide a full package of integrated facilities for structural biology and can serve as model for implementation of such resources for other infrastructures. PMID:26255961

  2. Biological sample preparation and {sup 41}Ca AMS measurement at LLNL

    SciTech Connect

    Freeman, S.P.H.T.; Southon, J.R.; Bench, G.S.; McAninch, J.E.; Serfass, R.E.; Fang, Y.; King, J.C.; Woodhouse, L.R.

    1994-10-10

    Calcium metabolism in biology may be better understood by the use of {sup 41}Ca labels, although detection by accelerator mass spectrometry (AMS) is required. Methodologies for preparation of urine samples and subsequent AMS measurement were investigated. Novel attempts at preparing CaH{sub 2} were unsuccessful, but CaF{sub 2} of sufficient purity could be produced by precipitation of calcium from urine as oxalate, followed by separation of calcium by cation exchange chromatography and washing the CaF{sub 2} precipitate. The presence of some remaining impurities could be compensated for by selecting the appropriate accelerated ion charge state for AMS. The use of projectile x rays for isobar discrimination was explored as an alternative to the conventional dE/dx device.

  3. Polymerase chain reaction system using magnetic beads for analyzing a sample that includes nucleic acid

    SciTech Connect

    Nasarabadi, Shanavaz

    2011-01-11

    A polymerase chain reaction system for analyzing a sample containing nucleic acid includes providing magnetic beads; providing a flow channel having a polymerase chain reaction chamber, a pre polymerase chain reaction magnet position adjacent the polymerase chain reaction chamber, and a post pre polymerase magnet position adjacent the polymerase chain reaction chamber. The nucleic acid is bound to the magnetic beads. The magnetic beads with the nucleic acid flow to the pre polymerase chain reaction magnet position in the flow channel. The magnetic beads and the nucleic acid are washed with ethanol. The nucleic acid in the polymerase chain reaction chamber is amplified. The magnetic beads and the nucleic acid are separated into a waste stream containing the magnetic beads and a post polymerase chain reaction mix containing the nucleic acid. The reaction mix containing the nucleic acid flows to an analysis unit in the channel for analysis.

  4. Purifying Nucleic Acids from Samples of Extremely Low Biomass

    NASA Technical Reports Server (NTRS)

    La Duc, Myron; Osman, Shariff; Venkateswaran, Kasthuri

    2008-01-01

    A new method is able to circumvent the bias to which one commercial DNA extraction method falls prey with regard to the lysing of certain types of microbial cells, resulting in a truncated spectrum of microbial diversity. By prefacing the protocol with glass-bead-beating agitation (mechanically lysing a much more encompassing array of cell types and spores), the resulting microbial diversity detection is greatly enhanced. In preliminary studies, a commercially available automated DNA extraction method is effective at delivering total DNA yield, but only the non-hardy members of the bacterial bisque were represented in clone libraries, suggesting that this method was ineffective at lysing the hardier cell types. To circumvent such a bias in cells, yet another extraction method was devised. In this technique, samples are first subjected to a stringent bead-beating step, and then are processed via standard protocols. Prior to being loaded into extraction vials, samples are placed in micro-centrifuge bead tubes containing 50 micro-L of commercially produced lysis solution. After inverting several times, tubes are agitated at maximum speed for two minutes. Following agitation, tubes are centrifuged at 10,000 x g for one minute. At this time, the aqueous volumes are removed from the bead tubes and are loaded into extraction vials to be further processed via extraction regime. The new method couples two independent methodologies in such as way as to yield the highest concentration of PCR-amplifiable DNA with consistent and reproducible results and with the most accurate and encompassing report of species richness.

  5. Homogeneous sample preparation for automated high throughput analysis with matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry.

    PubMed

    Onnerfjord, P; Ekström, S; Bergquist, J; Nilsson, J; Laurell, T; Marko-Varga, G

    1999-01-01

    This work presents a simple method for obtaining homogeneous sample surfaces in matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) for the automated analysis of peptides and proteins. The sample preparation method is based on applying the sample/matrix mixture onto a pre-deposited highly diluted matrix spot. The pre-deposited crystals act as seeds for the new sample containing crystals which become much smaller in size and more evenly distributed than with conventional methods. This 'seed-layer' method was developed, optimised and compared with the dried-droplet method using peptides and proteins in the 1000-20,000 Da range. The seed-layer method increases the surface homogeneity, spot to spot reproducibility and sample washability as compared with the commonly used dried-droplet method. This methodology is applicable to alpha-cyanohydroxycinnamic acid, sinapinic acid and ferulic acid, which all form homogeneous crystal surfaces. Within-spot variation and between-spot variation was investigated using statistics at a 95% confidence level (n = 36). The statistical values were generated from more than 5000 data points collected from 500 spectra. More than 90% of the sample locations results in high intensity spectra with relatively low standard deviations (RSDs). Typically obtained data showed an RSD of 19-35% within a sample spot as well as in-between spots for proteins, and an RSD of < or = 50% for peptides. Linear calibration curves were obtained within one order of magnitude using internal calibration with a point-RSD of 3% (n = 10). The sample homogeneity allows mass spectra (average of 16 laser shots) to be obtained on each individual sample within 15 sec, whereby a 100 spot target plate can be run in 25 min. High density target plates using the seed-layer method were prepared by spotting approximately 100 picoliter droplets onto the target, resulting in sample spots < or = 500 microns in diameter using a flow

  6. Analytical services Organization Union Valley sample Preparation facility Polychlorinated Biphenyl (PCB) Annual Inventory Document

    SciTech Connect

    Brown, B.J.

    1998-06-01

    The Analytical Services Organization (ASO), Union Valley Sample Preparation Facility (UVSPF), provides analytical testing in support of the Department of Energy (DOE), Oak Ridge Operations (ORO), and associated sites. Samples generated on the Oak Ridge Reservation (ORR) are routinely received at the WSPF for analytical evaluatiotiidentification. Many of these samples are polychlorinated biphenyl (PCB) regulated from a source or being sent to the facility to determine PCB content. PCB laboratory wastes in solid and liquid form are generated during the evaluation of these materials, requiring the WSPF staff to maintain formal storage areas for staging the materials prior to off-site shipment for disposal. The purpose of this report is to fulfill the requirements set forth in Title 40, Code of Federal Regulations (CFR), Part 761.180(a), Subpart J, which requires owners or operators of a facility using or storing PCBS to prepare an annual inventory document by July 1 of the current year which covers the previous calendar year. This report provides documentation of the inventory of PCB materials/wastes that were generated, stored for dispos~ and shipped off site for disposal for the period January 1, 1997, to January 1, 1998. The following is a summary of materials/wastes subject to the aforementioned reporting requirements.

  7. A sample preparation method for recovering suppressed analyte ions in MALDI TOF MS.

    PubMed

    Lou, Xianwen; de Waal, Bas F M; Milroy, Lech-Gustav; van Dongen, Joost L J

    2015-05-01

    In matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS), analyte signals can be substantially suppressed by other compounds in the sample. In this technical note, we describe a modified thin-layer sample preparation method that significantly reduces the analyte suppression effect (ASE). In our method, analytes are deposited on top of the surface of matrix preloaded on the MALDI plate. To prevent embedding of analyte into the matrix crystals, the sample solution were prepared without matrix and efforts were taken not to re-dissolve the preloaded matrix. The results with model mixtures of peptides, synthetic polymers and lipids show that detection of analyte ions, which were completely suppressed using the conventional dried-droplet method, could be effectively recovered by using our method. Our findings suggest that the incorporation of analytes in the matrix crystals has an important contributory effect on ASE. By reducing ASE, our method should be useful for the direct MALDI MS analysis of multicomponent mixtures. PMID:26259660

  8. microPREP: a new laser tool for high-volume sample preparation

    NASA Astrophysics Data System (ADS)

    Wagner, Uwe; Petsch, Tino; Krause, Michael; Höche, Thomas

    2016-03-01

    Over the past fifty year, lasers have perpetuated to find new, often groundbreaking applications in science and technology. The most important features of lasers are that photons are inherently free of elemental contamination, extremely high energy densities can be focused in very small areas and the laser beam can be precisely positioned using deflection mirrors. By reducing pulse lengths from a few nanoseconds down to the picosecond or femtosecond range, material's ablation is becoming increasingly "athermal", i.e. structure damage by local heating is reduced to well below a few microns. In view of these outstanding characteristics of lasers as tools for micromachining, it is very surprising that sample preparation for microstructure diagnostics so far hasn't made use of laser technology. microPREPTM, the all-new, patented laser-micromachining tool developed by 3D-Micromac is the first instrument to make fast, clean, and efficient laser ablation available for the preparation of samples for microstructure diagnostics. Exemplified for a sample to be investigated by transmission electron microscopy (TEM) and following a three-stage approach, a supporting basic structure is cut from the feedstock first. Second, the supported structure is thinned down to a few micron of residual thickness and third, the supported and thinned structure is polished using an ion broad beam. Illustrated by numerous examples, it is shown that this technology is ready to be applied on different areas of microstructure diagnostics and has very high potential for failure diagnostics.

  9. Acid and redox properties of mixed oxides prepared by calcination of chromate-containing layered double hydroxides

    SciTech Connect

    Arco, M. del; Carriazo, D.; Martin, C.; Perez-Grueso, A.M.; Rives, V. . E-mail: vrives@usal.es

    2005-11-15

    Layered double hydroxides (LDHs) with Mg and Al in the layers and carbonate, nitrate or chloride in the interlayer, or with Zn and Al in the layers and chloride in the interlayer, have been prepared by coprecipitation, and have been used as precursors to prepare chromate-containing LDHs. All these systems, as well as those obtained upon their calcination up to 800 deg. C, have been characterised by powder X-ray diffraction, FT-IR and vis-UV spectroscopies, temperature-programmed reduction (TPR), nitrogen adsorption at -196 deg. C for surface texture and porosity assessment, and FT-IR monitoring of pyridine adsorption for surface acidity determination. The results obtained show that the crystallinity of the chromate-containing LDH depends on the precursor used. The layered structure of the Mg, Al systems is stabilised up to 400 deg. C upon incorporation of chromate; however, the Zn,Al-chromate samples collapse between 200 and 300 deg. C, with simultaneous formation of ZnO. Calcination of the samples above 400 deg. C gives rise to a reduction of Cr(VI) to Cr(III), as concluded from vis-UV spectroscopic studies. The TPR profiles show that chromate in ZnAl hydrotalcite is more easily reduced than that incorporated in the magnesium ones. Moderately strong surface Lewis acid sites exist in all samples calcined below 500 deg. C.

  10. The search for and identification of amino acids, nucleobases and nucleosides in samples returned from Mars

    NASA Technical Reports Server (NTRS)

    Gehrke, Charles W.; Ponnamperuma, Cyril; Kuo, Kenneth C.; Stalling, David L.; Zumwalt, Robert W.

    1989-01-01

    An investigation of the returned Mars samples for biologically important organic compounds, with emphasis on amino acid, the puring and pyrimidine bases, and nucleosides is proposed. These studies would be conducted on subsurface samples obtained by drilling past the surface oxidizing layer with emphasis on samples containing the larges quantities of organic carbon as determined by the rover gas chromatographic mass spectrometer (GCMS). Extraction of these molecules from the returned samples will be performed using the hydrothermal extraction technique described by Cheng and Ponnamperuma. More rigorous extraction methods will be developed and evaluated. For analysis of the extract for free amino acids or amino acids present in a bound or peptidic form, aliquots will be analyzed by capillary GCMS both before and after hydrolysis with 6N hydrochloric acid. Establishment of the presence of amino acids would then lead to the next logical step which would be the use of chiral stationary gas chromatography phases to determine the enatiomeic composition of the amino acids present, and thus potentially establish their biotic or abiotic origin. Confirmational analyses for amino acids would include ion-exchange and reversed-phase liquid chromatographic analysis. For analyses of the returned Mars samples for nucleobases and nucleosides, affinity and reversed-phase liquid chromatography would be utilized. This technology coupled with scanning UV detection for identification, presents a powerful tool for nucleobase and nucleoside analysis. Mass spectrometric analysis of these compounds would confirm their presence in samples returned form Mars.

  11. Preparation and characterization of (10)B boric acid with high purity for nuclear industry.

    PubMed

    Zhang, Weijiang; Liu, Tianyu; Xu, Jiao

    2016-01-01

    Boric acid is often added into coolant as neutron capture agent for pressurized water reactor, whose amount is influenced by its abundance and purity. Therefore, the preparation of enriched (10)B boric acid with high purity is beneficial to nuclear industry. (10)B is also used in developing tumor-specific boronated drugs in boron neutron capture therapy. The boronated drug can be administered to patient intravenously, intratumorally, or deposited at tumor site in surgical excision. Thus, enriched (10)B boric acid is of practical significance in the field of medicine. Self-made boron trifluoride-methanol-complex solution was selected as one of the experimental reagents, and the preparation of (10)B acid was realized by one-step reaction for the complexes with water and calcium chloride. The determination of electrical conductivity in reaction process proves that the optimum reaction time was 16-20 h. Furthermore, the effect of reaction time, ratio of calcium chloride to complex as well as the amount of water on the purity and yield of boric acid was investigated. Finally, the optimum reaction time was 20 h, the optimal solid-liquid ratio (molar ratio) was 3:1, and the amount of water was 1 L of deionized water for each mol of the complex. H2O2 was added in the reaction process to remove Fe(2+). After recrystallization, IR spectra of (10)B boric acid was measured and compared with standard to verify the product of boric acid. The feasibility of the preparation method was determined by the detection of XRD of boric acid. To observe the morphology by polarizing microscope, crystal structure was obtained. The purity of the final product is 99.95 %, and the yield is 96.47 %. The ion concentration of boric acid accords with the national standard of high purity, which was determined by ICP. PMID:27516940

  12. Application and comparison of high-speed countercurrent chromatography and high performance liquid chromatography in preparative enantioseparation of α-substitution mandelic acids

    PubMed Central

    Tong, Shengqiang; Zhang, Hu; Shen, Mangmang; Ito, Yoichiro; Yan, Jizhong

    2014-01-01

    Preparative enantioseparations of α-cyclopentylmandelic acid and α-methylmandelic acid by high-speed countercurrent chromatography (HSCCC) and high performance liquid chromatography (HPLC) were compared using hydroxypropy-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD) as the chiral mobile phase additives. In preparative HPLC the enantioseparation was achieved on the ODS C18 reverse phase column with the mobile phase composed of a mixture of acetonitrile and 0.10 mol L−1 phosphate buffer at pH 2.68 containing 20 mmol L−1 HP-β-CD for α-cyclopentylmandelic acid and 20 mmol L−1 SBE-β-CD for α-methylmandelic acid. The maximum sample size for α-cyclopentylmandelic acid and α-methylmandelic acid was only about 10 mg and 5 mg, respectively. In preparative HSCCC the enantioseparations of these two racemates were performed with the two-phase solvent system composed of n-hexane-methyl tert.-butyl ether-0.1 molL−1 phosphate buffer solution at pH 2.67 containing 0.1 mol L−1 HP-β-CD for α-cyclopentylmandelic acid (8.5:1.5:10, v/v/v) and 0.1 mol L−1 SBE-β-CD for α-methylmandelic acid (3:7:10, v/v/v). Under the optimum separation conditions, total 250 mg of racemic α-cyclopentylmandelic acid could be completely enantioseparated by HSCCC with HP-β-CD as a chiral mobile phase additive in a single run, yielding 105-110 mg of enantiomers with 95-98% purity and 85-90% recovery. But, no complete enantioseparation of α-methylmandelic acid was achieved by preparative HSCCC with either of the chiral selectors due to their limited enantioselectivity. In this paper preparative enantioseparation by HSCCC and HPLC was compared from various aspects. PMID:25983356

  13. On-line microdialysis sample cleanup for electrospray ionization mass spectrometry of nucleic acid samples

    SciTech Connect

    Liu, C.; Wu, Q.; Harms, A.C.; Smith, R.D.

    1996-09-15

    A major limitation of electrospray ionization mass spectrometry (ESI-MS) for oligonucleotide analysis arises due to sodium adduction, a problem that increases with molecular weight. Sodium adduction can preclude useful measurements when limited sample sizes prevent off-line cleanup. A novel and generally useful on-line microdialysis technique is described for the rapid (nearly 1-5 min) DNA sample cleanup for ESI-MS. Mass spectra of oligonucleotides of different size and sequence showing no significant sodium adduct peaks were obtained using the on-line microdialysis system with sodium chloride concentrations as high as 250 mM. Signal-to-noise ratios were also greatly enhanced compared to direct infusion of the original samples. By using ammonium acetate as the dialysis buffer, it was also found that the noncovalent association of double-stranded oligonucleotides could be preserved during the microdialysis process, allowing analysis by ESI-MS. 33 refs., 6 figs.

  14. Review of sample preparation strategies for MS-based metabolomic studies in industrial biotechnology.

    PubMed

    Causon, Tim J; Hann, Stephan

    2016-09-28

    Fermentation and cell culture biotechnology in the form of so-called "cell factories" now play an increasingly significant role in production of both large (e.g. proteins, biopharmaceuticals) and small organic molecules for a wide variety of applications. However, associated metabolic engineering optimisation processes relying on genetic modification of organisms used in cell factories, or alteration of production conditions remain a challenging undertaking for improving the final yield and quality of cell factory products. In addition to genomic, transcriptomic and proteomic workflows, analytical metabolomics continues to play a critical role in studying detailed aspects of critical pathways (e.g. via targeted quantification of metabolites), identification of biosynthetic intermediates, and also for phenotype differentiation and the elucidation of previously unknown pathways (e.g. via non-targeted strategies). However, the diversity of primary and secondary metabolites and the broad concentration ranges encompassed during typical biotechnological processes means that simultaneous extraction and robust analytical determination of all parts of interest of the metabolome is effectively impossible. As the integration of metabolome data with transcriptome and proteome data is an essential goal of both targeted and non-targeted methods addressing production optimisation goals, additional sample preparation steps beyond necessary sampling, quenching and extraction protocols including clean-up, analyte enrichment, and derivatisation are important considerations for some classes of metabolites, especially those present in low concentrations or exhibiting poor stability. This contribution critically assesses the potential of current sample preparation strategies applied in metabolomic studies of industrially-relevant cell factory organisms using mass spectrometry-based platforms primarily coupled to liquid-phase sample introduction (i.e. flow injection, liquid

  15. An analytical method for trifluoroacetic Acid in water and air samples using headspace gas chromatographic determination of the methyl ester.

    PubMed

    Zehavi, D; Seiber, J N

    1996-10-01

    An analytical method has been developed for the determination of trace levels of trifluoroacetic acid (TFA), an atmospheric breakdown product of several of the hydrofluorocarbon (HFC) and hydrochlorofluorocarbon (HCFC) replacements for the chlorofluorocarbon (CFC) refrigerants, in water and air. TFA is derivatized to the volatile methyl trifluoroacetate (MTFA) and determined by automated headspace gas chromatography (HSGC) with electron-capture detection or manual HSGC using GC/MS in the selected ion monitoring (SIM) mode. The method is based on the reaction of an aqueous sample containing TFA with dimethyl sulfate (DMS) in concentrated sulfuric acid in a sealed headspace vial under conditions favoring distribution of MTFA to the vapor phase. Water samples are prepared by evaporative concentration, during which TFA is retained as the anion, followed by extraction with diethyl ether of the acidified sample and then back-extraction of TFA (as the anion) in aqueous bicarbonate solution. The extraction step is required for samples with a relatively high background of other salts and organic materials. Air samples are collected in sodium bicarbonate-glycerin-coated glass denuder tubes and prepared by rinsing the denuder contents with water to form an aqueous sample for derivatization and analysis. Recoveries of TFA from spiked water, with and without evaporative concentration, and from spiked air were quantitative, with estimated detection limits of 10 ng/mL (unconcentrated) and 25 pg/mL (concentrated 250 mL:1 mL) for water and 1 ng/m(3) (72 h at 5 L/min) for air. Several environmental air, fogwater, rainwater, and surface water samples were successfully analyzed; many showed the presence of TFA. PMID:21619278

  16. Effects of sampling, preparation and defecation on metal concentrations in selected invertebrates at urban sites.

    PubMed

    Zödl, Bettina; Wittmann, Karl J

    2003-08-01

    In order to obtain basic information for designing standardized test preparation methods, the heavy metals Zn, Cu, Cd and Pb were measured in gastropods (Xerolenta obvia), oligochaetes (Lumbricus terrestris), isopods (Armadillidium vulgare, Trachelipus rathkei) and carabids (Harpalus rubripes, Calathus fuscipes) using different sampling methods and different modes of sample treatment. In some of the experiments, higher Zn, Cd and Pb, and lower Cu-contents were observed in isopods and carabids trapped with formalin-pitfalls compared to manually collected specimens (which were allowed to defecate). Defecation had marked effects on the levels of all four metals investigated in oligochaetes, and on Cd and Pb in gastropods and isopods. Cellulose was fed as an accelerator of gut passage and showed a significant effect on the Pb concentration in the soft body of gastropods. Deionate-washed isopods (A. vulgare) showed higher Cd concentrations than ultrasonic-cleaned individuals. No marked differences were observed between heat-dried and freeze-dried isopods. Carabids showed strong sex-specific differences in metal concentrations. Based on these and previous results, invertebrates should be: collected in vivo, allowed to defecate, be freeze-fixed and (at least in arthropods) ultrasonic-cleaned, determined to species level and in certain groups (carabids) also to sex, and then be sized or sorted by size (age) before further preparation and analysis. If any of these treatments is impractical, comparable sampling and preparation methods are recommended as a minimum requirement in order to avoid bias in the results and/or interpretation. PMID:12820990

  17. Preparation of certain derivatives of ursolic acid and their antimicrobial activity

    SciTech Connect

    Zaletova, N.I.; Shchavlinskii, A.N.; Tolkachev, O.N.; Vichkanova, S.A.; Fateeva, T.V.; Krutikova, N.M.; Yartseva, I.V.; Klyuev, N.A.

    1987-03-01

    The authors studied the industrial wastes from the production of an antitumorigenic preparation rosevin, in which about 18% of ursolic acid was found. They obtained several oxygen-substituted derivatives of ursolic acid by oxidation with chromic acid and KMnO/sub 4/ in different media to study their biological activity. The structure of the compounds obtained was confirmed by the data of IR and PMR spectra and also by the data of molecular mass spectroscopy with ionization of the molecules under an electron impact.

  18. Capillary gas chromatography determination of volatile organic acids in rain and fog samples

    SciTech Connect

    Kawamura, K.; Kaplan, I.R.

    1984-08-01

    A fused silica capillary gas chromatography technique is described for the determination of volatile acids (C/sub 1/-C/sub 7/) in rain samples using p-bromophenacyl esters. As the sensitivity of this method is high (GC detection limit is ca. 10 pmol), a small volume of rain (25-50 mL) or fog (1-2 mL) is needed. Spiked experiments showed that the measured concentrations of volatile acids in the spiked rain samples linearly increased with a slope of approx.1 in proportion to the concentrations of volatile acids added in the rainwater. Repeated analyses of rain samples showed that relative standard deviations are less than or equal to 18% for C/sub 1/, C/sub 2/, and C/sub 3/ acids, which are the major volatile acids.

  19. Workshop on Mars 2001: Integrated Science in Preparation for Sample Return and Human Exploration

    NASA Technical Reports Server (NTRS)

    Marshall, John (Editor); Weitz, Cathy (Editor)

    1999-01-01

    The Workshop on Mars 2001: Integrated Science in Preparation for Sample Return and Human Exploration was held on October 2-4, 1999, at the Lunar and Planetary Institute in Houston, Texas. The workshop was sponsored by the Lunar and Planetary Institute, the Mars Program Office of the Jet Propulsion Laboratory, and the National Aeronautics and Space Administration. The three-day meeting was attended by 133 scientists whose purpose was to share results from recent missions, to share plans for the 2001 mission, and to come to an agreement on a landing site for this mission.

  20. A study of the Perkin-Elmer laboratory robotic system for analytical sample preparation

    SciTech Connect

    Hartenstein, S.D.; Delmastro, J.R.

    1988-09-01

    The purpose of this study was to evaluate the abilities of a Perkin-Elmer (PE) robotic system in performing complex analytical sample preparation procedures. Until this time, reports have been written describing the physical capabilities of the robotic arm marketed by PE and the use of this arm in a pick-and-place application at the Idaho Chemical Processing Plant (ICPP). Since the robotic arm is only capable of handling and transporting objects, the ability of the PE system is dependent upon the performance capabilities of the auxiliary devices marketed with the arm. 2 refs., 2 figs., 1 tab.

  1. Preparation of magnetic polylactic acid microspheres and investigation of its releasing property for loading curcumin

    NASA Astrophysics Data System (ADS)

    Li, Fengxia; Li, Xiaoli; Li, Bin

    2011-11-01

    In order to obtain a targeting drug carrier system, magnetic polylactic acid (PLA) microspheres loading curcumin were synthesized by the classical oil-in-water emulsion solvent-evaporation method. In the Fourier transform infrared spectra of microspheres, the present functional groups of PLA were all kept invariably. The morphology and size distribution of magnetic microspheres were observed with scanning electron microscopy and dynamic light scattering, respectively. The results showed that the microspheres were regularly spherical and the surface was smooth with a diameter of 0.55-0.75 μm. Magnetic Fe 3O 4 was loaded in PLA microspheres and the content of magnetic particles was 12 wt% through thermogravimetric analysis. The magnetic property of prepared microspheres was measured by vibrating sample magnetometer. The results showed that the magnetic microspheres exhibited typical superparamagnetic behavior and the saturated magnetization was 14.38 emu/g. Through analysis of differential scanning calorimetry, the curcumin was in an amorphous state in the magnetic microspheres. The drug loading, encapsulation efficiency and releasing properties of curcumin in vitro were also investigated by ultraviolet-visible spectrum analysis. The results showed that the drug loading and encapsulation efficiency were 8.0% and 24.2%, respectively. And curcumin was obviously slowly released because the cumulative release percentage of magnetic microspheres in the phosphate buffer (pH=7.4) solution was only 49.01% in 72 h, and the basic release of curcumin finished in 120 h.

  2. Preparation and Characterization of Nanoliposomes Entrapping Medium-Chain Fatty Acids and Vitamin C by Lyophilization

    PubMed Central

    Yang, Shuibing; Liu, Chengmei; Liu, Wei; Yu, Haixia; Zheng, Huijuan; Zhou, Wei; Hu, Yaqin

    2013-01-01

    The complex nanoliposomes encapsulating both a hydrophilic drug vitamin C (vit C) and hydrophobic drug medium-chain fatty acids (MCFAs) was prepared by combining double emulsion method with dynamic high pressure microfluidization. The complex nanoliposomes was further freeze-dried under −86 °C for 48 h with sucrose at the sucrose/lipids ratio of 2:1(w/w) in order to enhance its stability. The freeze-dried complex nanoliposomes under the suitable conditions exhibited high entrapment efficiency of MCFAs (44.26 ± 3.34)%, relatively high entrapment efficiency of vit C (62.25 ± 3.43)%, low average size diameter (110.4 ± 7.28) nm and good storage stability at 4 °C for 60 days with slight changes in mean particle diameter and drug entrapment efficiencies. The results of transmission electron microscopy of freeze-dried complex nanoliposomes also showed that the freeze-dried samples with sucrose were stable without great increase in their particle sizes and without destroying their spherical shape. The results indicated that sucrose presented well protection effects in MCFAs-vit C complex nanoliposomes, suggesting the possibility of further usage in commercial liposomes. PMID:24084723

  3. Background and Artifacts Generated by the by the Sample Preparation Experiment on SAM

    NASA Astrophysics Data System (ADS)

    Belmahdi, Imene; Buch, Arnaud; Szopa, Cyril; Freissinet, Caroline; Glavin, Daniel; Coll, Patrice; Cabane, Michel; Millan, Maeva; Eigenbrode, Jennifer; Navarro-Gonzalez, Rafael; Stern, Jennifer; Coscia, David; Bonnet, Jean-Yves; Teinturier, Samuel; Morisson, Marietta; Stambouli, Moncef; Dequaire, Tristan; Mahaffy, Paul

    2016-04-01

    Sample Analysis at Mars (SAM) is one of the instruments of the Mars Science Laboratory mission. Three analytical devices composed the SAM experiment: the Tunable Laser Spectrometer (TLS), the Gas Chromatography (GC) and the Mass Spectrometer (MS). To adapt the nature of a sample to the analytical devices used, a sample preparation and gas processing system implemented with (a) a pyrolysis system, (b) wet chemistry: MTBSTFA and TMAH (c) the hydrocarbon trap (silica beads, Tenax® TA and Carbosieve G) and the injection trap (Tenax® GR composed of Tenax® TA and 30% of graphite) are employed to concentrate volatiles released from the sample prior to GC-MS analysis. Our study investigates several propositions for chlorinated hydrocarbon formation detected in the SAM background by looking for: (a) all products coming from the interaction of Tenax® and perchlorates present on Mars, (b) also between some soil sample and perchlorates and (c) sources of chlorinated hydrocarbon precursors. Here we report on the detection of chlorohydrocarbon compounds and their potential origin.

  4. Fuel properties of heptadecene isomers prepared via tandem isomerization-decarboxylation of oleic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heptadecene isomers were prepared via tandem isomerization-decarboxylation of oleic acid using catalytic triruthenium dodecacarbonyl [Ru3(CO)12]. Chromatographic and spectroscopic characterization of the isolated heptadecene mixture indicated that it consisted of 96% internal trans isomers and 4% ar...

  5. Esterification of pseudoephedrine hydrochloride by citric acid in a solid dose pharmaceutical preparation.

    PubMed

    Goel, Alok; Zhao, Zhicheng; Sørensen, Dan; Zhou, Jay; Zhang, Fa

    2016-09-10

    Esterification of pseudoephedrine hydrochloride (PSE) by citric acid was observed in a solid dose pharmaceutical preparation at room temperature and accelerated stability condition (40°C/75% relative humidity). The esterification of PSE with citric acid was confirmed by a solid-state binary reaction in the presence of minor level of water at elevated temperature to generate three isomeric esters. The structures of the pseudoephedrine citric acid esters were elucidated using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy (NMR). Occurrence of esterification in solid state, instead of amidation which is generally more favorable than esterification, is likely due to remaining HCl salt form of solid pseudoephedrine hydrochloride to protect its amino group from amidation with citric acid. In contrast, the esterification was not observed from solution reaction between PSE and citric acid. PMID:27474946

  6. Methods for point-of-care detection of nucleic acid in a sample

    DOEpatents

    Bearinger, Jane P.; Dugan, Lawrence C.

    2015-12-29

    Provided herein are methods and apparatus for detecting a target nucleic acid in a sample and related methods and apparatus for diagnosing a condition in an individual. The condition is associated with presence of nucleic acid produced by certain pathogens in the individual.

  7. Apparatus for point-of-care detection of nucleic acid in a sample

    DOEpatents

    Bearinger, Jane P.; Dugan, Lawrence C.

    2016-04-19

    Provided herein are methods and apparatus for detecting a target nucleic acid in a sample and related methods and apparatus for diagnosing a condition in an individual. The condition is associated with presence of nucleic acid produced by certain pathogens in the individual.

  8. Acid-Soluble Internal Capsules for Closed-Face Cassette Elemental Sampling and Analysis of Workplace Air

    PubMed Central

    Harper, Martin; Ashley, Kevin

    2013-01-01

    Airborne particles that are collected using closed-face filter cassettes (CFCs), which are used widely in the sampling of workplace aerosols, can deposit in places other than on the filter and thereby may not be included in the ensuing analysis. A technique for ensuring that internal non-filter deposits are included in the analysis is to collect airborne particles within an acid-soluble internal capsule that, following sampling, can be dissolved along with the filter for subsequent elemental analysis. An interlaboratory study (ILS) was carried out to evaluate the use of cellulosic CFC capsule inserts for their suitability in the determination of trace elements in airborne samples. The ILS was performed in accordance with an applicable ASTM International standard practice, ASTM E691, which describes statistical procedures for investigating interlaboratory precision. Performance evaluation materials consisted of prototype cellulose acetate capsules attached to mixed-cellulose ester filters. Batches of capsules were dosed with Pb-containing materials (standard aqueous solutions, and certified reference material soil and paint). Also, aerosol samples containing nine target analyte elements (As, Cd, Co, Cr, Cu, Fe, Pb, Mn, and Ni) were generated using a multiport sampler; various concentrations and sampling times were employed to yield samples fortified at desired loading levels. Triplicates of spiked capsules at three different loadings were conveyed to each volunteer laboratory; loading levels were unknown to the participants. The laboratories were asked to prepare the samples by acid dissolution and to analyze aliquots of extracted samples by atomic spectrometry in accordance with applicable ASTM International Standards. Participants were asked to report their results in units of μg of each target element per sample. For the elements investigated, interlaboratory precision and recovery estimates from the participating laboratories demonstrated the utility of the

  9. Capacitive deionization on-chip as a method for microfluidic sample preparation.

    PubMed

    Roelofs, Susan H; Kim, Bumjoo; Eijkel, Jan C T; Han, Jongyoon; van den Berg, Albert; Odijk, Mathieu

    2015-03-21

    Desalination as a sample preparation step is essential for noise reduction and reproducibility of mass spectrometry measurements. A specific example is the analysis of proteins for medical research and clinical applications. Salts and buffers that are present in samples need to be removed before analysis to improve the signal-to-noise ratio. Capacitive deionization is an electrostatic desalination (CDI) technique which uses two porous electrodes facing each other to remove ions from a solution. Upon the application of a potential of 0.5 V ions migrate to the electrodes and are stored in the electrical double layer. In this article we demonstrate CDI on a chip, and desalinate a solution by the removal of 23% of Na(+) and Cl(-) ions, while the concentration of a larger molecule (FITC-dextran) remains unchanged. For the first time impedance spectroscopy is introduced to monitor the salt concentration in situ in real-time in between the two desalination electrodes. PMID:25607349

  10. Sample preparation methods for quantitative detection of DNA by molecular assays and marine biosensors.

    PubMed

    Cox, Annie M; Goodwin, Kelly D

    2013-08-15

    The need for quantitative molecular methods is growing in environmental, food, and medical fields but is hindered by low and variable DNA extraction and by co-extraction of PCR inhibitors. DNA extracts from Enterococcus faecium, seawater, and seawater spiked with E. faecium and Vibrio parahaemolyticus were tested by qPCR for target recovery and inhibition. Conventional and novel methods were tested, including Synchronous Coefficient of Drag Alteration (SCODA) and lysis and purification systems used on an automated genetic sensor (the Environmental Sample Processor, ESP). Variable qPCR target recovery and inhibition were measured, significantly affecting target quantification. An aggressive lysis method that utilized chemical, enzymatic, and mechanical disruption enhanced target recovery compared to commercial kit protocols. SCODA purification did not show marked improvement over commercial spin columns. Overall, data suggested a general need to improve sample preparation and to accurately assess and account for DNA recovery and inhibition in qPCR applications. PMID:23790450

  11. An efficient and sensitive method for preparing cDNA libraries from scarce biological samples

    PubMed Central

    Sterling, Catherine H.; Veksler-Lublinsky, Isana; Ambros, Victor

    2015-01-01

    The preparation and high-throughput sequencing of cDNA libraries from samples of small RNA is a powerful tool to quantify known small RNAs (such as microRNAs) and to discover novel RNA species. Interest in identifying the small RNA repertoire present in tissues and in biofluids has grown substantially with the findings that small RNAs can serve as indicators of biological conditions and disease states. Here we describe a novel and straightforward method to clone cDNA libraries from small quantities of input RNA. This method permits the generation of cDNA libraries from sub-picogram quantities of RNA robustly, efficiently and reproducibly. We demonstrate that the method provides a significant improvement in sensitivity compared to previous cloning methods while maintaining reproducible identification of diverse small RNA species. This method should have widespread applications in a variety of contexts, including biomarker discovery from scarce samples of human tissue or body fluids. PMID:25056322

  12. Device and method of optically orienting biaxial crystals for sample preparation

    NASA Astrophysics Data System (ADS)

    Thomas, Timothy; Rossman, George R.; Sandstrom, Mark

    2014-09-01

    An optical instrument we refer to as the "biaxial orientation device" has been developed for finding the optical plane, acute bisectrix, and obtuse bisectrix in biaxial crystals by means of optically aligning conoscopically formed melatopes and measuring the angular coordinates of the melatopes, where the angular values allow for determination of the optical plane containing the optical axes using a vector algebra approach. After determination of the optical plane, the instrument allows for the sample to be aligned in the acute bisectrix or obtuse bisectrix orientations and to be transferred to a simple mechanical component for subsequent grinding and polishing, while preserving the orientation of the polished faces relative to the optical plane, acute bisectrix, and obtuse bisectrix during the grinding and polishing process. Biaxial crystalline material samples prepared in the manner are suitable for accurate spectroscopic absorption measurements in the acute bisectrix and obtuse bisectrix directions as well as perpendicular to the optical plane.

  13. Preparation and evaluation of advanced catalysts for phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Stonehart, P.; Baris, J.; Hockmuth, J.; Pagliaro, P.

    1984-01-01

    The platinum electrocatalysts were characterized for their crystallite sizes and the degree of dispersion on the carbon supports. One application of these electrocatalysts was for anodic oxidation of hydrogen in hot phosphoric acid fuel cells, coupled with the influence of low concentrations of carbon monoxide in the fuel gas stream. In a similar way, these platinum on carbon electrocatalysts were evaluated for oxygen reduction in hot phosphoric acid. Binary noble metal alloys were prepared for anodic oxidation of hydrogen and noble metal-refractory metal mixtures were prepared for oxygen reduction. An exemplar alloy of platinum and palladium (50/50 atom %) was discovered for anodic oxidation of hydrogen in the presence of carbon monoxide, and patent disclosures were submitted. For the cathode, platinum-vanadium alloys were prepared showing improved performance over pure platinum. Preliminary experiments on electrocatalyst utilization in electrode structures showed low utilization of the noble metal when the electrocatalyst loading exceeded one weight percent on the carbon.

  14. Preparation of silver-poly(acrylamide-co-methacrylic acid) composite microspheres with patterned surface structures.

    PubMed

    Xia, Huiyun; Zhang, Ying; Peng, Junxia; Fang, Yu; Gu, Zhongze

    2006-01-01

    Acrylamide (AM) and methacrylic acid (MAA) copolymer microgels were prepared by a reverse suspension polymerization technique. The microgels were used as templates for the preparation of silver-poly(acrylamide-co-methacrylic acid) [Ag-P(AM-co-MAA)] composite microspheres. The surface structures of the microspheres prepared in this way are characterized by zigzag-like structures. It was found that the composition of the microgels, the nature and dosage of surfactants, the quantity of the metal, and even the reduction methods employed have a significant effect upon the surface structures of the microspheres. X-ray diffraction analysis confirmed that Ag formed during the process is in a crystal state of a face-centered cubic structure. PMID:24058232

  15. Recent developments on field gas extraction and sample preparation methods for radiokrypton dating of groundwater

    NASA Astrophysics Data System (ADS)

    Yokochi, Reika

    2016-09-01

    Current and foreseen population growths will lead to an increased demand in freshwater, large quantities of which is stored as groundwater. The ventilation age is crucial to the assessment of groundwater resources, complementing the hydrological model approach based on hydrogeological parameters. Ultra-trace radioactive isotopes of Kr (81 Kr and 85 Kr) possess the ideal physical and chemical properties for groundwater dating. The recent advent of atom trap trace analyses (ATTA) has enabled determination of ultra-trace noble gas radioisotope abundances using 5-10 μ L of pure Kr. Anticipated developments will enable ATTA to analyze radiokrypton isotope abundances at high sample throughput, which necessitates simple and efficient sample preparation techniques that are adaptable to various sample chemistries. Recent developments of field gas extraction devices and simple and rapid Kr separation method at the University of Chicago are presented herein. Two field gas extraction devices optimized for different sampling conditions were recently designed and constructed, aiming at operational simplicity and portability. A newly developed Kr purification system enriches Kr by flowing a sample gas through a moderately cooled (138 K) activated charcoal column, followed by a gentle fractionating desorption. This simple process uses a single adsorbent and separates 99% of the bulk atmospheric gases from Kr without significant loss. The subsequent two stages of gas chromatographic separation and a hot Ti sponge getter further purify the Kr-enriched gas. Abundant CH4 necessitates multiple passages through one of the gas chromatographic separation columns. The presented Kr separation system has a demonstrated capability of extracting Kr with > 90% yield and 99% purity within 75 min from 1.2 to 26.8 L STP of atmospheric air with various concentrations of CH4. The apparatuses have successfully been deployed for sampling in the field and purification of groundwater samples.

  16. Comparison of Sample Preparation Methods Used for the Next-Generation Sequencing of Mycobacterium tuberculosis

    PubMed Central

    Tyler, Andrea D.; Christianson, Sara; Knox, Natalie C.; Mabon, Philip; Wolfe, Joyce; Van Domselaar, Gary; Graham, Morag R.; Sharma, Meenu K.

    2016-01-01

    The advent and widespread application of next-generation sequencing (NGS) technologies to the study of microbial genomes has led to a substantial increase in the number of studies in which whole genome sequencing (WGS) is applied to the analysis of microbial genomic epidemiology. However, microorganisms such as Mycobacterium tuberculosis (MTB) present unique problems for sequencing and downstream analysis based on their unique physiology and the composition of their genomes. In this study, we compare the quality of sequence data generated using the Nextera and TruSeq isolate preparation kits for library construction prior to Illumina sequencing-by-synthesis. Our results confirm that MTB NGS data quality is highly dependent on the purity of the DNA sample submitted for sequencing and its guanine-cytosine content (or GC-content). Our data additionally demonstrate that the choice of library preparation method plays an important role in mitigating downstream sequencing quality issues. Importantly for MTB, the Illumina TruSeq library preparation kit produces more uniform data quality than the Nextera XT method, regardless of the quality of the input DNA. Furthermore, specific genomic sequence motifs are commonly missed by the Nextera XT method, as are regions of especially high GC-content relative to the rest of the MTB genome. As coverage bias is highly undesirable, this study illustrates the importance of appropriate protocol selection when performing NGS studies in order to ensure that sound inferences can be made regarding mycobacterial genomes. PMID:26849565

  17. Comparison of Sample Preparation Methods Used for the Next-Generation Sequencing of Mycobacterium tuberculosis.

    PubMed

    Tyler, Andrea D; Christianson, Sara; Knox, Natalie C; Mabon, Philip; Wolfe, Joyce; Van Domselaar, Gary; Graham, Morag R; Sharma, Meenu K

    2016-01-01

    The advent and widespread application of next-generation sequencing (NGS) technologies to the study of microbial genomes has led to a substantial increase in the number of studies in which whole genome sequencing (WGS) is applied to the analysis of microbial genomic epidemiology. However, microorganisms such as Mycobacterium tuberculosis (MTB) present unique problems for sequencing and downstream analysis based on their unique physiology and the composition of their genomes. In this study, we compare the quality of sequence data generated using the Nextera and TruSeq isolate preparation kits for library construction prior to Illumina sequencing-by-synthesis. Our results confirm that MTB NGS data quality is highly dependent on the purity of the DNA sample submitted for sequencing and its guanine-cytosine content (or GC-content). Our data additionally demonstrate that the choice of library preparation method plays an important role in mitigating downstream sequencing quality issues. Importantly for MTB, the Illumina TruSeq library preparation kit produces more uniform data quality than the Nextera XT method, regardless of the quality of the input DNA. Furthermore, specific genomic sequence motifs are commonly missed by the Nextera XT method, as are regions of especially high GC-content relative to the rest of the MTB genome. As coverage bias is highly undesirable, this study illustrates the importance of appropriate protocol selection when performing NGS studies in order to ensure that sound inferences can be made regarding mycobacterial genomes. PMID:26849565

  18. Study of UltraHigh Performance Supercritical Fluid Chromatography to measure free fatty acids with out fatty acid ester preparation.

    PubMed

    Ashraf-Khorassani, M; Isaac, G; Rainville, P; Fountain, K; Taylor, L T

    2015-08-01

    Most lipids are best characterized by their fatty acids which may differ in (a) chain length, (b) degree of unsaturation, (c) configuration and position of the double bonds, and (d) the presence of other functionalities. Thus, a fast, simple, and quantitative analytical technique to determine naturally occurring free fatty acids (FFA) in different samples is very important. Just as for saponified acylglycerols, the determination of FFA's has generally been carried out by high resolution gas chromatography (HRGC). The use of an open tubular capillary column coupled with a flame ionization or mass spectrometric detector provides for both high resolution and quantification of FFA's but only after conversion of all free fatty acids to fatty acid methyl esters (FAME) or pentafluorobenzyl esters. Unfortunately, volatilization of labile ester derivatives of mono- and poly-unsaturated FFA's can cause both thermal degradation and isomerization of the fatty acid during HRGC. The employment of a second generation instrument (here referred to as UltraHigh Performance Supercritical Fluid Chromatograph, UHPSFC) with high precision for modified flow and repeated back pressure adjustment in conjunction with sub-2μm various bonded silica particles (coupled with evaporative light scattering, ELSD, and mass spectrometric, MS, detection) for separation and detection of the following mixtures is described: (a) 31 free fatty acids, (b) isomeric FFA's, and (c) lipophilic materials in two real world fish oil samples. Limits of detection for FFA's via UHPSFC/MS and UHPSFC/ELSD versus detection of FAME's via HRGC/MS are quantitatively compared. PMID:26093119

  19. High-efficiency sample preparation approach to determine acrylamide levels in high-fat foods.

    PubMed

    Li, Xiaodan; Li, Jinwei; Cao, Peirang; Liu, Yuanfa

    2016-08-01

    An improved sample preparation method was developed to enhance acrylamide recovery in high-fat foods. Prior to concentration, distilled deionized water was added to protect acrylamide from degradation, resulting in a higher acrylamide recovery rate from fried potato chips. A Chrome-Matrix C18 column (2.6 μm, 2.1 × 100 mm) was used for the first time to analyze acrylamide levels using ultra high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry, displaying good separation of acrylamide from interference. A solid-phase extraction procedure was avoided, and an average recovery of >89.00% was achieved from different food matrices for three different acrylamide spiking levels. Good reproducibility was observed, with an intraday relative standard deviation of 0.04-2.38%, and an interday relative standard deviation of 2.34-3.26%. Thus, combining the improved sample preparation method for acrylamide analysis with the separation on a Chrome-Matrix C18 column (2.6 μm, 2.1 × 100 mm) using ultra high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry is highly useful for analyzing acrylamide levels in complex food matrices. PMID:27279364

  20. Pitfalls in the sample preparation and analysis of N-acylethanolamines[S

    PubMed Central

    Skonberg, Christian; Artmann, Andreas; Cornett, Claus; Hansen, Steen Honoré; Hansen, Harald S.

    2010-01-01

    N-acylethanolamines (NAEs) are a group of lipid mediators synthesized in response to a number of physiological and pathological stimuli. Because of the low tissue concentrations of NAEs, analyses often include liquid extraction followed by solid-phase extraction and subsequent quantitation by LC/MS or GC/MS. Reported levels of NAEs vary considerably, however, and often no explanation is given for these discrepancies. Brought on by difficulties encountered during method development, the effects of using four different brands of silica-containing solid phase extraction (SPE) columns and five different brands of chloroform for sample preparation were investigated. Considerable variation in the retention and recoveries of seven NAEs and 2-arachidonoylglycerol existed between the SPE columns. Furthermore, it was found that some chloroforms contained quantifiable amounts of N-palmitoylethanolamine and N-stearoylethanolamine. Finally, it was found that use of one of the chloroforms resulted in a loss of N-oleoylethanolamine from solution due to addition of chlorine to the ω-9 bond. The identity of this reaction product was confirmed by LC-MS/MS and NMR. It is recommended that these aspects of sample preparation and analysis should be thoroughly validated during method development and the relevant information on specific brands used be reported in future communications in order to better estimate the validity of reported quantitative data. PMID:20447930

  1. Matrix compatible solid phase microextraction coating, a greener approach to sample preparation in vegetable matrices.

    PubMed

    Naccarato, Attilio; Pawliszyn, Janusz

    2016-09-01

    This work proposes the novel PDMS/DVB/PDMS fiber as a greener strategy for analysis by direct immersion solid phase microextraction (SPME) in vegetables. SPME is an established sample preparation approach that has not yet been adequately explored for food analysis in direct immersion mode due to the limitations of the available commercial coatings. The robustness and endurance of this new coating were investigated by direct immersion extractions in raw blended vegetables without any further sample preparation steps. The PDMS/DVB/PDMS coating exhibited superior features related to the capability of the external PDMS layer to protect the commercial coating, and showed improvements in terms of extraction capability and in the cleanability of the coating surface. In addition to having contributed to the recognition of the superior features of this new fiber concept before commercialization, the outcomes of this work serve to confirm advancements in the matrix compatibility of the PDMS-modified fiber, and open new prospects for the development of greener high-throughput analytical methods in food analysis using solid phase microextraction in the near future. PMID:27041299

  2. Semiautomated Sample Preparation for Protein Stability and Formulation Screening via Buffer Exchange.

    PubMed

    Ying, William; Levons, Jaquan K; Carney, Andrea; Gandhi, Rajesh; Vydra, Vicky; Rubin, A Erik

    2016-06-01

    A novel semiautomated buffer exchange process workflow was developed to enable efficient early protein formulation screening. An antibody fragment protein, BMSdab, was used to demonstrate the workflow. The process afforded 60% to 80% cycle time and scientist time savings and significant material efficiencies. These efficiencies ultimately facilitated execution of this stability work earlier in the drug development process, allowing this tool to inform the developability of potential candidates for development from a formulation perspective. To overcome the key technical challenges, the protein solution was buffer-exchanged by centrifuge filtration into formulations for stability screening in a 96-well plate with an ultrafiltration membrane, leveraging automated liquid handling and acoustic volume measurements to allow several cycles of exchanges. The formulations were transferred into a vacuum manifold and sterile filtered into a rack holding 96 glass vials. The vials were sealed with a capmat of individual caps and placed in stability stations. Stability of the samples prepared by this process and by the standard process was demonstrated to be comparable. This process enabled screening a number of formulations of a protein at an early pharmaceutical development stage with a short sample preparation time. PMID:25969451

  3. Monoaminergic uptake in synaptosomes prepared from frozen brain tissue samples of normal and narcoleptic canines.

    PubMed

    Valtier, D; Dement, W C; Mignot, E

    1992-08-14

    Canine narcolepsy, a model of the human disorder, is associated with altered catecholamine but not serotonin (5-HT) metabolism in some brain areas, particularly the amygdala. A possible explanation for these global changes could be the existence of specific defects in monoamine uptake processes. We have studied the uptake of [3H]norepinephrine (NE), [3H]dopamine (DA) and [3H]5-HT in synaptosomes prepared from cortex and amygdala of narcoleptic and control Doberman pinscher brains. Since narcoleptic canines are relatively few in number, we have used a specific brain freezing procedure that has been reported to allow restoration of metabolically functional tissue upon thawing. Preliminary studies comparing monoamine uptake in fresh and frozen brain samples of both groups of dogs were carried out and demonstrated that this procedure significantly altered serotoninergic but not noradrenergic and dopaminergic uptake. All further investigations were then done on synaptosomes prepared from frozen samples. Our results demonstrate that synaptosomal uptake of [3H]NE, [3H]DA and [3H]5-HT in cortex and amygdala are not altered in narcolepsy. PMID:1393561

  4. Review of online coupling of sample preparation techniques with liquid chromatography.

    PubMed

    Pan, Jialiang; Zhang, Chengjiang; Zhang, Zhuomin; Li, Gongke

    2014-03-01

    Sample preparation is still considered as the bottleneck of the whole analytical procedure, and efforts has been conducted towards the automation, improvement of sensitivity and accuracy, and low comsuption of organic solvents. Development of online sample preparation techniques (SP) coupled with liquid chromatography (LC) is a promising way to achieve these goals, which has attracted great attention. This article reviews the recent advances on the online SP-LC techniques. Various online SP techniques have been described and summarized, including solid-phase-based extraction, liquid-phase-based extraction assisted with membrane, microwave assisted extraction, ultrasonic assisted extraction, accelerated solvent extraction and supercritical fluids extraction. Specially, the coupling approaches of online SP-LC systems and the corresponding interfaces have been discussed and reviewed in detail, such as online injector, autosampler combined with transport unit, desorption chamber and column switching. Typical applications of the online SP-LC techniques have been summarized. Then the problems and expected trends in this field are attempted to be discussed and proposed in order to encourage the further development of online SP-LC techniques. PMID:24560367

  5. Preparation of an immunoaffinity column and its application in sample cleanup for methandrostenolone residues detection.

    PubMed

    Wang, Yun; Xu, Yan; Zhang, Xun; Wang, Enlan; Dong, Ying

    2011-07-15

    Methandrostenolone (MA) is a steroid used as veterinary medicine on stockbreeding to promote animal growth. The use of MA has been strictly regulated because of its harmful effect on consumers. This paper describes the production of polyclonal antibody (pAb) against MA, the preparation of immunoaffinity column (IAC) and its potential application to the selective extraction of MA residues from animal tissue and feed samples. The produced pAb exhibited good sensitivity to MA with an IC(50) value of 5.6 ng/mL. The cross-reactivity values of the antibody with MA structurally related compounds of testosterone propionate (TP) and trenbolone (TR) were lower than 0.6%. By coupling the produced antibody with CNBr-activated Sepharose 4B, an IAC was prepared. 2% methanol and 80% methanol were selected as loading and eluting solution by optimization. The maximum capacity of the column for MA was approximately 334 ng/mL gel. The average recovery of 20, 40 and 60 ng/mL MA standard solutions from IACs was 97.9% with the relative standard deviation (RSD) among columns of 6.7%. After 3 times of repeated usage, the column capacity and recovery rate still remained 82.0% and 92.6% respectively. The IACs were then challenged with MA-fortified animal tissue and feed samples, recoveries of MA were found to be in the range of 83.5-99.7%. PMID:21703946

  6. Electrochemical Preparation of a Molecularly Imprinted Polypyrrole-modified Pencil Graphite Electrode for Determination of Ascorbic Acid

    PubMed Central

    Özcan, Levent; Şahin, Mutlu; Şahin, Yücel

    2008-01-01

    A molecularly imprinted polymer (MIP) polypyrrole (PPy)-based film was fabricated for the determination of ascorbic acid. The film was prepared by incorporation of a template molecule (ascorbic acid) during the electropolymerization of pyrrole onto a pencil graphite electrode (PGE) in aqueous solution using a cyclic voltammetry method. The performance of the imprinted and non-imprinted (NIP) films was evaluated by differential pulse voltammetry (DPV). The effect of pH, monomer and template concentrations, electropolymerization cycles and interferents on the performance of the MIP electrode was investigated and optimized. The molecularly imprinted film exhibited a high selectivity and sensitivity toward ascorbic acid. The DPV peak current showed a linear dependence on the ascorbic acid concentration and a linear calibration curve was obtained in the range of 0.25 to 7.0 mM of ascorbic acid with a correlation coefficient of 0.9946. The detection limit (3σ) was determined as 7.4×10−5 M (S/N=3). The molecularly-imprinted polypyrrole-modified pencil graphite electrode showed a stable and reproducible response, without any influence of interferents commonly existing in pharmaceutical samples. The proposed method is simple and quick. The PPy electrodes have a low response time, good mechanical stability and are disposable simple to construct.

  7. Sample preparation for beta-exotoxin determination in Bacillus thuringiensis cultures by reversed-phase high-performance liquid chromatography.

    PubMed

    Gohar, M; Perchat, S

    2001-11-01

    Beta-exotoxin is a nucleotide analogue produced by the entomopathogenic bacterium Bacillus thuringiensis. We have defined two new HPLC procedures for quantification of this exotoxin in culture supernatants of B. thuringiensis grown in poor or rich medium. The sample is prepared either by precipitation in solvent or by solid-phase extraction. Solvent precipitation is achieved treating the sample with acetone and acetonitrile. Solid-phase extraction is performed with a C18 and an anion-exchange cartridge. Reversed-phase HPLC with gradient elution of the prepared samples gives a limit of quantitation of 2 microg/ml for samples prepared by solvent precipitation and of 0.3 microg/ml for samples prepared by solid-phase extraction. PMID:11673902

  8. Sample preparation of x-ray diffraction analysis and clay mineralogy of Devonian shale from the Appalachian basin

    SciTech Connect

    Hosterman, J.W.; Loferski, P.J.

    1981-03-01

    Three well-known methods of preparing the clay fraction for x-ray diffraction analysis were tested and evaluated. Kaolinite was not identified in samples prepared by the two settling methods because of layering due to differing/settling rates of the clay minerals. It is suggested that if one of the two settling methods of sample preparation is used that the clay film should be thin enough for the x-ray beam to penetrate the entire thickness of clay. The vacuum method of sample preparation is preferred. Chlorite, kaolinite, 2M illite (muscovite), and mixed layer are the clay minerals found by x-ray diffraction analysis in Devonian shale of the Appalachian basin. The proportions of mixed-layer clay minerals were determined by comparing areas of selected basal peaks on x-ray diffraction traces of untreated samples with those of samples that had been heated and saturated by ethylene glycol.

  9. Preparation of Magnetic Hollow Molecularly Imprinted Polymers for Detection of Triazines in Food Samples.

    PubMed

    Wang, Aixiang; Lu, Hongzhi; Xu, Shoufang

    2016-06-22

    Novel magnetic hollow molecularly imprinted polymers (M-H-MIPs) were proposed for highly selective recognition and fast enrichment of triazines in food samples. M-H-MIPs were prepared on the basis of multi-step swelling polymerization, followed by in situ growth of magnetic Fe3O4 nanoparticles on the surface of hollow molecularly imprinted polymers (H-MIPs). Transmission electron microscopy and scanning electron microscopy confirmed the successful immobilization of Fe3O4 nanoparticles on the surface of H-MIPs. M-H-MIPs could be separated simply using an external magnet. The binding adsorption results indicated that M-H-MIPs displayed high binding capacity and fast mass transfer property and class selective property for triazines. Langmuir isotherm and pseudo-second-order kinetic models fitted the best adsorption models for M-H-MIPs. M-H-MIPs were used to analyze atrazine, simazine, propazine, and terbuthylazine in corn, wheat, and soybean samples. Satisfactory recoveries were in the range of 80.62-101.69%, and relative standard deviation was lower than 5.2%. Limits of detection from 0.16 to 0.39 μg L(-1) were obtained. When the method was applied to test positive samples that were contaminated with triazines, the results agree well with those obtained from an accredited method. Thus, the M-H-MIP-based dispersive solid-phase extraction method proved to be a convenient and practical platform for detection of triazines in food samples. PMID:27257079

  10. Preparation and characterization of humic acid-carbon hybrid materials as adsorbents for organic micro-pollutants.

    PubMed

    Radwan, Emad K; Abdel Ghafar, Hany H; Moursy, Ahmed S; Langford, Cooper H; Bedair, Ahmed H; Achari, Gopal

    2015-08-01

    The present work involves the preparation of novel adsorbent materials by the insolubilization and hybridization of humic acid (HA) with carbon. The prepared materials were characterized by N2 adsorption, elemental analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, solid-state (13)C cross polarization magic angle spinning nuclear magnetic resonance, and low-field nuclear magnetic resonance (NMR) relaxometry on wetted samples. The water solubility of these materials and the lack of effect of oxidants were also confirmed. With this background, the adsorption capacities toward phenol, 2,4,6-tricholrophenol, and atrazine were evaluated, using these as model compounds for organic micropollutants of concern in water. Experimental results show that the prepared materials are mesoporous and have a higher surface area than humic acid and even than the porous carbon in the case of carbon coating. They retain the basic features of the starting materials with lowered functional group content. Moreover, there are interesting new features. NMR relaxometry shows that equilibration of water uptake is very fast, making use in water simple. They have higher adsorption capacities than the pure materials, and they can be applied under a wide range of environmental conditions. PMID:25874433

  11. Carbon Isotopic Ratios of Amino Acids in Stardust-Returned Samples

    NASA Technical Reports Server (NTRS)

    Elsila, Jamie E.; Glavin, Daniel P.; Dworkin, Jason P.

    2009-01-01

    NASA's Stardust spacecraft returned to Earth samples from comet 81P/Wild 2 in January 2006. Preliminary examinations revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds could not be identified. Here. we present the carbon isotopic ratios of glycine and E-aminocaproic acid (EACH), the two most abundant amino acids observed, in Stardust-returned foil samples measured by gas chromatography-combustion-isotope ratio crass spectrometry coupled with quadrupole mass spectrometry (GC-QMS/IRMS).

  12. Carbon Isotopic Measurements of Amino Acids in Stardust-Returned Samples

    NASA Technical Reports Server (NTRS)

    Elsila, Jamie

    2009-01-01

    NASA's Stardust spacecraft returned to Earth samples from comet 81P/Wild 2 in January 2006. Preliminary examinations revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds could not be identified. Here, we present the carbon isotopic ratios of glycine and e-aminocaproic acid (EACA), the two most abundant amino acids, in Stardust-returned foil samples measured by gas chromatography-combustion-isotope ratio mass spectrometry coupled with quadrupole mass spectrometry (GC-CAMS/IRMS).

  13. Preparing and measuring ultra-small radiocarbon samples with the ARTEMIS AMS facility in Saclay, France

    NASA Astrophysics Data System (ADS)

    Delqué-Količ, E.; Comby-Zerbino, C.; Ferkane, S.; Moreau, C.; Dumoulin, J. P.; Caffy, I.; Souprayen, C.; Quilès, A.; Bavay, D.; Hain, S.; Setti, V.

    2013-01-01

    The ARTEMIS facility in Saclay France measures, on average, 4500 samples a year for French organizations working in an array of fields, including environmental sciences, archeology and hydrology. In response to an increasing demand for the isolation of specific soil compounds and organic water fractions, we were motivated to evaluate our ability to reduce microgram samples using our standard graphitization lines and to measure the graphite thus obtained with our 3MV NEC Pelletron AMS. Our reduction facility consists of two fully automated graphitization lines. Each line has 12 reduction reactors with a reduction volume of 18 ml for the first line and 12 ml for the second. Under routine conditions, we determined that we could reduce the samples down to 10 μg of carbon, even if the graphitization yield is consequently affected by the lower sample mass. Our results when testing different Fe/C ratios suggest that an amount of 1.5 mg of Fe powder was ideal (instead of lower amounts of catalyst) to prevent the sample from deteriorating too quickly under the Cs+ beam, and to facilitate pressing procedures. Several sets of microsamples produced from HOxI standard, international references and backgrounds were measured. When measuring 14C-free wood charcoal and HOxI samples we determined that our modern and dead blanks, due to the various preparation steps, were of 1.1 ± 0.8 and 0.2 ± 0.1 μg, respectively. The results presented here were obtained for IAEA-C1, 14C-free wood, IAEA-C6, IAEA-C2 and FIRI C.

  14. Antioxidant activity and fatty acid profile of fermented milk prepared by Pediococcus pentosaceus.

    PubMed

    Balakrishnan, Gayathri; Agrawal, Renu

    2014-12-01

    Probiotics are the class of beneficial microorganisms that have positive influence on the health when ingested in adequate amounts. Probiotic fermented milk is one of the dairy products that is prepared by using probiotic lactic acid bacteria. The study comprised preparation of fermented milk from various sources such as cow, goat and camel. Pediococcus pentosaceus which is a native laboratory isolate from cheese was utilized for the product formation. Changes in functional properties in the fermented milks obtained from three different species were evaluated. Antioxidant activity determined by DPPH assay showed activity in probiotic fermented milk obtained from all the products being highest in goat milk (93 %) followed by product from camel milk (86 %) and then product from cow milk (79 %). The composition of beneficial fatty acids such as stearic acid, oleic acid and linoleic acid were higher in fermented milk than the unfermented ones. Results suggested that probiotic bacteria are able to utilize the nutrients in goat and camel milk more efficiently compared to cow milk. Increase in antioxidant activity and fatty acid profile of fermented milks enhances the therapeutic value of the products. PMID:25477694

  15. Determination of Mycotoxins in Brown Rice Using QuEChERS Sample Preparation and UHPLC-MS-MS.

    PubMed

    Jettanajit, Adisorn; Nhujak, Thumnoon

    2016-05-01

    QuEChERS sample preparation was optimized and validated using solvent extraction with 10% (v/v) acetic acid-containing acetonitrile in the presence of four salts (anh. MgSO4, NaCl, sodium citrate tribasic dihydrate and sodium citrate dibasic sesquihydrate) and dispersive solid-phase extraction with mixed sorbents (octadecylsilane, primary and secondary amine and silica sorbents) for an ultra high performance liquid chromatography-tandem mass spectrometric determination of nine mycotoxins in brown rice: aflatoxins (AFB1, AFB2, AFG1 and AFG2), fumonisins (FB1 and FB2), deoxynivalenol, ochratoxin A and zearalenone (ZON). Our developed method allows for the determination of trace levels of mycotoxins with method detection limits in the range of 1.4-25 µg/kg, below the maximum limits of EU regulations, and with an acceptable accuracy and precision, and recoveries in the range of 81-101% with relative standard deviations of 5-19% over a mycotoxin concentration range of 5.0-1,000 µg/kg. Six out of fourteen real samples of brown rice were found to be contaminated with at least one of these mycotoxins, ranging from 2.49-5.41 µg/kg of FB1, 4.33 ± 0.04 µg/kg of FB2 and 6.10-14.88 µg/kg of ZON. PMID:26796964

  16. Photo-oxidation of gaseous ethanol on photocatalyst prepared by acid leaching of titanium oxide/hydroxyapatite composite

    SciTech Connect

    Ono, Y.; Rachi, T.; Yokouchi, M.; Kamimoto, Y.; Nakajima, A.; Okada, K.

    2013-06-01

    Highlights: ► Photocatalyst powder was prepared by acid leaching of TiO{sub 2}/apatite composite. ► The photocatalytic activity was evaluated from in situ FT-IR study using ethanol. ► Apatite in the composite had positive effect for the photo-oxidation of ethanol. ► The enhanced oxidation rate was explained by the difference in deactivation rate. - Abstract: Highly active photocatalysts were synthesized by leaching of heat-treated titanium dioxide (TiO{sub 2})/hydroxyapatite (HAp) powder with hydrochloric acid at 0.25, 0.50, 0.75 mol/l, and their photocatalytic activities were evaluated from in situ Fourier transform infrared (FT-IR) study of photo-oxidation of gaseous ethanol. By changing the acid concentration, the TiO{sub 2}/HAp composite had different atomic ratios of Ca/Ti (0.0–2.8) and P/Ti (0.3–2.1). It was found that phosphate group remained on the surface of TiO{sub 2} particle even in the sample treated with concentrated acid (0.75 mol/l). These acid-treated samples showed higher rates for ethanol photo-oxidation than the commercial TiO{sub 2} powder, Degussa P25. The highest rate was obtained in the TiO{sub 2}/HAp composite treated with the dilute (0.25 mol/l) acid in spite of its low content of TiO{sub 2} photocatalyst. This enhanced photocatalytic activity was attributed to the result that the deactivation with repeated injections of ethanol gas was suppressed in the TiO{sub 2}/HAp composites compared with the TiO{sub 2} powders.

  17. Hydrofluoric Acid Corrosion Testing on Unplated and Electroless Gold-Plated Samples

    SciTech Connect

    Osborne, P.E.

    2000-08-03

    The Molten Salt Reactor Experiment (MSRE) remediation requires that almost 40 kg of uranium hexafluoride (UF{sub 6}) be converted to uranium oxide (U{sub 3}O{sub 8}). In the process of this conversion, six moles of hydrofluoric acid (HF) are produced for each mole of UF{sub 6} converted. The entire conversion process can be summarized by the following reaction: UF{sub 6} + 3H{sub 2}O {yields} UO{sub 3} + 6HF. (The UO{sub 3} is not stable at high temperatures and therefore decomposes to U{sub 3}O{sub 8}). HF is well known for its ability to attack most metals and silica-containing compounds. It reacts rapidly to destroy protective films and can be fatal in very small quantities (e.g., 2% exposure of the body or 50 ppm in air). Because most of the conversion system is made of various metals, the sections that come in contact with HF must be able to withstand corrosion, high temperatures, elevated pressures, and radiation. Consequently, most of these sections will be plated with gold for increased protection of the metal. This report summarizes the results from the tests that were performed on the metal samples. Section 2 covers the approach to the tests, gives a general background of the sample preparation, and then reports the data from the tests. The final section presents a discussion of what was learned from the data and recommendations for uses of these metals in the MSRE conversion process.

  18. Electrochemical determination of hydrochlorothiazide and folic acid in real samples using a modified graphene oxide sheet paste electrode.

    PubMed

    Beitollahi, Hadi; Hamzavi, Mozhdeh; Torkzadeh-Mahani, Masoud

    2015-01-01

    A new ferrocene-derivative compound, 2-chlorobenzoyl ferrocene, was synthesized and used to construct a modified graphene oxide sheet paste electrode. The electrooxidation of hydrochlorothiazide at the surface of the modified electrode was studied. Under optimized conditions, the square wave voltammetric (SWV) peak current of hydrochlorothiazide increased linearly with hydrochlorothiazide concentration in the range of 5.0 × 10(-8) to 2.0 × 10(-4) M and a detection limit of 20.0 nM was obtained for hydrochlorothiazide. The diffusion coefficient and kinetic parameters (such as electron transfer coefficient and the heterogeneous rate constant) for hydrochlorothiazide oxidation were also determined. The prepared modified electrode exhibits a very good resolution between the voltammetric peaks of hydrochlorothiazide and folic acid which makes it suitable for the detection of hydrochlorothiazide in the presence of folic acid in real samples. PMID:25953571

  19. Preparation and characterization of monodisperse molecularly imprinted polymers for the recognition and enrichment of oleanolic acid.

    PubMed

    Tang, Zonggui; Liu, Changbin; Wang, Jing; Li, Hongmin; Ji, Yong; Wang, Guohong; Lu, Chunxia

    2016-04-01

    Monodisperse molecularly imprinted polymers for oleanolic acid were successfully prepared by a precipitation polymerization method using oleanolic acid as a template, methacrylic acid as a functional monomer, and divinylbenzene/ethylene glycol dimethacrylate as a crosslinker in a mixture of acetonitrile and ethanol (3:1, v/v). The imprinted polymers and nonimprinted polymers were characterized by using scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The resulting imprinted polymers had average diameters of 3.15 μm and monodispersity values of 1.024. The results clearly demonstrate that use of ethanol as a cosolvent is indeed exceedingly effective in promoting the dissolution of oleanolic acid and in obtaining uniform microspheres. Molecular recognition properties and binding capability to oleanolic acid were evaluated by adsorption testing, which indicated that the imprinted polymers displayed optimal binding performance with a maximum adsorption capacity of 17.3 mg/g and a binding saturation time of 80 min. Meanwhile, the produced imprinted polymers exhibited higher selectivity to oleanolic acid than that for ursolic acid and rhein. Herein, the studies can provide theoretical and experimental references for the oleanolic acid molecular imprinted system. PMID:27106769

  20. Preparation of sphingolipid fatty acid methyl esters for determination by gas-liquid chromatography.

    PubMed

    MacGee, J; Williams, M G

    1981-01-30

    Sphingolipid fatty acids are first converted to a mixture of free acids and their n-butyl esters by heating the specimen at 85 degree C in aqueous butanolic hydrogen chloride; the butyl esters are then saponified with methanolic potassium hydroxide. After acidification and extraction into hexane, the fatty acids are extracted into a very small volume of aqueous trimethyl(m-trifluorotolyl)ammonium hydroxide (TMTFTH), injection of an aliquot of the TMTFTH extract into the gas chromatograph yields the fatty acid methyl esters by pyrolytic methylation of the quaternary ammonium salts of the fatty acids. The preparation of a specimen ready for the gas--liquid chromatographic (GLC) analysis with quantitative recovery of the sphingolipid fatty acids can be accomplished in less than 2 h. By comparison, none of a number of well-accepted techniques for the release of sphingomyelin fatty acids by hydrolysis or methanolysis released the fatty acids quantitatively in less than 3 h, and all required additional manipulations before GLC analysis. PMID:7217267

  1. Microfluidic Preparation of Polymer-Nucleic Acid Nanocomplexes Improves Nonviral Gene Transfer

    NASA Astrophysics Data System (ADS)

    Grigsby, Christopher L.; Ho, Yi-Ping; Lin, Chao; Engbersen, Johan F. J.; Leong, Kam W.

    2013-11-01

    As the designs of polymer systems used to deliver nucleic acids continue to evolve, it is becoming increasingly apparent that the basic bulk manufacturing techniques of the past will be insufficient to produce polymer-nucleic acid nanocomplexes that possess the uniformity, stability, and potency required for their successful clinical translation and widespread commercialization. Traditional bulk-prepared products are often physicochemically heterogeneous and may vary significantly from one batch to the next. Here we show that preparation of bioreducible nanocomplexes with an emulsion-based droplet microfluidic system produces significantly improved nanoparticles that are up to fifty percent smaller, more uniform, and are less prone to aggregation. The intracellular integrity of nanocomplexes prepared with this microfluidic method is significantly prolonged, as detected using a high-throughput flow cytometric quantum dot Förster resonance energy transfer nanosensor system. These physical attributes conspire to consistently enhance the delivery of both plasmid DNA and messenger RNA payloads in stem cells, primary cells, and human cell lines. Innovation in processing is necessary to move the field toward the broader clinical implementation of safe and effective nonviral nucleic acid therapeutics, and preparation with droplet microfluidics represents a step forward in addressing the critical barrier of robust and reproducible nanocomplex production.

  2. Preparative production of colominic acid oligomers via a facile microwave hydrolysis

    PubMed Central

    Patane, Jonathan; Trapani, Vincent; Villavert, Janice; McReynolds, Katherine Dawn

    2009-01-01

    The hydrolysis of colominic acid via microwave irradiation was studied for the production of short chain oligomers with a degree of polymerization (DP) of 1–6. This method was compared to the traditional acid hydrolytic method for the production of preparative quantities of short colominic acid oligomers. The oligomers were purified by size exclusion chromatography and characterized by 1H NMR. Optimal conditions for producing the dimer were found to be 12 minutes at 10% power in a 1000 Watt domestic microwave. This method is advantageous over the traditional technique in that the hydrolysis can be completed in just a few minutes, rather than hours, it is reproducible, and yields large quantities of the desirable short chain oligomers of colominic acid. PMID:19281967

  3. Enhanced Enzymatic Preparation of Biodiesel Using Ricinoleic Acid as Acyl Donor: Optimization Using Response Surface Methodology.

    PubMed

    Wang, Ping; Sun, Shangde

    2016-09-01

    Castor oil methyl ester is a kind of biodiesel from castor oil. However, in those previous methods for biodiesel preparation using castor oil as feedstock, glycerol was the main by-product, which had a strong blocking effect on the immobilized enzyme activity and affected the mass transfer of reaction system. For avoiding the negative effect of glycerol on the enzymatic esterification, biodiesel was prepared using ricinoleic acid (RA) as acyl donor. Enzyme screening was also studied, and the effects of reaction temperature, molar ratio of ricinoleic acid and methanol, enzyme load, and reaction time, on the preparation of castor methyl ester were also evaluated. Response surface methodology (RSM) was used to optimize the interaction effect of reaction variables (reaction temperature (30-70°C), enzyme load (2-7%; relative to the weight of total substrates), molar ratio of methanol to ricinoleic acid (2:1-10:1), and reaction time (0.5-2.5 h)) on the acid value (AV) and the degree of esterification (DE). Validation of the RSM model was verified by the good agreement between the experimental and the predicted values of AV and DE. The optimum preparation conditions were as follows: reaction temperature, 48.2°C; enzyme load, 5.8%; molar ratio of methanol to ricinoleic acid, 5.56:1; reaction time, 2.36 h. Under these conditions, the AV and DE of the esterification reaction are 10.36±1.05 mgKOH/g and 94.03±0.60%, respectively. The relationship between initial reaction rate and temperature was also established, and the activation energy (Ea) of the enzymatic esterification is 33.87 KJ/mol. PMID:27477073

  4. Tank 12H Acidic Chemical Cleaning Sample Analysis And Material Balance

    SciTech Connect

    Martino, C. J.; Reboul, S. H.; Wiersma, B. J.; Coleman, C. J.

    2013-11-08

    A process of Bulk Oxalic Acid (BOA) chemical cleaning was performed for Tank 12H during June and July of 2013 to remove all or a portion of the approximately 4400 gallon sludge heel. Three strikes of oxalic acid (nominally 4 wt% or 2 wt%) were used at 55°C and tank volumes of 96- to 140-thousand gallons. This report details the sample analysis of a scrape sample taken prior to BOA cleaning and dip samples taken during BOA cleaning. It also documents a rudimentary material balance for the Tank 12H cleaning results.

  5. Incorporation of Mevalonic Acid into Ribosylzeatin in Tobacco Callus Ribonucleic Acid Preparations 1

    PubMed Central

    Murai, Norimoto; Armstrong, Donald J.; Skoog, Folke

    1975-01-01

    The incorporation of 14C-2-mevalonic acid into transfer RNA and ribosomal RNA (high molecular weight RNA) in rapidly growing, cytokinin-dependent tobacco (Nicotiana tabacum var. Wisconsin No. 38) callus cultures has been investigated. Approximately 40% of the label incorporated into transfer RNA was present in a ribonucleoside with chromatographic properties identical to those of cis-ribosylzeatin. The remainder of the label in the transfer RNA appears to be nonspecific incorporation resulting from degradation and metabolism of 14C-2-mevalonic acid by the tobacco callus tissue. Although the total radioactivity incorporated into ribosomal RNA was roughly the same as in transfer RNA, the specific radioactivity of the transfer RNA was about four times higher than that of the ribosomal RNA, and the ribosomal RNA labeling could be distinguished from the cytokinin labeling observed in transfer RNA. The distributions of the 14C-2-mevalonic acid label and cytokinin activity in tobacco callus transfer RNA fractionated by benzoylated diethylaminoethylcellulose chromatography indicate that at least two cytokinin-containing transfer RNA species are present in this tissue. PMID:16659180

  6. Preparation of finely dispersed O/W emulsion from fatty acid solubilized in subcritical water.

    PubMed

    Khuwijitjaru, Pramote; Kimura, Yukitaka; Matsuno, Ryuichi; Adachi, Shuji

    2004-10-01

    A novel method for preparing a finely dispersed oil-in-water emulsion is proposed. Octanoic acid dissolved in water at a high temperature of 220 or 230 degrees C at 15 MPa was combined with an aqueous solution of a surfactant and then the mixture was cooled. When a nonionic surfactant, decaglycerol monolaurate (ML-750) or polyoxyethylene sorbitan monolaurate (Tween 20), was used, fine emulsions with a median oil droplet diameter of 100 nm or less were successfully prepared at ML-750 and Tween 20 concentrations of 0.083% (w/v) and 0.042%, respectively, or higher. The diameters were much smaller than those of oil droplets prepared by the conventional homogenization method using a rotor/stator homogenizer. However, an anionic surfactant, sodium dodecyl sulfate, was not adequate for the preparation of such fine emulsions by the proposed method. Although the interfacial tensions between octanoic acid and the surfactant solutions were measured at different temperatures, they were not an indication for selecting a surfactant for the successful preparation of the fine emulsion by the proposed method. PMID:15313654

  7. Microwave Processing for Sample Preparation to Evaluate Mitochondrial Ultrastructural Damage in Hemorrhagic Shock

    NASA Astrophysics Data System (ADS)

    Josephsen, Gary D.; Josephsen, Kelly A.; Beilman, Greg J.; Taylor, Jodie H.; Muiler, Kristine E.

    2005-12-01

    This is a report of the adaptation of microwave processing in the preparation of liver biopsies for transmission electron microscopy (TEM) to examine ultrastructural damage of mitochondria in the setting of metabolic stress. Hemorrhagic shock was induced in pigs via 35% total blood volume bleed and a 90-min period of shock followed by resuscitation. Hepatic biopsies were collected before shock and after resuscitation. Following collection, biopsies were processed for TEM by a rapid method involving microwave irradiation (Giberson, 2001). Samples pre- and postshock of each of two animals were viewed and scored using the mitochondrial ultrastructure scoring system (Crouser et al., 2002), a system used to quantify the severity of ultrastructural damage during shock. Results showed evidence of increased ultrastructural damage in the postshock samples, which scored 4.00 and 3.42, versus their preshock controls, which scored 1.18 and 1.27. The results of this analysis were similar to those obtained in another model of shock (Crouser et al., 2002). However, the amount of time used to process the samples was significantly shortened with methods involving microwave irradiation.

  8. Modular approach to customise sample preparation procedures for viral metagenomics: a reproducible protocol for virome analysis

    PubMed Central

    Conceição-Neto, Nádia; Zeller, Mark; Lefrère, Hanne; De Bruyn, Pieter; Beller, Leen; Deboutte, Ward; Yinda, Claude Kwe; Lavigne, Rob; Maes, Piet; Ranst, Marc Van; Heylen, Elisabeth; Matthijnssens, Jelle

    2015-01-01

    A major limitation for better understanding the role of the human gut virome in health and disease is the lack of validated methods that allow high throughput virome analysis. To overcome this, we evaluated the quantitative effect of homogenisation, centrifugation, filtration, chloroform treatment and random amplification on a mock-virome (containing nine highly diverse viruses) and a bacterial mock-community (containing four faecal bacterial species) using quantitative PCR and next-generation sequencing. This resulted in an optimised protocol that was able to recover all viruses present in the mock-virome and strongly alters the ratio of viral versus bacterial and 16S rRNA genetic material in favour of viruses (from 43.2% to 96.7% viral reads and from 47.6% to 0.19% bacterial reads). Furthermore, our study indicated that most of the currently used virome protocols, using small filter pores and/or stringent centrifugation conditions may have largely overlooked large viruses present in viromes. We propose NetoVIR (Novel enrichment technique of VIRomes), which allows for a fast, reproducible and high throughput sample preparation for viral metagenomics studies, introducing minimal bias. This procedure is optimised mainly for faecal samples, but with appropriate concentration steps can also be used for other sample types with lower initial viral loads. PMID:26559140

  9. Sample preparation, data collection and preliminary data analysis in biomolecular solution X-ray scattering

    PubMed Central

    Grishaev, Alexander

    2012-01-01

    In addition to the classic methods of structural biology - X-ray crystallography and NMR, solution X-ray scattering (SAXS) is starting to play an important role in experiential structural investigation of biological macromolecules. Ease of SAXS data collection and sophistication of its data analysis tools increasingly used as black boxes can be seen as both a blessing and a curse. On one hand, a sample set aside for solution scattering will always yield experimental data, including cases when macromolecule cannot be crystallized or when it is too large for application of solution NMR. On the other hand, any sample, whether pure or contaminated, whether mono- or polydisperse, will yield scattering data and it is up to the user to ensure the absence of artifacts in them and to choose a proper structural modeling strategy. We will discuss experimental aspects of X-ray solution scattering including sample preparation, data collection, as well as the steps in data processing and preliminary analysis that need to be carried out to ensure the absence of artifacts. Our goal is to summarize everything than can possibly go wrong with SAXS data measurement so that the user can have confidence in the data before they enter structural modeling. PMID:23151743

  10. Development of automated preparation system for isotopocule analysis of N2O in various air samples

    NASA Astrophysics Data System (ADS)

    Toyoda, Sakae; Yoshida, Naohiro

    2016-05-01

    Nitrous oxide (N2O), an increasingly abundant greenhouse gas in the atmosphere, is the most important stratospheric ozone-depleting gas of this century. Natural abundance ratios of isotopocules of N2O, NNO molecules substituted with stable isotopes of nitrogen and oxygen, are a promising index of various sources or production pathways of N2O and of its sink or decomposition pathways. Several automated methods have been reported to improve the analytical precision for the isotopocule ratio of atmospheric N2O and to reduce the labor necessary for complicated sample preparation procedures related to mass spectrometric analysis. However, no method accommodates flask samples with limited volume or pressure. Here we present an automated preconcentration system which offers flexibility with respect to the available gas volume, pressure, and N2O concentration. The shortest processing time for a single analysis of typical atmospheric sample is 40 min. Precision values of isotopocule ratio analysis are < 0.1 ‰ for δ15Nbulk (average abundances of 14N15N16O and 15N14N16O relative to 14N14N16O), < 0.2 ‰ for δ18O (relative abundance of 14N14N18O), and < 0.5 ‰ for site preference (SP; difference between relative abundance of 14N15N16O and 15N14N16O). This precision is comparable to that of other automated systems, but better than that of our previously reported manual measurement system.

  11. Using Exclusion-Based Sample Preparation (ESP) to Reduce Viral Load Assay Cost

    PubMed Central

    Berry, Scott M.; Pezzi, Hannah M.; Williams, Eram D.; Loeb, Jennifer M.; Guckenberger, David J.; Lavanway, Alex J.; Puchalski, Alice A.; Kityo, Cissy M.; Mugyenyi, Peter N.; Graziano, Franklin M.; Beebe, David J.

    2015-01-01

    Viral load (VL) measurements are critical to the proper management of HIV in developing countries. However, access to VL assays is limited by the high cost and complexity of existing assays. While there is a need for low cost VL assays, performance must not be compromised. Thus, new assays must be validated on metrics of limit of detection (LOD), accuracy, and dynamic range. Patient plasma samples from the Joint Clinical Research Centre in Uganda were de-identified and measured using both an existing VL assay (Abbott RealTime HIV-1) and our assay, which combines low cost reagents with a simplified method of RNA isolation termed Exclusion-Based Sample Preparation (ESP).71 patient samples with VLs ranging from <40 to >3,000,000 copies/mL were used to compare the two methods. We demonstrated equivalent LOD (~50 copies/mL) and high accuracy (average difference between methods of 0.08 log, R2 = 0.97). Using expenditures from this trial, we estimate that the cost of the reagents and consumables for this assay to be approximately $5 USD. As cost is a significant barrier to implementation of VL testing, we anticipate that our assay will enhance access to this critical monitoring test in developing countries. PMID:26630135

  12. Fully Automated Sample Preparation for Ultrafast N-Glycosylation Analysis of Antibody Therapeutics.

    PubMed

    Szigeti, Marton; Lew, Clarence; Roby, Keith; Guttman, Andras

    2016-04-01

    There is a growing demand in the biopharmaceutical industry for high-throughput, large-scale N-glycosylation profiling of therapeutic antibodies in all phases of product development, but especially during clone selection when hundreds of samples should be analyzed in a short period of time to assure their glycosylation-based biological activity. Our group has recently developed a magnetic bead-based protocol for N-glycosylation analysis of glycoproteins to alleviate the hard-to-automate centrifugation and vacuum-centrifugation steps of the currently used protocols. Glycan release, fluorophore labeling, and cleanup were all optimized, resulting in a <4 h magnetic bead-based process with excellent yield and good repeatability. This article demonstrates the next level of this work by automating all steps of the optimized magnetic bead-based protocol from endoglycosidase digestion, through fluorophore labeling and cleanup with high-throughput sample processing in 96-well plate format, using an automated laboratory workstation. Capillary electrophoresis analysis of the fluorophore-labeled glycans was also optimized for rapid (<3 min) separation to accommodate the high-throughput processing of the automated sample preparation workflow. Ultrafast N-glycosylation analyses of several commercially relevant antibody therapeutics are also shown and compared to their biosimilar counterparts, addressing the biological significance of the differences. PMID:26429557

  13. Sample preparation bias in carbon stable isotope ratio analysis of fruit juices and sweeteners.

    PubMed

    Krueger, D A

    1993-01-01

    Two sample preparation methods are commonly used for carbon stable isotope ratio analysis (SIRA). One involves combustion of the sample with oxygen at 850 degrees C; the other involves combustion of the sample with CuO in an evacuated glass tube at 550 degrees C. I observed in our laboratory that these 2 methods yield different results for sugar-based products such as fruit juices, sweeteners, and vanillin. The CuO method yields results approximately 1%. more positive than the oxygen combustion method. This bias is also observed in other laboratories, as shown in an analysis of the results of the AOAC collaborative studies of carbon SIRA of maple syrup, orange juice, honey, and honey protein. The oxygen combustion method is the AOAC method for honey, apple juice, and orange juice; both methods are incorporated into the AOAC method for maple syrup. I recommend that data generated by the CuO combustion method be appropriately corrected to yield results concordant with the official oxygen combustion method. PMID:8471867

  14. Urine sample preparation in 96-well filter plates for quantitative clinical proteomics.

    PubMed

    Yu, Yanbao; Suh, Moo-Jin; Sikorski, Patricia; Kwon, Keehwan; Nelson, Karen E; Pieper, Rembert

    2014-06-01

    Urine is an important, noninvasively collected body fluid source for the diagnosis and prognosis of human diseases. Liquid chromatography mass spectrometry (LC-MS) based shotgun proteomics has evolved as a sensitive and informative technique to discover candidate disease biomarkers from urine specimens. Filter-aided sample preparation (FASP) generates peptide samples from protein mixtures of cell lysate or body fluid origin. Here, we describe a FASP method adapted to 96-well filter plates, named 96FASP. Soluble urine concentrates containing ~10 μg of total protein were processed by 96FASP and LC-MS resulting in 700-900 protein identifications at a 1% false discovery rate (FDR). The experimental repeatability, as assessed by label-free quantification and Pearson correlation analysis for shared proteins among replicates, was high (R ≥ 0.97). Application to urinary pellet lysates which is of particular interest in the context of urinary tract infection analysis was also demonstrated. On average, 1700 proteins (±398) were identified in five experiments. In a pilot study using 96FASP for analysis of eight soluble urine samples, we demonstrated that protein profiles of technical replicates invariably clustered; the protein profiles for distinct urine donors were very different from each other. Robust, highly parallel methods to generate peptide mixtures from urine and other body fluids are critical to increase cost-effectiveness in clinical proteomics projects. This 96FASP method has potential to become a gold standard for high-throughput quantitative clinical proteomics. PMID:24797144

  15. Amino acid analysis in micrograms of meteorite sample by nanoliquid chromatography-high-resolution mass spectrometry.

    PubMed

    Callahan, Michael P; Martin, Mildred G; Burton, Aaron S; Glavin, Daniel P; Dworkin, Jason P

    2014-03-01

    Amino acids and their enantiomers in a 360 microgram sample of Murchison meteorite were unambiguously identified and quantified using chemical derivatization and nanoliquid chromatography coupled to nanoelectrospray ionization high resolution orbitrap mass spectrometry techniques. The distribution and abundance of amino acids were similar to past studies of Murchison meteorite but the samples used here were three orders of magnitude lower. The analytical method was also highly sensitive, and some amino acid reference standards were successfully detected at a level of ∼200 attomoles (on column). These results may open up the possibility for investigating other less studied, sample-limited extraterrestrial samples (e.g., micrometeorites, interplanetary dust particles, and cometary particles) for biologically-relevant organic molecules. PMID:24529954

  16. Multiple stable isotope characterization as a forensic tool to distinguish acid scavenger samples

    SciTech Connect

    Moran, James J.; Kreuzer, Helen W.; Carman, April J.; Wahl, Jon H.; Duckworth, Douglas C.

    2012-01-01

    Acid scavengers are frequently used as stabilizer compounds in a variety of applications. When used to stabilize volatile compounds such as nerve agents, the lower volatility and higher stability of acid scavengers make them more persistent in a post-event forensic setting. We are employing compound-specific stable isotope analysis of the carbon, nitrogen, and hydrogen components of three acid scavenging compounds (N,N-diethylaniline, tributylamine, and triethylamine) as a tool for distinguishing between different samples of the stabilizers. Combined analysis of three stable isotopes in these samples improves the technique’s resolving potential, enhancing sample matching capabilities. The compound specific methods developed here can be applied to instances where these compounds are not pure, such as when mixed with an agent or when found as a residue at an event site. Effective sample matching can be crucial for linking compounds at multiple event sites or linking a supply inventory to an event.

  17. CTEPP STANDARD OPERATING PROCEDURE FOR COLLECTION OF FOOD PREPARATION SURFACE WIPE SAMPLES FOR PERSISTENT ORGANIC POLLUTANTS (SOP-2.17)

    EPA Science Inventory

    This SOP describes the method for collection of the food preparation surface wipe samples for the measurement of persistent organic pollutants (POP). This method uses a wipe to collect POP residues from a surface where a study participant prepares food the most often (i.e., kitch...

  18. Spectroscopic studies of alumina-supported nickel catalysts precursors. Part I. Catalysts prepared from acidic solutions

    NASA Astrophysics Data System (ADS)

    Pasieczna-Patkowska, S.; Ryczkowski, J.

    2007-04-01

    Nickel alumina-supported catalysts were prepared from acidic solutions of nickel nitrate by the CIM and DIM methods (classical and double impregnation, respectively). The catalysts exhibited different nickel species due to the existence of various metal-support interaction strengths. As a consequence, the reducibility and other surface properties changed as a function of the preparation method. The aim of this work was to study the interaction between the metal precursor and the alumina surface by means of FT-IR (Fourier transform infrared) and FT-IR/PAS (FT-IR photoacoustic spectroscopy).

  19. Derivatives of imidopyrophosphoric acids as extractants. Part I. The preparation and fundamental constants of tetraalkylimidopyrophosphoric acids

    SciTech Connect

    Preez, J.G.H. du; Knabl, K.U.; Krueger, L.; Brecht, B.J.A.M. van )

    1992-12-01

    Improved methods for the preparation of imidotetraalkylpyrophosphates are reported. The dissociation constant of the water soluble tetraethyl analogue was determined by potentiometric titration. The values for the partition constant and aggregation constant of the tetradodecyl analogue were determined by two phase EMF potentiometric titration of which the data were processed through a sophisticated general optimization technique. The application of this method also made it possible to obtain a species distribution curve of the organic phase in terms of variation of pH in the aqueous phase. 17 refs., 7 figs., 4 tabs.

  20. Applicability Comparison of Methods for Acid Generation Assessment of Rock Samples

    NASA Astrophysics Data System (ADS)

    Oh, Chamteut; Ji, Sangwoo; Yim, Giljae; Cheong, Youngwook

    2014-05-01

    Minerals including various forms of sulfur could generate AMD (Acid Mine Drainage) or ARD (Acid Rock Drainage), which can have serious effects on the ecosystem and even on human when exposed to air and/or water. To minimize the hazards by acid drainage, it is necessary to assess in advance the acid generation possibility of rocks and estimate the amount of acid generation. Because of its relatively simple and effective experiment procedure, the method of combining the results of ABA (Acid Base Accounting) and NAG (Net Acid Generation) tests have been commonly used in determining acid drainage conditions. The simplicity and effectiveness of the above method however, are derived from massive assumptions of simplified chemical reactions and this often leads to results of classifying the samples as UC (Uncertain) which would then require additional experimental or field data to reclassify them properly. This paper therefore, attempts to find the reasons that cause samples to be classified as UC and suggest new series of experiments where samples can be reclassified appropriately. Study precedents on evaluating potential acid generation and neutralization capacity were reviewed and as a result three individual experiments were selected in the light of applicability and compatibility of minimizing unnecessary influence among other experiments. The proposed experiments include sulfur speciation, ABCC (Acid Buffering Characteristic Curve), and Modified NAG which are all improved versions of existing experiments of Total S, ANC (Acid Neutralizing Capacity), and NAG respectively. To assure the applicability of the experiments, 36 samples from 19 sites with diverse geologies, field properties, and weathering conditions were collected. The samples were then subject to existing experiments and as a result, 14 samples which either were classified as UC or could be used as a comparison group had been selected. Afterwards, the selected samples were used to conduct the suggested

  1. Preparation of molecularly imprinted polymers using theanine as dummy template and its application as SPE sorbent for the determination of eighteen amino acids in tobacco.

    PubMed

    Zhu, Fengling; Wang, Jing; Zhu, Lijun; Tan, Lanlan; Feng, Guanglin; Liu, Shaomin; Dai, Ya; Wang, Hua

    2016-04-01

    In this paper, a novel dummy template molecularly imprinted polymer (DMIP) based on a vinyl-SiO2 microspheres surface for the simultaneous selective recognition and enrichment of 18 amino acids was prepared via a surface molecular imprinting technique using theanine as a dummy template. Compared to the imprinted polymers prepared using traditional polymerization techniques, the obtained DMIPs exhibited a regular spherical shape and were relatively monodisperse. The maximal sorption capacity (Qmax) of the resulting DMIPs for the 18 amino acids was up to 1444.3 mg g(-1). A kinetic binding study showed that the sorption capacity reached 85.40% of Qmax in 25 min and sorption equilibrium at 30 min. The imprint factors of the sorbents ranged from 2.86 to 6.9 for the 18 amino acids, which indicated that the DMIP sorbents have high selectivity. An HPLC-UV method for the simultaneous determination of 18 amino acids in tobacco and tobacco smoke was developed using the DMIPs as sorbents for solid phase extraction (SPE) in the sample pretreatment procedure. Under the optimum experimental conditions, the materials had enrichment factors of up to 200 for the amino acids, and the recoveries of the 18 amino acids in tobacco smoke were in the range from 79% to 104% with relative standard deviations of less than 7.4%. It indicated that the obtained DMIP sorbents could specifically recognize the amino acids from complicated samples. PMID:26838422

  2. Lights Will Guide You : Sample Preparation and Applications for Integrated Laser and Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Karreman, M. A.

    2013-03-01

    Correlative microscopy is the combined use of two different forms of microscopy in the study of a specimen, allowing for the exploitation of the advantages of both imaging tools. The integrated Laser and Electron Microscope (iLEM), developed at Utrecht University, combines a fluorescence microscope (FM) and a transmission electron microscope (TEM) in a single set-up. The region of interest in the specimen is labeled or tagged with a fluorescent probe and can easily be identified within a large field of view with the FM. Next, this same area is retraced in the TEM and can be studied at high resolution. The iLEM demands samples that can be imaged with both FM and TEM. Biological specimen, typically composed of light elements, generate low image contrast in the TEM. Therefore, these samples are often ‘contrasted’ with heavy metal stains. FM, on the other hand, images fluorescent samples. Sample preparation for correlative microscopy, and iLEM in particular, is complicated by the fact that the heavy metals stains employed for TEM quench the fluorescent signal of the probe that is imaged with FM. The first part of this thesis outlines preparation procedures for biological material yielding specimen that can be imaged with the iLEM. Here, approaches for the contrasting of thin sections of cells and tissue are introduced that do not affect the fluorescence signal of the probe that marks the region of interest. Furthermore, two novel procedures, VIS2FIXH and VIS2FIX­FS are described that allow for the chemical fixation of thin sections of cryo-immobilized material. These procedures greatly expedite the sample preparation process, and open up novel possibilities for the immuno-labeling of difficult antigens, eg. proteins and lipids that are challenging to preserve. The second part of this thesis describes applications of iLEM in research in the field of life and material science. The iLEM was employed in the study of UVC induced apoptosis (programmed cell death) of

  3. Boronic Acid functionalized core-shell polymer nanoparticles prepared by distillation precipitation polymerization for glycopeptide enrichment.

    PubMed

    Qu, Yanyan; Liu, Jianxi; Yang, Kaiguang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2012-07-16

    The boronic acid-functionalized core-shell polymer nanoparticles, poly(N,N-methylenebisacrylamide-co-methacrylic acid)@4-vinylphenylboronic acid (poly(MBA-co-MAA)@VPBA), were successfully synthesized for enriching glycosylated peptides. Such nanoparticles were composed of a hydrophilic polymer core prepared by distillation precipitation polymerization (DPP) and a boronic acid-functionalized shell designed for capturing glycopeptides. Owing to the relatively large amount of residual vinyl groups introduced by DPP on the core surface, the VPBA monomer was coated with high efficiency, working as the shell. Moreover, the overall polymerization route, especially the use of DPP, made the synthesis of nanoparticles facile and time-saving. With the poly(MBA-co-MAA)@VPBA nanoparticles, 18 glycopeptides from horseradish peroxidase (HRP) digest were captured and identified by MALDI-TOF mass spectrometric analysis, relative to eight glycopeptides enriched by using commercially available meta-aminophenylboronic acid agarose under the same conditions. When the concentration of the HRP digest was decreased to as low as 5 nmol, glycopeptides could still be selectively isolated by the prepared nanoparticles. Our results demonstrated that the synthetic poly(MBA-co-MAA)@VPBA nanoparticles might be a promising selective enrichment material for glycoproteome analysis. PMID:22707097

  4. Preparation of sulfonic acid-containing rubbers from natural rubber vulcanizates

    NASA Astrophysics Data System (ADS)

    Poonsawat, Worapong; Poompradub, Sirilux; Ngamcharussrivichai, Chawalit

    2014-06-01

    In this work, a series of sulfonic acid-containing rubbers were prepared by aqueous phase oxidation of natural rubber vulcanizates in the presence of hydrogen peroxide (H2O2) and formic acid (HCOOH). The starting vulcanizates were neatly prepared via an efficient vulcanization (EV) system by varying mass ratio of N-cyclohexyl-2-benzothiazole sulfonamide (CBS), as an accelerator, to sulfur. The oxidation conditions were controlled at the molar ratio of H2O2: HCOOH = 1:1, the concentration of H2O2 = 15 wt.%, the temperature = 50 °C, and the reaction time = 3 h. The rubber materials before and after the oxidation were characterized for their physicochemical properties by using Fourier transform infrared spectroscopy, bomb calorimetry, acid-base titration and swelling measurements. The results indicated the presence of sulfonic acid group in the oxidized rubbers, generated by the oxidative cleaves of sulfide crosslinks in the rubber vulcanizates. The oxidation decreased the sulfur content of the rubber in which the level of sulfur loss was determined by the CBS/sulfur ratio. Moreover, the acidity of the oxidized products was correlated with the amount of sulfur remaining.

  5. Preparation of κ-carra-oligosaccharides with microwave assisted acid hydrolysis method

    NASA Astrophysics Data System (ADS)

    Li, Guangsheng; Zhao, Xia; Lv, Youjing; Li, Miaomiao; Yu, Guangli

    2015-04-01

    A rapid method of microwave assisted acid hydrolysis was established to prepare κ-carra-oligosaccharides. The optimal hydrolysis condition was determined by an orthogonal test. The degree of polymerization (DP) of oligosaccharides was detected by high performance thin layer chromatography (HPTLC) and polyacrylamide gel electrophoresis (PAGE). Considering the results of HPTLC and PAGE, the optimum condition of microwave assisted acid hydrolysis was determined. The concentration of κ-carrageenan was 5 mg mL-1; the reaction solution was adjusted to pH 3 with diluted hydrochloric acid; the solution was hydrolyzed under microwave irradiation at 100 for 15 °C min. Oligosaccharides were separated by a Superdex 30 column (2.6 cm × 90 cm) using AKTA Purifier UPC100 and detected with an online refractive index detector. Each fraction was characterized by electrospray ionization mass spectrometry (ESI-MS). The data showed that odd-numbered κ-carra-oligosaccharides with DP ranging from 3 to 21 could be obtained with this method, and the structures of the oligosaccharides were consistent with those obtained by traditional mild acid hydrolysis. The new method was more convenient, efficient and environment-friendly than traditional mild acid hydrolysis. Our results provided a useful reference for the preparation of oligosaccharides from other polysaccharides.

  6. Study of the first paramagnetic to ferromagnetic transition in as prepared samples of Mn-Fe-P-Si magnetocaloric compounds prepared by different synthesis routes

    NASA Astrophysics Data System (ADS)

    Bartok, A.; Kustov, M.; Cohen, L. F.; Pasko, A.; Zehani, K.; Bessais, L.; Mazaleyrat, F.; LoBue, M.

    2016-02-01

    Magnetocaloric materials with composition of Mn1.3Fe0.65P0.5 Si0.5 have been prepared by ball milling and solid-state reaction methods and consolidated using powder annealing, and conventional and spark plasma sintering. Magnetic and calorimetric measurements show remarkable differences upon first cooling, and slight differences on second and further coolings between the samples prepared by different synthesis routes. Further measurements using Hall probe imaging in high magnetic field have been also carried out. As-prepared samples have been cooled down just above the critical temperature, and the first phase transition has been induced by application of a magnetic field. Bulk samples show staircase isothermal magnetization curves whereas powders show smoother transition curves.

  7. A comparison of sample preparation methodology in the evaluation of geosynthetic clay liner (GCL) hydraulic conductivity

    SciTech Connect

    Siebken, J.R.; Lucas, S.

    1997-11-01

    The method of preparing a single needle-punched GCL product for evaluation of hydraulic conductivity in a flexible wall permeameter was examined. The test protocol utilized for this evaluation was GRI Test Method GCL-2 Permeability of GCLs. The GCL product consisted of bentonite clay material supported by a woven and a non-woven geotextile on either side. The method preparation focused on the procedure for separating the test specimen from the larger sample and whether these methods produced difficulty in generating reliable test data. The methods examined included cutting with a razor knife, scissors, and a circular die with the perimeter of the test area under wet and dry conditions. In order to generate as much data as possible, tests were kept brief. Flow was monitored only long enough to determine whether or not preferential flow paths appeared to be present. The results appear to indicate that any of the methods involved will work. Difficulties arose not from the development of preferential flow paths around the edges of the specimens, but from the loss of bentonite from the edges during handling.

  8. Ultrastructure of Plant Leaf Cuticles in relation to Sample Preparation as Observed by Transmission Electron Microscopy

    PubMed Central

    Guzmán, Paula; Fernández, Victoria; García, María Luisa; Fernández, Agustín; Gil, Luis

    2014-01-01

    The leaf cuticular ultrastructure of some plant species has been examined by transmission electron microscopy (TEM) in only few studies. Attending to the different cuticle layers and inner structure, plant cuticles have been grouped into six general morphological types. With the aim of critically examining the effect of cuticle isolation and preparation for TEM analysis on cuticular ultrastructure, adaxial leaf cuticles of blue-gum eucalypt, grey poplar, and European pear were assessed, following a membrane science approach. The embedding and staining protocols affected the ultrastructure of the cuticles analysed. The solubility parameter, surface tension, and contact angles with water of pure Spurr's and LR-White resins were within a similar range. Differences were however estimated for resin : solvent mixtures, since Spurr's resin is combined with acetone and LR-White resin is mixed with ethanol. Given the composite hydrophilic and lipophilic nature of plant cuticles, the particular TEM tissue embedding and staining procedures employed may affect sample ultrastructure and the interpretation of the results in physicochemical and biological terms. It is concluded that tissue preparation procedures may be optimised to facilitate the observation of the micro- and nanostructure of cuticular layers and components with different degrees of polarity and hydrophobicity. PMID:24895682

  9. Development of a harmonised method for the profiling of amphetamines: IV. Optimisation of sample preparation.

    PubMed

    Andersson, Kjell; Jalava, Kaisa; Lock, Eric; Huizer, Henk; Kaa, Elisabet; Lopes, Alvaro; Poortman-van der Meer, Anneke; Cole, Michael D; Dahlén, Johan; Sippola, Erkki

    2007-06-14

    The suitability of liquid-liquid extraction (LLE) and solid-phase extraction (SPE) for the preparation of impurity extracts intended for gas chromatographic profiling analyses of amphetamine were evaluated. Both techniques were optimised with respect to the extraction of selected target compounds by use of full factorial designs in which the variables affecting the performance were evaluated. Test samples consisted of amphetamine synthesised by the Leuckart reaction, by reductive amination of benzyl methyl ketone and by the nitrostyrene route. The performance of LLE and SPE were comparable in terms of repeatability and recovery of the target compounds. LLE was considered the better choice for the present harmonised amphetamine profiling method due to the lack of information on the long-term stability of SPE columns. PMID:17134863

  10. NGSI FY15 Final Report. Innovative Sample Preparation for in-Field Uranium Isotopic Determinations

    SciTech Connect

    Yoshida, Thomas M.; Meyers, Lisa

    2015-11-10

    Our FY14 Final Report included an introduction to the project, background, literature search of uranium dissolution methods, assessment of commercial off the shelf (COTS) automated sample preparation systems, as well as data and results for dissolution of bulk quantities of uranium oxides, and dissolution of uranium oxides from swipe filter materials using ammonium bifluoride (ABF). Also, discussed were reaction studies of solid ABF with uranium oxide that provided a basis for determining the ABF/uranium oxide dissolution mechanism. This report details the final experiments for optimizing dissolution of U3O8 and UO2 using ABF and steps leading to development of a Standard Operating Procedure (SOP) for dissolution of uranium oxides on swipe filters.

  11. Sample processing and cDNA preparation for microbial metatranscriptomics in complex soil communities.

    PubMed

    Carvalhais, Lilia C; Schenk, Peer M

    2013-01-01

    Soil presents one of the most complex environments for microbial communities as it provides many microhabitats that allow coexistence of thousands of species with important ecosystem functions. These include biomass and nutrient cycling, mineralization, and detoxification. Culture-independent DNA-based methods, such as metagenomics, have revealed operational taxonomic units that suggest a high diversity of microbial species and associated functions in soil. An emerging but technically challenging area to profile the functions of microorganisms and their activities is mRNA-based metatranscriptomics. Here, we describe issues and important considerations of soil sample processing and cDNA preparation for metatranscriptomics from bacteria and archaea and provide a set of methods that can be used in the required experimental steps. PMID:24060125

  12. Raman scattering study of the lattice dynamic of URu2Si2 and sample's preparation

    NASA Astrophysics Data System (ADS)

    Buhot, Jonathan; Méasson, Marie-Aude; Gallais, Yann; Cazayous, Maximilien; Sacuto, Alain; Lapertot, Gérard; Aoki, Dai

    2013-05-01

    We report Raman scattering measurements on URu2Si2 single crystals as a function of temperature down to 2 K. We probe all the Raman active symmetries. Only when the sample is prepared with a surface perpendicular to a-axis, we observe an extrinsic hardening and broadening of the A1 g and B1 g phonons after polishing, which disappears after annealing. Moreover, a parasitic phase with Si-excess compared to URu2Si2 composition appears on the a-axis surface when annealing is at 1075 °C. No parasitic phase is induced when annealing is done at 950 °C. The temperature dependance of the A1 g , and two E g phonons shows a hardening with decreasing temperature. The B1 g phonon mode's behavior is more unusual, its energy stays stable down to ˜ 30 K before softens at lower temperature. An electron-phonon coupling is certainly at play here.

  13. Polymer-coated fibrous extraction medium for sample preparation coupled to microcolumn liquid-phase separations.

    PubMed

    Imaizumi, Motohiro; Saito, Yoshihiro; Hayashida, Makiko; Takeichi, Tsutomu; Wada, Hiroo; Jinno, Kiyokatsu

    2003-01-15

    Polymer-coated fibrous material has been introduced as the extraction medium for a miniaturized sample preparation method being coupled with microcolumn liquid chromatography. The preconcentration and the subsequent liquid chromatographic separation of tricyclic antidepressants (TCAs) drugs, amitriptyline, imipramine, nortriptyline and desipramine, was carried out with the hyphenated system. Several basic experimental parameters, such as extraction and separation conditions, were investigated along with the applicability of the method for the analysis of biological fluids. The results clearly showed that the on-line coupled system could be a powerful tool for the analysis of complex mixtures in biological matrix without a large solvent consumption and specially designed instruments. The lowest limit of quantification was quite acceptable for the analysis of TCAs in clinical and forensic situations. PMID:12485721

  14. Sample selection, preparation methods, and the apparent tensile properties of silkworm (B. mori) cocoon silk.

    PubMed

    Reed, Emily J; Bianchini, Lindsay L; Viney, Christopher

    2012-06-01

    Reported literature values of the tensile properties of natural silk cover a wide range. While much of this inconsistency is the result of variability that is intrinsic to silk, some is also a consequence of differences in the way that silk is prepared for tensile tests. Here we explore how measured mechanical properties of Bombyx mori cocoon silk are affected by two intrinsic factors (the location from which the silk is collected within the cocoon, and the color of the silk), and two extrinsic factors (the storage conditions prior to testing, and different styles of reeling the fiber). We find that extrinsic and therefore controllable factors can affect the properties more than the intrinsic ones studied. Our results suggest that enhanced inter-laboratory collaborations, that lead to standardized sample collection, handling, and storage protocols prior to mechanical testing, would help to decrease unnecessary (and complicating) variation in reported tensile properties. PMID:22057343

  15. Preparation of linoleic acid-capped silver nanoparticles and their antimicrobial effect.

    PubMed

    Das, R; Gang, S; Nath, S S; Bhattacharjee, R

    2012-06-01

    Silver nanoparticles have been prepared through the chemical reduction of silver ions by ethanol using linoleic acid as a stabilising agent. This colloidal solution shows an absorption band in the visible range with an absorption peak at 421 nm. The peaks in the X-ray diffraction (XRD) pattern matches well with the standard values of the face-centred-cubic form of metallic silver. Transmission Electron Microscope (TEM) micrograph shows a nearly uniform distribution of the particles with an average size of 8 nm. This linoleic acid-capped silver nanoparticles show antimicrobial activity against Escherichia coli and Staphylococcus aureus. PMID:22559712

  16. Preparation of carboxylic acid-bearing polysaccharide nanofiber made from euglenoid β-1,3-glucans.

    PubMed

    Shibakami, Motonari; Tsubouchi, Gen; Nakamura, Makoto; Hayashi, Masahiro

    2013-10-15

    This paper introduces a new strategy for creating surface modified polysaccharide nanofibers. To demonstrate proof of principle, the synthesis, structure, and self-assembly behavior of a carboxylic acid-bearing polysaccharide made from paramylon (β-1,3-glucan) and succinic anhydride were investigated. Examination by a combination of NMR, FT-IR, and SEC-MALLS confirmed that successful preparation of the desired succinylated paramylon without significant depolymerization. NMR, SEC-MALLS, visible absorption and CD spectroscopic analyses indicated that the paramylon derivative forms the triplex structure in solutions. SEM observation revealed that succinylated paramylon forms a nanofiber that has carboxylic acid on the surface. PMID:23987321

  17. Data supporting the rat brain sample preparation and validation assays for simultaneous determination of 8 neurotransmitters and their metabolites using liquid chromatography-tandem mass spectrometry.

    PubMed

    Wojnicz, Aneta; Ortiz, José Avendaño; Casas, Ana I; Freitas, Andiara E; López, Manuela G; Ruiz-Nuño, Ana

    2016-06-01

    The data presented in this article supports the rat brain sample preparation procedure previous to its injection into the liquid chromatography-tandem mass spectrometry (LC-MS/MS) system to monitor levels of adrenaline, noradrenaline, glutamic acid, γ-aminobutyric acid, dopamine, 5-hydroxytryptamine, 5-hydroxyindole acetic acid, and 3-methoxy-4-hydroxyphenylglycol. In addition, we describe the method validation assays (such as calibration curve, lower limit of quantification, precision and accuracy intra- and inter-day, selectivity, extraction recovery and matrix effect, stability, and carry-over effect) according to the United States Food and Drug Administration and European Medicine Agency to measure in one step different neurotransmitters and their metabolites. The data supplied in this article is related to the research study entitled: "Simultaneous determination of 8 neurotransmitters and their metabolite levels in rat brain using liquid chromatography in tandem with mass spectrometry: application to the murine Nrf2 model of depression" (Wojnicz et al. 2016) [1]. PMID:27054183

  18. Shear mechanical anisotropy of side chain liquid-crystal elastomers: Influence of sample preparation

    NASA Astrophysics Data System (ADS)

    Rogez, D.; Francius, G.; Finkelmann, H.; Martinoty, P.

    2006-08-01

    We study the mechanical anisotropy of a series of uniaxial side chain nematic elastomers prepared with the same chemical composition but with different preparation protocols. For all the compounds, the experiments performed as a function of temperature show no discontinuity in both G'// and G'⊥ (the labels // and ⊥ stand for the director parallel, respectively perpendicular to the shear displacement) around the nematic-isotropic (N-I) phase transition temperature determined by DSC. They also all show a small decrease in G'// starting at temperatures well above this temperature (from ˜ 4°C to ˜ 20°C depending on the compound studied) and leading to a small hydrodynamic value of the G'⊥/G'// ratio. The measurements taken as a function of frequency show that the second plateau in G'// and the associated dip in G//” expected from dynamic semi-soft elasticity are not observed. These results can be described by the de Gennes model, which predicts small elastic anisotropy in the hydrodynamic and linear regimes. They correspond to the behavior expected for compounds beyond the mechanical critical point, which is consistent with the NMR and specific heat measurements taken on similar compounds. We also show that a reduction in the cross-linking density does not change the non-soft character of the mechanical response. From the measurements taken as a function of frequency at several temperatures we deduce that the time-temperature superposition method does not apply. From these measurements, we also determine the temperature dependence of the longest relaxation time τE of the network for the situations where the director is either parallel or perpendicular to the shear velocity. Finally, we discuss the influence on the measurements of the mechanical constraint associated with the fact that the samples cannot change their shape around the pseudo phase transition, because of their strong adherence on the sample-bearing glass slides.

  19. Shear mechanical anisotropy of side chain liquid-crystal elastomers: influence of sample preparation.

    PubMed

    Rogez, D; Francius, G; Finkelmann, H; Martinoty, P

    2006-08-01

    We study the mechanical anisotropy of a series of uniaxial side chain nematic elastomers prepared with the same chemical composition but with different preparation protocols. For all the compounds, the experiments performed as a function of temperature show no discontinuity in both G' (//) and G' ( perpendicular) (the labels // and perpendicular stand for the director parallel, respectively perpendicular to the shear displacement) around the nematic-isotropic (N-I) phase transition temperature determined by DSC. They also all show a small decrease in G' (//) starting at temperatures well above this temperature (from approximately 4( degrees ) C to approximately 20( degrees ) C depending on the compound studied) and leading to a small hydrodynamic value of the G' ( perpendicular)/G' (//) ratio. The measurements taken as a function of frequency show that the second plateau in G' (//) and the associated dip in G (//)" expected from dynamic semi-soft elasticity are not observed. These results can be described by the de Gennes model, which predicts small elastic anisotropy in the hydrodynamic and linear regimes. They correspond to the behavior expected for compounds beyond the mechanical critical point, which is consistent with the NMR and specific heat measurements taken on similar compounds. We also show that a reduction in the cross-linking density does not change the non-soft character of the mechanical response. From the measurements taken as a function of frequency at several temperatures we deduce that the time-temperature superposition method does not apply. From these measurements, we also determine the temperature dependence of the longest relaxation time tau(E) of the network for the situations where the director is either parallel or perpendicular to the shear velocity. Finally, we discuss the influence on the measurements of the mechanical constraint associated with the fact that the samples cannot change their shape around the pseudo phase transition

  20. Microcalorimetric Studies of Surface Acid/Base Properties of Magnesium Iron Catalysts Prepared from Hydrotalcite-Type Precursors

    NASA Astrophysics Data System (ADS)

    Tu, Mai; Shen, Jianyi; Chen, Yi

    1997-01-01

    Magnesium-iron mixed oxides with Mg/Fe molar ratios 1,3, and 6 were prepared from hydrotalcite-type precursors. Microcalorimetric adsorption of NH 3and CO 2showed that the surface acidity and basicity of the mixed oxides after calcination at 673 K are similar despite the different Mg/Fe ratios. Increasing calcination temperature from 673 to 773 K significantly decreased the surface area of the 3 Mg/Fe oxide, but the densities of both the acid and base sites were not changed. Mössbauer spectroscopy revealed that the reduction of the 3 Mg/Fe oxide (Fe 2O 3/MgO) in H 2at 673 K converted all Fe 3+to Fe 2+. The resulted FeO/MgO exhibited the same acidity as that of the Fe 2O 3/MgO, but the basicity of the FeO/MgO was greatly enhanced. Reduction at 773 K resulted in the formation of 76% Fe 2+and 24% Fe 0as detected by Mössbauer spectroscopy. The Fe/FeO/MgO sample formed exhibited very low heat for the adsorption of NH 3(40 kJ/mol) indicating that all iron atoms on the surface are Fe 0. However, a substantial basicity remained on the surface of this sample that may account for its high olefin selectivity compared with pure iron catalyst in the Fischer-Tropsch synthesis.