Thermo-optical properties and nonlinear optical response of smectic liquid crystals containing gold nanoparticles.

PubMed

de Melo, P B; Nunes, A M; Omena, L; do Nascimento, S M S; da Silva, M G A; Meneghetti, M R; de Oliveira, I N

2015-10-01

The present work is devoted to the study of the thermo-optical and nonlinear optical properties of smectic samples containing gold nanoparticles with different shapes. By using the time-resolved Z-scan technique, we determine the effects of nanoparticle addition on the critical behavior of the thermal diffusivity and thermo-optical coefficient at the vicinity of the smectic-A-nematic phase transition. Our results reveal that introduction of gold nanoparticles affects the temperature dependence of thermo-optical parameters, due to the local distortions in the orientational order and heat generation provided by guest particles during the laser exposure. Further, we show that a nonlinear optical response may take place at temperatures where the smectic order is well established. We provide a detailed discussion of the effects associated with the introduction gold nanoparticles on the mechanisms behind the thermal transport and optical nonlinearity in liquid-crystal samples.

Rapid sample classification using an open port sampling interface coupled with liquid introduction atmospheric pressure ionization mass spectrometry.

PubMed

Van Berkel, Gary J; Kertesz, Vilmos

2017-02-15

An "Open Access"-like mass spectrometric platform to fully utilize the simplicity of the manual open port sampling interface for rapid characterization of unprocessed samples by liquid introduction atmospheric pressure ionization mass spectrometry has been lacking. The in-house developed integrated software with a simple, small and relatively low-cost mass spectrometry system introduced here fills this void. Software was developed to operate the mass spectrometer, to collect and process mass spectrometric data files, to build a database and to classify samples using such a database. These tasks were accomplished via the vendor-provided software libraries. Sample classification based on spectral comparison utilized the spectral contrast angle method. Using the developed software platform near real-time sample classification is exemplified using a series of commercially available blue ink rollerball pens and vegetable oils. In the case of the inks, full scan positive and negative ion ESI mass spectra were both used for database generation and sample classification. For the vegetable oils, full scan positive ion mode APCI mass spectra were recorded. The overall accuracy of the employed spectral contrast angle statistical model was 95.3% and 98% in case of the inks and oils, respectively, using leave-one-out cross-validation. This work illustrates that an open port sampling interface/mass spectrometer combination, with appropriate instrument control and data processing software, is a viable direct liquid extraction sampling and analysis system suitable for the non-expert user and near real-time sample classification via database matching. Published in 2016. This article is a U.S. Government work and is in the public domain in the USA. Published in 2016. This article is a U.S. Government work and is in the public domain in the USA.

Stationary microfluidics: molecular diagnostic assays by moving magnetic beads through non-moving liquids

NASA Astrophysics Data System (ADS)

Becker, Holger; Carstens, Cornelia; Kuhlmeier, Dirk; Sandetskaya, Natalia; Schröter, Nicole; Zilch, Christian; Gärtner, Claudia

2013-03-01

Commonly, microfluidic devices are based on the movement of fluids. For molecular diagnostics assays which often include steps like PCR, this practically always involves a more or less complicated set of external pumps, valves and liquid controls. In the presented paper, we follow a different approach in which the fluid after sample introduction remains stationary and the main bioactive sample molecules are moved through a chain of reaction compartments which contain the different reagents necessary for the assay. The big advantage of this concept is the lack of any external fluid actuation/control. Results on sample carry-over experiments and complete assays will be given.

High-pressure liquid chromatography with direct injection of gas sample.

PubMed

Astanin, Anton I; Baram, Grigory I

2017-06-09

The conventional method of using liquid chromatography to determine the composition of a gaseous mixture entails dissolving vapors in a suitable solvent, then obtaining a chromatograph of the resulting solution. We studied the direct introduction of a gaseous sample into a C18 reversed-phase column, followed by separation of the components by HPLC with UV detection. Since the chromatography was performed at high pressure, vapors readily dissolved in the eluent and the substances separated in the column as effectively as in liquid samples. Samples were injected into the column in two ways: a) through the valve without a flow stop; b) after stopping the flow and relieving all pressure. We showed that an injectable gas volume could reach 70% of column dead volume. When an injected gaseous sample volume was less than 10% of the column dead volume, the resulting peaks were symmetrical and the column efficiency was high. Copyright © 2017 Elsevier B.V. All rights reserved.

Liquid biopsy for brain tumors

PubMed Central

Shankar, Ganesh M.; Balaj, Leonora; Stott, Shannon L.; Nahed, Brian; Carter, Bob S.

2018-01-01

Introduction Minimally invasive methods will augment the clinical approach for establishing the diagnosis or monitoring treatment response of central nervous system tumors. Liquid biopsy by blood or cerebrospinal fluid sampling holds promise in this regard. Areas covered In this literature review, the authors highlight recent studies describing the analysis of circulating tumor cells, cell free nucleic acids, and extracellular vesicles as strategies to accomplish liquid biopsy in glioblastoma and metastatic tumors. The authors then discuss the continued efforts to improve signal detection, standardize the liquid biopsy handling and preparation, develop platforms for clinical application, and establish a role for liquid biopsies in personalized medicine. Expert commentary As the technologies used to analyze these biomarkers continue to evolve, we propose that there is a future potential to precisely diagnose and monitor treatment response with liquid biopsies. PMID:28875730

Improvements in the processing of large grain, bulk Y-Ba-Cu-O superconductors via the use of additional liquid phase

NASA Astrophysics Data System (ADS)

Congreve, Jasmin V. J.; Shi, Yunhua; Dennis, Anthony R.; Durrell, John H.; Cardwell, David A.

2017-01-01

A major limitation to the widespread application of Y-Ba-Cu-O (YBCO) bulk superconductors is the relative complexity and low yield of the top seeded melt growth (TSMG) process, by which these materials are commonly fabricated. It has been demonstrated in previous work on the recycling of samples in which the primary growth had failed, that the provision of an additional liquid-rich phase to replenish liquid lost during the failed growth process leads to the reliable growth of relatively high quality recycled samples. In this paper we describe the adaptation of the liquid phase enrichment technique to the primary TSMG fabrication process. We further describe the observed differences between the microstructure and superconducting properties of samples grown with additional liquid-rich phase and control samples grown using a conventional TSMG process. We observe that the introduction of the additional liquid-rich phase leads to the formation of a higher concentration of Y species at the growth front, which leads, in turn, to a more uniform composition at the growth front. Importantly, the increased uniformity at the growth front leads directly to an increased homogeneity in the distribution of the Y-211 inclusions in the superconducting Y-123 phase matrix and to a more uniform Y-123 phase itself. Overall, the provision of an additional liquid-rich phase improves significantly both the reliability of grain growth through the sample thickness and the magnitude and homogeneity of the superconducting properties of these samples compared to those fabricated by a conventional TSMG process.

Analysis of biofluids in aqueous environment based on mid-infrared spectroscopy.

PubMed

Fabian, Heinz; Lasch, Peter; Naumann, Dieter

2005-01-01

In this study we describe a semiautomatic Fourier transform infrared spectroscopic methodology for the analysis of liquid serum samples, which combines simple sample introduction with high sample throughput. The applicability of this new infrared technology to the analysis of liquid serum samples from a cohort of cattle naturally infected with bovine spongiform encephalopathy and from controls was explored in comparison to the conventional approach based on transmission infrared spectroscopy of dried serum films. Artifical neural network analysis of the infrared data was performed to differentiate between bovine spongiform encephalopathy-negative controls and animals in the late stage of the disease. After training of artifical neural network classifiers, infrared spectra of sera from an independent external validation data set were analyzed. In this way, sensitivities between 90 and 96% and specificities between 84 and 92% were achieved, respectively, depending upon the strategy of data collection and data analysis. Based on these results, the advantages and limitations of the liquid sample technique and the dried film approach for routine analysis of biofluids are discussed. 2005 Society of Photo-Optical Instrumentation Engineers.

Laser-desorption tandem time-of-flight mass spectrometry with continuous liquid introduction

NASA Astrophysics Data System (ADS)

Williams, Evan R.; Jones, Glenn C., Jr.; Fang, LiLing; Nagata, Takeshi; Zare, Richard N.

1992-05-01

A new method to combine aqueous sample introduction with matrix assisted laser desorption mass spectrometry (MS) for interfacing liquid-chromatographic techniques, such as capillary electrophoresis, to MS is described. Aqueous sample solution is introduced directly into the ion source of a time-of-. flight (TOF) mass spectrometer through a fused silica capillary; evaporative cooling results in ice formation at the end of the capillary. The ice can be made to extrude continuously by using localized resistive heating. With direct laser desorption, molecular ions from proteins as large as bovine insulin (5734 Da) can be produced. Two-step desorption/photoionization with a variety of wavelengths is demonstrated, and has the advantages of improved resolution and shot-to-shot reproducibility. Ion structural information is obtained using surface-induced dissociation with an in-line collision device in the reflectron mirror of the TOF instrument. Product ion resolution of ~70 is obtained at m/z77. Extensive fragmentation can be produced with dissociation efficiencies between 7-15% obtained for molecular ions of small organic molecules. Efficiencies approaching 30% are obtained for larger peptide ions.

Evaluation of Electronic Cigarette Liquids and Aerosol for the Presence of Selected Inhalation Toxins

PubMed Central

Kistler, Kurt A.; Gillman, Gene; Voudris, Vassilis

2015-01-01

Introduction: The purpose of this study was to evaluate sweet-flavored electronic cigarette (EC) liquids for the presence of diacetyl (DA) and acetyl propionyl (AP), which are chemicals approved for food use but are associated with respiratory disease when inhaled. Methods: In total, 159 samples were purchased from 36 manufacturers and retailers in 7 countries. Additionally, 3 liquids were prepared by dissolving a concentrated flavor sample of known DA and AP levels at 5%, 10%, and 20% concentration in a mixture of propylene glycol and glycerol. Aerosol produced by an EC was analyzed to determine the concentration of DA and AP. Results: DA and AP were found in 74.2% of the samples, with more samples containing DA. Similar concentrations were found in liquid and aerosol for both chemicals. The median daily exposure levels were 56 μg/day (IQR: 26–278 μg/day) for DA and 91 μg/day (IQR: 20–432 μg/day) for AP. They were slightly lower than the strict NIOSH-defined safety limits for occupational exposure and 100 and 10 times lower compared with smoking respectively; however, 47.3% of DA and 41.5% of AP-containing samples exposed consumers to levels higher than the safety limits. Conclusions: DA and AP were found in a large proportion of sweet-flavored EC liquids, with many of them exposing users to higher than safety levels. Their presence in EC liquids represents an avoidable risk. Proper measures should be taken by EC liquid manufacturers and flavoring suppliers to eliminate these hazards from the products without necessarily limiting the availability of sweet flavors. PMID:25180080

Flow-based analysis using microfluidics-chemiluminescence systems.

PubMed

Al Lawati, Haider A J

2013-01-01

This review will discuss various approaches and techniques in which analysis using microfluidics-chemiluminescence systems (MF-CL) has been reported. A variety of applications is examined, including environmental, pharmaceutical, biological, food and herbal analysis. Reported uses of CL reagents, sample introduction techniques, sample pretreatment methods, CL signal enhancement and detection systems are discussed. A hydrodynamic pumping system is predominately used for these applications. However, several reports are available in which electro-osmotic (EO) pumping has been implemented. Various sample pretreatment methods have been used, including liquid-liquid extraction, solid-phase extraction and molecularly imprinted polymers. A wide range of innovative techniques has been reported for CL signal enhancement. Most of these techniques are based on enhancement of the mixing process in the microfluidics channels, which leads to enhancement of the CL signal. However, other techniques are also reported, such as mirror reaction, liquid core waveguide, on-line pre-derivatization and the use of an opaque white chip with a thin transparent seal. Photodetectors are the most commonly used detectors; however, other detection systems have also been used, including integrated electrochemiluminescence (ECL) and organic photodiodes (OPDs). Copyright © 2012 John Wiley & Sons, Ltd.

Comparison of a high temperature torch integrated sample introduction system with a desolvation system for the analysis of microsamples through inductively coupled plasma mass spectrometry

NASA Astrophysics Data System (ADS)

Sánchez, Raquel; Cañabate, Águeda; Bresson, Carole; Chartier, Frédéric; Isnard, Hélène; Maestre, Salvador; Nonell, Anthony; Todolí, José-Luis

2017-03-01

This work describes for the first time the comparison of the analytical performances obtained with a high temperature torch integrated sample introduction system (hTISIS) against those found with a commercially available desolvation system (APEX) associated with inductively coupled plasma mass spectrometry (ICP-MS). A double pass spray chamber was taken as the reference system. Similar detection limits and sensitivities were obtained in continuous injection mode at low liquid flow rates for the APEX and hTISIS operating at high temperatures. In contrast, in the air-segmented injection mode, the detection limits obtained with hTISIS at high temperatures were up to 12 times lower than those found for the APEX. Regarding memory effects, wash out times were shorter in continuous mode and peaks were narrower in air segmented mode for the hTISIS as compared to the APEX. Non spectral interferences (matrix effects) were studied with 10% nitric acid, 2% methanol, for an ICP multielemental solution and a hydro-organic matrix containing 70% (v/v) acetonitrile in water, 15 mmol L- 1 ammonium acetate and 0.5% formic acid containing lanthanide complexes. In all the cases, matrix effects were less severe for the hTISIS operating at 200 °C and the APEX than for the double pass spray chamber. Finally, two spiked reference materials (sea water and Antartic krill) were analyzed. The hTISIS operating at 200 °C gave the best results compared to those obtained with the APEX and the double pass spray chamber. In conclusion, despite the simplicity of the hTISIS, it provided, at low liquid flow rates, results similar to or better than those obtained with the by other sample introduction systems.

Quantitative evaluation of analyte transport on microfluidic paper-based analytical devices (μPADs).

PubMed

Ota, Riki; Yamada, Kentaro; Suzuki, Koji; Citterio, Daniel

2018-02-07

The transport efficiency during capillary flow-driven sample transport on microfluidic paper-based analytical devices (μPADs) made from filter paper has been investigated for a selection of model analytes (Ni 2+ , Zn 2+ , Cu 2+ , PO 4 3- , bovine serum albumin, sulforhodamine B, amaranth) representing metal cations, complex anions, proteins and anionic molecules. For the first time, the transport of the analytical target compounds rather than the sample liquid, has been quantitatively evaluated by means of colorimetry and absorption spectrometry-based methods. The experiments have revealed that small paperfluidic channel dimensions, additional user operation steps (e.g. control of sample volume, sample dilution, washing step) as well as the introduction of sample liquid wicking areas allow to increase analyte transport efficiency. It is also shown that the interaction of analytes with the negatively charged cellulosic paper substrate surface is strongly influenced by the physico-chemical properties of the model analyte and can in some cases (Cu 2+ ) result in nearly complete analyte depletion during sample transport. The quantitative information gained through these experiments is expected to contribute to the development of more sensitive μPADs.

Design and development of a highly sensitive, field portable plasma source instrument for on-line liquid stream monitoring and real-time sample analysis

NASA Astrophysics Data System (ADS)

Duan, Yixiang; Su, Yongxuan; Jin, Zhe; Abeln, Stephen P.

2000-03-01

The development of a highly sensitive, field portable, low-powered instrument for on-site, real-time liquid waste stream monitoring is described in this article. A series of factors such as system sensitivity and portability, plasma source, sample introduction, desolvation system, power supply, and the instrument configuration, were carefully considered in the design of the portable instrument. A newly designed, miniature, modified microwave plasma source was selected as the emission source for spectroscopy measurement, and an integrated small spectrometer with a charge-coupled device detector was installed for signal processing and detection. An innovative beam collection system with optical fibers was designed and used for emission signal collection. Microwave plasma can be sustained with various gases at relatively low power, and it possesses high detection capabilities for both metal and nonmetal pollutants, making it desirable to use for on-site, real-time, liquid waste stream monitoring. An effective in situ sampling system was coupled with a high efficiency desolvation device for direct-sampling liquid samples into the plasma. A portable computer control system is used for data processing. The new, integrated instrument can be easily used for on-site, real-time monitoring in the field. The system possesses a series of advantages, including high sensitivity for metal and nonmetal elements; in situ sampling; compact structure; low cost; and ease of operation and handling. These advantages will significantly overcome the limitations of previous monitoring techniques and make great contributions to environmental restoration and monitoring.

Room temperature ionic liquid-based dispersive liquid phase microextraction for the separation/preconcentration of trace Cd(2+) as 1-(2-pyridylazo)-2-naphthol (PAN) complex from environmental and biological samples and determined by FAAS.

PubMed

Khan, Sumaira; Soylak, Mustafa; Kazi, Tasneem Gul

2013-12-01

The current work develops a new green methodology for the separation/preconcentration of cadmium ions (Cd(2+)) using room temperature ionic liquid-dispersive liquid phase microextraction (RTIL-DLME) prior to analysis by flame atomic absorption spectrometry with microsample introduction system. Room temperature ionic liquids (RTIL) are considered "Green Solvents" for their thermally stable and non-volatile properties, here 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] was used as an extractant. The preconcentration of Cd(2+) in different waters and acid digested scalp hair samples were complexed with 1-(2-pyridylazo)-2-naphthol and extracted into the fine drops of RTILs. Some significant factors influencing the extraction efficiency of Cd(2+) and its subsequent determination, including pH, amount of ligand, volume of RTIL, dispersant solvent, sample volume, temperature, and incubation time were investigated in detail. The limit of detection and the enhancement factor under the optimal conditions were 0.05 μg/L and 50, respectively. The relative standard deviation of 100 μg/L Cd(2+) was 4.3 %. The validity of the proposed method was checked by determining Cd(2+) in certified reference material (TM-25.3 fortified water). The sufficient recovery (>98 %) of Cd(2+) with the certified value. The mean concentrations of Cd in lake water 13.2, waste water 15.7 and hair sample 16.8 μg/L, respectively and the developed method was applied satisfactorily to the preconcentration and determination of Cd(2+) in real samples.

Evaluation of a direct injection nebulizer interface for flow injection analysis and high performance liquid chromatography with inductively coupled plasma-atomic emission spectroscopic detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

LaFreniere, K.E.

A direct injection nebulizer (DIN) was designed, developed and evaluated to determine its potential utilization as an effective interface for flow injection analysis (FIA) and high performance liquid chromatography (HPLC) coupled with inductively coupled plasma-atomic emission spectroscopic detection. The analytical figures of merit for the DIN when used as an interface for FIA-ICP-AES were found to be comparable to or better than those obtained with conventional pneumatic nebulization in terms of limits of detection (LODs), reproducibility, linearity, and interelement effects. In the HPLC mode, the LODDs were found to be comparable to those obtained by continuous-flow sample introduction into themore » ICP, or inferior by up to only a factor of four. Stable plasma operation was maintained for the DIN sample introduction of a variety of pure organic solvents, including acetonitrile, methanol, methyl-isobutylketone, and pyridine. The HPLC-DIN-ICP-AES facility was specifically applied for the speciation of inorganic and organo-metallic species contained in synthetic mixtures, vanilla extracts and a variety of energy-related materials, such as shale oil process water, coal extracts, shale oil, crude oil, and an SRC II. Suggestions for future research are also considered.« less

A full 3D model of fluid flow and heat transfer in an E.B. heated liquid metal bath

NASA Astrophysics Data System (ADS)

Matveichev, A.; Jardy, A.; Bellot, J. P.

2016-07-01

In order to study the dissolution of exogeneous inclusions in the liquid metal during processing of titanium alloys, a series of dipping experiments has been performed in an Electron Beam Melting laboratory furnace. Precise determination of the dissolution kinetics requires knowing and mastering the exact thermohydrodynamic behavior of the melt pool, which implies full 3D modeling of the process. To achieve this goal, one needs to describe momentum and heat transfer, phase change, as well as the development of flow turbulence in the liquid. EB power input, thermal radiation, heat loss through the cooling circuit, surface tension effects (i.e. Marangoni-induced flow) must also be addressed in the model. Therefore a new solver dealing with all these phenomena was implemented within OpenFOAM platform. Numerical results were compared with experimental data from actual Ti melting, showing a pretty good agreement. In the second stage, the immersion of a refractory sample rod in the liquid pool was simulated. Results of the simulations showed that the introduction of the sample slightly disturbs the flow field inside the bath. The amount of such disturbance depends on the exact location of the dipping.

WtF‐Nano: One‐Pot Dewatering and Water‐Free Topochemical Modification of Nanocellulose in Ionic Liquids or γ‐Valerolactone

PubMed Central

Laaksonen, Tiina; Helminen, Jussi K. J.; Lemetti, Laura; Långbacka, Jesper; Rico del Cerro, Daniel; Hummel, Michael; Rantamäki, Antti H.; Kakko, Tia; Kemell, Marianna L.; Wiedmer, Susanne K.; Heikkinen, Sami; Kilpeläinen, Ilkka

2017-01-01

Abstract Ionic liquids are used to dewater a suspension of birch Kraft pulp cellulose nanofibrils (CNF) and as a medium for water‐free topochemical modification of the nanocellulose (a process denoted as “WtF‐Nano”). Acetylation was applied as a model reaction to investigate the degree of modification and scope of effective ionic liquid structures. Little difference in reactivity was observed when water was removed, after introduction of an ionic liquid or molecular co‐solvent. However, the viscoelastic properties of the CNF suspended in two ionic liquids show that the more basic, but non‐dissolving ionic liquid, allows for better solvation of the CNF. Vibrio fischeri bacterial tests show that all ionic liquids in this study were harmless. Scanning electron microscopy and wide‐angle X‐ray scattering on regenerated samples show that the acetylated CNF is still in a fibrillar form. 1 D and 2 D NMR analyses, after direct dissolution in a novel ionic liquid electrolyte solution, indicate that both cellulose and residual xylan on the surface of the nanofibrils reacts to give acetate esters. PMID:29112334

Acidic Ionic Liquids.

PubMed

Amarasekara, Ananda S

2016-05-25

Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition.

Chemical Characterization of an Envelope B/D Sample from Hanford Tank 241-AZ-102

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hay, M.S.

2000-08-23

A sample from Hanford waste tank 241-AZ-102 was received at the Savannah River Technology Center (SRTC) and chemically characterized. The sample containing supernate and a small amount of sludge solids was analyzed as-received. The filtered supernatant liquid, the total dried solids of the sample, and the washed insoluble solids obtained from filtration of the sample were analyzed. A mass balance calculation of the three fractions of the sample analyzed indicate the analytical results appear relatively self-consistent for major components of the sample. However, some inconsistency was observed between results were more than one method of determination was employed and formore » species present in low concentrations. The actinides isotopes, plutonium, americium, and curium, present analytical challenges due to the low concentration of these species and the potential for introduction of small amounts of contamination during sampling handling resulting in large uncertainties. A direct comparison to previous analyses of material from tank 241-AZ-102 showed good agreement with the filtered supernatant liquid. However, the comparison of solids data showed poor agreement. The poor agreement shown between the current results for the solids samples and previous analyses most likely results from the uncertainties associated with obtaining small solids samples from a large non-homogenized waste tank.« less

A Portable, Field-Deployable Analyzer for Isotopic Water Measurements

NASA Astrophysics Data System (ADS)

Berman, E. S.; Gupta, M.; Huang, Y. W.; Lacelle, D.; McKay, C. P.; Fortson, S.

2015-12-01

Water stable isotopes have for many years been used to study the hydrological cycle, catchment hydrology, and polar climate among other applications. Typically, discrete water samples are collected and transported to a laboratory for isotope analysis. Due to the expense and labor associated with such sampling, isotope studies have generally been limited in scope and time-resolution. Field sampling of water isotopes has been shown in recent years to provide dense data sets with the increased time resolution illuminating substantially greater short term variability than is generally observed during discrete sampling. A truly portable instrument also opens the possibility to utilize the instrument as a tool for identifying which water samples would be particularly interesting for further laboratory investigation. To make possible such field measurements of liquid water isotopes, Los Gatos Research has developed a miniaturized, field-deployable liquid water isotope analyzer. The prototype miniature liquid water isotope analyzer (mini-LWIA) uses LGR's patented Off-Axis ICOS (Integrated Cavity Output Spectroscopy) technology in a rugged, Pelican case housing for easy transport and field operations. The analyzer simultaneously measures both δ2H and δ18O from liquid water, with both manual and automatic water introduction options. The laboratory precision for δ2H is 0.6 ‰, and for δ18O is 0.3 ‰. The mini-LWIA was deployed in the high Arctic during the summer of 2015 at Inuvik in the Canadian Northwest Territories. Samples were collected from Sachs Harbor, on the southwest coast of Banks Island, including buried basal ice from the Lurentide Ice Sheet, some ice wedges, and other types of ground ice. Methodology and water analysis results from this extreme field deployment will be presented.

Development of a Thermal Desorption Gas Chromatography-Mass Spectrometry Analysis Method for Airborne Dichlorodiphenyltrichloroethane

DTIC Science & Technology

2013-05-28

span of 1-250 ng DDT. Furthermore, laboratory and field experiments utilizing this method confirmed that significant DDT concentration differences ... different between the two sample introduction methods when comparing the same DDT mass which may be due to differences in the precision of split...degradation of DDT was significantly different between the liquid and TD methods (t-test; p < 0.001). For TD analyses the relative percent

Evaluating Surgical Margins with Optical Spectroscopy and Spectral Imaging Following Breast Cancer Resection

DTIC Science & Technology

2009-08-01

Raman spectral features of hydroxyapatite crystals (found in breast calcifications) through overlying lean chicken breast tissue [18]. Thus, the...form o f spectral imaging to examine entire margins in a single acquisition . 23 1. INTRODUCTION Of the approxim ately 180,000 patien ts each...ination sources into a single, 10-mm-core liquid light guide, which delivered the illumination light to the sample. 2.3 Data acquisition For lum

Ionic liquids in solid-phase microextraction: a review.

PubMed

Ho, Tien D; Canestraro, Anthony J; Anderson, Jared L

2011-06-10

Solid-phase microextraction (SPME) has undergone a surge in popularity within the field of analytical chemistry in the past two decades since its introduction. Owing to its nature of extraction, SPME has become widely known as a quick and cost-effective sample preparation technique. Although SPME has demonstrated extraordinary versatility in sampling capabilities, the technique continues to experience a tremendous growth in innovation. Presently, increasing efforts have been directed towards the engineering of novel sorbent material in order to expand the applicability of SPME for a wider range of analytes and matrices. This review highlights the application of ionic liquids (ILs) and polymeric ionic liquids (PILs) as innovative sorbent materials for SPME. Characterized by their unique physico-chemical properties, these compounds can be structurally-designed to selectively extract target analytes based on unique molecular interactions. To examine the advantages of IL and PIL-based sorbent coatings in SPME, the field is reviewed by gathering available experimental data and exploring the sensitivity, linear calibration range, as well as detection limits for a variety of target analytes in the methods that have been developed. Copyright © 2011 Elsevier B.V. All rights reserved.

A comparative study between different alternatives to prepare gaseous standards for calibrating UV-Ion Mobility Spectrometers.

PubMed

Criado-García, Laura; Garrido-Delgado, Rocío; Arce, Lourdes; Valcárcel, Miguel

2013-07-15

An UV-Ion Mobility Spectrometer is a simple, rapid, inexpensive instrument widely used in environmental analysis among other fields. The advantageous features of its underlying technology can be of great help towards developing reliable, economical methods for determining gaseous compounds from gaseous, liquid and solid samples. Developing an effective method using UV-Ion Mobility Spectrometry (UV-IMS) to determine volatile analytes entails using appropriate gaseous standards for calibrating the spectrometer. In this work, two home-made sample introduction systems (SISs) and a commercial gas generator were used to obtain such gaseous standards. The first home-made SIS used was a static head-space to measure compounds present in liquid samples and the other home-made system was an exponential dilution set-up to measure compounds present in gaseous samples. Gaseous compounds generated by each method were determined on-line by UV-IMS. Target analytes chosen for this comparative study were ethanol, acetone, benzene, toluene, ethylbenzene and xylene isomers. The different alternatives were acceptable in terms of sensitivity, precision and selectivity. Copyright © 2013 Elsevier B.V. All rights reserved.

Radial line-scans as representative sampling strategy in dried-droplet laser ablation of liquid samples deposited on pre-cut filter paper disks

NASA Astrophysics Data System (ADS)

Nischkauer, Winfried; Vanhaecke, Frank; Bernacchi, Sébastien; Herwig, Christoph; Limbeck, Andreas

2014-11-01

Nebulising liquid samples and using the aerosol thus obtained for further analysis is the standard method in many current analytical techniques, also with inductively coupled plasma (ICP)-based devices. With such a set-up, quantification via external calibration is usually straightforward for samples with aqueous or close-to-aqueous matrix composition. However, there is a variety of more complex samples. Such samples can be found in medical, biological, technological and industrial contexts and can range from body fluids, like blood or urine, to fuel additives or fermentation broths. Specialized nebulizer systems or careful digestion and dilution are required to tackle such demanding sample matrices. One alternative approach is to convert the liquid into a dried solid and to use laser ablation for sample introduction. Up to now, this approach required the application of internal standards or matrix-adjusted calibration due to matrix effects. In this contribution, we show a way to circumvent these matrix effects while using simple external calibration for quantification. The principle of representative sampling that we propose uses radial line-scans across the dried residue. This compensates for centro-symmetric inhomogeneities typically observed in dried spots. The effectiveness of the proposed sampling strategy is exemplified via the determination of phosphorus in biochemical fermentation media. However, the universal viability of the presented measurement protocol is postulated. Detection limits using laser ablation-ICP-optical emission spectrometry were in the order of 40 μg mL- 1 with a reproducibility of 10 % relative standard deviation (n = 4, concentration = 10 times the quantification limit). The reported sensitivity is fit-for-purpose in the biochemical context described here, but could be improved using ICP-mass spectrometry, if future analytical tasks would require it. Trueness of the proposed method was investigated by cross-validation with conventional liquid measurements, and by analyzing IAEA-153 reference material (Trace Elements in Milk Powder); a good agreement with the certified value for phosphorus was obtained.

Blister pouches for effective reagent storage and release for low cost point-of-care diagnostic applications

NASA Astrophysics Data System (ADS)

Smith, Suzanne; Sewart, Rene; Land, Kevin; Roux, Pieter; Gärtner, Claudia; Becker, Holger

2016-03-01

Lab-on-a-chip devices are often applied to point-of-care diagnostic solutions as they are low-cost, compact, disposable, and require only small sample volumes. For such devices, various reagents are required for sample preparation and analysis and, for an integrated solution to be realized, on-chip reagent storage and automated introduction are required. This work describes the implementation and characterization of effective liquid reagent storage and release mechanisms utilizing blister pouches applied to various point-of-care diagnostic device applications. The manufacturing aspects as well as performance parameters are evaluated.

Scientific Research in Aircraft Mechanical/Thermal Technology

DTIC Science & Technology

2003-12-01

Pipes 1 1.1 A bstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Introduction ...Liquid-Vapor Interface 34 2.1 Abstract .......... ...................................... 34 2.2 Introduction ...71 3.2 Introduction ......... .................................... 71 iii 3.3 Mathematical Model ........ ............................... 72 3.4

Determination of As, Se, and Hg in fuel samples by in-chamber chemical vapor generation ICP OES using a Flow Blurring® multinebulizer.

PubMed

García, Miriam; Aguirre, Miguel Ángel; Canals, Antonio

2017-09-01

In this work, a new and simple analytical methodology based on in-chamber chemical vapor generation has been developed for the spectrochemical analysis of commercial fuel samples. A multiple nebulizer with three nebulization units has been employed for this purpose: One unit was used for sample introduction, while the other two were used for the necessary reagent introduction. In this way, the aerosols were mixed inside the spray chamber. Through this method, analyte transport and, therefore, sensitivity are improved in inductively coupled plasma-optical emission spectrometry. The factors (i.e., variables), influencing chemical vapor generation, have been optimized using a multivariate approach. Under optimum chemical vapor generation conditions ([NaBH 4 ] = 1.39%, [HCl] = 2.97 M, total liquid flow = 936 μL min -1 ), the proposed sample introduction system allowed the determination of arsenic, selenium, and mercury up to 5 μg g -1 with a limit of detection of 25, 140, and 13 μg kg -1 , respectively. Analyzing spiked commercial fuel samples, recovery values obtained were between 96 and 113%, and expanded uncertainty values ranged from 4 to 16%. The most striking practical conclusion of this investigation is that no carbon deposit appears on the plasma torch after extended periods of working. Graphical abstract A new and simple analytical methodology based on in-chamber chemical vapor generation has been developed for the spectrochemical analysis of commercial fuel samples in ICP OES.

An Introduction to the Understanding of Solubility.

ERIC Educational Resources Information Center

Letcher, Trevor M.; Battino, Rubin

2001-01-01

Explores different solubility processes and related issues, including the second law of thermodynamics and ideal mixtures, real liquids, intermolecular forces, and solids in liquids or gases in liquids. (Contains 22 references.) (ASK)

Research News: Emulsion Liquid Membrane Extraction in a Hollow-Fiber Contactor

NASA Technical Reports Server (NTRS)

Wiencek, John M.; Hu, Shih-Yao

2000-01-01

This article describes how ELMs (emulsion liquid membranes) can be used for extraction. The article addresses the disadvantages of ELM extraction in a stirred contactor, and the advantages of SELMs (supported emulsion liquid membranes). The introduction of the article provides background information on liquid-liquid solvent extraction and dispersion-free solvent extraction.

High Precision Isotopic Analysis of Actinide Bearing Materials: Performance of a New Generation of Purpose Built Actinide Multi-Collector ICPMS Instruments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eiden, Gregory C.; Duffin, Andrew M.; Liezers, Martin

2014-11-14

Recently, a new class of multi-collector inductively coupled plasma mass spectrometers (MC-ICPMS) has been introduced commercially that includes detector arrays purpose built for actinide measurements. These detector arrays significantly enhance the data quality possible for applications encountered in nuclear forensics. Two such instruments are described in this paper, the NeptunePlusTM, developed by Thermo-Fisher (Bremen, Germany), and the NuPlasma2, developed by Nu Instruments (Wrexham, UK). Research results are presented that have been obtained by the authors using the first commercial NeptunePlusTM. This paper also presents performance characteristics and results for traditional liquid introduction, including a means for ultra-trace detection via electrochemicalmore » separation prior to solution nebulization, as well as solid sample introduction with femtosecond-laser ablation. We also discuss the advantages and limitations of the current systems for detection of the transient signals associated with these two methods for introducing sample into the plasma.« less

Single-step CE for miniaturized and easy-to-use system.

PubMed

Ono, Koichi; Kaneda, Shohei; Fujii, Teruo

2013-03-01

We developed a novel single-step capillary electrophoresis (SSCE) scheme for miniaturized and easy to use system by using a microchannel chip, which was made from the hydrophilic material polymethyl methacrylate (PMMA), equipped with a capillary stop valve. Taking the surface tension property of liquids into consideration, the capillary effect was used to introduce liquids and control capillary stop valves in a partial barrier structure in the wall of the microchannel. Through the combined action of stop valves and air vents, both sample plug formation for electrophoresis and sample injection into a separation channel were successfully performed in a single step. To optimize SSCE, different stop valve structures were evaluated using actual microchannel chips and the finite element method with the level set method. A partial barrier structure at the bottom of the channel functioned efficiently as a stop valve. The stability of stop valve was confirmed by a shock test, which was performed by dropping the microchannel chip to a floor. Sample plug deformation could be reduced by minimizing the size of the side partial barrier. By dissolving hydroxyl ethyl cellulose and using it as the sample solution, the EOF and adsorption of the sample into the PMMA microchannel were successfully reduced. Using this method, a 100-bp DNA ladder was concentrated; good separation was observed within 1 min. At a separation length of 5 mm, the signal was approximately 20-fold higher than a signal of original sample solution by field-amplified sample stacking effect. All operations, including liquid introduction and sample separation, can be completed within 2 min by using the SSCE scheme. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solvation structures of water in trihexyltetradecylphosphonium-orthoborate ionic liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yong-Lei, E-mail: wangyonl@gmail.com; System and Component Design, Department of Machine Design, KTH Royal Institute of Technology, SE-100 44 Stockholm; Sarman, Sten

2016-08-14

Atomistic molecular dynamics simulations have been performed to investigate effective interactions of isolated water molecules dispersed in trihexyltetradecylphosphonium-orthoborate ionic liquids (ILs). The intrinsic free energy changes in solvating one water molecule from gas phase into bulk IL matrices were estimated as a function of temperature, and thereafter, the calculations of potential of mean force between two dispersed water molecules within different IL matrices were performed using umbrella sampling simulations. The systematic analyses of local ionic microstructures, orientational preferences, probability and spatial distributions of dispersed water molecules around neighboring ionic species indicate their preferential coordinations to central polar segments in orthoboratemore » anions. The effective interactions between two dispersed water molecules are partially or totally screened as their separation distance increases due to interference of ionic species in between. These computational results connect microscopic anionic structures with macroscopically and experimentally observed difficulty in completely removing water from synthesized IL samples and suggest that the introduction of hydrophobic groups to central polar segments and the formation of conjugated ionic structures in orthoborate anions can effectively reduce residual water content in the corresponding IL samples.« less

The Effect of Acid Neutralization on Analytical Results Produced from SW846 Method 8330 after the Alkaline Hydrolysis of Explosives in Soil

DTIC Science & Technology

2012-09-01

basic form of phosphoric acid or sodium phosphate NO2- Nitrite OH- Hydroxide ion ERDC/EL TR-12-14 1 1 Introduction Alkaline hydrolysis has...into amber sample vials and refrigerated until analyzed. TNT analyses were conducted by high performance liquid chromatography (HPLC) with a C-18...The explosives concentrations of the different soils were quantified using a DIONEX HPLC system equipped with a C-18 reverse phase column and a

An Introduction to Rockets - or - Never Leave Geeks Unsupervised

NASA Technical Reports Server (NTRS)

Mellett, Kevin

2006-01-01

An introduction to rockets along with a brief history Newton's third law is presented. The contents include: 1) What is a Rocket?; 2) A Brief History; 3) Newton's Third Law; 4) A Brief History; 5) Mission Requirements; 6) Some Orbital Measurements; 7) Self Eating Watermelon; 8) Orbital Inclinations; 9) 28.5 Equatorial Orbit; 10) 51.6 Orbit (ISS); 11) Polar Orbit; 12) Geostationary Orbit; 13) Liquid Rocket; 13) Liquids vs. Solids; 14) Liquids; 15) Systems Integration; 16) Integration (NFL!); 17) Guidance Systems; 18) Vectored Thrust; 19) Spin Stabilization; 20) Aerodynamic Stability (Fire Arrows); and 21) Center of Gravity & Center of Pressure.

Thermally-actuated, phase change flow control for microfluidic systems.

PubMed

Chen, Zongyuan; Wang, Jing; Qian, Shizhi; Bau, Haim H

2005-11-01

An easy to implement, thermally-actuated, noninvasive method for flow control in microfluidic devices is described. This technique takes advantage of the phase change of the working liquid itself-the freezing and melting of a portion of a liquid slug-to noninvasively close and open flow passages (referred to as a phase change valve). The valve was designed for use in a miniature diagnostic system for detecting pathogens in oral fluids at the point of care. The paper describes the modeling, construction, and characteristics of the valve. The experimental results favorably agree with theoretical predictions. In addition, the paper demonstrates the use of the phase change valves for flow control, sample metering and distribution into multiple analysis paths, sealing of a polymerase chain reaction (PCR) chamber, and sample introduction into and withdrawal from a closed loop. The phase change valve is electronically addressable, does not require any moving parts, introduces only minimal dead volume, is leakage and contamination free, and is biocompatible.

Improved sensitivity of ochratoxin A analysis in coffee using high-performance liquid chromatography with hybrid triple quadrupole-linear ion trap mass spectrometry (LC-QqQLIT-MS/MS).

PubMed

Kokina, Aija; Pugajeva, Iveta; Bartkevics, Vadims

2016-01-01

A novel and sensitive method utilising high-performance liquid chromatography coupled to triple quadrupole-linear ion trap mass spectrometry (LC-QqQLIT-MS/MS) was developed in order to analyse the content of ochratoxin A (OTA) in coffee samples. The introduction of the triple-stage MS scanning mode (MS(3)) has been shown to increase greatly sensitivity and selectivity by eliminating the high chromatographic baseline caused by interference of complex coffee matrices. The analysis included the sample preparation procedure involving extraction of OTA using a methanol-water mixture and clean-up by immunoaffinity columns and detection using the MS(3) scanning mode of LC-QqQLIT-MS/MS. The proposed method offered a good linear correlation (r(2) > 0.998), excellent precision (RSD < 2.9%) and recovery (94%). The limit of quantification (LOQ) for coffee beans and espresso beverages was 0.010 and 0.003 µg kg(-1), respectively. The developed procedure was compared with traditional methods employing liquid chromatography coupled to fluorescent and tandem quadrupole detectors in conjunction with QuEChERS and solid-phase extraction. The proposed method was successfully applied to the determination of OTA in 15 samples of coffee beans and in 15 samples of espresso coffee beverages obtained from the Latvian market. OTA was found in 10 samples of coffee beans and in two samples of espresso in the ranges of 0.018-1.80 µg kg(-1) and 0.020-0.440 µg l(-1), respectively. No samples exceeded the maximum permitted level of OTA in the European Union (5.0 µg kg(-1)).

Recent advances in monolithic columns for protein and peptide separation by capillary liquid chromatography.

PubMed

Liang, Yu; Zhang, Lihua; Zhang, Yukui

2013-03-01

Capillary liquid chromatography (cLC) has great potential for protein and peptide separation, with advantages of high efficiency, high resolution, low sample consumption, and high sensitivity when coupled with mass spectrometry. In recent years, monoliths have been widely used as the stationary phases for capillary columns, owing to easy preparation, high permeability, fast mass transfer, and low backpressure. This review summarizes recent advances (2007-2012) in monolithic columns for protein and peptide separation by cLC. After a brief introduction on the preparation of monolithic capillary columns, the emphasis of this review is focused on the recent application of such columns for protein and peptide separation by cLC. Furthermore, the challenges and potential hot points of monolithic capillary columns in the future are discussed.

Measurement of isotope ratios on transient signals by MC-ICP-MS.

PubMed

Günther-Leopold, Ines; Wernli, Beat; Kopajtic, Zlatko; Günther, Detlef

2004-01-01

Precise and accurate isotope ratio measurements are an important task in many applications such as isotope-dilution mass spectrometry, bioavailability studies, or the determination of isotope variations in geological or nuclear samples. The technique of MC-ICP-MS has attracted much attention because it permits the precise measurement of isotope compositions for a wide range of elements combined with excellent detection limits due to high ionisation efficiencies. However, the results are based mainly on measurements using continuous sample introduction. In the present study the determination of isotope ratios on various transient signals with a time duration of 30 to 60 s has been achieved by coupling high-performance liquid chromatography to a multicollector inductively coupled plasma mass spectrometer. In order to investigate the origin of ratio drifts across the transient signals for this hyphenated technique, measurements with the same standard solutions were also carried out using a flow-injection device for sample introduction. As a result of this application it could be concluded that the main source of the bias in the measured isotope ratios is within the ICP-MS instead of fractionation effects on the chromatographic column material. Preliminary studies on short transient signals of gaseous samples (dry plasma) showed a reverse fractionation effect compared with wet plasma conditions (flow injection and HPLC).

Externally pressurized porous cylinder for multiple surface aerosol generation and method of generation

DOEpatents

Apel, Charles T.; Layman, Lawrence R.; Gallimore, David L.

1988-01-01

A nebulizer for generating aerosol having small droplet sizes and high efficiency at low sample introduction rates. The nebulizer has a cylindrical gas permeable active surface. A sleeve is disposed around the cylinder and gas is provided from the sleeve to the interior of the cylinder formed by the active surface. In operation, a liquid is provided to the inside of the gas permeable surface. The gas contacts the wetted surface and forms small bubbles which burst to form an aerosol. Those bubbles which are large are carried by momentum to another part of the cylinder where they are renebulized. This process continues until the entire sample is nebulized into aerosol sized droplets.

Extractive electrospray ionization mass spectrometry toward in situ analysis without sample pretreatment.

PubMed

Li, Ming; Hu, Bin; Li, Jianqiang; Chen, Rong; Zhang, Xie; Chen, Huanwen

2009-09-15

A homemade novel nanoextractive electrospray ionization (nanoEESI) source has been characterized for in situ mass spectrometric analysis of ambient samples without sample pretreatment. The primary ions generated using a nanospray emitter interact with the neutral sample plume created by manually nebulizing liquid samples, allowing production of the analyte ions in the spatial cross section of the nanoEESI source. The performance of nanoEESI is experimentally investigated by coupling the nanoEESI source to a commercial LTQ mass spectrometer for rapid analysis of various ambient samples using positive/negative ion detection modes. Compounds of interest in actual samples such as aerosol drug preparations, beverages, milk suspensions, farmland water, and groundwater were unambiguously detected using tandem nanoEESI ion trap mass spectrometry. The limit of detection was low picogram per milliliter levels for the compounds tested. Acceptable relative standard deviation (RSD) values (5-10%) were obtained for direct measurement of analytes in complex matrixes, providing linear dynamic signal responses using manual sample introduction. A single sample analysis was completed within 1.2 s. Requiring no sheath gas for either primary ion production or neutral sample introduction, the nanoEESI has advantages including readiness for miniaturization and integration, simple maintenance, easy operation, and low cost. The experimental data demonstrate that the nanoEESI is a promising tool for high-throughput, sensitive, quantitative, in situ analysis of ambient complex samples, showing potential applications for in situ analysis in multiple disciplines including but not limited to pharmaceutical analysis, food quality control, pesticides residue detection, and homeland security.

Changes to Serum Sample Tube and Processing Methodology Does Not Cause Inter-Individual Variation in Automated Whole Serum N-Glycan Profiling in Health and Disease

PubMed Central

Shubhakar, Archana; Kalla, Rahul; Nimmo, Elaine R.; Fernandes, Daryl L.; Satsangi, Jack; Spencer, Daniel I. R.

2015-01-01

Introduction Serum N-glycans have been identified as putative biomarkers for numerous diseases. The impact of different serum sample tubes and processing methods on N-glycan analysis has received relatively little attention. This study aimed to determine the effect of different sample tubes and processing methods on the whole serum N-glycan profile in both health and disease. A secondary objective was to describe a robot automated N-glycan release, labeling and cleanup process for use in a biomarker discovery system. Methods 25 patients with active and quiescent inflammatory bowel disease and controls had three different serum sample tubes taken at the same draw. Two different processing methods were used for three types of tube (with and without gel-separation medium). Samples were randomised and processed in a blinded fashion. Whole serum N-glycan release, 2-aminobenzamide labeling and cleanup was automated using a Hamilton Microlab STARlet Liquid Handling robot. Samples were analysed using a hydrophilic interaction liquid chromatography/ethylene bridged hybrid(BEH) column on an ultra-high performance liquid chromatography instrument. Data were analysed quantitatively by pairwise correlation and hierarchical clustering using the area under each chromatogram peak. Qualitatively, a blinded assessor attempted to match chromatograms to each individual. Results There was small intra-individual variation in serum N-glycan profiles from samples collected using different sample processing methods. Intra-individual correlation coefficients were between 0.99 and 1. Unsupervised hierarchical clustering and principal coordinate analyses accurately matched samples from the same individual. Qualitative analysis demonstrated good chromatogram overlay and a blinded assessor was able to accurately match individuals based on chromatogram profile, regardless of disease status. Conclusions The three different serum sample tubes processed using the described methods cause minimal inter-individual variation in serum whole N-glycan profile when processed using an automated workstream. This has important implications for N-glycan biomarker discovery studies using different serum processing standard operating procedures. PMID:25831126

On the decoupling of relaxation modes in a molecular liquid caused by isothermal introduction of 2 nm structural inhomogeneities.

PubMed

Ueno, Kazuhide; Angell, C Austen

2011-12-08

To support a new interpretation of the origin of the dynamic heterogeneity observed pervasively in fragile liquids as they approach their glass transition temperatures T(g), we demonstrate that the introduction of ~2 nm structural inhomogeneities into a homogeneous glass former leads to a decoupling of diffusion from viscosity similar to that observed during the cooling of orthoterphenyl (OTP) below T(A,) where Arrhenius behavior is lost. Further, the decoupling effect grows stronger as temperature decreases (and viscosity increases). The liquid is cresol, and the ~2 nm inhomogeneities are cresol-soluble asymmetric derivatized tetrasiloxy-based (polyhedral oligomeric silsesquioxane (POSS)) molecules. The decoupling is the phenomenon predicted by Onsager in discussing the approach to a liquid-liquid phase separation with decreasing temperature. In the present case the observations support the notion of a polyamorphic transition in fragile liquids that is hidden below the glass transition. A similar decoupling can be expected as a globular protein is dissolved in dilute aqueous solutions or in protic ionic liquids. © 2011 American Chemical Society

Pharmaceuticals, hormones, anthropogenic waste indicators, and total estrogenicity in liquid and solid samples from municipal sludge stabilization and dewatering

USGS Publications Warehouse

Furlong, Edward T.; Gray, James L.; Quanrud, David M.; Teske, Sondra S.; Werner, Stephen L.; Esposito, Kathleen; Marine, Jeremy; Ela, Wendell P.; Zaugg, Steven D.; Phillips, Patrick J.; Stinson, Beverley

2012-01-01

The ubiquitous presence of pharmaceuticals and other emerging contaminants, or trace organic compounds, in surface water has resulted in research and monitoring efforts to identify contaminant sources to surface waters and to better understand loadings from these sources. Wastewater treatment plant discharges have been identified as an important point source of trace organic compounds to surface water and understanding the transport and transformation of these contaminants through wastewater treatment process is essential to controlling their introduction to receiving waters.

Condensed Phase Membrane Introduction Mass Spectrometry with Direct Electron Ionization: On-line Measurement of PAHs in Complex Aqueous Samples

NASA Astrophysics Data System (ADS)

Termopoli, Veronica; Famiglini, Giorgio; Palma, Pierangela; Cappiello, Achille; Vandergrift, Gregory W.; Krogh, Erik T.; Gill, Chris G.

2016-02-01

Polycyclic aromatic hydrocarbons (PAHs) are USEPA regulated priority pollutants. Their low aqueous solubility requires very sensitive analytical methods for their detection, typically involving preconcentration steps. Presented is the first demonstrated `proof of concept' use of condensed phase membrane introduction mass spectrometry (CP-MIMS) coupled with direct liquid electron ionization (DEI) for the direct, on-line measurement of PAHs in aqueous samples. DEI is very well suited for the ionization of PAHs and other nonpolar compounds, and is not significantly influenced by the co-elution of matrix components. Linear calibration data for low ppb levels of aqueous naphthalene, anthracene, and pyrene is demonstrated, with measured detection limits of 4 ppb. Analytical response times (t10%-90% signal rise) ranged from 2.8 min for naphthalene to 4.7 min for pyrene. Both intra- and interday reproducibility has been assessed (<3% and 5% RSD, respectively). Direct measurements of ppb level PAHs spiked in a variety of real, complex environmental sample matrices is examined, including natural waters, sea waters, and a hydrocarbon extraction production waste water sample. For these spiked, complex samples, direct PAH measurement by CP-MIMS-DEI yielded minimal signal suppression from sample matrix effects (81%-104%). We demonstrate the use of this analytical approach to directly monitor real-time changes in aqueous PAH concentrations with potential applications for continuous on-line monitoring strategies and binding/adsorption studies in heterogeneous samples.

Novel Techniques for Quantification of Correlation Between Primary Liquid Jet Breakup and Downstream Spray Characteristics

DTIC Science & Technology

2016-05-08

unlimited. 5 1. Introduction Several liquid -fuelled combustion systems, such as liquid propellant rocket engines and gas turbines...AFRL-AFOSR-JP-TR-2016-0084 Novel techniques for quantification of correlation between primary liquid jet breakup and downstream spray characteristics...to 17 Apr 2016 4.  TITLE AND SUBTITLE Novel techniques for quantification of correlation between primary liquid jet breakup and downstream spray

Novel Techniques for Quantification of Correlation Between Primary Liquid Jet Breakup and Downstream Spray Characteristics

DTIC Science & Technology

2016-10-05

unlimited. 5 1. Introduction Several liquid -fuelled combustion systems, such as liquid propellant rocket engines and gas turbines...AFRL-AFOSR-JP-TR-2016-0084 Novel techniques for quantification of correlation between primary liquid jet breakup and downstream spray characteristics...to 17 Apr 2016 4.  TITLE AND SUBTITLE Novel techniques for quantification of correlation between primary liquid jet breakup and downstream spray

High-pressure liquid chromatography: A brief introduction and its application in analyzing the degradation of a C-ether (Thio-ether) liquid lubricant

NASA Technical Reports Server (NTRS)

1983-01-01

The general principles of classical liquid chromatography and high pressure liquid chromatography (HPLC) are reviewed, and their advantages and disadvantages are compared. Several chromatographic techniques are reviewed, and the analytical separation of a C-ether liquid lubricant by each technique is illustrated. A practical application of HPLC is then demonstrated by analyzing a degraded C-ether liquid lubricant from full scale, high temperature bearing tests.

Determination of mercury compounds in fish by microwave-assisted extraction and liquid chromatography-vapor generation-inductively coupled plasma mass spectrometry

NASA Astrophysics Data System (ADS)

Chiou, Chwei-Sheng; Jiang, Shiuh-Jen; Kumar Danadurai, K. Suresh

2001-07-01

A method employing a vapor generation system and LC combined with inductively coupled plasma mass spectrometry (LC-ICP-MS) is presented for the determination of mercury in biological tissues. An open vessel microwave digestion system was used to extract the mercury compounds from the sample matrix. The efficiency of the mobile phase, a mixture of L-cysteine and 2-mercaptoethanol, was evaluated for LC separation of inorganic mercury [Hg(II)], methylmercury (methyl-Hg) and ethylmercury (ethyl-Hg). The sensitivity, detection limits and repeatability of the liquid chromatography (LC) ICP-MS system with a vapor generator were comparable to, or better than, that of an LC-ICP-MS system with conventional pneumatic nebulization, or other sample introduction techniques. The experimental detection limits for various mercury species were in the range of 0.05-0.09 ng ml -1 Hg, based on peak height. The proposed method was successfully applied to the determination of mercury compounds in a swordfish sample purchased from the local market. The accuracy of the method was evaluated by analyzing a marine biological certified reference material (DORM-2, NRCC).

Method optimization and quality assurance in speciation analysis using high performance liquid chromatography with detection by inductively coupled plasma mass spectrometry

NASA Astrophysics Data System (ADS)

Larsen, Erik H.

1998-02-01

Achievement of optimum selectivity, sensitivity and robustness in speciation analysis using high performance liquid chromatography (HPLC) with inductively coupled mass spectrometry (ICP-MS) detection requires that each instrumental component is selected and optimized with a view to the ideal operating characteristics of the entire hyphenated system. An isocratic HPLC system, which employs an aqueous mobile phase with organic buffer constituents, is well suited for introduction into the ICP-MS because of the stability of the detector response and high degree of analyte sensitivity attained. Anion and cation exchange HPLC systems, which meet these requirements, were used for the seperation of selenium and arsenic species in crude extracts of biological samples. Furthermore, the signal-to-noise ratios obtained for these incompletely ionized elements in the argon ICP were further enhanced by a factor of four by continously introducing carbon as methanol via the mobile phase into the ICP. Sources of error in the HPLC system (column overload), in the sample introduction system (memory by organic solvents) and in the ICP-MS (spectroscopic interferences) and their prevention are also discussed. The optimized anion and cation exchange HPLC-ICP-MS systems were used for arsenic speciation in contaminated ground water and in an in-house shrimp reference sample. For the purpose of verification, HPLC coupled with tandem mass spectrometry with electrospray ionization was additionally used for arsenic speciation in the shrimp sample. With this analytical technique the HPLC retention time in combination with mass analysis of the molecular ions and their collision-induced fragments provide almost conclusive evidence of the identity of the analyte species. The speciation methods are validated by establishing a mass balance of the analytes in each fraction of the extraction procedure, by recovery of spikes and by employing and comparing independent techniques. The urgent need for reference materials certified for elemental species is stressed.

Chemical and Electrochemical Studies in Ionic Liquids

DTIC Science & Technology

1990-01-12

Electrochemistry and Witchcraft ", Gordon Research Conference on Electrochemistry", Santa Barbara, CA, January, 1985. OR. A. Osteryoung, ’An Introduction to...Temperature Chloroaluminate Ionic Liquids: Chemistry, Electrochemistry and Witchcraft ", Chemistry Department Colloquium, University of Alabama...Tuscaloosa, Alabama, December 1, 1988. OR. A. Osteryoung, "Ambient Temperature Chloroaluminate Ionic Liquids: Chemistry, Electrochemistry and Witchcraft

Improved Segmented-Flow Tracer-Monitored Titration for Automated Measurement of Total Alkalinity in Seawater

NASA Astrophysics Data System (ADS)

Spaulding, R. S.; Hales, B.; Beck, J. C.; Degrandpre, M. D.

2008-12-01

The four measurable inorganic carbon parameters commonly measured as part of oceanic carbon cycle studies are total dissolved inorganic carbon (DIC), total alkalinity (AT), hydrogen ion concentration (pH) and partial pressure of CO2 (pCO2). AT determination is critical for anthropogenic CO2 inventory calculations and for quantifying CaCO3 saturation. Additionally, measurement of AT in combination with one other carbonate parameter can be used to describe the inorganic carbon equilibria. Current methods for measuring AT require calibrated volumetric flasks and burettes, gravimetry, or precise flow measurements. These methods also require analysis times of ˜15 min and sample volumes of ˜200 mL, and sample introduction is not automated, resulting in labor-intensive measurements and low temporal resolution. The Tracer Monitored Titration (TMT) system was previously developed at the University of Montana for AT measurements. The TMT is not dependent on accurate gravimetric, volumetric or flow rate measurements because it relies on a pH-sensitive indicator (tracer) to track the amount of titrant added to the sample. Sample and a titrant-indicator mixture are mechanically stirred in an optical flow cell and pH is calculated using the indicator equilibrium constant and the spectrophotometrically determined concentrations of the acid and base forms of the indicator. AT is then determined using these data in a non-linear least squares regression of the AT mass and proton balances. The precision and accuracy of the TMT are 2 and 4 micromol per kg in 16 min using 110-mL of sample. The TMT is dependent on complete mixing of titrant with the sample and accurate absorbance measurements. We have developed the segmented-flow TMT (SF- TMT) to improve on these aspects and decrease sample analysis time. The TMT uses segmented flow instead of active mixing and a white LED instead of a tungsten-halogen light source. Air is added to the liquid flow stream, producing segments of liquid separated by air bubbles. Because liquid is not transferred between flow segments, there is rapid flushing which reduces sample volume to <10 mL. Additionally, the slower movement of liquid at the tube walls compared to that at the tube center creates circulation within each liquid segment, mixing the sample and eliminating the need for mechanical stirring. The white LED has higher output at the wavelengths of interest, thus improving the precision of absorbance measurements. These improvements result in a faster, simpler method for measuring AT.

Flowmeter for determining average rate of flow of liquid in a conduit

DOEpatents

Kennerly, J.M.; Lindner, G.M.; Rowe, J.C.

1981-04-30

This invention is a compact, precise, and relatively simple device for use in determining the average rate of flow of a liquid through a conduit. The liquid may be turbulent and contain bubbles of gas. In a preferred embodiment, the flowmeter includes an electrical circuit and a flow vessel which is connected as a segment of the conduit conveying the liquid. The vessel is provided with a valved outlet and is partitioned by a vertical baffle into coaxial chambers whose upper regions are vented to permit the escape of gas. The inner chamber receives turbulent downflowing liquid from the conduit and is sized to operate at a lower pressure than the conduit, thus promoting evolution of gas from the liquid. Lower zones of the two chambers are interconnected so that the downflowing liquid establishes liquid levels in both chambers. The liquid level in the outer chamber is comparatively calm, being to a large extent isolated from the turbulence in the inner chamber once the liquid in the outer chamber has risen above the liquid-introduction zone for that chamber. Lower and upper probes are provided in the outer chamber for sensing the liquid level therein at points above its liquid-introduction zone. An electrical circuit is connected to the probes to display the time required for the liquid level in the outer chamber to successively contact the lower and upper probes. The average rate of flow through the conduit can be determined from the above-mentioned time and the vessel volume filled by the liquid during that time.

Flowmeter for determining average rate of flow of liquid in a conduit

DOEpatents

Kennerly, John M.; Lindner, Gordon M.; Rowe, John C.

1982-01-01

This invention is a compact, precise, and relatively simple device for use in determining the average rate of flow of a liquid through a conduit. The liquid may be turbulent and contain bubbles of gas. In a preferred embodiment, the flowmeter includes an electrical circuit and a flow vessel which is connected as a segment of the conduit conveying the liquid. The vessel is provided with a valved outlet and is partitioned by a vertical baffle into coaxial chambers whose upper regions are vented to permit the escape of gas. The inner chamber receives turbulent downflowing liquid from the conduit and is sized to operate at a lower pressure than the conduit, thus promoting evolution of gas from the liquid. Lower zones of the two chambers are interconnected so that the downflowing liquid establishes liquid levels in both chambers. The liquid level in the outer chamber is comparatively calm, being to a large extent isolated from the turbulence in the inner chamber once the liquid in the outer chamber has risen above the liquid-introduction zone for that chamber. Lower and upper probes are provided in the outer chamber for sensing the liquid level therein at points above its liquid-introduction zone. An electrical circuit is connected to the probes to display the time required for the liquid level in the outer chamber to successively contact the lower and upper probes. The average rate of flow through the conduit can be determined from the above-mentioned time and the vessel volume filled by the liquid during that time.

Externally pressurized porous cylinder for multiple surface aerosol generation and method of generation

DOEpatents

Apel, C.T.; Layman, L.R.; Gallimore, D.L.

1988-05-10

A nebulizer is described for generating aerosol having small droplet sizes and high efficiency at low sample introduction rates. The nebulizer has a cylindrical gas permeable active surface. A sleeve is disposed around the cylinder and gas is provided from the sleeve to the interior of the cylinder formed by the active surface. In operation, a liquid is provided to the inside of the gas permeable surface. The gas contacts the wetted surface and forms small bubbles which burst to form an aerosol. Those bubbles which are large are carried by momentum to another part of the cylinder where they are renebulized. This process continues until the entire sample is nebulized into aerosol sized droplets. 2 figs.

Liquid chromatography-mass spectrometry in metabolomics research: mass analyzers in ultra high pressure liquid chromatography coupling.

PubMed

Forcisi, Sara; Moritz, Franco; Kanawati, Basem; Tziotis, Dimitrios; Lehmann, Rainer; Schmitt-Kopplin, Philippe

2013-05-31

The present review gives an introduction into the concept of metabolomics and provides an overview of the analytical tools applied in non-targeted metabolomics with a focus on liquid chromatography (LC). LC is a powerful analytical tool in the study of complex sample matrices. A further development and configuration employing Ultra-High Pressure Liquid Chromatography (UHPLC) is optimized to provide the largest known liquid chromatographic resolution and peak capacity. Reasonably UHPLC plays an important role in separation and consequent metabolite identification of complex molecular mixtures such as bio-fluids. The most sensitive detectors for these purposes are mass spectrometers. Almost any mass analyzer can be optimized to identify and quantify small pre-defined sets of targets; however, the number of analytes in metabolomics is far greater. Optimized protocols for quantification of large sets of targets may be rendered inapplicable. Results on small target set analyses on different sample matrices are easily comparable with each other. In non-targeted metabolomics there is almost no analytical method which is applicable to all different matrices due to limitations pertaining to mass analyzers and chromatographic tools. The specifications of the most important interfaces and mass analyzers are discussed. We additionally provide an exemplary application in order to demonstrate the level of complexity which remains intractable up to date. The potential of coupling a high field Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (ICR-FT/MS), the mass analyzer with the largest known mass resolving power, to UHPLC is given with an example of one human pre-treated plasma sample. This experimental example illustrates one way of overcoming the necessity of faster scanning rates in the coupling with UHPLC. The experiment enabled the extraction of thousands of features (analytical signals). A small subset of this compositional space could be mapped into a mass difference network whose topology shows specificity toward putative metabolite classes and retention time. Copyright © 2013 Elsevier B.V. All rights reserved.

7 CFR 766.1 - Introduction.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) Have loan security being liquidated voluntarily or involuntarily. (b) The Agency services direct FLP... SPECIAL PROGRAMS DIRECT LOAN SERVICING-SPECIAL Overview § 766.1 Introduction. (a) This part describes the Agency's servicing policies for direct loan borrowers who: (1) Are financially distressed; (2) Are...

Preferring more e-cigarette flavors is associated with e-cigarette use frequency among adolescents but not adults

PubMed Central

Butler, Ellyn R.; Bold, Krysten W.; Kong, Grace; Camenga, Deepa R.; Cavallo, Dana A.; Simon, Patricia; O’Malley, Stephanie S.; Krishnan-Sarin, Suchitra

2018-01-01

Introduction Many e-cigarette users find the variety of e-cigarette flavors appealing. We examined whether preferences for e-liquid flavors and the total number of flavors preferred differed between samples of adolescent and adult e-cigarette users. We also examined whether these preferences were associated with e-cigarette use frequency for adolescents or adults, respectively. Materials and methods The analytic samples comprised 1) 396 adolescent, past-month e-cigarette users from 5 Connecticut high schools who completed an anonymous, school-based survey in Fall 2014 (56.1% male; 16.18 [1.18] years; 42.2% past-month smokers), and 2) 590 adult, past-month e-cigarette users who completed an anonymous, MTurk survey in Fall 2014 (53.7% male; 34.25 [9.89] years; 51.2% past-month smokers). Results Compared to adults, a larger proportion of adolescents preferred fruit, alcohol, and “other”-flavored e-liquids, whereas adults disproportionately preferred tobacco, menthol, mint, coffee, and spice-flavored e-liquids (p-values < .05). Adults also preferred a greater total number of flavors compared to adolescents and used e-cigarettes more frequently (p-values < .001). Flavor preferences uniquely were associated with frequency of e-cigarette use within the adolescent sample; the total number of flavors preferred was associated with more days of e-cigarette use (ηp2 = 0.04), as were preferences for fruit (ηp2 = 0.02), dessert (ηp2 = 0.02), and alcohol-flavored (ηp2 = 0.02) e-liquids. Conclusions Flavor preferences differed between adolescent and adult samples. While youth reported less frequent e-cigarette use overall, their preferences for specific flavors and the total number of flavors preferred were associated with more days of e-cigarette use, indicating that flavor preferences may play an important role in adolescent e-cigarette use. PMID:29300749

Employee and customer handling of nicotine-containing e-liquids in vape shops

PubMed Central

Garcia, Robert; Allem, Jon Patrick; Baezconde-Garbanati, Lourdes; Unger, Jennifer Beth; Sussman, Steve

2017-01-01

INTRODUCTION Vape shops sell electronic cigarettes and related products such as e-liquids, which may contain nicotine. Direct contact with nicotine can lead to adverse health effects, and few regulations exist on how nicotine is handled in vape shops. This study examined how customers and employees come into contact with, and handle, nicotine-containing e-liquids in vape shops with the goal of informing potential future regulation of nicotine handling in vape shops. METHODS Data were collected from 77 vape shops in the Los Angeles basin. Characteristics of the shops were documented by employee interviews and in store observations. Data collection was focused on shops located in areas with high concentrations of communities of interest; 20 shops from African-American communities, 17 from Hispanic communities, 18 from Korean communities, and 22 from non-Hispanic White communities. RESULTS Half of the vape shops allowed customers to sample e-liquids with nicotine. Most of the shops (83%) provided self-service sampling stations for customers. A majority of shop employees (72%) reported that spills of e-liquids containing nicotine had occurred in the past. While 64% of the shops provided safety equipment, only 34% provided equipment for proper nicotine handling. Furthermore, 62% of shop employees reported handling nicotine without gloves or other safety equipment. CONCLUSIONS Regulation on the handling of nicotine by customers and vape shop employees is important to prevent unsafe practices and subsequent injury. The frequent occurrence of spills and limited availability of safety equipment in vape shops highlights the need for the creation and enforcement of regulations to protect employees and customers. Appropriate safety training and equipment should be provided to employees to prevent accidental exposure to nicotine. Information on ways to safely handle nicotine should be communicated to vape shop employees and customers. PMID:28660255

High-Intensity Sweeteners in Alternative Tobacco Products

PubMed Central

Miao, Shida; Beach, Evan S.; Sommer, Toby J.; Zimmerman, Julie B.

2016-01-01

Introduction: Sweeteners in tobacco products may influence use initiation and reinforcement, with special appeal to adolescents. Recent analytical studies of smokeless tobacco products (snuff, snus, dissolvables) detected flavorants identical to those added to confectionary products such as hard candy and chewing gum. However, these studies did not determine the levels of sweeteners. The objective of the present study was to quantify added sweeteners in smokeless tobacco products, a dissolvable product, electronic cigarette liquids and to compare with sweetener levels in confectionary products. Methods: Sweetener content of US-sourced smokeless tobacco, electronic cigarette liquid, and confectionary product samples was analyzed by liquid chromatography-electrospray ionization–mass spectrometry (LC-ESI-MS). Results: All smokeless products contained synthetic high intensity sweeteners, with snus and dissolvables exceeding levels in confectionary products (as much as 25-fold). All snus samples contained sucralose and most also aspartame, but no saccharin. In contrast, all moist snuff samples contained saccharin. The dissolvable sample contained sucralose and sorbitol. Ethyl maltol was the most common sweet-associated component in electronic cigarette liquids. Discussion: Sweetener content was dependent on product category, with saccharin in moist snuff, an older category, sucralose added at high levels to more recently introduced products (snus, dissolvable) and ethyl maltol in electronic cigarette liquid. The very high sweetener concentrations may be necessary for the consumer to tolerate the otherwise aversive flavors of tobacco ingredients. Regulation of sweetener levels in smokeless tobacco products may be an effective measure to modify product attractiveness, initiation and use patterns. Implications: Dissolvables, snus and electronic cigarettes have been promoted as risk-mitigation products due to their relatively low content of nitrosamines and other tobacco toxicants. This study is the first to quantify high intensity sweeteners in snus and dissolvable products. Snus and dissolvables contain the high intensity sweetener, sucralose, at levels higher than in confectionary products. The high sweetness of alternative tobacco products makes these products attractive to adolescents. Regulation of sweetener content in non-cigarette products is suggested as an efficient means to control product palatability and to reduce initiation in adolescents. PMID:27217475

A hydrophobic ionic liquid compartmentalized sampling/labeling and its separation techniques in polydimethylsiloxane microchip capillary electrophoresis.

PubMed

Quan, Hong Hua; Li, Ming; Huang, Yan; Hahn, Jong Hoon

2017-01-01

This paper demonstrates a novel compartmentalized sampling/labeling method and its separation techniques using a hydrophobic ionic liquid (IL)-1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imidate (BmimNTf 2 )-as the immiscible phase, which is capable of minimizing signal losses during microchip capillary electrophoresis (MCE). The MCE device consists of a silica tube connected to a straight polydimethylsiloxane (PDMS) separation channel. Poly(diallyldimethylammonium chloride) (PDDAC) was coated on the inner surface of channel to ease the introduction of IL plugs and enhance the IL wetting on the PDMS surface for sample releasing. Electroosmotic flow (EOF)-based sample compartmentalization was carried out through a sequenced injection into sampling tubes with the following order: leading IL plug/sample segment/terminal IL plug. The movement of the sample segment was easily controlled by applying an electrical voltage across both ends of the chip without a sample volume change. This approach effectively prevented analyte diffusion before injection into MCE channels. When the sample segment was manipulated to the PDDAC-modified PDMS channel, the sample plug then was released from isolation under EOF while IL plugs adsorbed onto channel surfaces owing to strong adhesion. A mixture of flavin adenine nucleotides (FAD) and flavin mononucleotides (FMN) was successfully separated on a 2.5 cm long separation channel, for which the theoretical numbers of plates were 15 000 and 17 000, respectively. The obtained peak intensity was increased 6.3-fold over the corresponding value from conventional electrokinetic injection with the same sampling time. Furthermore, based on the compartmented sample segment serving as an interim reactor, an on-chip fluorescence labeling is demonstrated. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microfluidic interconnects

DOEpatents

Benett, William J.; Krulevitch, Peter A.

2001-01-01

A miniature connector for introducing microliter quantities of solutions into microfabricated fluidic devices. The fluidic connector, for example, joins standard high pressure liquid chromatography (HPLC) tubing to 1 mm diameter holes in silicon or glass, enabling ml-sized volumes of sample solutions to be merged with .mu.l-sized devices. The connector has many features, including ease of connect and disconnect; a small footprint which enables numerous connectors to be located in a small area; low dead volume; helium leak-tight; and tubing does not twist during connection. Thus the connector enables easy and effective change of microfluidic devices and introduction of different solutions in the devices.

Solid Lubrication Fundamentals and Applications: Introduction and Background. Revision 1

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

1998-01-01

This chapter presents an introduction and historical background to the field of tribology, especially solid lubrication and lubricants and sets them in the perspective of techniques and materials in lubrication. Also, solid and liquid lubrication films are defined and described.

Solid Lubrication Fundamentals and Applications. Chapter 1; Introduction and Background

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

1996-01-01

This chapter presents an introduction and historical background to the field of tribology, especially solid lubrication and lubricants and sets them in the perspective of techniques and materials in lubrication. Also, solid and liquid lubrication films are defined and described.

Micro liquid chromatography-mass spectrometry with direct liquid introduction used for separation and quantitation of all-trans- and 13-cis-retinoic acids and their 4-oxo metabolites in human plasma.

PubMed

Ranalder, U B; Lausecker, B B; Huselton, C

1993-07-23

The separation and quantitation of the pentafluorobenzyl derivatives of all-trans- and 13-cis-retinoic acids and their 4-oxo metabolites in human plasma on micro high-performance liquid chromatographic columns (0.32 mm I.D.) is described. The column outlet was directly coupled to the source of a quadrupole mass spectrometer via a simple SFC-frit interface. Negative ion chemical ionization conditions were obtained by coaxial introduction of ammonia as a reagent gas. A signal-to-noise ratio well above 3 was obtained for 1 pg of each analyte injected. The limit of quantitation calculated from spiked biological plasma extracts was 0.3 ng/ml.

Characterization of selenium species in biological extracts by enhanced ion-pair liquid chromatography with inductively coupled plasma-mass spectrometry and by referenced electrospray ionization-mass spectrometry

NASA Astrophysics Data System (ADS)

Kotrebai, Mihály; Bird, Susan M.; Tyson, Julian F.; Block, Eric; Uden, Peter C.

1999-11-01

Selenium is an essential nutrient for humans; selenium compounds catalyze intermediate metabolism reactions and inhibit the toxic effects of heavy metals such as arsenic, cadmium and mercury. Some extracts of selenium-enriched biological materials show cancer preventive effects, tentatively attributable to the biological functions of selenoamino acids. An improved ion pair chromatographic method with methodological enhancements for the separation, qualitative and quantitative determination of non-volatile selenium compounds extracted from different samples has been developed using ICP-MS as an element-selective detector. Separation power early in the chromatogram was increased to baseline separation in the standard mixture as a result of decreasing spray chamber size from 97 to 14 ml, and increasing trifluoracetic acid (TFA) concentration in the mobile phase from 0.1 to 0.6%. The former pH was restored by the addition of ammonia to the mobile phase, which also served to increase the column recovery of inorganic anions. Calibration curves for different selenoamino acids showed statistically different behavior. Biological sample extracts were characterized using HPLC-ICP-MS. Mass spectral behavior of selenoamino acids, using electrospray and ion trap technology with direct infusion and liquid chromatographic sample introduction, is also reported.

Hydraulics.

ERIC Educational Resources Information Center

Engelbrecht, Nancy; And Others

These instructional materials provide an orientation to hydraulics for use at the postsecondary level. The first of 12 sections presents an introduction to hydraulics, including discussion of principles of liquids, definitions, liquid flow, the two types of hydraulic fluids, pressure gauges, and strainers and filters. The second section identifies…

A novel dynamic flow immunochromatographic test (DFICT) using gold nanoparticles for the serological detection of Toxoplasma gondii infection in dogs and cats.

PubMed

Jiang, Wei; Liu, Yingchun; Chen, Yongjun; Yang, Qiufeng; Chun, Peter; Yao, Kailing; Han, Xiangan; Wang, Shaohui; Yu, Shengqing; Liu, Yongjie; Wang, Quan

2015-10-15

A novel dynamic flow immunochromatographic test (DFICT) is proposed for rapid assay utilizing Toxoplasma gondii as a model. The test is based on a proprietary technology that combines the principles of immunochromatography and fluid dynamics. Gold nanoparticles conjugated to staphylococcal protein A (SPA) were prepared in liquid form and used as signal vehicles. T. gondii-specific recombinant antigens and SPA were sprayed onto a nitrocellulose membrane in strips at positions designated as T and C, respectively. The DFICT is performed by applying a 100 µL aliquot of liquid gold-SPA conjugate to the reagent hole and a 5 μL aliquot of serum sample to the sample hole. The results were observable within 5 min by the naked eye. The lowest detectable limit of the assay was determined as the highest dilution (1:320) of positive serum. No cross-reaction of the antibodies with other related canine or feline pathogens was observed. The DFICT can be stored for 12 months at 4°C or 6 months with no loss of sensitivity or specificity. A high degree of consistency was observed between the DFICT and the standard ELISA kit, supporting the reliability of the novel test strip. The introduction of a liquid gold nanoparticle conjugate reagent provides this method with several attractive characteristics, such as ease of manufacture, low sample volume requirements, high selectivity and high efficiency. This method opens a novel pathway for rapid diagnostic screening and field analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

Contaminant screening of wastewater with HPLC-IM-qTOF-MS and LC+LC-IM-qTOF-MS using a CCS database.

PubMed

Stephan, Susanne; Hippler, Joerg; Köhler, Timo; Deeb, Ahmad A; Schmidt, Torsten C; Schmitz, Oliver J

2016-09-01

Non-target analysis has become an important tool in the field of water analysis since a broad variety of pollutants from different sources are released to the water cycle. For identification of compounds in such complex samples, liquid chromatography coupled to high resolution mass spectrometry are often used. The introduction of ion mobility spectrometry provides an additional separation dimension and allows determining collision cross sections (CCS) of the analytes as a further physicochemical constant supporting the identification. A CCS database with more than 500 standard substances including drug-like compounds and pesticides was used for CCS data base search in this work. A non-target analysis of a wastewater sample was initially performed with high performance liquid chromatography (HPLC) coupled to an ion mobility-quadrupole-time of flight mass spectrometer (IM-qTOF-MS). A database search including exact mass (±5 ppm) and CCS (±1 %) delivered 22 different compounds. Furthermore, the same sample was analyzed with a two-dimensional LC method, called LC+LC, developed in our group for the coupling to IM-qTOF-MS. This four dimensional separation platform revealed 53 different compounds, identified over exact mass and CCS, in the examined wastewater sample. It is demonstrated that the CCS database can also help to distinguish between isobaric structures exemplified for cyclophosphamide and ifosfamide. Graphical Abstract Scheme of sample analysis and database screening.

AFM fluid delivery/liquid extraction surface sampling/electrostatic spray cantilever probe

DOEpatents

Van Berkel, Gary J.

2015-06-23

An electrospray system comprises a liquid extraction surface sampling probe. The probe comprises a probe body having a liquid inlet and a liquid outlet, and having a liquid extraction tip. A solvent delivery conduit is provided for receiving solvent liquid from the liquid inlet and delivering the solvent liquid to the liquid extraction tip. An open liquid extraction channel extends across an exterior surface of the probe body from the liquid extraction tip to the liquid outlet. An electrospray emitter tip is in liquid communication with the liquid outlet of the liquid extraction surface sampling probe. A system for analyzing samples, a liquid junction surface sampling system, and a method of analyzing samples are also disclosed.

Liquid Crystals in Chromatography

NASA Astrophysics Data System (ADS)

Witkiewicz, Zygfryd

The following sections are included: * INTRODUCTION * LIQUID CRYSTALS SUITABLE FOR GAS CHROMATOGRAPHY * Monomeric Liquid Crystal Stationary Phases * Polymeric Liquid Crystal Stationary Phases * Polymeric Liquid Crystal Stationary Phases * Conventional Analytical Columns * Capillary Columns * FACTORS AFFECTING THE CHROMATOGRAPHIC SEPARATIONS ON LIQUID CRYSTAL STATIONARY PHASES * Kind of Mesophase of the Liquid Crystal * Molecular Structure of the Liquid Crystals and of the Chromatographed Substances * Substrate on which the Liquid Crystal is Deposited * ANALYTICAL APPLICATIONS OF LIQUID CRYSTAL STATIONARY PHASES IN GAS CHROMATOGRAPHY * Separation of Isomers of Benzene and Naphthalene Derivatives * Separation of Alkane and Alkene Isomers * Separation of Mixtures of Benzene and Aliphatic Hydrocarbon Derivatives Containing Heteroatoms * Separation of Polynuclear Hydrocarbons * INVESTIGATION OF THE PROPERTIES OF LIQUID CRYSTALS BY GAS CHROMATOGRAPHY * APPLICATION OF LIQUID CRYSTALS IN LIQUID CHROMATOGRAPHY * Column Chromatography * Thin-Layer Chromatography * APPLICATION OF LIQUID CRYSTAL STATIONARY PHASES IN SUPERCRITICAL FLUID CHROMATOGRAPHY * FINAL REMARKS * References

Ordering of Glass Rods in Nematic and Cholesteric Liquid Crystals

DTIC Science & Technology

2011-12-01

3), 483–508 (2007). 2. M. D. Lynch and D. L. Patrick, “Controlling the orientation of micron-sized rod-shaped SiC particles with nematic liquid...Elastic torque and the levitation of metal wires by a nematic liquid crystal,” Science 303(5658), 652–655 (2004). 17. R. Eelkema, M. M. Pollard, J...Building Blocks for Iterative Methods, 2nd ed. (SIAM, 1994). 1. Introduction Incorporating rod-like particles into liquid crystal (LC) media can lead

Analysis of benzo(a)pyrene in airborne particulates by gas chromatography

NASA Technical Reports Server (NTRS)

Luedecke, E.

1976-01-01

A routine method was developed to measure benzo(a)pyrene in airborne particulates. Samples were collected on a filter and the organic portion was extracted with cyclohexane. The polynuclear hydrocarbon (PNHC) fraction was separated from the aliphatics by column chromatography. An internal standard was added to the extract and a portion of it was injected into a gas chromatograph. Although the gas chromatographic method has often been reported in the literature, satisfactory separation of benzo(a)pyrene and benzo(e)pyrene has not been achieved. With the introduction of a nematic liquid crystal as the stationary phase good separation is now possible.

Influence of Zwitterions on Thermomechanical Properties and Morphology of Acrylic Copolymers: Implications for Electroactive Applications

DTIC Science & Technology

2011-09-30

transducers from branched sulfonated polysulfones.7 The mechanical strength of the membranes drastically decreased upon introduction of ionic liquids to... liquids ,8 and zwitterionomers maintained mechanical strengths upon swelling with 10 wt % ionic liquid . Zwitterions are chargedmolecules that contain...water purification5 to biotechnology.6 A unique combination of physical properties of ionomeric membranes is the ionic con- ductivity of lowmolar mass

An Introduction to Mars ISPP Technologies

NASA Technical Reports Server (NTRS)

Lueck, Dale E.

2003-01-01

This viewgraph presentation provides information on potential In Situ Propellant Production (ISPP) technologies for Mars. The presentation discusses Sabatier reactors, water electrolysis, the advantages of methane fuel, oxygen production, PEM cell electrolyzers, zirconia solid electrolyte cells, reverse water gas shift (RWGS), molten carbonate electrolysis, liquid CO2, and ionic liquids.

Going Beyond, Going Further: An Inexpensive Experiment for the Introduction of High Performance Liquid Chromatography.

ERIC Educational Resources Information Center

Bidlingmeyer, Brian A.; Warren, F. Vincent, Jr.

1984-01-01

Background information, materials needed, laboratory procedures, and typical results are provided for five high performance liquid chromatography experiments (three isocratic and two step gradient separations). Suggestions for further experimentation are also provided, including quantitative determinations and separation of charged solutes. (JN)

A Practical Introduction to Separation and Purification Techniques for the Beginning Organic Chemistry Laboratory.

ERIC Educational Resources Information Center

Leonard, Jack E.

1981-01-01

Describes a sequence of experiments developed at Texas A&M University for use in one-semester and two-semester (nonmajors) organic chemistry courses to teach a maximum number of separation and purification techniques such as distillations, recrystallization, liquid-liquid extraction, and chromatography. (SK)

Automation of static and dynamic non-dispersive liquid phase microextraction. Part 1: Approaches based on extractant drop-, plug-, film- and microflow-formation.

PubMed

Alexovič, Michal; Horstkotte, Burkhard; Solich, Petr; Sabo, Ján

2016-02-04

Simplicity, effectiveness, swiftness, and environmental friendliness - these are the typical requirements for the state of the art development of green analytical techniques. Liquid phase microextraction (LPME) stands for a family of elegant sample pretreatment and analyte preconcentration techniques preserving these principles in numerous applications. By using only fractions of solvent and sample compared to classical liquid-liquid extraction, the extraction kinetics, the preconcentration factor, and the cost efficiency can be increased. Moreover, significant improvements can be made by automation, which is still a hot topic in analytical chemistry. This review surveys comprehensively and in two parts the developments of automation of non-dispersive LPME methodologies performed in static and dynamic modes. Their advantages and limitations and the reported analytical performances are discussed and put into perspective with the corresponding manual procedures. The automation strategies, techniques, and their operation advantages as well as their potentials are further described and discussed. In this first part, an introduction to LPME and their static and dynamic operation modes as well as their automation methodologies is given. The LPME techniques are classified according to the different approaches of protection of the extraction solvent using either a tip-like (needle/tube/rod) support (drop-based approaches), a wall support (film-based approaches), or microfluidic devices. In the second part, the LPME techniques based on porous supports for the extraction solvent such as membranes and porous media are overviewed. An outlook on future demands and perspectives in this promising area of analytical chemistry is finally given. Copyright © 2015 Elsevier B.V. All rights reserved.

Pseudolinear gradient ultrahigh-pressure liquid chromatography using an injection valve assembly.

PubMed

Xiang, Yanqiao; Liu, Yansheng; Stearns, Stanley D; Plistil, Alex; Brisbin, Martin P; Lee, Milton L

2006-02-01

The use of ultrahigh pressures in liquid chromatography (UHPLC) imposes stringent requirements on hardware such as pumps, valves, injectors, connecting tubing, and columns. One of the most difficult components of the UHPLC system to develop has been the sample injector. Static-split injection, which can be performed at pressures up to 6900 bar (100,000 psi), consumes a large sample volume and is very irreproducible. A pressure-balanced injection valve provided better reproducibility, shorter injection time, reduced sample consumption, and greater ease of use; however, it could only withstand pressures up to approximately 1000 bar (15,000 psi). In this study, a new injection valve assembly that can operate at pressures as high as 2070 bar (30,000 psi) was evaluated for UHPLC. This assembly contains six miniature electronically controlled needle valves to provide accurate and precise volumes for introduction into the capillary LC column. It was found that sample volumes as small as several tenths of a nanoliter can be injected, which are comparable to the results obtained from the static-split injector. The reproducibilities of retention time, efficiency, and peak area were investigated, and the results showed that the relative standard deviations of these parameters were small enough for quantitative analyses. Separation experiments using the UHPLC system with this new injection valve assembly showed that this new injector is suitable for both isocratic and gradient operation modes. A newly designed capillary connector was used at a pressure as high as 2070 bar (30,000 psi).

Introduction of liquid-based cytology and human papillomavirus testing in cervical cancer screening in Luxembourg.

PubMed

Latsuzbaia, Ardashel; Hebette, Gaëtan; Fischer, Marc; Arbyn, Marc; Weyers, Steven; Vielh, Philippe; Schmitt, Fernando; Mossong, Joël

2017-05-01

In 2014, liquid-based cytology with HPV triage replaced conventional cytology. The aim of our study was to compare conventional and liquid-based cytology (LBC), estimate the prevalence of abnormal cervical cytology and high risk HPV (hrHPV) infection and their correlation, among screened women in Luxembourg. Between the first January 2013 and 31st December 2015, 315,868 cervical samples from 150,815 women (mean age 42.2 years) were investigated by the national cytology laboratory. Slides were prepared and screened according to European Guidelines. All cytological results were classified according to the Bethesda 2001 system terminology. The prevalence of abnormal cervical lesions was as follows: atypical squamous cells of undetermined significance (ASC-US), 1.3%; low-grade squamous intraepithelial lesion (LSIL), 1.9%; high-grade squamous intraepithelial lesion (HSIL), 0.4%. The detection rate of cytological lesions was significantly higher with LBC than with conventional cytology. Based on 11,838 samples with concomitant cytology and HPV testing, hrHPV was detected in 9.5, 45.3, 70.0, and 92.6% of women with negative cytology, ASC-US, LSIL, and HSIL, respectively. More cervical lesions were identified using LBC compared to conventional cytology. HrHPV infection was correlated with the severity of intraepithelial lesions. The current findings provide important information to evaluate the prevention of cervical cancer in Luxembourg and for monitoring the future impact of HPV vaccination. Diagn. Cytopathol. 2017;45:384-390. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Liquid crystals in micron-scale droplets, shells and fibers

NASA Astrophysics Data System (ADS)

Urbanski, Martin; Reyes, Catherine G.; Noh, JungHyun; Sharma, Anshul; Geng, Yong; Subba Rao Jampani, Venkata; Lagerwall, Jan P. F.

2017-04-01

The extraordinary responsiveness and large diversity of self-assembled structures of liquid crystals are well documented and they have been extensively used in devices like displays. For long, this application route strongly influenced academic research, which frequently focused on the performance of liquid crystals in display-like geometries, typically between flat, rigid substrates of glass or similar solids. Today a new trend is clearly visible, where liquid crystals confined within curved, often soft and flexible, interfaces are in focus. Innovation in microfluidic technology has opened for high-throughput production of liquid crystal droplets or shells with exquisite monodispersity, and modern characterization methods allow detailed analysis of complex director arrangements. The introduction of electrospinning in liquid crystal research has enabled encapsulation in optically transparent polymeric cylinders with very small radius, allowing studies of confinement effects that were not easily accessible before. It also opened the prospect of functionalizing textile fibers with liquid crystals in the core, triggering activities that target wearable devices with true textile form factor for seamless integration in clothing. Together, these developments have brought issues center stage that might previously have been considered esoteric, like the interaction of topological defects on spherical surfaces, saddle-splay curvature-induced spontaneous chiral symmetry breaking, or the non-trivial shape changes of curved liquid crystal elastomers with non-uniform director fields that undergo a phase transition to an isotropic state. The new research thrusts are motivated equally by the intriguing soft matter physics showcased by liquid crystals in these unconventional geometries, and by the many novel application opportunities that arise when we can reproducibly manufacture these systems on a commercial scale. This review attempts to summarize the current understanding of liquid crystals in spherical and cylindrical geometry, the state of the art of producing such samples, as well as the perspectives for innovative applications that have been put forward.

Analysis of pharmaceutical adulterants in plant food supplements by UHPLC-MS/MS.

PubMed

Paíga, Paula; Rodrigues, Manuela J E; Correia, Manuela; Amaral, Joana S; Oliveira, M Beatriz P P; Delerue-Matos, Cristina

2017-03-01

A method based on the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction and ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) was successfully developed and validated for the analysis of 26 pharmaceutical compounds belonging to different therapeutic classes (anorexics, stimulants, anxiolytics, antidepressants and laxatives), which are all prone to be illegally added into weight-loss plant food supplements (PFS) for their pharmacological activity. Internal standard calibration with six isotopically labelled compounds rendered good linearity in the range of 5 to 1000μg/l, depending on the compound, and good sensitivity with limits of quantification in the range of 0.02-9.80μg/l. Recoveries were assessed for all the 16 samples analysed and were found between 70% and 120% for over 90% of the analytes. The average recovery value was 90.8%, for the different studied matrices (liquids, liquid ampoules, tablets and capsules), with RSD values lower than 10% for all forms. The changes introduced to the QuEChERS procedure maintained the good performance characteristics of the extraction method while preserving the chromatographic system for the introduction of unwanted matrix compounds. Synephrine was the only compound detected and quantified in one sample, but at a very low concentration (768μg/l) and its presence may be due to the plant extracts used in the formulation, as synephrine is known to be a natural constituent of Citrus aurantium amara. Despite none of the 16 evaluated samples were found to be adulterated by the illegal addition of the drugs included in this work, the developed methodology can be very useful for monitoring the adulteration of weight-loss PFS. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthetic phosphodiesterase-5-inhibitors use/abuse and interest of hair testing: reporting of a rape case.

PubMed

Duez, Mathieu; Etter, Matthieu; Klinger, Nadine; Cirimele, Vincent

2014-06-01

If classic phosphodiesterase-5 (PDE-5) inhibitors are well known, new synthetic PDE-5 analogues are of more recent introduction. Some of them have already been tested in dietary supplements. We describe here a rape case following the consumption of pills bought on the Internet and containing new synthetic PDE-5 inhibitors. The assailant declared that he lost control after ingesting these pills for the first time. Analyses of conventional matrices (blood, urine) don't allow us to highlight the intake of any substances in relation to this offence due to late sampling (5 days after the offence). Therefore, we have developed an analytical approach to test for PDE-5 inhibitors in hair including the two new synthetic PDE-5 inhibitors analogues - thiosildenafil and hydroxythiohomosildenafil - previously identified in the pills. This new method was validated and applied to the hair samples of the victim and the suspect. Analyses were conducted using a liquid/liquid extraction followed by liquid chromatography coupled with a mass spectrometer in multiple reaction monitoring mode detection. The 2-centimetre proximal hair section of the suspect revealed the presence of thiosildenafil (48 pg/mg), hydroxythiohomosildenafil (24 pg/mg), and sildenafil (7.5 pg/mg). To our knowledge, it is the first time that these two new synthetic PDE-5 inhibitors were detected in biological samples and especially in hair. Complementary investigations showed that a single pill taken by a volunteer provided similar levels in thiosildenafil (35 pg/mg), hydroxythiohomosildenafil (17 pg/mg), and sildenafil (8 pg/mg) to those found in the previous case described here. Copyright © 2014 John Wiley & Sons, Ltd.

Quasi-2D Liquid State at Metal-Organic Interface and Adsorption State Manipulation

NASA Astrophysics Data System (ADS)

Mehdizadeh, Masih

The metal/organic interface between noble metal close-packed (111) surfaces and organic semiconducting molecules is studied using Scanning tunneling microscopy and Photoelectron Spectroscopy, supplemented by first principles density functional theory calculations and Markov Chain Monte Carlo simulations. Copper Phthalocyanine molecules were shown to have dual adsorption states: a liquid state where intermolecular interactions were shown to be repulsive in nature and largely due to entropic effects, and a disordered immobilized state triggered by annealing or applying a tip-sample bias larger than a certain temperature or voltage respectively where intermolecular forces were demonstrated to be attractive. A methodology for altering molecular orientation on the aforementioned surfaces is also proposed through introduction of a Fullerene C60 buffer layer. Density functional theory calculations demonstrate orientation-switching of Copper Phthalocyanine molecules based on the amount of charges transferred to/from the substrate to the C60-CuPc layers; suggesting existence of critical substrate work functions that cause reorientation.

76 FR 68238 - Self-Regulatory Organizations; Options Clearing Corporation; Order Approving Proposed Rule Change...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-03

... Defaulting Clearing Member's Accounts October 28, 2011. I. Introduction On July 28, 2011, the Options..._occ_11_08_a_1.pdf . The liquidation of open long and short positions through exchange transactions is... expected to result in a shorter liquidation period and reduced execution risk. During Lehman Brothers...

Inactivation kinetics of a four-strain composite of Salmonella Enteritidis and Oranienberg in commercially-acquired liquid egg yolk

USDA-ARS?s Scientific Manuscript database

Introduction: Current liquid egg pasteurization requirements are based on command and control prescribed time/temperature combinations for specified egg products. Requirements are found in the Code of Federal Regulations, Title 9, Ch. III, Sec. 590.570. These standards were based on data for the ...

Aerosol feed direct methanol fuel cell

NASA Technical Reports Server (NTRS)

Kindler, Andrew (Inventor); Narayanan, Sekharipuram R. (Inventor); Valdez, Thomas I. (Inventor)

2002-01-01

Improvements to fuel cells include introduction of the fuel as an aerosol of liquid fuel droplets suspended in a gas. The particle size of the liquid fuel droplets may be controlled for optimal fuel cell performance by selection of different aerosol generators or by separating droplets based upon size using a particle size conditioner.

Fractionated dynamic headspace sampling in the analysis of matrices of vegetable origin in the food field.

PubMed

Liberto, Erica; Cagliero, Cecilia; Cordero, Chiara; Rubiolo, Patrizia; Bicchi, Carlo; Sgorbini, Barbara

2017-03-17

Recent technological advances in dynamic headspace sampling (D-HS) and the possibility to automate this sampling method have lead to a marked improvement in its the performance, a strong renewal of interest in it, and have extended its fields of application. The introduction of in-parallel and in-series automatic multi-sampling and of new trapping materials, plus the possibility to design an effective sampling process by correctly applying the breakthrough volume theory, have make profiling more representative, and have enhanced selectivity, and flexibility, also offering the possibility of fractionated enrichment in particular for high-volatility compounds. This study deals with fractionated D-HS ability to produce a sample representative of the volatile fraction of solid or liquid matrices. Experiments were carried out on a model equimolar (0.5mM) EtOH/water solution, comprising 16 compounds with different polarities and volatilities, structures ranging from C5 to C15 and vapor pressures from 4.15kPa (2,3-pentandione) to 0.004kPa (t-β-caryophyllene), and on an Arabica roasted coffee powder. Three trapping materials were considered: Tenax TA™ (TX), Polydimethylsiloxane foam (PDMS), and a three-carbon cartridge Carbopack B/Carbopack C/Carbosieve S-III™ (CBS). The influence of several parameters on the design of successful fractionated D-HS sampling. Including the physical and chemical characteristics of analytes and matrix, trapping material, analyte breakthrough, purge gas volumes, and sampling temperature, were investigated. The results show that, by appropriately choosing sampling conditions, fractionated D-HS sampling, based on component volatility, can produce a fast and representative profile of the matrix volatile fraction, with total recoveries comparable to those obtained by full evaporation D-HS for liquid samples, and very high concentration factors for solid samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Multielemental Determination of As, Bi, Ge, Sb, and Sn in Agricultural Samples Using Hydride Generation Coupled to Microwave-Induced Plasma Optical Emission Spectrometry.

PubMed

Machado, Raquel C; Amaral, Clarice D B; Nóbrega, Joaquim A; Araujo Nogueira, Ana Rita

2017-06-14

A microwave-induced plasma optical emission spectrometer with N 2 -based plasma was combined with a multimode sample introduction system (MSIS) for hydride generation (HG) and multielemental determination of As, Bi, Ge, Sb, and Sn in samples of forage, bovine liver, powdered milk, agricultural gypsum, rice, and mineral fertilizer, using a single condition of prereduction and reduction. The accuracy of the developed analytical method was evaluated using certified reference materials of water and mineral fertilizer, and recoveries ranged from 95 to 106%. Addition and recovery experiments were carried out, and the recoveries varied from 85 to 117% for all samples evaluated. The limits of detection for As, Bi, Ge, Sb, and Sn were 0.46, 0.09, 0.19, 0.46, and 5.2 μg/L, respectively, for liquid samples, and 0.18, 0.04, 0.08, 0.19, and 2.1 mg/kg, respectively, for solid samples. The method proposed offers a simple, fast, multielemental, and robust alternative for successful determination of all five analytes in agricultural samples with low operational cost without compromising analytical performance.

Principles of Stagewise Separation Process Calculations: A Simple Algebraic Approach Using Solvent Extraction.

ERIC Educational Resources Information Center

Crittenden, Barry D.

1991-01-01

A simple liquid-liquid equilibrium (LLE) system involving a constant partition coefficient based on solute ratios is used to develop an algebraic understanding of multistage contacting in a first-year separation processes course. This algebraic approach to the LLE system is shown to be operable for the introduction of graphical techniques…

Design of an interface to allow microfluidic electrophoresis chips to drink from the fire hose of the external environment.

PubMed

Attiya, S; Jemere, A B; Tang, T; Fitzpatrick, G; Seiler, K; Chiem, N; Harrison, D J

2001-01-01

An interface design is presented that facilitates automated sample introduction into an electrokinetic microchip, without perturbing the liquids within the microfluidic device. The design utilizes an interface flow channel with a volume flow resistance that is 0.54-4.1 x 10(6) times lower than the volume flow resistance of the electrokinetic fluid manifold used for mixing, reaction, separation, and analysis. A channel, 300 microm deep, 1 mm wide and 15-20 mm long, was etched in glass substrates to create the sample introduction channel (SIC) for a manifold of electrokinetic flow channels in the range of 10-13 microm depth and 36-275 microm width. Volume flow rates of up to 1 mL/min were pumped through the SIC without perturbing the solutions within the electrokinetic channel manifold. Calculations support this observation, suggesting a leakage flow to electroosmotic flow ratio of 0.1:1% in the electrokinetic channels, arising from 66-700 microL/min pressure-driven flow rates in the SIC. Peak heights for capillary electrophoresis separations in the electrokinetic flow manifold showed no dependence on whether the SIC pump was on or off. On-chip mixing, reaction and separation of anti-ovalbumin and ovalbumin could be performed with good quantitative results, independent of the SIC pump operation. Reproducibility of injection performance, estimated from peak height variations, ranged from 1.5-4%, depending upon the device design and the sample composition.

Open port sampling interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Berkel, Gary J

A system for sampling a sample material includes a probe which can have an outer probe housing with an open end. A liquid supply conduit within the housing has an outlet positioned to deliver liquid to the open end of the housing. The liquid supply conduit can be connectable to a liquid supply for delivering liquid at a first volumetric flow rate to the open end of the housing. A liquid exhaust conduit within the housing is provided for removing liquid from the open end of the housing. A liquid exhaust system can be provided for removing liquid from themore » liquid exhaust conduit at a second volumetric flow rate, the first volumetric flow rate exceeding the second volumetric flow rate, wherein liquid at the open end will receive sample, liquid containing sample material will be drawn into and through the liquid exhaust conduit, and liquid will overflow from the open end.« less

Ground-Based Aerosol Measurements | Science Inventory ...

EPA Pesticide Factsheets

Atmospheric particulate matter (PM) is a complex chemical mixture of liquid and solid particles suspended in air (Seinfeld and Pandis 2016). Measurements of this complex mixture form the basis of our knowledge regarding particle formation, source-receptor relationships, data to test and verify complex air quality models, and how PM impacts human health, visibility, global warming, and ecological systems (EPA 2009). Historically, PM samples have been collected on filters or other substrates with subsequent chemical analysis in the laboratory and this is still the major approach for routine networks (Chow 2005; Solomon et al. 2014) as well as in research studies. In this approach, air, at a specified flow rate and time period, is typically drawn through an inlet, usually a size selective inlet, and then drawn through filters, 1 INTRODUCTION Atmospheric particulate matter (PM) is a complex chemical mixture of liquid and solid particles suspended in air (Seinfeld and Pandis 2016). Measurements of this complex mixture form the basis of our knowledge regarding particle formation, source-receptor relationships, data to test and verify complex air quality models, and how PM impacts human health, visibility, global warming, and ecological systems (EPA 2009). Historically, PM samples have been collected on filters or other substrates with subsequent chemical analysis in the laboratory and this is still the major approach for routine networks (Chow 2005; Solomo

Frontiers of in situ electron microscopy

DOE PAGES

Zheng, Haimei; Zhu, Yimei; Meng, Shirley Ying

2015-01-01

In situ transmission electron microscopy (TEM) has become an increasingly important tool for materials characterization. It provides key information on the structural dynamics of a material during transformations and the correlation between structure and properties of materials. With the recent advances in instrumentation, including aberration corrected optics, sample environment control, the sample stage, and fast and sensitive data acquisition, in situ TEM characterization has become more and more powerful. In this article, a brief review of the current status and future opportunities of in situ TEM is included. It also provides an introduction to the six articles covered by inmore » this issue of MRS Bulletin explore the frontiers of in situ electron microscopy, including liquid and gas environmental TEM, dynamic four-dimensional TEM, nanomechanics, ferroelectric domain switching studied by in situ TEM, and state-of-the-art atomic imaging of light elements (i.e., carbon atoms) and individual defects.« less

Gradient index liquid crystal devices and method of fabrication thereof

DOEpatents

Lee, J.C.; Jacobs, S.

1991-10-29

Laser beam apodizers using cholesteric liquid crystals provides soft edge profile by use of two separate cholesteric liquid crystal mixtures with different selective reflection bands which in an overlap region have a gradient index where reflectivity changes as a function of position. The apodizers can be configured as a one-dimensional beam apod INTRODUCTION The U.S. government has rights in the invention under Contract No. DE-FC03-85DP40200 between the University of Rochester and the Department of Energy.

Gradient index liquid crystal devices and method of fabrication thereof

DOEpatents

Lee, Jae-Cheul; Jacobs, Stephen

1991-01-01

Laser beam apodizers using cholesteric liquid crystals provides soft edge profile by use of two separate cholesteric liquid crystal mixtures with different selective reflection bands which in an overlap region have a gradient index where reflectivity changes as a function of position. The apodizers can be configured as a one-dimensional beam apod INTRODUCTION The U.S. government has rights in the invention under Contract No. DE-FC03-85DP40200 between the University of Rochester and the Department of Energy.

Method for removing solid particulate material from within liquid fuel injector assemblies

DOEpatents

Simandl, R.F.; Brown, J.D.; Andriulli, J.B.; Strain, P.D.

1998-09-08

A method is described for removing residual solid particulate material from the interior of liquid fuel injectors and other fluid flow control mechanisms having or being operatively associated with a flow-regulating fixed or variable orifice. The method comprises the sequential and alternate introduction of columns of a non-compressible liquid phase and columns of a compressed gas phase into the body of a fuel injector whereby the expansion of each column of the gas phase across the orifice accelerates the liquid phase in each trailing column of the liquid phase and thereby generates turbulence in each liquid phase for lifting and entraining the solid particulates for the subsequent removal thereof from the body of the fuel injector. 1 fig.

Method for removing solid particulate material from within liquid fuel injector assemblies

DOEpatents

Simandl, Ronald F.; Brown, John D.; Andriulli, John B.; Strain, Paul D.

1998-01-01

A method for removing residual solid particulate material from the interior of liquid fuel injectors and other fluid flow control mechanisms having or being operatively associated with a flow-regulating fixed or variable orifice. The method comprises the sequential and alternate introduction of columns of a non-compressible liquid phase and columns of a compressed gas phase into the body of a fuel injector whereby the expansion of each column of the gas phase across the orifice accelerates the liquid phase in each trailing column of the liquid phase and thereby generates turbulence in each liquid phase for lifting and entraining the solid particulates for the subsequent removal thereof from the body of the fuel injector.

Is the E-Liquid Industry Regulating Itself? A Look at E-Liquid Internet Vendors in the United States

PubMed Central

Timberlake, David S.; Williams, Rebecca S.

2016-01-01

Abstract Introduction: The objective of this study was to assess whether the nascent, but rapidly growing e-liquid industry prohibits Internet sales to minors and employs safety measures to prevent accidental poisonings. Methods: A stratified simple random sample (n = 120) was selected from the target population (N = 1107) of US online vendors of e-liquid in July 2015. The vendors were stratified and subsequently oversampled by trade association membership and vendor popularity. Three minors aged 16 to 17, who were supervised by adult research staff, attempted to purchase e-liquid from the 120 online vendors using debit cards issued in their names. Measures included vendors’ use of age verification, warning labels on e-liquid bottles, and child-resistant packaging. Results: Statistically significant differences were observed by vendor popularity, but not by membership in a trade association. The differences by vendor popularity, however, occurred for measures that were limited to an age warning and list of ingredients. The most striking finding was the scant vendors (n = 4) who successfully prevented the sale of e-liquid to the minors. In contrast, 87.5% and 53.9% of the bottles contained child-resistant packaging and a health warning label, respectively. Conclusions: Irrespective of trade association membership or vendor popularity, online vendors of e-liquids are not taking the proper precautions in preventing sales to minors. The FDA’s upcoming deeming rules on e-cigarette products should include explicit requirements for offline and online e-liquid vendors, particularly the use of effective age verification, warning labels, and child-resistant packaging. Implications: This study demonstrates that, in the absence of any current FDA regulation of e-liquid products, self-regulation among vendors is not effective in preventing product acquisition by minors. Lax oversight of the e-liquid industry may draw consumers to bypass current tobacco control restrictions implemented in face-to-face sales settings. As a consequence, there may be an increase in online sales to minors. Further regulation of the industry may increase the already prevalent use of child-resistant packaging, leading to fewer cases of accidental nicotine poisoning. PMID:26995792

Review of Peak Detection Algorithms in Liquid-Chromatography-Mass Spectrometry

PubMed Central

Zhang, Jianqiu; Gonzalez, Elias; Hestilow, Travis; Haskins, William; Huang, Yufei

2009-01-01

In this review, we will discuss peak detection in Liquid-Chromatography-Mass Spectrometry (LC/MS) from a signal processing perspective. A brief introduction to LC/MS is followed by a description of the major processing steps in LC/MS. Specifically, the problem of peak detection is formulated and various peak detection algorithms are described and compared. PMID:20190954

IDENTIFICATION OF MICROCYSTIN TOXINS FROM A STRAIN OF MICROCYSTIS AERUGINOSA BY LIQUID CHROMATOGRAPHY INTRODUCTION INTO A HYBRID LINEAR ION TRAP-FOURIER TRANSFORM ION CYCLOTRON RESONANCE MASS SPECTROMETER

EPA Science Inventory

The cyclic heptapeptide microcystin toxins produced by a strain of Microcystis aeruginosa that has not been investigated previously were separated by liquid chromatography and identified by high-accuracy m/z measurements of their [M + H]+ ions and the fragment i...

7 CFR 1980.301 - Introduction.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., sex, national origin, color, familial status, religion, age, or physical or mental disability (the... liquidating such loans. Any processing or servicing activity conducted pursuant to this subpart involving...

7 CFR 1980.301 - Introduction.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., sex, national origin, color, familial status, religion, age, or physical or mental disability (the... liquidating such loans. Any processing or servicing activity conducted pursuant to this subpart involving...

Biobriefcase aerosol collector

DOEpatents

Bell, Perry M [Tracy, CA; Christian, Allen T [Madison, WI; Bailey, Christopher G [Pleasanton, CA; Willis, Ladona [Manteca, CA; Masquelier, Donald A [Tracy, CA; Nasarabadi, Shanavaz L [Livermore, CA

2009-09-22

A system for sampling air and collecting particles entrained in the air that potentially include bioagents. The system comprises providing a receiving surface, directing a liquid to the receiving surface and producing a liquid surface. Collecting samples of the air and directing the samples of air so that the samples of air with particles entrained in the air impact the liquid surface. The particles potentially including bioagents become captured in the liquid. The air with particles entrained in the air impacts the liquid surface with sufficient velocity to entrain the particles into the liquid but cause minor turbulence. The liquid surface has a surface tension and the collector samples the air and directs the air to the liquid surface so that the air with particles entrained in the air impacts the liquid surface with sufficient velocity to entrain the particles into the liquid, but cause minor turbulence on the surface resulting in insignificant evaporation of the liquid.

Architecture, Assembly, and Emerging Applications of Branched Functional Polyelectrolytes and Poly(ionic liquid)s.

PubMed

Xu, Weinan; Ledin, Petr A; Shevchenko, Valery V; Tsukruk, Vladimir V

2015-06-17

Branched polyelectrolytes with cylindrical brush, dendritic, hyperbranched, grafted, and star architectures bearing ionizable functional groups possess complex and unique assembly behavior in solution at surfaces and interfaces as compared to their linear counterparts. This review summarizes the recent developments in the introduction of various architectures and understanding of the assembly behavior of branched polyelectrolytes with a focus on functional polyelectrolytes and poly(ionic liquid)s with responsive properties. The branched polyelectrolytes and poly(ionic liquid)s interact electrostatically with small molecules, linear polyelectrolytes, or other branched polyelectrolytes to form assemblies of hybrid nanoparticles, multilayer thin films, responsive microcapsules, and ion-conductive membranes. The branched structures lead to unconventional assemblies and complex hierarchical structures with responsive properties as summarized in this review. Finally, we discuss prospectives for emerging applications of branched polyelectrolytes and poly(ionic liquid)s for energy harvesting and storage, controlled delivery, chemical microreactors, adaptive surfaces, and ion-exchange membranes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Berkel, Gary J.

A system for sampling a sample material includes a probe which can have an outer probe housing with an open end. A liquid supply conduit within the housing has an outlet positioned to deliver liquid to the open end of the housing. The liquid supply conduit can be connectable to a liquid supply for delivering liquid at a first volumetric flow rate to the open end of the housing. A liquid exhaust conduit within the housing is provided for removing liquid from the open end of the housing. A liquid exhaust system can be provided for removing liquid from themore » liquid exhaust conduit at a second volumetric flow rate, the first volumetric flow rate exceeding the second volumetric flow rate, wherein liquid at the open end will receive sample, liquid containing sample material will be drawn into and through the liquid exhaust conduit, and liquid will overflow from the open end.« less

POSS Ionic Liquid.

PubMed

Tanaka, Kazuo; Ishiguro, Fumiyasu; Chujo, Yoshiki

2010-12-22

We report the synthesis of a stable room-temperature ionic liquid consisting of an octacarboxy polyhedral oligomeric silsesquioxane (POSS) anion and an imidazolium cation. The introduction of the POSS moiety enhances the thermal stability and reduces the melting temperature. From an evaluation of the thermodynamic parameters during the melting, it was found that the rigidity and cubic structure of POSS can contribute to the enhancement of these thermal properties.

Chemical Kinetics Interpretation of Hypergolicity of Ionic Liquid-Based Systems

DTIC Science & Technology

2009-04-01

acid (WFNA) mixtures 6 4. Thermochemistry of imidazoles, triazoles and tetrazoles 8 5. Thermochemistry of compounds formed...reactivity of gaseous mixtures formed above ionic liquids (ILs) when mixed with white fuming nitric acid (WFNA). After a general introduction on the...replacement for NTO is also of interest but probably less crucial. For instance, NTO could be replaced by nitric acid (or by any other suitable

Rotor for processing liquids using movable capillary tubes

DOEpatents

Johnson, Wayne F.; Burtis, Carl A.; Walker, William A.

1989-01-01

A rotor assembly for processing liquids, especially whole blood samples, is disclosed. The assembly includes apparatus for separating non-liquid components of whole blood samples from liquid components, apparatus for diluting the separated liquid component with a diluent and apparatus for transferring the diluted sample to an external apparatus for analysis. The rotor assembly employs several movable capillary tubes to handle the sample and diluents. A method for using the rotor assembly to process liquids is also described.

Rotor for processing liquids using movable capillary tubes

DOEpatents

Johnson, Wayne F [Loudon, TN; Burtis, Carl A [Oak Ridge, TN; Walker, William A [Knoxville, TN

1989-05-30

A rotor assembly for processing liquids, especially whole blood samples, is disclosed. The assembly includes apparatus for separating non-liquid components of whole blood samples from liquid components, apparatus for diluting the separated liquid component with a diluent and apparatus for transferring the diluted sample to an external apparatus for analysis. The rotor assembly employs several movable capillary tubes to handle the sample and diluents. A method for using the rotor assembly to process liquids is also described.

Microfluidic interconnects

DOEpatents

Benett, William J.; Krulevitch, Peter A.

2001-01-01

A miniature connector for introducing microliter quantities of solutions into microfabricated fluidic devices, and which incorporates a molded ring or seal set into a ferrule cartridge, with or without a compression screw. The fluidic connector, for example, joins standard high pressure liquid chromatography (HPLC) tubing to 1 mm diameter holes in silicon or glass, enabling ml-sized volumes of sample solutions to be merged with .mu.l-sized devices. The connector has many features, including ease of connect and disconnect; a small footprint which enables numerous connectors to be located in a small area; low dead volume; helium leak-tight; and tubing does not twist during connection. Thus the connector enables easy and effective change of microfluidic devices and introduction of different solutions in the devices.

Minimizing corrosion in coal liquid distillation

DOEpatents

Baumert, Kenneth L.; Sagues, Alberto A.; Davis, Burtron H.

1985-01-01

In an atmospheric distillation tower of a coal liquefaction process, tower materials corrosion is reduced or eliminated by introduction of boiling point differentiated streams to boiling point differentiated tower regions.

Systems and methods for analyzing liquids under vacuum

DOEpatents

Yu, Xiao-Ying; Yang, Li; Cowin, James P.; Iedema, Martin J.; Zhu, Zihua

2013-10-15

Systems and methods for supporting a liquid against a vacuum pressure in a chamber can enable analysis of the liquid surface using vacuum-based chemical analysis instruments. No electrical or fluid connections are required to pass through the chamber walls. The systems can include a reservoir, a pump, and a liquid flow path. The reservoir contains a liquid-phase sample. The pump drives flow of the sample from the reservoir, through the liquid flow path, and back to the reservoir. The flow of the sample is not substantially driven by a differential between pressures inside and outside of the liquid flow path. An aperture in the liquid flow path exposes a stable portion of the liquid-phase sample to the vacuum pressure within the chamber. The radius, or size, of the aperture is less than or equal to a critical value required to support a meniscus of the liquid-phase sample by surface tension.

Characterization of vitamin D3 metabolites using continuous-flow fast atom bombardment tandem mass spectrometry and high-performance liquid chromatography.

PubMed

Yeung, B; Vouros, P; Reddy, G S

1993-08-13

A mass spectrometric method for the detection of vitamin D3 metabolites is described. This method involves the derivatization of the metabolites by cycloaddition with 4-phenyl-1,2,4-triazoline-3,5-dione, followed by their characterization by continuous-flow fast atom bombardment (CF-FAB) tandem mass spectrometry (MS-MS) and high-performance liquid chromatography (HPLC). Using HPLC, this derivatization has been shown to increase the UV detectability of 25-hydroxyvitamin D3 by about 5-fold. The FAB spectra of the adducts are dominated by peaks corresponding to a protonated molecule and a fragment ion derived in part from the loss of the side chain. Multiple reaction monitoring (MRM) of this transition by MS-MS may be utilized for trace level analysis of vitamin D metabolites. Sample introduction by flow injection yields detection limits in the low nanogram to high picogram range, whereas the use of on-line capillary LC has been found to decrease the detection limits to the low picogram level.

Mercury speciation by differential photochemical vapor generation at UV-B vs. UV-C wavelength

NASA Astrophysics Data System (ADS)

Chen, Guoying; Lai, Bunhong; Mei, Ni; Liu, Jixin; Mao, Xuefei

2017-11-01

Photochemical vapor generation (PVG) is an effective sample introduction scheme for volatile mercury (Hg). Speciation of Hg++ and MeHg+ was fulfilled for the first time by differential PVG under UV-B vs. UV-C wavelength and applied to fish oil supplements. After liquid-liquid extraction, the aqueous extract was mixed with 0.4% anthranilic acid (AA)-20% formic acid (FA) in a quartz coil, and exposed sequentially to 311 nm or 254 nm UV light. The resulting Hg0 vapor was detected by atomic fluorescence spectrometry (AFS). At each wavelength, the AFS intensity was a linear function of Hg++ and MeHg+ concentrations, which were solvable from a set of two equations. This method achieved ultrahigh sensitivity with 0.50 and 0.63 ng mL- 1 limits of detection for Hg++ and MeHg+, respectively, and 73% recovery for MeHg+ at 10 ng mL- 1. Validation was performed by ICP-MS on total Hg. Obviation of chemical or chromatographic separation rendered this method rapid, green, and cost-effective.

Evaluation of a direct injection nebulizer interface for flow injection analysis and high performance liquid chromatography with inductively coupled plasma-atomic emission spectroscopic detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

LaFreniere, K.E.

A direct injection nebulizer (DIN) was designed, developed, and evaluated to determine its potential utilization as an effective interface for flow injection analysis (FIA) and high performance liquid chromatography (HPLC) coupled with inductively coupled plasma-atomic emission spectroscopic detection. The analytical figures of merit for the DIN when used as an interface for FIA-ICP-AES were found to be comparable to or better than those obtained with conventional pneumatic nebulization in terms of limits of detection (LODs), reproducibility, linearity, and interelement effects. Stable plasma operation was maintained for the DIN sample introduction of a variety of pure organic solvents, including acetonitrile, methanol,more » methylisobutylketone, and pyridine. The HPLC-DIN-ICP-AES facility was specifically applied for the speciation of inorganic and organometallic species contained in synthetic mixtures, vanilla extracts, and a variety of energy-related materials, such as shale oil process water, coal extracts, shale oil, crude oil, and an SRC II. Suggestions for future research are also considered. 227 refs., 44 figs., 15 tabs.« less

Rotor for processing liquids using movable capillary tubes

DOEpatents

Johnson, W.F.; Burtis, C.A.; Walker, W.A.

1987-07-17

A rotor assembly for processing liquids, especially whole blood samples, is disclosed. The assembly includes apparatus for separating non-liquid components of whole blood samples from liquid components, apparatus for diluting the separated liquid component with a diluent and apparatus for transferring the diluted sample to an external apparatus for analysis. The rotor assembly employs several movable capillary tubes to handle the sample and diluents. A method for using the rotor assembly to process liquids is also described. 5 figs.

Development of a split-flow system for high precision variable sample introduction in supercritical fluid chromatography.

PubMed

Sakai, Miho; Hayakawa, Yoshihiro; Funada, Yasuhiro; Ando, Takashi; Fukusaki, Eiichiro; Bamba, Takeshi

2017-09-15

In this study, we propose a novel variable sample injection system based on full-loop injection, named the split-flow sample introduction system, for application in supercritical fluid chromatography (SFC). In this system, the mobile phase is split by the differential pressure between two back pressure regulators (BPRs) after full-loop injection suitable for SFC, and this differential pressure determines the introduction rate. Nine compounds with a wide range of characteristics were introduced with high reproducibility and universality, confirming that a robust variable sample injection system was achieved. We also investigated the control factors of our proposed system. Sample introduction was controlled by the ratio between the column-side pressure drops in splitless and split flow, ΔP columnsideinsplitless and ΔP columnsideinsplit , respectively, where ΔP columnsideinsplitless is related to the mobile phase flow rate and composition and the column resistance. When all other conditions are kept constant, increasing the make-up flow induces an additional pressure drop on the column side of the system, which leads to a reduced column-side flow rate, and hence decreased the amount of sample injected, even when the net pressure drop on the column side remains the same. Thus, sample introduction could be highly controlled at low sample introduction rate, regardless of the introduction conditions. This feature is advantageous because, as a control factor, the solvent in the make-up pump is independent of the column-side pressure drop. Copyright © 2017. Published by Elsevier B.V.

Capillary pumping independent of the liquid surface energy and viscosity

NASA Astrophysics Data System (ADS)

Guo, Weijin; Hansson, Jonas; van der Wijngaart, Wouter

2018-03-01

Capillary pumping is an attractive means of liquid actuation because it is a passive mechanism, i.e., it does not rely on an external energy supply during operation. The capillary flow rate generally depends on the liquid sample viscosity and surface energy. This poses a problem for capillary-driven systems that rely on a predictable flow rate and for which the sample viscosity or surface energy are not precisely known. Here, we introduce the capillary pumping of sample liquids with a flow rate that is constant in time and independent of the sample viscosity and sample surface energy. These features are enabled by a design in which a well-characterized pump liquid is capillarily imbibed into the downstream section of the pump and thereby pulls the unknown sample liquid into the upstream pump section. The downstream pump geometry is designed to exert a Laplace pressure and fluidic resistance that are substantially larger than those exerted by the upstream pump geometry on the sample liquid. Hence, the influence of the unknown sample liquid on the flow rate is negligible. We experimentally tested pumps of the new design with a variety of sample liquids, including water, different samples of whole blood, different samples of urine, isopropanol, mineral oil, and glycerol. The capillary filling speeds of these liquids vary by more than a factor 1000 when imbibed to a standard constant cross-section glass capillary. In our new pump design, 20 filling tests involving these liquid samples with vastly different properties resulted in a constant volumetric flow rate in the range of 20.96-24.76 μL/min. We expect this novel capillary design to have immediate applications in lab-on-a-chip systems and diagnostic devices.

On-line monitoring of in-vitro oral bioaccessibility tests as front-end to liquid chromatography for determination of chlorogenic acid isomers in dietary supplements.

PubMed

Kremr, Daniel; Cocovi-Solberg, David J; Bajerová, Petra; Ventura, Karel; Miró, Manuel

2017-05-01

A novel fully automated in-vitro oral dissolution test assay as a front-end to liquid chromatography has been developed and validated for on-line chemical profiling and monitoring of temporal release profiles of three caffeoylquinic acid (CQA) isomers, namely, 3-CQA,4-CQA and 5-CQA, known as chlorogenic acids, in dietary supplements. Tangential-flow filtration is harnessed as a sample processing approach for on-line handling of CQA containing extracts of hard gelatin capsules and introduction of protein-free samples into the liquid chromatograph. Oral bioaccessibility/dissolution test assays were performed at 37.0±0.5°C as per US Pharmacopeia recommendations using pepsin with activity of ca. 749,000 USP units/L in 0.1mol/L HCl as the extraction medium and a paddle apparatus stirred at 50rpm. CQA release rates and steady-state dissolution conditions were determined accurately by fitting the chromatographic datasets, namely, the average cumulative concentrations of bioaccessible pools of every individual isomer monitored during 200min, with temporal resolutions of ≥10min, to a first-order dissolution kinetic model. Distinct solid-to-liquid phase ratios in the mimicry of physiological extraction conditions were assessed. Relative standard deviations for intra-day repeatability and inter-day intermediate precision of 5-CQA within the 5-40µg/mL concentration range were <3.4% and <5.5%, respectively. Trueness of the automatic flow method for determination of 5-CQA released from dietary supplements in gastric fluid surrogate was demonstrated by spike recoveries, spanning from 91.5-104.0%, upon completion of the dissolution process. The proposed hyphenated setup was resorted for evaluating potential differences in dissolution profiles and content of the three most abundant chlorogenic acid isomers in dietary supplements from varied manufacturers. Copyright © 2016 Elsevier B.V. All rights reserved.

Performance evaluation of laser induced breakdown spectroscopy in the measurement of liquid and solid samples

NASA Astrophysics Data System (ADS)

Bilge, Gonca; Sezer, Banu; Boyaci, Ismail Hakki; Eseller, Kemal Efe; Berberoglu, Halil

2018-07-01

Liquid analysis by using LIBS is a complicated process due to difficulties encountered during the collection of light and formation of plasma in liquid. To avoid these, some applications are performed such as aerosol formation and transforming liquid into solid state. However, performance of LIBS in liquid samples still remains a challenging issue. In this study, performance evaluation of LIBS and parameter optimizations in liquid and solid phase samples were performed. For this purpose, milk was chosen as model sample; milk powder was used as solid sample, and milk was used as liquid sample in the experiments. Different experimental setups have been constructed for each sampling technique, and optimizations were performed to determine suitable parameters such as delay time, laser energy, repetition rate and speed of rotary table for solid sampling technique, and flow rate of carrier gas for liquid sampling technique. Target element was determined as Ca, which is a critically important element in milk for determining its nutritional value and Ca addition. In optimum parameters, limit of detection (LOD), limit of quantification (LOQ) and relative standard deviation (RSD) values were calculated as 0.11%, 0.36% and 8.29% respectively for milk powders samples; while LOD, LOQ and RSD values were calculated as 0.24%, 0.81%, and 10.93% respectively for milk samples. It can be said that LIBS is an applicable method in both liquid and solid samples with suitable systems and parameters. However, liquid analysis requires much more developed systems for more accurate results.

15 CFR 742.1 - Introduction.

Code of Federal Regulations, 2014 CFR

2014-01-01

... (certain other petroleum products); 1C983 (Natural gas liquids and other natural gas derivatives); 1C984 (certain manufactured gas and synthetic natural gas (except when commingled with natural gas and thus...

15 CFR 742.1 - Introduction.

Code of Federal Regulations, 2010 CFR

2010-01-01

... (certain other petroleum products); 1C983 (Natural gas liquids and other natural gas derivatives); 1C984 (certain manufactured gas and synthetic natural gas (except when commingled with natural gas and thus...

15 CFR 742.1 - Introduction.

Code of Federal Regulations, 2012 CFR

2012-01-01

... (certain other petroleum products); 1C983 (Natural gas liquids and other natural gas derivatives); 1C984 (certain manufactured gas and synthetic natural gas (except when commingled with natural gas and thus...

15 CFR 742.1 - Introduction.

Code of Federal Regulations, 2011 CFR

2011-01-01

... (certain other petroleum products); 1C983 (Natural gas liquids and other natural gas derivatives); 1C984 (certain manufactured gas and synthetic natural gas (except when commingled with natural gas and thus...

15 CFR 742.1 - Introduction.

Code of Federal Regulations, 2013 CFR

2013-01-01

... (certain other petroleum products); 1C983 (Natural gas liquids and other natural gas derivatives); 1C984 (certain manufactured gas and synthetic natural gas (except when commingled with natural gas and thus...

40 CFR 761.269 - Sampling liquid PCB remediation waste.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Sampling liquid PCB remediation waste..., AND USE PROHIBITIONS Cleanup Site Characterization Sampling for PCB Remediation Waste in Accordance with § 761.61(a)(2) § 761.269 Sampling liquid PCB remediation waste. (a) If the liquid is single phase...

Visualization and characterization of engineered nanoparticles in complex environmental and food matrices using atmospheric scanning electron microscopy.

PubMed

Luo, P; Morrison, I; Dudkiewicz, A; Tiede, K; Boyes, E; O'Toole, P; Park, S; Boxall, A B

2013-04-01

Imaging and characterization of engineered nanoparticles (ENPs) in water, soils, sediment and food matrices is very important for research into the risks of ENPs to consumers and the environment. However, these analyses pose a significant challenge as most existing techniques require some form of sample manipulation prior to imaging and characterization, which can result in changes in the ENPs in a sample and in the introduction of analytical artefacts. This study therefore explored the application of a newly designed instrument, the atmospheric scanning electron microscope (ASEM), which allows the direct characterization of ENPs in liquid matrices and which therefore overcomes some of the limitations associated with existing imaging methods. ASEM was used to characterize the size distribution of a range of ENPs in a selection of environmental and food matrices, including supernatant of natural sediment, test medium used in ecotoxicology studies, bovine serum albumin and tomato soup under atmospheric conditions. The obtained imaging results were compared to results obtained using conventional imaging by transmission electron microscope (TEM) and SEM as well as to size distribution data derived from nanoparticle tracking analysis (NTA). ASEM analysis was found to be a complementary technique to existing methods that is able to visualize ENPs in complex liquid matrices and to provide ENP size information without extensive sample preparation. ASEM images can detect ENPs in liquids down to 30 nm and to a level of 1 mg L(-1) (9×10(8) particles mL(-1) , 50 nm Au ENPs). The results indicate ASEM is a highly complementary method to existing approaches for analyzing ENPs in complex media and that its use will allow those studying to study ENP behavior in situ, something that is currently extremely challenging to do. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

Epidemiological trends for hospital admissions for acute rotavirus gastroenteritis in Belgium following the introduction of routine rotavirus vaccination and the subsequent switch from lyophilized to liquid formulation of Rotarix™.

PubMed

Raes, M; Strens, D; Kleintjens, J; Biundo, E; Morel, T; Vyse, A

2016-10-01

This study describes epidemiological trends for acute rotavirus gastroenteritis (RVGE) in Belgium in children aged ⩽5 years during the period June 2007 to May 2014 after the introduction of routine rotavirus (RV) vaccination. This period encompassed the switch from lyophilized to the liquid formulation of Rotarix™ (GlaxoSmithKline, Belgium) in August 2011. Uptake of RV vaccine remained consistently high throughout the study period with Rotarix the brand most often used. RV was present in 9% (1139/12 511) of hospitalized cases with acute gastroenteritis included in the study. Epidemiological trends for hospital admissions for RVGE remained consistent throughout the study period, with no evidence of any change associated with the switch from lyophilized to liquid formulation of Rotarix. This suggests both formulations perform similarly, with the liquid formulation not inferior regarding ability to reduce hospital admissions for acute RVGE in children aged ⩽5 years. A strong seasonal effect was observed with most RVGE occurring in the winter months but with some variability in intensity, with highest incidence found in those aged 6-24 months. The main observation was the decreased number of hospital admissions for RVGE in Belgium that occurred during winter 2013/2014.

Electronic Cigarette Nicotine Delivery Can Exceed that of Combustible Cigarettes: A Preliminary Report

PubMed Central

Ramôa, Carolina P.; Hiler, Marzena M.; Spindle, Tory R; Lopez, Alexa A.; Karaoghlanian, Nareg; Lipato, Thokozeni; Breland, Alison B.; Shihadeh, Alan; Eissenberg, Thomas

2016-01-01

Introduction Electronic cigarettes (ECIGs) aerosolize a liquid that usually contains propylene glycol and/or vegetable glycerin, flavorants, and the dependence-producing drug nicotine in various concentrations. This laboratory study examined the relationship between liquid nicotine concentration on plasma nicotine concentration and puffing behavior in experienced ECIG users. Methods Sixteen ECIG-experienced participants used a 3.3-Volt ECIG battery attached to a 1.5-Ohm dual-coil “cartomizer” loaded with 1 ml of a flavored propylene glycol/vegetable glycerin liquid to complete four sessions, at least 2 days apart, that differed by nicotine concentration (0, 8, 18, or 36 mg/ml). In each session, participants completed two 10-puff ECIG use bouts (30-sec puff interval) separated by 60 minutes. Venous blood was sampled to determine plasma nicotine concentration. Puff duration, volume, and average flow rate were measured. Results Immediately after bout 1, mean plasma nicotine concentration was 5.5 ng/ml (SD=7.7) for 0 mg/ml liquid, with significantly (p<0.05) higher mean concentrations observed for the 8 (mean=17.8 ng/ml, SD=14.6), 18 (mean=25.9 ng/ml, SD=17.5), and 36 mg/ml (mean=30.2 ng/ml; SD=20.0) concentrations; a similar pattern was observed for bout 2. For bout 1, at 36 mg/ml, the mean post- minus pre-bout difference was 24.1 ng/ml (SD=18.3). Puff topography data were consistent with previous results and revealed few reliable differences across conditions. Discussion This study demonstrates a relationship between ECIG liquid nicotine concentration and user plasma nicotine concentration in experienced ECIG users. Nicotine delivery from some ECIGs may exceed that of a combustible cigarette. The rationale for this higher level of nicotine delivery is uncertain. PMID:26324250

15 CFR 754.1 - Introduction.

Code of Federal Regulations, 2010 CFR

2010-01-01

... (Other petroleum products); (C) ECCN 1C983 (Natural gas liquids and other natural gas derivatives); and (D) ECCN 1C984 (Manufactured gas and synthetic natural gas (except when commingled with natural gas...

15 CFR 754.1 - Introduction.

Code of Federal Regulations, 2014 CFR

2014-01-01

... (Other petroleum products); (C) ECCN 1C983 (Natural gas liquids and other natural gas derivatives); and (D) ECCN 1C984 (Manufactured gas and synthetic natural gas (except when commingled with natural gas...

15 CFR 754.1 - Introduction.

Code of Federal Regulations, 2012 CFR

2012-01-01

... (Other petroleum products); (C) ECCN 1C983 (Natural gas liquids and other natural gas derivatives); and (D) ECCN 1C984 (Manufactured gas and synthetic natural gas (except when commingled with natural gas...

15 CFR 754.1 - Introduction.

Code of Federal Regulations, 2011 CFR

2011-01-01

... (Other petroleum products); (C) ECCN 1C983 (Natural gas liquids and other natural gas derivatives); and (D) ECCN 1C984 (Manufactured gas and synthetic natural gas (except when commingled with natural gas...

15 CFR 754.1 - Introduction.

Code of Federal Regulations, 2013 CFR

2013-01-01

... (Other petroleum products); (C) ECCN 1C983 (Natural gas liquids and other natural gas derivatives); and (D) ECCN 1C984 (Manufactured gas and synthetic natural gas (except when commingled with natural gas...

Cervical cytology biobanking in Europe.

PubMed

Arbyn, Marc; Van Veen, Evert-Ben; Andersson, Kristin; Bogers, Johannes; Boulet, Gaëlle; Bergeron, Christine; von Knebel-Doeberitz, Magnus; Dillner, Joakim

2010-01-01

A cervical cytology biobank (CCB) is an extension of current cytopathology laboratory practice consisting in the systematic storage of Pap smears or liquid-based cytology samples from women participating in cervical cancer screening with the explicit purpose to facilitate future scientific research and quality audit of preventive services. A CCB should use an internationally agreed uniform cytology terminology, be integrated in a national or regional screening registry, and be linked to other registries (histology, cancer, vaccination). Legal and ethical principles concerning personal integrity and data safety must be respected strictly. Biobank-based studies require approval of ethical review boards. A CCB is an almost inexhaustible resource for fundamental and applied biological research. In particular, it can contribute to answering questions on the natural history of HPV infection and HPV-induced lesions and cancers, screening effectiveness, exploration of new biomarkers, and surveillance of the short- and long-term effects of the introduction of HPV vaccination. To understand the limitations of CCB, more studies are needed on the quality of samples in relation to sample type, storage procedures, and duration of storage.

An integrated, self-contained microfluidic cassette for isolation, amplification, and detection of nucleic acids

PubMed Central

Chen, Dafeng; Mauk, Michael; Qiu, Xianbo; Liu, Changchun; Kim, Jitae; Ramprasad, Sudhir; Ongagna, Serge; Abrams, William R.; Malamud, Daniel; Corstjens, Paul L. A. M.

2010-01-01

A self-contained, integrated, disposable, sample-to-answer, polycarbonate microfluidic cassette for nucleic acid—based detection of pathogens at the point of care was designed, constructed, and tested. The cassette comprises on-chip sample lysis, nucleic acid isolation, enzymatic amplification (polymerase chain reaction and, when needed, reverse transcription), amplicon labeling, and detection. On-chip pouches and valves facilitate fluid flow control. All the liquids and dry reagents needed for the various reactions are pre-stored in the cassette. The liquid reagents are stored in flexible pouches formed on the chip surface. Dry (RT-)PCR reagents are pre-stored in the thermal cycling, reaction chamber. The process operations include sample introduction; lysis of cells and viruses; solid-phase extraction, concentration, and purification of nucleic acids from the lysate; elution of the nucleic acids into a thermal cycling chamber and mixing with pre-stored (RT-)PCR dry reagents; thermal cycling; and detection. The PCR amplicons are labeled with digoxigenin and biotin and transmitted onto a lateral flow strip, where the target analytes bind to a test line consisting of immobilized avidin-D. The immobilized nucleic acids are labeled with up-converting phosphor (UCP) reporter particles. The operation of the cassette is automatically controlled by an analyzer that provides pouch and valve actuation with electrical motors and heating for the thermal cycling. The functionality of the device is demonstrated by detecting the presence of bacterial B.Cereus, viral armored RNA HIV, and HIV I virus in saliva samples. The cassette and actuator described here can be used to detect other diseases as well as the presence of bacterial and viral pathogens in the water supply and other fluids. PMID:20401537

An integrated, self-contained microfluidic cassette for isolation, amplification, and detection of nucleic acids.

PubMed

Chen, Dafeng; Mauk, Michael; Qiu, Xianbo; Liu, Changchun; Kim, Jitae; Ramprasad, Sudhir; Ongagna, Serge; Abrams, William R; Malamud, Daniel; Corstjens, Paul L A M; Bau, Haim H

2010-08-01

A self-contained, integrated, disposable, sample-to-answer, polycarbonate microfluidic cassette for nucleic acid-based detection of pathogens at the point of care was designed, constructed, and tested. The cassette comprises on-chip sample lysis, nucleic acid isolation, enzymatic amplification (polymerase chain reaction and, when needed, reverse transcription), amplicon labeling, and detection. On-chip pouches and valves facilitate fluid flow control. All the liquids and dry reagents needed for the various reactions are pre-stored in the cassette. The liquid reagents are stored in flexible pouches formed on the chip surface. Dry (RT-)PCR reagents are pre-stored in the thermal cycling, reaction chamber. The process operations include sample introduction; lysis of cells and viruses; solid-phase extraction, concentration, and purification of nucleic acids from the lysate; elution of the nucleic acids into a thermal cycling chamber and mixing with pre-stored (RT-)PCR dry reagents; thermal cycling; and detection. The PCR amplicons are labeled with digoxigenin and biotin and transmitted onto a lateral flow strip, where the target analytes bind to a test line consisting of immobilized avidin-D. The immobilized nucleic acids are labeled with up-converting phosphor (UCP) reporter particles. The operation of the cassette is automatically controlled by an analyzer that provides pouch and valve actuation with electrical motors and heating for the thermal cycling. The functionality of the device is demonstrated by detecting the presence of bacterial B.Cereus, viral armored RNA HIV, and HIV I virus in saliva samples. The cassette and actuator described here can be used to detect other diseases as well as the presence of bacterial and viral pathogens in the water supply and other fluids.

Comparative performance study of different sample introduction techniques for rapid and precise selenium isotope ratio determination using multi-collector inductively coupled plasma mass spectrometry (MC-ICP/MS).

PubMed

Elwaer, Nagmeddin; Hintelmann, Holger

2007-11-01

The analytical performance of five sample introduction systems, a cross flow nebulizer spray chamber, two different solvent desolvation systems, a multi-mode sample introduction system (MSIS), and a hydride generation (LI2) system were compared for the determination of Se isotope ratio measurements using multi-collector inductively coupled plasma mass spectrometry (MC-ICP/MS). The optimal operating parameters for obtaining the highest Se signal-to-noise (S/N) ratios and isotope ratio precision for each sample introduction were determined. The hydride generation (LI2) system was identified as the most suitable sample introduction method yielding maximum sensitivity and precision for Se isotope ratio measurement. It provided five times higher S/N ratios for all Se isotopes compared to the MSIS, 20 times the S/N ratios of both desolvation units, and 100 times the S/N ratios produced by the conventional spray chamber sample introduction method. The internal precision achieved for the (78)Se/(82)Se ratio at 100 ng mL(-1) Se with the spray chamber, two desolvation, MSIS, and the LI2 systems coupled to MC-ICP/MS was 150, 125, 114, 13, and 7 ppm, respectively. Instrument mass bias factors (K) were calculated using an exponential law correction function. Among the five studied sample introduction systems the LI2 showed the lowest mass bias of -0.0265 and the desolvation system showed the largest bias with -0.0321.

Accelerated solvent extraction combined with dispersive liquid-liquid microextraction before gas chromatography with mass spectrometry for the sensitive determination of phenols in soil samples.

PubMed

Xing, Han-Zhu; Wang, Xia; Chen, Xiang-Feng; Wang, Ming-Lin; Zhao, Ru-Song

2015-05-01

A method combining accelerated solvent extraction with dispersive liquid-liquid microextraction was developed for the first time as a sample pretreatment for the rapid analysis of phenols (including phenol, m-cresol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol) in soil samples. In the accelerated solvent extraction procedure, water was used as an extraction solvent, and phenols were extracted from soil samples into water. The dispersive liquid-liquid microextraction technique was then performed on the obtained aqueous solution. Important accelerated solvent extraction and dispersive liquid-liquid microextraction parameters were investigated and optimized. Under optimized conditions, the new method provided wide linearity (6.1-3080 ng/g), low limits of detection (0.06-1.83 ng/g), and excellent reproducibility (<10%) for phenols. Four real soil samples were analyzed by the proposed method to assess its applicability. Experimental results showed that the soil samples were free of our target compounds, and average recoveries were in the range of 87.9-110%. These findings indicate that accelerated solvent extraction with dispersive liquid-liquid microextraction as a sample pretreatment procedure coupled with gas chromatography and mass spectrometry is an excellent method for the rapid analysis of trace levels of phenols in environmental soil samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In situ derivatization-ultrasound-assisted dispersive liquid-liquid microextraction for the determination of neurotransmitters in Parkinson's rat brain microdialysates by ultra high performance liquid chromatography-tandem mass spectrometry.

PubMed

He, Yongrui; Zhao, Xian-En; Zhu, Shuyun; Wei, Na; Sun, Jing; Zhou, Yubi; Liu, Shu; Liu, Zhiqiang; Chen, Guang; Suo, Yourui; You, Jinmao

2016-08-05

Simultaneous monitoring of several neurotransmitters (NTs) linked to Parkinson's disease (PD) has important scientific significance for PD related pathology, pharmacology and drug screening. A new simple, fast and sensitive analytical method, based on in situ derivatization-ultrasound-assisted dispersive liquid-liquid microextraction (in situ DUADLLME) in a single step, has been proposed for the quantitative determination of catecholamines and their biosynthesis precursors and metabolites in rat brain microdialysates. The method involved the rapid injection of the mixture of low toxic bromobenzene (extractant) and acetonitrile (dispersant), which containing commercial Lissamine rhodamine B sulfonyl chloride (LRSC) as derivatization reagent, into the aqueous phase of sample and buffer, and the following in situ DUADLLME procedure. After centrifugation, 50μL of the sedimented phase (bromobenzene) was directly injected for ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) detection in multiple reaction monitoring (MRM) mode. This interesting combination brought the advantages of speediness, simpleness, low matrix effects and high sensitivity in an effective way. Parameters of in situ DUADLLME and UHPLC-MS/MS conditions were all optimized in detail. The optimum conditions of in situ DUADLLME were found to be 30μL of microdialysates, 150μL of acetonitrile containing LRSC, 50μL of bromobenzene and 800μL of NaHCO3-Na2CO3 buffer (pH 10.5) for 3.0min at 37°C. Under the optimized conditions, good linearity was observed with LODs (S/N>3) and LOQs (S/N>10) of LRSC derivatized-NTs in the range of 0.002-0.004 and 0.007-0.015 nmol/L, respectively. It also brought good precision (3.2-12.8%, peak area CVs%), accuracy (94.2-108.6%), recovery (94.5-105.5%) and stability (3.8-8.1%, peak area CVs%) results. Moreover, LRSC derivatization significantly improved chromatographic resolution and MS detection sensitivity of NTs when compared with the reported studies through the introduction of a permanent charged moiety from LRSC into NTs. Taken together, this in situ DUADLLME method was successfully applied for the simultaneous determination of six NTs in biological samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Ketogenic Diet in Refractory Childhood Epilepsy: Starting With a Liquid Formulation in an Outpatient Setting.

PubMed

Weijenberg, Amerins; van Rijn, Margreet; Callenbach, Petra M C; de Koning, Tom J; Brouwer, Oebele F

2018-01-01

Ketogenic diet in children with epilepsy has a considerable impact on daily life and is usually adopted for at least 3 months. Our aim was to evaluate whether the introduction of an all-liquid ketogenic diet in an outpatient setting is feasible, and if an earlier assessment of its efficacy can be achieved. The authors conducted a prospective, observational study in a consecutive group of children with refractory epilepsy aged 2 to 14 years indicated for ketogenic diet. Ketogenic diet was started as an all-liquid formulation of the classical ketogenic diet, KetoCal 4:1 LQ, taken orally or by tube. After 6 weeks, the liquid diet was converted into solid meals. The primary outcome parameter was time-to-response (>50% seizure reduction). Secondary outcome parameters were time to achieve stable ketosis, the number of children showing a positive response, and the retention rate at 26 weeks. Sixteen children were included. Four of them responded well with respect to seizure frequency, the median time-to-response was 14 days (range 7-28 days). The mean time to achieve stable ketosis was 7 days. The retention rate at 26 weeks was 50%. Of the 8 children who started this protocol orally fed, 6 completed it without requiring a nasogastric tube. Introduction of ketogenic diet with a liquid formulation can be accomplished in orally fed children without major complications. It allowed for fast and stable ketosis.

Interface for the rapid analysis of liquid samples by accelerator mass spectrometry

DOEpatents

Turteltaub, Kenneth; Ognibene, Ted; Thomas, Avi; Daley, Paul F; Salazar Quintero, Gary A; Bench, Graham

2014-02-04

An interface for the analysis of liquid sample having carbon content by an accelerator mass spectrometer including a wire, defects on the wire, a system for moving the wire, a droplet maker for producing droplets of the liquid sample and placing the droplets of the liquid sample on the wire in the defects, a system that converts the carbon content of the droplets of the liquid sample to carbon dioxide gas in a helium stream, and a gas-accepting ion source connected to the accelerator mass spectrometer that receives the carbon dioxide gas of the sample in a helium stream and introduces the carbon dioxide gas of the sample into the accelerator mass spectrometer.

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 chromatography, or capillary electrophoresis). Particular focus is placed on the selectivity and degree of enrichment attainable, as well as demands of speed, absolute quantification, robustness and, ultimately, consideration of fully-integrated bioanalytical solutions to optimise sample handling and throughput. Copyright © 2016 Elsevier B.V. All rights reserved.

Method and apparatus for transport, introduction, atomization and excitation of emission spectrum for quantitative analysis of high temperature gas sample streams containing vapor and particulates without degradation of sample stream temperature

DOEpatents

Eckels, David E.; Hass, William J.

1989-05-30

A sample transport, sample introduction, and flame excitation system for spectrometric analysis of high temperature gas streams which eliminates degradation of the sample stream by condensation losses.

Antibacterial performance of nano polypropylene filter media containing nano-TiO2 and clay particles

NASA Astrophysics Data System (ADS)

Shafiee, Sara; Zarrebini, Mohammad; Naghashzargar, Elham; Semnani, Dariush

2015-10-01

Disinfection and elimination of pathogenic microorganisms from liquid can be achieved by filtration process using antibacterial filter media. The advent of nanotechnology has facilitated the introduction of membranes consisting of nano-fiber in filtration operations. The melt electro-spun fibers due to their extremely small diameters are used in the production of this particular filtration medium. In this work, antibacterial polypropylene filter medium containing clay particles and nano-TiO2 were made using melt electro-spun technology. Antibacterial performance of polypropylene nano-filters was evaluated using E. coli bacteria. Additionally, filtration efficiency of the samples in terms fiber diameter, filter porosity, and fiber distribution using image processing technique was determined. Air permeability and dust aerosol tests were conducted to establish the suitability of the samples as a filter medium. It was concluded that as far as antibacterial property is concerned, nano-fibers filter media containing clay particles are preferential to similar media containing TiO2 nanoparticles.

Breakdown Characteristic Analysis of Paper- Oil Insulation under AC and DC Voltage

NASA Astrophysics Data System (ADS)

Anuar, N. F.; Jamail, N. A. M.; Rahman, R. A.; Kamarudin, M. S.

2017-08-01

This paper presents the study of breakdown characteristic of Kraft paper insulated with two different types of insulating fluid, which are Palm oil and Coconut oil. Palm oil and Coconut oil are chosen as the alternative fluid to the transformer oil because it has high potential and environmentally-friendly. The Segezha Kraft papers with various thicknesses (65.5 gsm, 75 gsm, 85gsm, 90 gsm) have been used in this research. High Voltage Direct Current (HVDC), High Voltage Alternating Current (HVAC) and carbon track and severity analysis is conducted to observe the sample of aging Kraft paper. These samples have been immersed using Palm oil and Coconut oil up to 90 days to observe the absorption rate. All samples started to reach saturation level at 70 days of immersion. HVDC and HVAC breakdown experiments have been done after the samples had reached the saturation level based on normal condition, immersed in Palm oil and immersed in Coconut oil. All samples immersed in liquid show different breakdown voltage reading compared to normal condition. The analysis of carbon track and severity on surface has been done using Analytical Scanning Electron Microscope (SEM) Analysis. The results of the experiment show that the sample of Kraft paper immersed in Palm oil was better than Coconut oil immersed sample. Therefore the sample condition was the main factor that determines the value of breakdown voltage test. Introduction

Introduction to the Physics of the Cryosphere

NASA Astrophysics Data System (ADS)

Sandells, Melody; Flocco, Daniela

2014-11-01

Introduction to the Physics of the Cryosphere is intended for graduates with a numerical sciences background, particularly those who are heading towards postgraduate study or are generally interested in environmental physics. Conservation equations underpin the physics encompassed in this book, although the interesting part comes in how the necessary variables and boundary conditions are defined to be able to simulate changes in the cryosphere. Phase changes between ice, liquid water and water vapour also come into play.

Introduction to Cavitation and Supercavitation

DTIC Science & Technology

2001-02-01

supercavities and leant on the old wake theory (Helmholtz 1868; Kirchhoff 1869; Levi - Civita 1907; Villat 1913 ; Riabouchinski 1920 - those references...cavity. Phil. Mag., 34, 94 sq. TULIN, M.P. -1953- Steady two -dimensional cavity flows about slender bodies . D.T.M.B., Rept 834. WU, T.Y.T. -1956- A...above a liquid contained in a bowl: if the oscillation amplitude is large enough, bubbles can appear inside the liquid. * A solid body with sharp

Dense Non Aqueous Phase Liquid (DNAPL) Removal from Fractured Rock using Thermal Conductive Heating (TCH)

DTIC Science & Technology

2013-01-01

of 95% or greater in parent compounds . The data also show that most rock concentrations were lowered to around 0-5...INTRODUCTION 1.1 BACKGROUND The removal of dense non-aqueous phase liquids (DNAPL) and associated dissolved phase compounds is challenging in ...trend as presented in Figure 10. Figure 10. Vapor stream VOC concentrations for the dominant compounds . The more or less consistent level of

Computational Modeling of Supercritical and Transcritical Flows

DTIC Science & Technology

2017-01-09

Acentric factor I. Introduction Liquid rocket and gas turbine engines operate at high pressures. For gas turbines, the combustor pressurecan be 60 − 100...an approach the liquid gas interface is tracked.4 We note that an overwhelming majority of the computational studies have similarly focused on purely...A standard approach for supercritical flows is to treat the multicomponent mixture of species as a dense fluid using a real gas equation of state such

Lysimeter apparatus

DOEpatents

Clark, Don T.; Erickson, Eugene E.; Casper, William L.; Everett, David M.; Hubbell, Joel M.; Sisson, James B.

2005-09-06

A suction lysimeter for sampling subsurface liquids includes a lysimeter casing having a drive portion, a reservoir portion, and a tip portion, the tip portion including a membrane through which subsurface liquids may be sampled; a fluid conduit coupled in fluid flowing relation relative to the membrane, and which in operation facilitates the delivery of the sampled subsurface liquids from the membrane to the reservoir portion; and a plurality of tubes coupled in fluid flowing relation relative to the reservoir portion, the tubes in operation facilitating delivery of the sampled subsurface liquids from the reservoir portion for testing. A method of sampling subsurface liquids comprises using this lysimeter.

Preservation of Liquid Biological Samples

NASA Technical Reports Server (NTRS)

Putcha, Lakshmi (Inventor); Nimmagudda, Ramalingeshwara R. (Inventor)

2000-01-01

The present invention provides a method of preserving a liquid biological sample, comprising the step of: contacting said liquid biological sample with a preservative comprising, sodium benzoate in an amount of at least about 0.15% of the sample (weight/volume) and citric acid in an amount of at least about 0.025% of the sample (weight/volume).

An introduction to hybrid ion trap/time-of-flight mass spectrometry coupled with liquid chromatography applied to drug metabolism studies.

PubMed

Liu, Zhao-Ying

2012-12-01

Metabolism studies play an important role at various stages of drug discovery and development. Liquid chromatography combined with mass spectrometry (LC/MS) has become a most powerful and widely used analytical tool for identifying drug metabolites. The suitability of different types of mass spectrometers for metabolite profiling differs widely, and therefore, the data quality and reliability of the results also depend on which instrumentation is used. As one of the latest LC/MS instrumentation designs, hybrid ion trap/time-of-flight MS coupled with LC (LC-IT-TOF-MS) has successfully integrated ease of operation, compatibility with LC flow rates and data-dependent MS(n) with high mass accuracy and mass resolving power. The MS(n) and accurate mass capabilities are routinely utilized to rapidly confirm the identification of expected metabolites or to elucidate the structures of uncommon or unexpected metabolites. These features make the LC-IT-TOF-MS a very powerful analytical tool for metabolite identification. This paper begins with a brief introduction to some basic principles and main properties of a hybrid IT-TOF instrument. Then, a general workflow for metabolite profiling using LC-IT-TOF-MS, starting from sample collection and preparation to final identification of the metabolite structures, is discussed in detail. The data extraction and mining techniques to find and confirm metabolites are discussed and illustrated with some examples. This paper is directed to readers with no prior experience with LC-IT-TOF-MS and will provide a broad understanding of the development and utility of this instrument for drug metabolism studies. Copyright © 2012 John Wiley & Sons, Ltd.

Effect of additives on the clouding and aggregation behavior of Triton X-100

NASA Astrophysics Data System (ADS)

Semwal, Divyam; Sen, Indrani Das; Jayaram, Radha V.

2018-04-01

The present study investigates the effect of additives such as CsNO3 and imidazolium ionic liquids on the cloud point (CP) of Triton X-100. Thermodynamic parameters of the clouding process were determined in order to understand the interactions. CP was found to increase with the increase in concentration of most of the ionic liquids studied. This increase of CP reflects the solubilization of the ionic liquids in the micellar phase1. The thermodynamic parameters on the introduction of CsNO3 in TX-100 - ionic liquid system helps in understanding the different interactions occurring in the system. All ΔG values for clouding were found to be positive and hence made the process non spontaneous.

Ionic liquids in tribology.

PubMed

Minami, Ichiro

2009-06-24

Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided.

Lysimeter methods and apparatus

DOEpatents

Clark, Don T.; Erickson, Eugene E.; Casper, William L.; Everett, David M.; Hubbell, Joel M.; Sisson, James B.

2004-12-07

A suction lysimeter for sampling subsurface liquids includes a lysimeter casing having a drive portion, a reservoir portion, and a tip portion, the tip portion including a membrane through which subsurface liquids may be sampled; a fluid conduit coupled in fluid flowing relation relative to the membrane, and which in operation facilitates the delivery of the sampled subsurface liquids from the membrane to the reservoir portion; and a plurality of tubes coupled in fluid flowing relation relative to the reservoir portion, the tubes in operation facilitating delivery of the sampled subsurface liquids from the reservoir portion for testing. A method of sampling subsurface liquids comprises using this lysimeter.

Determination of sulfonamides in butter samples by ionic liquid magnetic bar liquid-phase microextraction high-performance liquid chromatography.

PubMed

Wu, Lijie; Song, Ying; Hu, Mingzhu; Xu, Xu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

2015-01-01

A novel, simple, and environmentally friendly pretreatment method, ionic liquid magnetic bar liquid-phase microextraction, was developed for the determination of sulfonamides in butter samples by high-performance liquid chromatography. The ionic liquid magnetic bar was prepared by inserting a stainless steel wire into the hollow of a hollow fiber and immobilizing ionic liquid in the micropores of the hollow fiber. In the extraction process, the ionic liquid magnetic bars were used to stir the mixture of sample and extraction solvent and enrich the sulfonamides in the mixture. After extraction, the analyte-adsorbed ionic liquid magnetic bars were readily isolated with a magnet from the extraction system. It is notable that the present method was environmentally friendly since water and only several microliters of ionic liquid were used in the whole extraction process. Several parameters affecting the extraction efficiency were investigated and optimized, including the type of ionic liquid, sample-to-extraction solvent ratio, the number of ionic liquid magnetic bars, extraction temperature, extraction time, salt concentration, stirring speed, pH of the extraction solvent, and desorption conditions. The recoveries were in the range of 73.25-103.85 % and the relative standard deviations were lower than 6.84 %. The experiment results indicated that the present method was effective for the extraction of sulfonamides in high-fat content samples.

Design and characterization of poly(dimethylsiloxane)-based valves for interfacing continuous-flow sampling to microchip electrophoresis.

PubMed

Li, Michelle W; Huynh, Bryan H; Hulvey, Matthew K; Lunte, Susan M; Martin, R Scott

2006-02-15

This work describes the fabrication and evaluation of a poly(dimethyl)siloxane (PDMS)-based device that enables the discrete injection of a sample plug from a continuous-flow stream into a microchannel for subsequent analysis by electrophoresis. Devices were fabricated by aligning valving and flow channel layers followed by plasma sealing the combined layers onto a glass plate that contained fittings for the introduction of liquid sample and nitrogen gas. The design incorporates a reduced-volume pneumatic valve that actuates (on the order of hundreds of milliseconds) to allow analyte from a continuously flowing sampling channel to be injected into a separation channel for electrophoresis. The injector design was optimized to include a pushback channel to flush away stagnant sample associated with the injector dead volume. The effect of the valve actuation time, the pushback voltage, and the sampling stream flow rate on the performance of the device was characterized. Using the optimized design and an injection frequency of 0.64 Hz showed that the injection process is reproducible (RSD of 1.77%, n = 15). Concentration change experiments using fluorescein as the analyte showed that the device could achieve a lag time as small as 14 s. Finally, to demonstrate the potential uses of this device, the microchip was coupled to a microdialysis probe to monitor a concentration change and sample a fluorescein dye mixture.

Fluorescent probe studies of polarity and solvation within room temperature ionic liquids: a review.

PubMed

Pandey, Shubha; Baker, Sheila N; Pandey, Siddharth; Baker, Gary A

2012-09-01

Ionic liquids display an array of useful and sometimes unconventional, solvent features and have attracted considerable interest in the field of green chemistry for the potential they hold to significantly reduce environmental emissions. Some of these points have a bearing on the chemical reactivity of these systems and have also generated interest in the physical and theoretical aspects of solvation in ionic liquids. This review presents an introduction to the field of ionic liquids, followed by discussion of investigations into the solvation properties of neat ionic liquids or mixed systems including ionic liquids as a major or minor component. The ionic liquid based multicomponent systems discussed are composed of other solvents, other ionic liquids, carbon dioxide, surfactants or surfactant solutions. Although we clearly focus on fluorescence spectroscopy as a tool to illuminate ionic liquid systems, the issues discussed herein are of general relevance to discussions of polarity and solvent effects in ionic liquids. Transient solvation measurements carried out by means of time-resolved fluorescence measurements are particularly powerful for their ability to parameterize the kinetics of the solvation process in ionic liquids and are discussed as well.

Continuous cell introduction and rapid dynamic lysis for high-throughput single-cell analysis on microfludic chips with hydrodynamic focusing.

PubMed

Xu, Chun-Xiu; Yin, Xue-Feng

2011-02-04

A chip-based microfluidic system for high-throughput single-cell analysis is described. The system was integrated with continuous introduction of individual cells, rapid dynamic lysis, capillary electrophoretic (CE) separation and laser induced fluorescence (LIF) detection. A cross microfluidic chip with one sheath-flow channel located on each side of the sampling channel was designed. The labeled cells were hydrodynamically focused by sheath-flow streams and sequentially introduced into the cross section of the microchip under hydrostatic pressure generated by adjusting liquid levels in the reservoirs. Combined with the electric field applied on the separation channel, the aligned cells were driven into the separation channel and rapidly lysed within 33ms at the entry of the separation channel by Triton X-100 added in the sheath-flow solution. The maximum rate for introducing individual cells into the separation channel was about 150cells/min. The introduction of sheath-flow streams also significantly reduced the concentration of phosphate-buffered saline (PBS) injected into the separation channel along with single cells, thus reducing Joule heating during electrophoretic separation. The performance of this microfluidic system was evaluated by analysis of reduced glutathione (GSH) and reactive oxygen species (ROS) in single erythrocytes. A throughput of 38cells/min was obtained. The proposed method is simple and robust for high-throughput single-cell analysis, allowing for analysis of cell population with considerable size to generate results with statistical significance. Copyright © 2010 Elsevier B.V. All rights reserved.

HAER Level II Documentation of Launch Complexes 1/2, 3/4, 9/10, 14, and 34 at Cape Canaveral Air Force Station, Florida

DTIC Science & Technology

2016-06-01

Helium was used for first stage pressurization, for upper-stage in-flight storage spheres, and for liquid oxygen tank bubbling to prevent temperature ...LOX liquid oxygen MFL Missile Firing Laboratory MIPR Military Interdepartmental Purchase Request MTTP multi-service tactics, techniques, and...TR-16-1 vi Introduction Background Congress codified the National Historic Preservation Act of 1966 (NHPA), the nation’s most effective cultural

Ketogenic Diet in Refractory Childhood Epilepsy

PubMed Central

Weijenberg, Amerins; van Rijn, Margreet; de Koning, Tom J.; Brouwer, Oebele F.

2018-01-01

Background: Ketogenic diet in children with epilepsy has a considerable impact on daily life and is usually adopted for at least 3 months. Our aim was to evaluate whether the introduction of an all-liquid ketogenic diet in an outpatient setting is feasible, and if an earlier assessment of its efficacy can be achieved. Methods: The authors conducted a prospective, observational study in a consecutive group of children with refractory epilepsy aged 2 to 14 years indicated for ketogenic diet. Ketogenic diet was started as an all-liquid formulation of the classical ketogenic diet, KetoCal 4:1 LQ, taken orally or by tube. After 6 weeks, the liquid diet was converted into solid meals. The primary outcome parameter was time-to-response (>50% seizure reduction). Secondary outcome parameters were time to achieve stable ketosis, the number of children showing a positive response, and the retention rate at 26 weeks. Results: Sixteen children were included. Four of them responded well with respect to seizure frequency, the median time-to-response was 14 days (range 7-28 days). The mean time to achieve stable ketosis was 7 days. The retention rate at 26 weeks was 50%. Of the 8 children who started this protocol orally fed, 6 completed it without requiring a nasogastric tube. Conclusions: Introduction of ketogenic diet with a liquid formulation can be accomplished in orally fed children without major complications. It allowed for fast and stable ketosis. PMID:29872664

Sample introduction apparatus for a flow cytometer

DOEpatents

Van den Engh, Ger

1998-01-01

A sample introduction system for a flow cytometer allows easy change of sample containers such as test tubes and facilitates use in high pressure environments. The sample container includes a cap having a pressure supply chamber and a sample container attachment cavity. A sample container may be automatically positioned into the attachment cavity so as to sealably engage the end of the sample container as its outer surface. This positioning may be accomplished through some sample introduction mechanism. To facilitate cleaning HPLC tubing and fittings may be used in a manner which facilitates removable of the entire tubing from both the nozzle container and other sample container cap to permit its replacement to avoid contamination. The sample container support may include horizontal stops which loosely limit the movement of the sample container and thus avoid further stresses upon it.

Sample introduction system for a flow cytometer

DOEpatents

Van den Engh, Ger

1997-01-01

A sample introduction system for a flow cytometer allows easy change of sample containers such as test tubes and facilitates use in high pressure environments. The sample container includes a cap having a pressure supply chamber and a sample container attachment cavity. A sample container may be automatically positioned into the attachment cavity so as to sealably engage the end of the sample container as its outer surface. This positioning may be accomplished through some sample introduction mechanism. To facilitate cleaning, HPLC tubing and fittings may be used in a manner which facilitates removing of the entire tubing from both the nozzle container and other sample container cap to permit its replacement to avoid contamination. The sample container support may include horizontal stops which loosely limit the movement of the sample container and thus avoid further stresses upon it.

Sample introduction apparatus for a flow cytometer

DOEpatents

Van den Engh, G.

1998-03-10

A sample introduction system for a flow cytometer allows easy change of sample containers such as test tubes and facilitates use in high pressure environments. The sample container includes a cap having a pressure supply chamber and a sample container attachment cavity. A sample container may be automatically positioned into the attachment cavity so as to sealably engage the end of the sample container as its outer surface. This positioning may be accomplished through some sample introduction mechanism. To facilitate cleaning HPLC tubing and fittings may be used in a manner which facilitates removable of the entire tubing from both the nozzle container and other sample container cap to permit its replacement to avoid contamination. The sample container support may include horizontal stops which loosely limit the movement of the sample container and thus avoid further stresses upon it. 3 figs.

Sample introduction system for a flow cytometer

DOEpatents

Engh, G. van den

1997-02-11

A sample introduction system for a flow cytometer allows easy change of sample containers such as test tubes and facilitates use in high pressure environments. The sample container includes a cap having a pressure supply chamber and a sample container attachment cavity. A sample container may be automatically positioned into the attachment cavity so as to sealably engage the end of the sample container as its outer surface. This positioning may be accomplished through some sample introduction mechanism. To facilitate cleaning, HPLC tubing and fittings may be used in a manner which facilitates removing of the entire tubing from both the nozzle container and other sample container cap to permit its replacement to avoid contamination. The sample container support may include horizontal stops which loosely limit the movement of the sample container and thus avoid further stresses upon it. 3 figs.

Topological Spin Glass in Diluted Spin Ice

NASA Astrophysics Data System (ADS)

Sen, Arnab; Moessner, R.

2015-06-01

It is a salient experimental fact that a large fraction of candidate spin liquid materials freeze as the temperature is lowered. The question naturally arises whether such freezing is intrinsic to the spin liquid ("disorder-free glassiness") or extrinsic, in the sense that a topological phase simply coexists with standard freezing of impurities. Here, we demonstrate a surprising third alternative, namely, that freezing and topological liquidity are inseparably linked. The topological phase reacts to the introduction of disorder by generating degrees of freedom of a new type (along with interactions between them), which in turn undergo a freezing transition while the topological phase supporting them remains intact.

Topological Spin Glass in Diluted Spin Ice.

PubMed

Sen, Arnab; Moessner, R

2015-06-19

It is a salient experimental fact that a large fraction of candidate spin liquid materials freeze as the temperature is lowered. The question naturally arises whether such freezing is intrinsic to the spin liquid ("disorder-free glassiness") or extrinsic, in the sense that a topological phase simply coexists with standard freezing of impurities. Here, we demonstrate a surprising third alternative, namely, that freezing and topological liquidity are inseparably linked. The topological phase reacts to the introduction of disorder by generating degrees of freedom of a new type (along with interactions between them), which in turn undergo a freezing transition while the topological phase supporting them remains intact.

System and method for liquid extraction electrospray-assisted sample transfer to solution for chemical analysis

DOEpatents

Kertesz, Vilmos; Van Berkel, Gary J.

2016-07-12

A system for sampling a surface includes a surface sampling probe comprising a solvent liquid supply conduit and a distal end, and a sample collector for suspending a sample collection liquid adjacent to the distal end of the probe. A first electrode provides a first voltage to solvent liquid at the distal end of the probe. The first voltage produces a field sufficient to generate electrospray plume at the distal end of the probe. A second electrode provides a second voltage and is positioned to produce a plume-directing field sufficient to direct the electrospray droplets and ions to the suspended sample collection liquid. The second voltage is less than the first voltage in absolute value. A voltage supply system supplies the voltages to the first electrode and the second electrode. The first electrode can apply the first voltage directly to the solvent liquid. A method for sampling for a surface is also disclosed.

Condition of copper and organic matter in the soil contaminated with metal remediation of humic substances.

NASA Astrophysics Data System (ADS)

Kolchanova, Kseniia; Barsova, Natalia; Motuzova, Galina; Stepanov, Andrey; Karpukhin, Mikhail

2017-04-01

The aim of this study was to investigate the forms of copper and transformation of organic matter in the soil under the influence of humic substances (potassium humate, which was obtained from coal). The object of research was the top layer of soil model field experience. Field experiments were carried out in 10-liter plastic containers.The upper layers were constructed artificially as mixture of loam, sand and peat. Below it was a layer of loam, then gravel and under it we installed lysimeters. The experiment was conducted in 3 settings: 1) control, 2) control + Cu, and 3) control + Cu + potassium humate . Copper was deposited into upper layer at soil column construction as dry powder (CuSO4*5H2O), which is 1000mg per kg. Humic substance was introduced on surface as liquid form. The focus was the state of the copper and organic matter of solid and liquid phase. In the solid phase pH, carbon content, the molecular-mass distributions for the organic matter, total (HNO3 conc.+ H2O2; decomposition in a microwave oven) and acid-soluble (1H HNO3) copper content, sequential extraction of copper (1 M MgCl2, acetate buffer pH 4,8 (AAB), 1% EDTA) were determined. For liquid phase characteristics aqueous extract was obtained and identified therein: pH, total activity and copper content and water-soluble organic matter(WOM) amphiphilic properties. The introduction of copper is accompanied by a decrease in pH in soils from 7 to 6,3. The introduction of the humic substance softens this effect. Introducing humic preparation gives an increase in carbon at 0.5%. HS and copper has no significant effect on the molecular-mass distribution of solid organic matter. Only about 4% introduced copper accounted for the exchangeable form (MgCl2) for the variant only copper contaminated. Copper, mainly precipitated as hydroxides, moved in an AAB extract. And compared with the exchangeable forms its quantity increases by 10 times. Still more copper goes into an extract of EDTA, about half of the total. That is, the introduction of humic substances increases the amount of copper associated with organic matter in complexes with high stability constants. The total amount of copper of the results of extraction is 88-96% of the all total content. Water-soluble copper contains only 0.5% of the total. But the introduction of humic substances increases the amount of water-soluble copper is 3 times. This is due to the increase in the content of the WOM by 2.5-3 times, both due to the hydrophobic and hydrophilic factions of WOM. And this leads to a sharp reduction in the activity of copper in the liquid phase. Dual effect of introducing humic substances was obtained on the results of the work. On the one hand the introduction of humic substances contributes the immobilization of copper by increasing the fraction associated with organic matter in the solid phase. On the other hand the introduction of humic substances contributes the mobilization of copper in the liquid phase due to the increase of WOM.

Surveillance of low pathogenic novel H7N9 avian influenza in commercial poultry barns: detection of outbreaks and estimation of virus introduction time.

PubMed

Pinsent, Amy; Blake, Isobel M; White, Michael T; Riley, Steven

2014-08-01

Both high and low pathogenic subtype A avian influenza remain ongoing threats to the commercial poultry industry globally. The emergence of a novel low pathogenic H7N9 lineage in China presents itself as a new concern to both human and animal health and may necessitate additional surveillance in commercial poultry operations in affected regions. Sampling data was simulated using a mechanistic model of H7N9 influenza transmission within commercial poultry barns together with a stochastic observation process. Parameters were estimated using maximum likelihood. We assessed the probability of detecting an outbreak at time of slaughter using both real-time polymerase chain reaction (rt-PCR) and a hemagglutinin inhibition assay (HI assay) before considering more intense sampling prior to slaughter. The day of virus introduction and R0 were estimated jointly from weekly flock sampling data. For scenarios where R0 was known, we estimated the day of virus introduction into a barn under different sampling frequencies. If birds were tested at time of slaughter, there was a higher probability of detecting evidence of an outbreak using an HI assay compared to rt-PCR, except when the virus was introduced <2 weeks before time of slaughter. Prior to the initial detection of infection N sample = 50 (1%) of birds were sampled on a weekly basis once, but after infection was detected, N sample = 2000 birds (40%) were sampled to estimate both parameters. We accurately estimated the day of virus introduction in isolation with weekly and 2-weekly sampling. A strong sampling effort would be required to infer both the day of virus introduction and R0. Such a sampling effort would not be required to estimate the day of virus introduction alone once R0 was known, and sampling N sample = 50 of birds in the flock on a weekly or 2 weekly basis would be sufficient.

Rational approach to solvent system selection for liquid-liquid extraction-assisted sample pretreatment in counter-current chromatography.

PubMed

Wang, Jiajia; Gu, Dongyu; Wang, Miao; Guo, Xinfeng; Li, Haoquan; Dong, Yue; Guo, Hong; Wang, Yi; Fan, Mengqi; Yang, Yi

2017-05-15

A rational liquid-liquid extraction approach was established to pre-treat samples for high-speed counter-current chromatography (HSCCC). n-Hexane-ethyl acetate-methanol-water (4:5:4:5, v/v) and (1:5:1:5, v/v) were selected as solvent systems for liquid-liquid extraction by systematically screening K of target compounds to remove low- and high-polarity impurities in the sample, respectively. After liquid-liquid extraction was performed, 1.4g of crude sample II was obtained from 18.5g of crude sample I which was extracted from the flowers of Robinia pseudoacacia L., and then separated with HSCCC by using a solvent system composed of n-hexane-ethyl acetate-methanol-water (1:2:1:2, v/v). As a result, 31mg of robinin and 37mg of kaempferol 7-O-α-l-rhamnopyranoside were isolated from 200mg of crude sample II in a single run of HSCCC. A scale-up separation was also performed, and 160mg of robinin with 95% purity and 188mg of kaempferol 7-O-α-l-rhamnopyranoside with 97% purity were produced from 1.2g of crude sample II. Copyright © 2017 Elsevier B.V. All rights reserved.

Liquid sampling system

DOEpatents

Larson, L.L.

1984-09-17

A conduit extends from a reservoir through a sampling station and back to the reservoir in a closed loop. A jet ejector in the conduit establishes suction for withdrawing liquid from the reservoir. The conduit has a self-healing septum therein upstream of the jet ejector for receiving one end of a double-ended cannula, the other end of which is received in a serum bottle for sample collection. Gas is introduced into the conduit at a gas bleed between the sample collection bottle and the reservoir. The jet ejector evacuates gas from the conduit and the bottle and aspirates a column of liquid from the reservoir at a high rate. When the withdrawn liquid reaches the jet ejector the rate of flow therethrough reduces substantially and the gas bleed increases the pressure in the conduit for driving liquid into the sample bottle, the gas bleed forming a column of gas behind the withdrawn liquid column and interrupting the withdrawal of liquid from the reservoir. In the case of hazardous and toxic liquids, the sample bottle and the jet ejector may be isolated from the reservoir and may be further isolated from a control station containing remote manipulation means for the sample bottle and control valves for the jet ejector and gas bleed. 5 figs.

Liquid sampling system

DOEpatents

Larson, Loren L.

1987-01-01

A conduit extends from a reservoir through a sampling station and back to the reservoir in a closed loop. A jet ejector in the conduit establishes suction for withdrawing liquid from the reservoir. The conduit has a self-healing septum therein upstream of the jet ejector for receiving one end of a double-ended cannula, the other end of which is received in a serum bottle for sample collection. Gas is introduced into the conduit at a gas bleed between the sample collection bottle and the reservoir. The jet ejector evacuates gas from the conduit and the bottle and aspirates a column of liquid from the reservoir at a high rate. When the withdrawn liquid reaches the jet ejector the rate of flow therethrough reduces substantially and the gas bleed increases the pressure in the conduit for driving liquid into the sample bottle, the gas bleed forming a column of gas behind the withdrawn liquid column and interrupting the withdrawal of liquid from the reservoir. In the case of hazardous and toxic liquids, the sample bottle and the jet ejector may be isolated from the reservoir and may be further isolated from a control station containing remote manipulation means for the sample bottle and control valves for the jet ejector and gas bleed.

Particle-vortex symmetric liquid

NASA Astrophysics Data System (ADS)

Mulligan, Michael

2017-01-01

We introduce an effective theory with manifest particle-vortex symmetry for disordered thin films undergoing a magnetic field-tuned superconductor-insulator transition. The theory may enable one to access both the critical properties of the strong-disorder limit, which has recently been confirmed by Breznay et al. [Proc. Natl. Acad. Sci. USA 113, 280 (2016), 10.1073/pnas.1522435113] to exhibit particle-vortex symmetric electrical response, and the nearby metallic phase discovered earlier by Mason and Kapitulnik [Phys. Rev. Lett. 82, 5341 (1999), 10.1103/PhysRevLett.82.5341] in less disordered samples. Within the effective theory, the Cooper-pair and field-induced vortex degrees of freedom are simultaneously incorporated into an electrically neutral Dirac fermion minimally coupled to a (emergent) Chern-Simons gauge field. A derivation of the theory follows upon mapping the superconductor-insulator transition to the integer quantum Hall plateau transition and the subsequent use of Son's particle-hole symmetric composite Fermi liquid. Remarkably, particle-vortex symmetric response does not require the introduction of disorder; rather, it results when the Dirac fermions exhibit vanishing Hall effect. The theory predicts approximately equal (diagonal) thermopower and Nernst signal with a deviation parameterized by the measured electrical Hall response at the symmetric point.

A microfluidic platform with integrated arrays for immunologic assays for biological pathogen detection

NASA Astrophysics Data System (ADS)

Klemm, Richard; Becker, Holger; Hlawatsch, Nadine; Julich, Sandra; Miethe, Peter; Moche, Christian; Schattschneider, Sebastian; Tomaso, Herbert; Gärtner, Claudia

2014-05-01

The ability to integrate complete assays on a microfluidic chip helps to greatly simplify instrument requirements and allows the use of lab-on-a-chip technology in the field. A core application for such field-portable systems is the detection of pathogens in a CBRN scenario such as permanent monitoring of airborne pathogens, e.g. in subway stations or hospitals etc. An immunological assay was chosen as method for the pathogen identification. The conceptual approach was its realization as a lab-on-a-chip system, enabling an easy handling of the sample in an automated manner. The immunological detection takes place on an antibody array directly implemented in the microfluidic network. Different immobilization strategies will be presented showing the performance of the system. Central elements of the disposable microfluidic device like fluidic interface, turning valves, liquid introduction and waste storage, as well as the architecture of measurement and control fluidic network, will be introduced. Overall process times of about 30 minutes were achieved and assays for the detection of Francisella tularensis and Yersinia pestis are presented. An important feature of the integrated lab-on-a-chip approach is that all waste liquids remain on-chip and contamination risks can be avoided.

Ionic Liquid Dispersive Liquid-Liquid Microextraction Method for the Determination of Irinotecan, an Anticancer Drug, in Water and Urine Samples Using UV-Vis Spectrophotometry.

PubMed

Uysal, Deniz; Karadaş, Cennet; Kara, Derya

2017-05-01

A new, simple, efficient, and environmentally friendly ionic liquid dispersive liquid-liquid microextraction method was developed for the determination of irinotecan, an anticancer drug, in water and urine samples using UV-Vis spectrophotometry. The ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate was used as the extraction solvent, and ethanol was used as the disperser solvent. The main parameters affecting the extraction efficiency, including sample pH, volume of the ionic liquid, choice of the dispersive solvent and its volume, concentration of NaCl, and extraction and centrifugation times, were investigated and optimized. The effect of interfering species on the recovery of irinotecan was also examined. Under optimal conditions, the LOD (3σ) was 48.7 μg/L without any preconcentration. Because the urine sample was diluted 10-fold, the LOD for urine would be 487 μg/L. However, this could be improved 16-fold if preconcentration using a 40 mL aliquot of the sample is used. The proposed method was successfully applied to the determination of irinotecan in tap water, river water, and urine samples spiked with 10.20 mg/L for the water samples and 8.32 mg/L for the urine sample. The average recovery values of irinotecan determined were 99.1% for tap water, 109.4% for river water, and 96.1% for urine.

Effects of dry brining, liquid smoking and high-pressure treatment on the physical properties of aquacultured King salmon (Oncorhynchus tshawytscha) during refrigerated storage.

PubMed

Kong, Kelvin Jia Wey; Alçiçek, Zayde; Balaban, Murat O

2015-03-15

Aquacultured King salmon (Oncorhynchus tshawytscha) pieces were dry brined with a salt/brown sugar mix, dipped in liquid smoke for 3 min, vacuum packed, high hydrostatic pressure (HHP) treated at 600 or 200 MPa for 5 min and stored at 4 °C for up to 40 days. The surface redness (average a*) of the samples increased after dry brining, then decreased after liquid smoke treatment. HHP did not change the outside color of liquid-smoked samples. However, the inside color changed depending on pressure. HHP-treated control samples without dry brining and liquid smoking changed to a pale pink color. HHP at 600 MPa resulted in a significant increase in hardness. Compared with fresh samples, dry-brined samples had reduced water activity, while samples dipped in liquid smoke had lower pH values. Dry brining and liquid smoking protect the outside color of salmon against changes caused by HHP. The increase in hardness may counteract the softening of the smoked salmon tissue over time. © 2014 Society of Chemical Industry.

Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy.

PubMed

Hermannsdörfer, Justus; de Jonge, Niels

2017-02-05

Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a microfluidic chamber assembled in the specimen holder for Transmission Electron Microscopy (TEM) and STEM. The microfluidic system consists of two silicon microchips supporting thin Silicon Nitride (SiN) membrane windows. This article describes the basic steps of sample loading and data acquisition. Most important of all is to ensure that the liquid compartment is correctly assembled, thus providing a thin liquid layer and a vacuum seal. This protocol also includes a number of tests necessary to perform during sample loading in order to ensure correct assembly. Once the sample is loaded in the electron microscope, the liquid thickness needs to be measured. Incorrect assembly may result in a too-thick liquid, while a too-thin liquid may indicate the absence of liquid, such as when a bubble is formed. Finally, the protocol explains how images are taken and how dynamic processes can be studied. A sample containing AuNPs is imaged both in pure water and in saline.

Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy

PubMed Central

Hermannsdörfer, Justus; de Jonge, Niels

2017-01-01

Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a microfluidic chamber assembled in the specimen holder for Transmission Electron Microscopy (TEM) and STEM. The microfluidic system consists of two silicon microchips supporting thin Silicon Nitride (SiN) membrane windows. This article describes the basic steps of sample loading and data acquisition. Most important of all is to ensure that the liquid compartment is correctly assembled, thus providing a thin liquid layer and a vacuum seal. This protocol also includes a number of tests necessary to perform during sample loading in order to ensure correct assembly. Once the sample is loaded in the electron microscope, the liquid thickness needs to be measured. Incorrect assembly may result in a too-thick liquid, while a too-thin liquid may indicate the absence of liquid, such as when a bubble is formed. Finally, the protocol explains how images are taken and how dynamic processes can be studied. A sample containing AuNPs is imaged both in pure water and in saline. PMID:28190028

A simple and selective method for determination of phthalate biomarkers in vegetable samples by high pressure liquid chromatography-electrospray ionization-tandem mass spectrometry.

PubMed

Zhou, Xi; Cui, Kunyan; Zeng, Feng; Li, Shoucong; Zeng, Zunxiang

2016-06-01

In the present study, solid-phase extraction cartridges including silica reversed-phase Isolute C18, polymeric reversed-phase Oasis HLB and mixed-mode anion-exchange Oasis MAX, and liquid-liquid extractions with ethyl acetate, n-hexane, dichloromethane and its mixtures were compared for clean-up of phthalate monoesters from vegetable samples. Best recoveries and minimised matrix effects were achieved using ethyl acetate/n-hexane liquid-liquid extraction for these target compounds. A simple and selective method, based on sample preparation by ultrasonic extraction and liquid-liquid extraction clean-up, for the determination of phthalate monoesters in vegetable samples by liquid chromatography/electrospray ionisation-tandem mass spectrometry was developed. The method detection limits for phthalate monoesters ranged from 0.013 to 0.120 ng g(-1). Good linearity (r(2)>0.991) between MQLs and 1000× MQLs was achieved. The intra- and inter-day relative standard deviation values were less than 11.8%. The method was successfully used to determine phthalate monoester metabolites in the vegetable samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Determination of triazine herbicides in juice samples by microwave-assisted ionic liquid/ionic liquid dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography.

PubMed

Su, Rui; Li, Dan; Wu, Lijie; Han, Jing; Lian, Wenhui; Wang, Keren; Yang, Hongmei

2017-07-01

A novel microextraction method, termed microwave-assisted ionic liquid/ionic liquid dispersive liquid-liquid microextraction, has been developed for the rapid enrichment and analysis of triazine herbicides in fruit juice samples by high-performance liquid chromatography. Instead of using hazardous organic solvents, two kinds of ionic liquids, a hydrophobic ionic liquid (1-hexyl-3-methylimidazolium hexafluorophosphate) and a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate), were used as the extraction solvent and dispersion agent, respectively, in this method. The extraction procedure was induced by the formation of cloudy solution, which was composed of fine drops of 1-hexyl-3-methylimidazolium hexafluorophosphate dispersed entirely into sample solution with the help of 1-butyl-3-methylimidazolium tetrafluoroborate. In addition, an ion-pairing agent (NH 4 PF 6 ) was introduced to improve recoveries of the ionic liquid phase. Several experimental parameters that might affect the extraction efficiency were investigated. Under the optimum experimental conditions, the linearity for determining the analytes was in the range of 5.00-250.00 μg/L, with the correlation coefficients of 0.9982-0.9997. The practical application of this effective and green method is demonstrated by the successful analysis of triazine herbicides in four juice samples, with satisfactory recoveries (76.7-105.7%) and relative standard deviations (lower than 6.6%). In general, this method is fast, effective, and robust to determine triazine herbicides in juice samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of safe, green and high performance ionic liquids-based batteries (ILLIBATT project)

NASA Astrophysics Data System (ADS)

Balducci, A.; Jeong, S. S.; Kim, G. T.; Passerini, S.; Winter, M.; Schmuck, M.; Appetecchi, G. B.; Marcilla, R.; Mecerreyes, D.; Barsukov, V.; Khomenko, V.; Cantero, I.; De Meatza, I.; Holzapfel, M.; Tran, N.

This manuscript presents the work carried out within the European project ILLIBATT, which was dedicated to the development of green, safe and high performance ionic liquids-based lithium batteries. Different types of ionic liquids-based electrolytes were developed in the project, based on different ionic liquids and polymers. Using these electrolytes, the performance of several anodic and cathodic materials has been tested and promising results have been obtained. Also, electrodes were formulated using water soluble binders. Using these innovative components, lithium-ion and lithium-metal battery prototypes (0.7-0.8 Ah) have been assembled and cycled between 100% and 0% SOC. The results of these tests showed that such ionic liquids-based prototypes are able to display high capacity, high coulombic efficiency and high cycle life. Moreover, safety tests showed that the introduction of these alternative electrolytes positively contribute to the safety of the batteries.

Effect of Genetic Database Comprehensiveness on Fractional Proteomics of Escherichia coli O157:H7

DTIC Science & Technology

2014-01-01

proteins would be observed in the extracellular fraction. 15. SUBJECT TERMS Escherichia coli O157:H7 Liquid chromatography Mass spectrometry...Preparation ...............1 2.2 Liquid Chromatography /Mass Spectrometry Sample Preparation ....................2 2.3 Liquid Chromatography /Mass... Chromatography /Mass Spectrometry Sample Preparation. Samples were prepared for liquid chromatography tandem mass spectrometry (LC-MS/MS) in a similar

Possible overestimation of surface disinfection efficiency by assessment methods based on liquid sampling procedures as demonstrated by in situ quantification of spore viability.

PubMed

Grand, I; Bellon-Fontaine, M-N; Herry, J-M; Hilaire, D; Moriconi, F-X; Naïtali, M

2011-09-01

The standard test methods used to assess the efficiency of a disinfectant applied to surfaces are often based on counting the microbial survivors sampled in a liquid, but total cell removal from surfaces is seldom achieved. One might therefore wonder whether evaluations of microbial survivors in liquid-sampled cells are representative of the levels of survivors in whole populations. The present study was thus designed to determine the "damaged/undamaged" status induced by a peracetic acid disinfection for Bacillus atrophaeus spores deposited on glass coupons directly on this substrate and to compare it to the status of spores collected in liquid by a sampling procedure. The method utilized to assess the viability of both surface-associated and liquid-sampled spores included fluorescence labeling with a combination of Syto 61 and Chemchrome V6 dyes and quantifications by analyzing the images acquired by confocal laser scanning microscopy. The principal result of the study was that the viability of spores sampled in the liquid was found to be poorer than that of surface-associated spores. For example, after 2 min of peracetic acid disinfection, less than 17% ± 5% of viable cells were detected among liquid-sampled cells compared to 79% ± 5% or 47% ± 4%, respectively, when the viability was evaluated on the surface after or without the sampling procedure. Moreover, assessments of the survivors collected in the liquid phase, evaluated using the microscopic method and standard plate counts, were well correlated. Evaluations based on the determination of survivors among the liquid-sampled cells can thus overestimate the efficiency of surface disinfection procedures.

Possible Overestimation of Surface Disinfection Efficiency by Assessment Methods Based on Liquid Sampling Procedures as Demonstrated by In Situ Quantification of Spore Viability ▿

PubMed Central

Grand, I.; Bellon-Fontaine, M.-N.; Herry, J.-M.; Hilaire, D.; Moriconi, F.-X.; Naïtali, M.

2011-01-01

The standard test methods used to assess the efficiency of a disinfectant applied to surfaces are often based on counting the microbial survivors sampled in a liquid, but total cell removal from surfaces is seldom achieved. One might therefore wonder whether evaluations of microbial survivors in liquid-sampled cells are representative of the levels of survivors in whole populations. The present study was thus designed to determine the “damaged/undamaged” status induced by a peracetic acid disinfection for Bacillus atrophaeus spores deposited on glass coupons directly on this substrate and to compare it to the status of spores collected in liquid by a sampling procedure. The method utilized to assess the viability of both surface-associated and liquid-sampled spores included fluorescence labeling with a combination of Syto 61 and Chemchrome V6 dyes and quantifications by analyzing the images acquired by confocal laser scanning microscopy. The principal result of the study was that the viability of spores sampled in the liquid was found to be poorer than that of surface-associated spores. For example, after 2 min of peracetic acid disinfection, less than 17% ± 5% of viable cells were detected among liquid-sampled cells compared to 79% ± 5% or 47% ± 4%, respectively, when the viability was evaluated on the surface after or without the sampling procedure. Moreover, assessments of the survivors collected in the liquid phase, evaluated using the microscopic method and standard plate counts, were well correlated. Evaluations based on the determination of survivors among the liquid-sampled cells can thus overestimate the efficiency of surface disinfection procedures. PMID:21742922

Advances in the analysis of biological samples using ionic liquids.

PubMed

Clark, Kevin D; Trujillo-Rodríguez, María J; Anderson, Jared L

2018-02-12

Ionic liquids are a class of solvents and materials that hold great promise in bioanalytical chemistry. Task-specific ionic liquids have recently been designed for the selective extraction, separation, and detection of proteins, peptides, nucleic acids, and other physiologically relevant analytes from complex biological samples. To facilitate rapid bioanalysis, ionic liquids have been integrated in miniaturized and automated procedures. Bioanalytical separations have also benefited from the modification of nonspecific magnetic materials with ionic liquids or the implementation of ionic liquids with inherent magnetic properties. Furthermore, the direct detection of the extracted molecules in the analytical instrument has been demonstrated with structurally tuned ionic liquids and magnetic ionic liquids, providing a significant advantage in the analysis of low-abundance analytes. This article gives an overview of these advances that involve the application of ionic liquids and derivatives in bioanalysis. Graphical abstract Ionic liquids, magnetic ionic liquids, and ionic liquid-based sorbents are increasing the speed, selectivity, and sensitivity in the analysis of biological samples.

Validation of the ANSR(®) Listeria monocytogenes Method for Detection of Listeria monocytogenes in Selected Food and Environmental Samples.

PubMed

Caballero, Oscar; Alles, Susan; Le, Quynh-Nhi; Gray, R Lucas; Hosking, Edan; Pinkava, Lisa; Norton, Paul; Tolan, Jerry; Mozola, Mark; Rice, Jennifer; Chen, Yi; Ryser, Elliot; Odumeru, Joseph

2016-01-01

Work was conducted to validate performance of the ANSR(®) for Listeria monocytogenes method in selected food and environmental matrixes. This DNA-based assay involves amplification of nucleic acid via an isothermal reaction based on nicking enzyme amplification technology. Following single-step sample enrichment for 16-24 h for most matrixes, the assay is completed in 40 min using only simple instrumentation. When 50 distinct strains of L. monocytogenes were tested for inclusivity, 48 produced positive results, the exceptions being two strains confirmed by PCR to lack the assay target gene. Forty-seven nontarget strains (30 species), including multiple non-monocytogenes Listeria species as well as non-Listeria, Gram-positive bacteria, were tested, and all generated negative ANSR assay results. Performance of the ANSR method was compared with that of the U.S. Department of Agriculture, Food Safety and Inspection Service Microbiology Laboratory Guidebook reference culture procedure for detection of L. monocytogenes in hot dogs, pasteurized liquid egg, and sponge samples taken from an inoculated stainless steel surface. In addition, ANSR performance was measured against the U.S. Food and Drug Administration Bacteriological Analytical Manual reference method for detection of L. monocytogenes in Mexican-style cheese, cantaloupe, sprout irrigation water, and guacamole. With the single exception of pasteurized liquid egg at 16 h, ANSR method performance as quantified by the number of positives obtained was not statistically different from that of the reference methods. Robustness trials demonstrated that deliberate introduction of small deviations to the normal assay parameters did not affect ANSR method performance. Results of accelerated stability testing conducted using two manufactured lots of reagents predicts stability at the specified storage temperature of 4°C of more than 1 year.

Understanding Pressure: Didactical Transpositions and Pupils' Conceptions.

ERIC Educational Resources Information Center

Kariotogloy, Petros; And Others

1990-01-01

Described are features of a theoretical model for fluid pressure. Analyzes six introductory physics textbooks based on an introduction and meaning of the pressure concept; characteristics of pressure; and liquid as a pressure transmitter. Presents three models of pupils' conceptions. (YP)

Studies in Ambient Temperature Ionic Liquids.

DTIC Science & Technology

1987-06-30

by chronoamperometry, chronocoulometrV, linear sweep voltammetry and mediated oxidation of [Fe(2,2’-bipVridine) 5) 2 . Charge transport follows...September 2, 1983. OR. A. Osteryoung, "Introduction to Pulse Voltametry ", Tutorial Session on Electrochemistry, Division of Inorganic Chemistry

Semi-automated 96-well liquid-liquid extraction for quantitation of drugs in biological fluids.

PubMed

Zhang, N; Hoffman, K L; Li, W; Rossi, D T

2000-02-01

A semi-automated liquid-liquid extraction (LLE) technique for biological fluid sample preparation was introduced for the quantitation of four drugs in rat plasma. All liquid transferring during the sample preparation was automated using a Tomtec Quadra 96 Model 320 liquid handling robot, which processed up to 96 samples in parallel. The samples were either in 96-deep-well plate or tube-rack format. One plate of samples can be prepared in approximately 1.5 h, and the 96-well plate is directly compatible with the autosampler of an LC/MS system. Selection of organic solvents and recoveries are discussed. Also, precision, relative error, linearity and quantitation of the semi automated LLE method are estimated for four example drugs using LC/MS/MS with a multiple reaction monitoring (MRM) approach. The applicability of this method and future directions are evaluated.

Impact of hydration state and molecular oxygen on the chemical stability of levothyroxine sodium.

PubMed

Hamad, Mazen Lee; Engen, William; Morris, Kenneth R

2015-05-01

Levothyroxine sodium is an important medication used primarily for treating patients with hypothyroidism. Levothyroxine sodium tablets have been recalled many times since their 1955 introduction to the US market. These recalls resulted from the failure of lots to meet their content uniformity and potency specifications. The purpose of this study is to test the hypothesis that the chemical stability of levothyroxine sodium pentahydrate is compromised upon exposing the dehydrated substance to molecular oxygen. The impact of temperature, oxygen and humidity storage conditions on the stability of solid-state levothyroxine sodium was examined. After exposure to these storage conditions for selected periods of time, high performance liquid chromatography (HPLC) was used to quantify the formation of impurities. The results showed that levothyroxine sodium samples degraded significantly over a 32-day test period when subjected to dry conditions in the presence of molecular oxygen. However, dehydrated samples remained stable when oxygen was removed from the storage chamber. Furthermore, hydrated samples were stable in the presence of oxygen and in the absence of oxygen. These results reveal conditions that will degrade levothyroxine sodium pentahydrate and elucidate measures that can be taken to stabilize the drug substance.

Ion Clouds in the Inductively Coupled Plasma Torch: A Closer Look through Computations.

PubMed

Aghaei, Maryam; Lindner, Helmut; Bogaerts, Annemie

2016-08-16

We have computationally investigated the introduction of copper elemental particles in an inductively coupled plasma torch connected to a sampling cone, including for the first time the ionization of the sample. The sample is inserted as liquid particles, which are followed inside the entire torch, i.e., from the injector inlet up to the ionization and reaching the sampler. The spatial position of the ion clouds inside the torch as well as detailed information on the copper species fluxes at the position of the sampler orifice and the exhausts of the torch are provided. The effect of on- and off-axis injection is studied. We clearly show that the ion clouds of on-axis injected material are located closer to the sampler with less radial diffusion. This guarantees a higher transport efficiency through the sampler cone. Moreover, our model reveals the optimum ranges of applied power and flow rates, which ensure the proper position of ion clouds inside the torch, i.e., close enough to the sampler to increase the fraction that can enter the mass spectrometer and with minimum loss of material toward the exhausts as well as a sufficiently high plasma temperature for efficient ionization.

Liquid microjunction surface sampling coupled with high-pressure liquid chromatography-electrospray ionization-mass spectrometry for analysis of drugs and metabolites in whole-body thin tissue sections.

PubMed

Kertesz, Vilmos; Van Berkel, Gary J

2010-07-15

In this work, a commercially available autosampler was adapted to perform direct liquid microjunction (LMJ) surface sampling followed by a high-pressure liquid chromatography (HPLC) separation of the extract components and detection with electrospray ionization mass spectrometry (ESI-MS). To illustrate the utility of coupling a separation with this direct liquid extraction based surface sampling approach, four different organs (brain, lung, kidney, and liver) from whole-body thin tissue sections of propranolol dosed and control mice were examined. The parent drug was observed in the chromatograms of the surface sampling extracts from all the organs of the dosed mouse examined. In addition, two isomeric phase II metabolites of propranolol (an aliphatic and an aromatic hydroxypropranolol glucuronide) were observed in the chromatograms of the extracts from lung, kidney, and liver. Confirming the presence of one or the other or both of these glucuronides in the extract from the various organs was not possible without the separation. These drug and metabolite data obtained using the LMJ surface sampling/HPLC-MS method and the results achieved by analyzing similar samples by conventional extraction of the tissues and subsequent HPLC-MS analysis were consistent. The ability to directly and efficiently sample from thin tissue sections via a liquid extraction and then perform a subsequent liquid phase separation increases the utility of this liquid extraction surface sampling approach.

Clinical evaluation of human papillomavirus detection by careHPV™ test on physician-samples and self-samples using the indicating FTA Elute® card.

PubMed

Wang, Shao-Ming; Hu, Shang-Ying; Chen, Feng; Chen, Wen; Zhao, Fang-Hui; Zhang, Yu-Qing; Ma, Xin-Ming; Qiao, You-Lin

2014-01-01

To make the clinical evaluation of a solid-state human papillomavirus (HPV) sampling medium in combination with an economical HPV testing method (careHPV™) for cervical cancer screening. 396 women aged 25-65 years were enrolled for cervical cancer screening, and four samples were collected. Two samples were collected by woman themselves, among which one was stored in DCM preservative solution (called "liquid sample") and the other was applied on the Whatman Indicating FTA Elute® card (FTA card). Another two samples were collected by physician and stored in DCM preservative solution and FTA card, respectively. All the samples were detected by careHPV™ test. All the women were administered a colposcopy examination, and biopsies were taken for pathological confirmation if necessary. FTA card demonstrated a comparable sensitivity of detecting high grade Cervical Intraepithelial Neoplasia (CIN) with the liquid sample carrier for self and physician-sampling, but showed a higher specificity than that of liquid sample carrier for self-sampling (FTA vs Liquid: 79.0% vs 71.6%, p=0.02). Generally, the FTA card had a comparable accuracy with that of Liquid-based medium by different sampling operators, with an area under the curve of 0.807 for physician and FTA, 0.781 for physician and Liquid, 0.728 for self and FTA, and 0.733 for self and Liquid (p>0.05). FTA card is a promising sample carrier for cervical cancer screening. With appropriate education programmes and further optimization of the experimental workflow, FTA card based self-collection in combination with centralized careHPV™ testing can help expand the coverage of cervical cancer screening in low-resource areas.

Ionic liquid-based air-assisted liquid-liquid microextraction followed by high performance liquid chromatography for the determination of five fungicides in juice samples.

PubMed

You, Xiangwei; Chen, Xiaochu; Liu, Fengmao; Hou, Fan; Li, Yiqiang

2018-01-15

A novel and simple ionic liquid-based air-assisted liquid-liquid microextraction technique combined with high performance liquid chromatography was developed to analyze five fungicides in juice samples. In this method, ionic liquid was used instead of a volatile organic solvent as the extraction solvent. The emulsion was formed by pulling in and pushing out the mixture of aqueous sample solution and extraction solvent repeatedly using a 10mL glass syringe. No organic dispersive solvent was required. Under the optimized conditions, the limits of detection (LODs) were 0.4-1.8μgL -1 at a signal-to-noise ratio of 3. The limits of quantification (LOQs) set as the lowest spiking levels with acceptable recovery in juices were 10μgL -1 , except for fludioxonil whose LOQ was 20μgL -1 . The proposed method was applied to determine the target fungicides in juice samples, and acceptable recoveries ranging from 74.9% to 115.4% were achieved. Copyright © 2017. Published by Elsevier Ltd.

Some new features of Direct Analysis in Real Time mass spectrometry utilizing the desorption at an angle option.

PubMed

Chernetsova, Elena S; Revelsky, Alexander I; Morlock, Gertrud E

2011-08-30

The present study is a first step towards the unexplored capabilities of Direct Analysis in Real Time (DART) mass spectrometry (MS) arising from the possibility of the desorption at an angle: scanning analysis of surfaces, including the coupling of thin-layer chromatography (TLC) with DART-MS, and a more sensitive analysis due to the preliminary concentration of analytes dissolved in large volumes of liquids on glass surfaces. In order to select the most favorable conditions for DART-MS analysis, proper positioning of samples is important. Therefore, a simple and cheap technique for the visualization of the impact region of the DART gas stream onto a substrate was developed. A filter paper or TLC plate, previously loaded with the analyte, was immersed in a derivatization solution. On this substrate, owing to the impact of the hot DART gas, reaction of the analyte to a colored product occurred. An improved capability of detection of DART-MS for the analysis of liquids was demonstrated by applying large volumes of model solutions of coumaphos into small glass vessels and drying these solutions prior to DART-MS analysis under ambient conditions. This allowed the introduction of, by up to more than two orders of magnitude, increased quantities of analyte compared with the conventional DART-MS analysis of liquids. Through this improved detectability, the capabilities of DART-MS in trace analysis could be strengthened. Copyright © 2011 John Wiley & Sons, Ltd.

A fast passive and planar liquid sample micromixer.

PubMed

Melin, Jessica; Gimenéz, Guillem; Roxhed, Niclas; van der Wijngaart, Wouter; Stemme, Göran

2004-06-01

A novel microdevice for passively mixing liquid samples based on surface tension and a geometrical mixing chamber is presented. Due to the laminar flow regime on the microscale, mixing becomes difficult if not impossible. We present a micromixer where a constantly changing time dependent flow pattern inside a two sample liquid plug is created as the plug simply passes through the planar mixer chamber. The device requires no actuation during mixing and is fabricated using a single etch process. The effective mixing of two coloured liquid samples is demonstrated.

Tidal sampler

DOEpatents

Hayes, David W.

1978-01-01

An apparatus for pumping a sample of water or other liquid that uses the energy generated from the rise and fall of the liquid level to force a sample of the liquid into a collection vessel. A suction vessel and booster vessel with interconnecting tubing and check valves are responsive to an oscillating liquid level to pump a portion of said liquid into a collection vessel.

Microwave-assisted liquid-liquid microextraction based on solidification of ionic liquid for the determination of sulfonamides in environmental water samples.

PubMed

Song, Ying; Wu, Lijie; Lu, Chunmei; Li, Na; Hu, Mingzhu; Wang, Ziming

2014-12-01

An easy, quick, and green method, microwave-assisted liquid-liquid microextraction based on solidification of ionic liquid, was first developed and applied to the extraction of sulfonamides in environmental water samples. 1-Ethy-3-methylimidazolium hexafluorophosphate, which is a solid-state ionic liquid at room temperature, was used as extraction solvent in the present method. After microwave irradiation for 90 s, the solid-state ionic liquid was melted into liquid phase and used to finish the extraction of the analytes. The ionic liquid and sample matrix can be separated by freezing and centrifuging. Several experimental parameters, including amount of extraction solvent, microwave power and irradiation time, pH of sample solution, and ionic strength, were investigated and optimized. Under the optimum experimental conditions, good linearity was observed in the range of 2.00-400.00 μg/L with the correlation coefficients ranging from 0.9995 to 0.9999. The limits of detection for sulfathiazole, sulfachlorpyridazine, sulfamethoxazole, and sulfaphenazole were 0.39, 0.33, 0.62, and 0.85 μg/L, respectively. When the present method was applied to the analysis of environmental water samples, the recoveries of the analytes ranged from 75.09 to 115.78% and relative standard deviations were lower than 11.89%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yuzhan; Zhang, Yuehong; Rios, Orlando

The increasing demand for intelligent materials has driven the development of polymers with a variety of functionalities. However, combining multiple functionalities within one polymer is still challenging because of the difficulties encountered in coordinating different functional building blocks during fabrication. In this work, we demonstrate the fabrication of a multifunctional liquid crystalline epoxy network (LCEN) using the combination of thermotropic liquid crystals, photo-responsive azobenzene molecules, and exchangeable disulfide bonds. In addition to shape memory behavior enabled by the reversible liquid crystalline phase transition and photo-induced bending behavior resulting from the photo-responsive azobenzene molecules, the introduction of dynamic disulfide bonds intomore » the LCEN resulted in a structurally dynamic network, allowing the reshaping, repairing, and recycling of the material.« less

Preconcentration and determination of ceftazidime in real samples using dispersive liquid-liquid microextraction and high-performance liquid chromatography with the aid of experimental design.

PubMed

Razmi, Rasoul; Shahpari, Behrouz; Pourbasheer, Eslam; Boustanifar, Mohammad Hasan; Azari, Zhila; Ebadi, Amin

2016-11-01

A rapid and simple method for the extraction and preconcentration of ceftazidime in aqueous samples has been developed using dispersive liquid-liquid microextraction followed by high-performance liquid chromatography analysis. The extraction parameters, such as the volume of extraction solvent and disperser solvent, salt effect, sample volume, centrifuge rate, centrifuge time, extraction time, and temperature in the dispersive liquid-liquid microextraction process, were studied and optimized with the experimental design methods. Firstly, for the preliminary screening of the parameters the taguchi design was used and then, the fractional factorial design was used for significant factors optimization. At the optimum conditions, the calibration curves for ceftazidime indicated good linearity over the range of 0.001-10 μg/mL with correlation coefficients higher than the 0.98, and the limits of detection were 0.13 and 0.17 ng/mL, for water and urine samples, respectively. The proposed method successfully employed to determine ceftazidime in water and urine samples and good agreement between the experimental data and predictive values has been achieved. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highlights from BNL and RHIC 2015

NASA Astrophysics Data System (ADS)

Tannenbaum, M. J.

The following sections are included: * Introduction * News from BNL since ISSP2014 * RHIC Operations in 2015 and accelerator future plans * 10th Anniversary Celebration of the Perfect Liquid * RHIC Beam Energy Scan (BES) in search of a critical point-aided by Lattice QCD * References

Biobriefcase aerosol collector heater

DOEpatents

Bell, Perry M [Tracy, CA; Christian, Allen T [Madison, WI; Bailey, Christopher G [Pleasanton, CA; Willis, Ladona [Manteca, CA; Masquelier, Donald A [Tracy, CA; Nasarabadi, Shanavaz L [Livermore, CA

2009-03-17

A system for sampling air and collecting particles potentially including bioagents entrained in the air for detection. The system comprises collecting a sample of the air with the particles entrained in the air, directing the sample to a receiving surface, directing a liquid to the receiving surface thereby producing a liquid surface, wherein the particles potentially including bioagents become captured in the liquid, and heating the liquid wherein the particles potentially including bioagents become heated to lysis the bioagents.

Gas-liquid chromatographic and gas-liquid-mass spectometric determination of fenvalerate and permethrin residues in grasshoppers and duck tissue samples

USGS Publications Warehouse

Reichel, W.L.; Kolbe, E.J.; Stafford, C.J.

1981-01-01

A procedure is described for determining fenvalerate and permethrin residues in grasshoppers and duck tissues. Samples are Soxhlet-extracted with hexane and cleaned up by gel permeation chromatography with an in-line alumina column. Samples are analyzed by gas-liquid chromatography with electron capture detection, and confirmed by gas-liquid chromatography-mass spectrometry. The average recovery from fortified tissues was 97%.

Determination of Meteorite Porosity Using Liquid Nitrogen

NASA Technical Reports Server (NTRS)

Kohout, T.; Kletetschka, G.; Pesonen, L. J.; Wasilewski, P. J.

2005-01-01

We introduce a new harmless method for porosity measurement suitable for meteorite samples. The method is a modification of the traditional Archimedean method based on immersion of the samples in a liquid medium like water or organic liquids. In our case we used liquid nitrogen for its chemically inert characteristics.

An environmentally-friendly, highly efficient, gas pressure-assisted sample introduction system for ICP-MS and its application to detection of cadmium and lead in human plasma.

PubMed

Cao, Yupin; Deng, Biyang; Yan, Lizhen; Huang, Hongli

2017-05-15

An environmentally friendly and highly efficient gas pressure-assisted sample introduction system (GPASIS) was developed for inductively-coupled plasma mass spectrometry. A GPASIS consisting of a gas-pressure control device, a customized nebulizer, and a custom-made spray chamber was fabricated. The advantages of this GPASIS derive from its high nebulization efficiencies, small sample volume requirements, low memory effects, good precision, and zero waste emission. A GPASIS can continuously, and stably, nebulize 10% NaCl solution for more than an hour without clogging. Sensitivity, detection limits, precision, long-term stability, double charge and oxide ion levels, nebulization efficiencies, and matrix effects of the sample introduction system were evaluated. Experimental results indicated that the performance of this GPASIS, was equivalent to, or better than, those obtained by conventional sample introduction systems. This GPASIS was successfully used to determine Cd and Pb by ICP-MS in human plasma. Copyright © 2017 Elsevier B.V. All rights reserved.

Qualitative analysis of Pb liquid sample using laser-induced breakdown spectroscopy (LIBS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suyanto, Hery; Rupiasih, Ni Nyoman; Winardi, T. B.

2013-09-03

Qualitative analysis of liquid sample containing 1,000 ppm of Pb was performed by using LIBS technique. In order to avoid splashing off of the liquid sample during laser irradiation, a sample pretreatment was done, namely the liquid sample was absorbed by using commercial available stomach medicine. Two kinds of absorbent materials were chosen in this experiment, first containing 125 mg activated carbon and second 600 mg activated attapulgite. These absorbent materials were used since carbon sample gives better absorption of infrared laser irradiation used in this experiment. In order to characterize the absorption process, three treatments were conducted in thismore » experiment; first, without heating the sample but varying the absorption time before laser irradiation; second by varying the heating temperature after certain time of absorption process and third by varying the temperature only. The maximum emission intensity of Pb I 405.7 nm was found in the second treatment of heating the sample till 85°C after 30 minutes absorption of the liquid sample in both absorbent materials.« less

Surface tension determination using liquid sample micromirror property

NASA Astrophysics Data System (ADS)

Hošek, Jan

2007-05-01

This paper presents an application of adaptive optics principle onto small sample of liquid surface tension measurement. The principle of experimental method devised by Ferguson (1924) is based on measurement of pressure difference across a liquid sample placed into small diameter capillary on condition of one flat meniscus of the liquid sample. Planarity or curvature radius of the capillary tip meniscus has to be measured and controlled, in order to fulfill this condition during measurement. Two different optical set-ups using liquid meniscus micromirror property are presented and its suitability for meniscus profile determination is compared. Meniscus radius optical measurement, data processing and control algorithm of the adaptive micromirror profile set are presented too. The presented adaptive optics system can be used for focal length control of microsystems based on liquid micromirrors or microlenses with long focal distances especially.

Analysis of legal high materials by ultra-performance liquid chromatography with time of flight mass spectrometry as part of a toxicology vigilance system: what are the most popular novel psychoactive substances in the UK?

PubMed

Ford, Loretta T; Berg, Jonathan D

2017-03-01

Introduction Legal highs also known as novel psychoactive substances mimic the effects of classic drugs of abuse. Challenges to developing screening services for novel psychoactive substances include identifying which novel psychoactive substances are available to target. Using new techniques such as exact mass time of flight can help identify common novel psychoactive substances to target for screening patient samples by routine methods such as tandem mass spectrometry. We demonstrate this strategy working in our own clinical toxicology laboratory after qualitative analysis of 98 suspect materials for novel psychoactive substances by ultra-performance liquid chromatography with time of flight mass spectrometry. Results From July 2014 to July 2015 we received 98 requests to test a range of different suspect materials for novel psychoactive substances including herbs, tobacco, liquids, pills and powders. Overall, 87% of the suspect materials tested positive for novel psychoactive substances, and 15% for controlled drugs. Three common novel psychoactive substances were present in 74% of the suspect materials: methiopropamine, a methamphetamine analogue; ethylphenidate, a cocaine mimic; and the third generation synthetic cannabinoid 5F-AKB-48. For the 55 branded products we tested only 24% of the stated contents matched exactly the compounds we detected. Conclusion Testing suspect materials using ultra-performance liquid chromatography with time of flight mass spectrometry has identified three common novel psychoactive substances in use in the UK, simplifying the development of a relevant novel psychoactive substances screening service to our population. By incorporating this into our routine liquid chromatography tandem mass spectrometry drugs of abuse screen, then offers a clinically relevant novel psychoactive substances service to our users. This strategy ensures our clinical toxicology service continues to remain effective to meet the challenges of the changing drug use in the UK.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lorenz, Matthias; Ovchinnikova, Olga S; Van Berkel, Gary J

RATIONALE: Laser ablation provides for the possibility of sampling a large variety of surfaces with high spatial resolution. This type of sampling when employed in conjunction with liquid capture followed by nanoelectrospray ionization provides the opportunity for sensitive and prolonged interrogation of samples by mass spectrometry as well as the ability to analyze surfaces not amenable to direct liquid extraction. METHODS: A fully automated, reflection geometry, laser ablation liquid capture spot sampling system was achieved by incorporating appropriate laser fiber optics and a focusing lens into a commercially available, liquid extraction surface analysis (LESA ) ready Advion TriVersa NanoMate system.more » RESULTS: Under optimized conditions about 10% of laser ablated material could be captured in a droplet positioned vertically over the ablation region using the NanoMate robot controlled pipette. The sampling spot size area with this laser ablation liquid capture surface analysis (LA/LCSA) mode of operation (typically about 120 m x 160 m) was approximately 50 times smaller than that achievable by direct liquid extraction using LESA (ca. 1 mm diameter liquid extraction spot). The set-up was successfully applied for the analysis of ink on glass and paper as well as the endogenous components in Alstroemeria Yellow King flower petals. In a second mode of operation with a comparable sampling spot size, termed laser ablation/LESA , the laser system was used to drill through, penetrate, or otherwise expose material beneath a solvent resistant surface. Once drilled, LESA was effective in sampling soluble material exposed at that location on the surface. CONCLUSIONS: Incorporating the capability for different laser ablation liquid capture spot sampling modes of operation into a LESA ready Advion TriVersa NanoMate enhanced the spot sampling spatial resolution of this device and broadened the surface types amenable to analysis to include absorbent and solvent resistant materials.« less

Well-posed Euler model of shock-induced two-phase flow in bubbly liquid

NASA Astrophysics Data System (ADS)

Tukhvatullina, R. R.; Frolov, S. M.

2018-03-01

A well-posed mathematical model of non-isothermal two-phase two-velocity flow of bubbly liquid is proposed. The model is based on the two-phase Euler equations with the introduction of an additional pressure at the gas bubble surface, which ensures the well-posedness of the Cauchy problem for a system of governing equations with homogeneous initial conditions, and the Rayleigh-Plesset equation for radial pulsations of gas bubbles. The applicability conditions of the model are formulated. The model is validated by comparing one-dimensional calculations of shock wave propagation in liquids with gas bubbles with a gas volume fraction of 0.005-0.3 with experimental data. The model is shown to provide satisfactory results for the shock propagation velocity, pressure profiles, and the shock-induced motion of the bubbly liquid column.

Determination of chlorophenols in honey samples using in-situ ionic liquid-dispersive liquid-liquid microextraction as a pretreatment method followed by high-performance liquid chromatography.

PubMed

Fan, Chen; Li, Nai; Cao, Xueli

2015-05-01

In-situ ionic liquid-dispersive liquid-liquid microextraction (IL-DLLME) method was developed as a pretreatment method for the detection of six chlorophenols (CPs) in honey samples. The hydrophobic ionic liquid [C4MIM][NTf2], formed in-situ by the hydrophilic ionic liquid [C4MIM][BF4] and the ion exchange reagent LiNTf2 was used as the microextractant solvent of CPs from honey sample. Then the enriched analytes were back-extracted into 40 μL of 0.14 M NaOH solution and finally subjected to analysis by high-performance liquid chromatography. The method showed low limit of detection of CPs, 0.8-3.2 μg/L and high enrichment factor, 34-65 with the recoveries range from 91.60% to 114.33%. The method is simple, rapid, environmentally friendly and with high extraction efficiency. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

A Technique for Thermal Desorption Analyses Suitable for Thermally-Labile, Volatile Compounds.

PubMed

Alborn, Hans T

2018-02-01

Many plant and insect interactions are governed by odors released by the plants or insects and there exists a continual need for new or improved methods to collect and identify these odors. Our group has for some time studied below-ground, plant-produced volatile signals affecting nematode and insect behavior. The research requires repeated sampling of volatiles of intact plant/soil systems in the laboratory as well as the field with the help of probes to minimize unwanted effects on the systems we are studying. After evaluating solid adsorbent filters with solvent extraction or solid phase micro extraction fiber sample collection, we found dynamic sampling of small air volumes on Tenax TA filters followed by thermal desorption sample introduction to be the most suitable analytical technique for our applications. Here we present the development and evaluation of a low-cost and relatively simple thermal desorption technique where a cold trap cooled with liquid carbon dioxide is added as an integral part of a splitless injector. Temperature gradient-based focusing and low thermal mass minimizes aerosol formation and eliminates the need for flash heating, resulting in low sample degradation comparable to solvent-based on-column injections. Additionally, since the presence of the cold trap does not affect normal splitless injections, on-the-fly switching between splitless and thermal desorption modes can be used for external standard quantification.

2.45 GHz Microwave Processing and Its Influence on Glass Fiber Reinforced Plastics.

PubMed

Teufl, Daniel; Zaremba, Swen

2018-05-18

During the production of fiber-reinforced composite materials, liquid resin is introduced into the fiber material and cured, i.e., hardened. An elevated temperature is needed for this curing. Microwave curing of composites has been investigated for some time, but it has mostly been done using small domestic or laboratory equipment. However, no investigation has been carried out using an industrial-sized chamber-microwave for glass fiber-reinforced plastic (GFRP). Here, we show that microwave curing produces laminates of the same quality as oven-cured ones. The study shows that, if the process is done right, GFRP samples can be produced with an industrial scale microwave. Even if not fully cured, microwave samples show a glass transition temperature measured with DMA ( T g-DMA ) that is comparable to the T g-DMA according to the proposed cure cycle on the data sheet. Specific microwave-cured configurations show better inter-laminar shear strength than oven specimens. The results show that microwave-based heat introduction can be a beneficial curing method for GFRP laminates. A microwave-optimized process is faster and leads to better mechanical properties.

Validation of caffeine dehydrogenase from Pseudomonas sp. strain CBB1 as a suitable enzyme for a rapid caffeine detection and potential diagnostic test.

PubMed

Mohanty, Sujit K; Yu, Chi Li; Gopishetty, Sridhar; Subramanian, Mani

2014-08-06

Excess consumption of caffeine (>400 mg/day/adult) can lead to adverse health effects. Recent introduction of caffeinated products (gums, jelly beans, energy drinks) might lead to excessive consumption, especially among children and nursing mothers, hence attracting the Food and Drug Administration's attention and product withdrawals. An "in-home" test will aid vigilant consumers in detecting caffeine in beverages and milk easily and quickly, thereby restricting its consumption. Known diagnostic methods lack speed and sensitivity. We report a caffeine dehydrogenase (Cdh)-based test which is highly sensitive (1-5 ppm) and detects caffeine in beverages and mother's milk in 1 min. Other components in these complex test samples do not interfere with the detection. Caffeine-dependent reduction of the dye iodonitrotetrazolium chloride results in shades of pink proportional to the levels in test samples. This test also estimates caffeine levels in pharmaceuticals, comparable to high-performance liquid chromatography. The Cdh-based test is the first with the desired attributes of a rapid and robust caffeine diagnostic kit.

2.45 GHz Microwave Processing and Its Influence on Glass Fiber Reinforced Plastics

PubMed Central

Zaremba, Swen

2018-01-01

During the production of fiber-reinforced composite materials, liquid resin is introduced into the fiber material and cured, i.e., hardened. An elevated temperature is needed for this curing. Microwave curing of composites has been investigated for some time, but it has mostly been done using small domestic or laboratory equipment. However, no investigation has been carried out using an industrial-sized chamber-microwave for glass fiber-reinforced plastic (GFRP). Here, we show that microwave curing produces laminates of the same quality as oven-cured ones. The study shows that, if the process is done right, GFRP samples can be produced with an industrial scale microwave. Even if not fully cured, microwave samples show a glass transition temperature measured with DMA (Tg-DMA) that is comparable to the Tg-DMA according to the proposed cure cycle on the data sheet. Specific microwave-cured configurations show better inter-laminar shear strength than oven specimens. The results show that microwave-based heat introduction can be a beneficial curing method for GFRP laminates. A microwave-optimized process is faster and leads to better mechanical properties. PMID:29783684

Chemical derivatization for enhancing sensitivity during LC/ESI-MS/MS quantification of steroids in biological samples: a review.

PubMed

Higashi, Tatsuya; Ogawa, Shoujiro

2016-09-01

Sensitive and specific methods for the detection, characterization and quantification of endogenous steroids in body fluids or tissues are necessary for the diagnosis, pathological analysis and treatment of many diseases. Recently, liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) has been widely used for these purposes due to its specificity and versatility. However, the ESI efficiency and fragmentation behavior of some steroids are poor, which lead to a low sensitivity. Chemical derivatization is one of the most effective methods to improve the detection characteristics of steroids in ESI-MS/MS. Based on this background, this article reviews the recent advances in chemical derivatization for the trace quantification of steroids in biological samples by LC/ESI-MS/MS. The derivatization in ESI-MS/MS is based on tagging a proton-affinitive or permanently charged moiety on the target steroid. Introduction/formation of a fragmentable moiety suitable for the selected reaction monitoring by the derivatization also enhances the sensitivity. The stable isotope-coded derivatization procedures for the steroid analysis are also described. Copyright © 2015 Elsevier Ltd. All rights reserved.

Injection Characteristics of Non-Swirling and Swirling Annular Liquid Sheets

NASA Technical Reports Server (NTRS)

Harper, Brent (Technical Monitor); Ibrahim, E. A.; McKinney, T. R.

2004-01-01

A simplified mathematical model, based on body-fitted coordinates, is formulated to study the evolution of non-swirling and swirling liquid sheet emanated from an annular nozzle in a quiescent surrounding medium. The model provides predictions of sheet trajectory, thickness and velocity at various liquid mass flow rates and liquid-swirler angles. It is found that a non-swirling annular sheet converges toward its centerline and assumes a bell shape as it moves downstream from the nozzle. The bell radius, and length are more pronounced at higher liquid mass flow rates. The thickness of the non-swirling annular sheet increases while its stream-wise velocity decreases with an increase in mass flow rate. The introduction of swirl results in the formation of a diverging hollow-cone sheet. The hollow-cone divergence from its centerline is enhanced by an increase in liquid mass flow rate or liquid-swirler angle. The hollow- cone sheet its radius, curvature and stream-wise velocity increase while its thickness and tangential velocity decrease as a result of increasing the mass flow rate or liquid-swirler angle. The present results are compared with previous studies and conclusions are drawn.

Apparatus Induces And Fixes Small Aquatic Organisms

NASA Technical Reports Server (NTRS)

Todd, Christopher

1992-01-01

Syringe-and-bag assembly compact, lightweight self-contained, portable apparatus introducing liquids to aquatic organisms. Isolates organisms from toxic substances until time of introduction. Includes plastic syringes, each containing inner, sealed, burstable bag. Adaptable to use in biological tests and experiments at remote locations on Earth.

Recent advances on ionic liquid uses in separation techniques.

PubMed

Berthod, A; Ruiz-Ángel, M J; Carda-Broch, S

2018-07-20

The molten organic salts with melting point below 100°C, commonly called ionic liquids (ILs) have found numerous uses in separation sciences due to their exceptional properties as non molecular solvents, namely, a negligible vapor pressure, a high thermal stability, and unique solvating properties due to polarity and their ionic character of molten salts. Other properties, such as viscosity, boiling point, water solubility, and electrochemical window, are adjustable playing with which anion is associated with which cation. This review focuses on recent development of the uses of ILs in separation techniques actualizing our 2008 article (same authors, J. Chromatogr. A, 1184 (2008) 6-18) focusing on alkyl methylimidazolium salts. These developments include the use of ILs in nuclear waste reprocessing, highly thermally stable ILs that allowed for the introduction of polar gas chromatography capillary columns able to work at temperature never seen before (passing 300°C), the use of ILs in liquid chromatography and capillary electrophoresis, and the introduction of tailor-made ILs for mass spectrometry detection of trace anions at the few femtogram level. The recently introduced deep eutectic solvents are not exactly ILs, they are related enough so that their properties and uses in countercurrent chromatography are presented. Copyright © 2017 Elsevier B.V. All rights reserved.

Aktiv De-Orbiting Onboard System from Leo of Upper Stages of Launchers

NASA Astrophysics Data System (ADS)

Trushlyakov, V.; Shalay, V.; Shatrov, J.; Jakovlev, M.; Kostantino, A.

2009-03-01

The active de-orbiting onboard system (VDOS) of upper separable parts (USP) stage of launchers from LEO into orbits of utilization with term of existence orbital lifetimes till 25 years is offered. ADOS it is based on use of power resources of not produced rests of liquid fuel onboard USP launchers with liquid propulsion module (LPM). Following systems enter in structure VDOS: the gas jet propulsion system consisting of a system of gasification, chambers of gas engines (GE), a control system. For gasification of the rests of liquid fuel the heat-carrier received in the autonomous gas generator is used. The gasification propellant components from each tank with temperature and the pressure determined by strength of the corresponding tank, move in chambers of the GE established on a top of a fuel compartment. After separation of a payload execute twist USP for preservation of its position in the space by activity of the GE. Ways of increase of a system effectiveness of gasification are offered by superposition on the entered heat-carrier of ultrasonic oscillations, and also introduction in gaseous fuel nanopowder of aluminum. The volume of adaptations of construction USP, connected with introduction VDOS does not exceed 5 % from weight of a dry construction.

Trends in salmonella food poisoning in England and Wales 1941-72.

PubMed Central

McCoy, J. H.

1975-01-01

Cattle and pig herds and flocks of domestic fowl have formed the main reservoir of human salmonella food poisoning in England and Wales from 1941 to 1972. Changes in the incidence of human salmonella food poisoning and in the serotypes of salmonellas isolated from human infections are shown to have been associated with the introduction of new foods, with changes in animal husbandry, and with changes in the relative proportions of flesh food from different species consumed. New foods, dried powdered egg, liquid egg and frozen liquid egg were introduced during the period of food rationing which extended from 1940 to 1953. Changes in animal husbandry, in particular the intensive production of pigs, poultry and eggs, followed the re-establishment of pig herds and fowl flocks after the derationing of animal feed in 1953. The changes in the proportions of flesh foods consumed followed the introduction of frozen oven-ready fowl in the late 1950s and early 1960s which by 1964 became cheaper than traditional flesh foods. PMID:1054731

Liquid-Liquid Extraction of Insecticides from Juice: An Analytical Chemistry Laboratory Experiment

ERIC Educational Resources Information Center

Radford, Samantha A.; Hunter, Ronald E., Jr.; Barr, Dana Boyd; Ryan, P. Barry

2013-01-01

A laboratory experiment was developed to target analytical chemistry students and to teach them about insecticides in food, sample extraction, and cleanup. Micro concentrations (sub-microgram/mL levels) of 12 insecticides spiked into apple juice samples are extracted using liquid-liquid extraction and cleaned up using either a primary-secondary…

Rapid analysis of ultraviolet filters using dispersive liquid-liquid microextraction coupled to headspace gas chromatography and mass spectrometry.

PubMed

Pierson, Stephen A; Trujillo-Rodríguez, María J; Anderson, Jared L

2018-05-29

An ionic-liquid-based in situ dispersive liquid-liquid microextraction method coupled to headspace gas chromatography and mass spectrometry was developed for the rapid analysis of ultraviolet filters. The chemical structures of five ionic liquids were specifically designed to incorporate various functional groups for the favorable extraction of the target analytes. Extraction parameters including ionic liquid mass, molar ratio of ionic liquid to metathesis reagent, vortex time, ionic strength, pH, and total sample volume were studied and optimized. The effect of the headspace temperature and volume during the headspace sampling step was also evaluated to increase the sensitivity of the method. The optimized procedure is fast as it only required ∼7-10 min per extraction and allowed for multiple extractions to be performed simultaneously. In addition, the method exhibited high precision, good linearity, and low limits of detection for six ultraviolet filters in aqueous samples. The developed method was applied to both pool and lake water samples attaining acceptable relative recovery values. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Derivatization of amino acids with N,N-dimethyl-2,4-dinitro-5-fluorobenzylamine for liquid chromatography/electrospray ionization mass spectrometry.

PubMed

Liu, Zhongfa; Minkler, Paul E; Lin, De; Sayre, Lawrence M

2004-01-01

Derivatization, separation and identification of amino acids with a novel compound, N,N-dimethyl-2,4-dinitro-5-fluorobenzylamine (DMDNFB), using high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS) was demonstrated. Compared to derivatization with 2,4-dinitrofluorobenzene (DNFB), DMDNFB-derivatized amino acids and dipeptides exhibit much larger ion current signals in the commonly used ESI positive mode, which was attributed to the introduction of the N,N-dimethylaminomethyl protonatable site. Copyright 2004 John Wiley & Sons, Ltd.

Fluidic optics

NASA Astrophysics Data System (ADS)

Whitesides, George M.; Tang, Sindy K. Y.

2006-09-01

Fluidic optics is a new class of optical system with real-time tunability and reconfigurability enabled by the introduction of fluidic components into the optical path. We describe the design, fabrication, operation of a number of fluidic optical systems, and focus on three devices, liquid-core/liquid-cladding (L2) waveguides, microfluidic dye lasers, and diffraction gratings based on flowing, crystalline lattices of bubbles, to demonstrate the integration of microfluidics and optics. We fabricate these devices in poly(dimethylsiloxane) (PDMS) with soft-lithographic techniques. They are simple to construct, and readily integrable with microanalytical or lab-on-a-chip systems.

Novel Directional Solidification Processing of Hypermonotectic Alloys

NASA Technical Reports Server (NTRS)

Grugel, Richard N.

1999-01-01

Gravity driven separation precludes uniform microstructural development during controlled directional solidification (DS) processing of hypermonotectic alloys. It is well established that liquid/liquid suspensions, in which the respective components are immiscible and have significant density differences, can be established and maintained by utilizing ultrasound. A historical introduction to this work is presented with the intent of establishing the basis for applying the phenomena to promote microstructural uniformity during controlled directional solidification processing of immiscible mixtures. Experimental work based on transparent organics, as well as salt systems, will be presented in view of the processing parameters.

Displacement-dispersive liquid-liquid microextraction based on solidification of floating organic drop of trace amounts of palladium in water and road dust samples prior to graphite furnace atomic absorption spectrometry determination.

PubMed

Ghanbarian, Maryam; Afzali, Daryoush; Mostafavi, Ali; Fathirad, Fariba

2013-01-01

A new displacement-dispersive liquid-liquid microextraction method based on the solidification of floating organic drop was developed for separation and preconcentration of Pd(ll) in road dust and aqueous samples. This method involves two steps of dispersive liquid-liquid microextraction based on solidification. In Step 1, Cu ions react with diethyldithiocarbamate (DDTC) to form Cu-DDTC complex, which is extracted by dispersive liquid-liquid microextraction based on a solidification procedure using 1-undecanol (extraction solvent) and ethanol (dispersive solvent). In Step 2, the extracted complex is first dispersed using ethanol in a sample solution containing Pd ions, then a dispersive liquid-liquid microextraction based on a solidification procedure is performed creating an organic drop. In this step, Pd(ll) replaces Cu(ll) from the pre-extracted Cu-DDTC complex and goes into the extraction solvent phase. Finally, the Pd(ll)-containing drop is introduced into a graphite furnace using a microsyringe, and Pd(ll) is determined using atomic absorption spectrometry. Several factors that influence the extraction efficiency of Pd and its subsequent determination, such as extraction and dispersive solvent type and volume, pH of sample solution, centrifugation time, and concentration of DDTC, are optimized.

System and method for assaying radiation

DOEpatents

DiPrete, David P; Whiteside, Tad; Pak, Donald J; DiPrete, Cecilia C

2013-11-12

A system for assaying radiation includes a sample holder configured to hold a liquid scintillation solution. A photomultiplier receives light from the liquid scintillation solution and generates a signal reflective of the light. A control circuit biases the photomultiplier and receives the signal from the photomultiplier reflective of the light. A light impermeable casing surrounds the sample holder, photomultiplier, and control circuit. A method for assaying radiation includes placing a sample in a liquid scintillation solution, placing the liquid scintillation solution in a sample holder, and placing the sample holder inside a light impermeable casing. The method further includes positioning a photomultiplier inside the light impermeable casing and supplying power to a control circuit inside the light impermeable casing.

Experimental tobacco marketplace: substitutability of e-cigarette liquid for cigarettes as a function of nicotine strength.

PubMed

Pope, Derek A; Poe, Lindsey; Stein, Jeffrey S; Kaplan, Brent A; Heckman, Bryan W; Epstein, Leonard H; Bickel, Warren K

2018-04-18

The experimental tobacco marketplace (ETM) provides a method to estimate, prior to implementation, the effects of new products or policies on purchasing across various products in a complex tobacco marketplace. We used the ETM to examine the relationship between nicotine strength and substitutability of alternative products for cigarettes to contribute to the literature on regulation of e-liquid nicotine strength. The present study contained four sampling and four ETM purchasing sessions. During sampling sessions, participants were provided 1 of 4 e-liquid strengths (randomised) to sample for 2 days followed by an ETM purchasing session. The nicotine strength sampled in the 2 days prior to an ETM session was the same strength available for purchase in the next ETM. Each participant sampled and could purchase 0 mg/mL, 6 mg/mL, 12 mg/mL and 24 mg/mL e-liquid, among other products, during the study. Cigarette demand was unaltered across e-liquid strength. E-liquid was the only product to substitute for cigarettes across more than one e-liquid strength. Substitutability increased as a function of e-liquid strength, with the 24 mg/mL displaying the greatest substitutability of all products. The present study found that e-liquid substitutability increased with nicotine strength, at least up to 24 mg/mL e-liquid. However, the effects of e-liquid nicotine strength on cigarette purchasing were marginal and total nicotine purchased increased as e-liquid nicotine strength increased. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Determination of ten pyrethroids in various fruit juices: comparison of dispersive liquid-liquid microextraction sample preparation and QuEChERS method combined with dispersive liquid-liquid microextraction.

PubMed

Zhang, Yaohai; Zhang, Xuelian; Jiao, Bining

2014-09-15

Dispersive liquid-liquid microextraction (DLLME) sample preparation and the quick, easy, cheap, effective, rugged and safe (QuEChERS) method combined with DLLME were developed and compared for the analysis of ten pyrethroids in various fruit juices using gas chromatography-electron capture detection (GC-ECD). QuEChERS-DLLME method has found its widespread applications to all the fruit juices including those samples with more complex matrices (orange, lemon, kiwi and mango) while DLLME was confined to the fruit juices with simpler matrices (apple, pear, grape and peach). The two methods provided acceptable recoveries and repeatability. In addition, the applicabilities of two methods were demonstrated with the real samples and further confirmed by gas chromatography-mass spectrometry (GC-MS). Copyright © 2014. Published by Elsevier Ltd.

Determination of sudan dyes in red wine and fruit juice using ionic liquid-based liquid-liquid microextraction and high-performance liquid chromatography.

PubMed

Sun, Shuo; Wang, Ying; Yu, Wenzhi; Zhao, Tianqi; Gao, Shiqian; Kang, Mingqin; Zhang, Yupu; Zhang, Hanqi; Yu, Yong

2011-07-01

The liquid-liquid microextraction (LLME) was developed for extracting sudan dyes from red wine and fruit juice. Room temperature ionic liquid was used as the extraction solvent. The target analytes were determined by high-performance liquid chromatography. The extraction parameters were optimized. The optimal conditions are as follows: volume of [C(6)MIM][PF(6)] 50 μL; the extraction time 10 min; pH value of the sample solution 7.0; NaCl concentration in sample solution 5%. The extraction recoveries for the analytes in red wine and fruit samples are 86.79-108.28 and 68.54-85.66%, whereas RSDs are 1.42-5.12 and 1.43-6.19%, respectively. The limits of detection and quantification were 0.428 and 1.426 ng/mL for sudan I, 0.938 and 3.127 ng/mL for sudan II, 1.334 and 4.445 ng/mL for sudan III, 1.454 and 4.846 ng/mL for sudan IV, respectively. Compared with conventional liquid-liquid extraction (CLLE) and ultrasonic extraction (UE), when LLME was applied, the sample amount was less (LLME: 4 mL; CLLE: 10 mL; UE: 10 mL), the extraction time was shorter (LLME: 15 min; CLLE: 110 min; UE: 50 min) and the extraction solvent amount was less (LLME: 0.05 mL IL; CLLE: 15 mL hexane; UE: 20 mL hexane). The proposed method offers a simple, rapid and efficient sample preparation for determining sudan dyes in red wine and fruit juice samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Qualitative Analysis of E-Liquid Emissions as a Function of Flavor Additives Using Two Aerosol Capture Methods.

PubMed

Eddingsaas, Nathan; Pagano, Todd; Cummings, Cody; Rahman, Irfan; Robinson, Risa; Hensel, Edward

2018-02-13

This work investigates emissions sampling methods employed for qualitative identification of compounds in e-liquids and their resultant aerosols to assess what capture methods may be sufficient to identify harmful and potentially harmful constituents present. Three popular e-liquid flavors (cinnamon, mango, vanilla) were analyzed using qualitative gas chromatography-mass spectrometry (GC-MS) in the un-puffed state. Each liquid was also machine-puffed under realistic-use flow rate conditions and emissions were captured using two techniques: filter pads and methanol impingers. GC-MS analysis was conducted on the emissions captured using both techniques from all three e-liquids. The e-liquid GC-MS analysis resulted in positive identification of 13 compounds from the cinnamon flavor e-liquid, 31 from mango, and 19 from vanilla, including a number of compounds observed in all e-liquid experiments. Nineteen compounds were observed in emissions which were not present in the un-puffed e-liquid. Qualitative GC-MS analysis of the emissions samples identify compounds observed in all three samples: e-liquid, impinge, and filter pads, and each subset thereof. A limited number of compounds were observed in emissions captured with impingers, but were not observed in emissions captured using filter pads; a larger number of compounds were observed on emissions collected from the filter pads, but not those captured with impingers. It is demonstrated that sampling methods have different sampling efficiencies and some compounds might be missed using only one method. It is recommended to investigate filter pads, impingers, thermal desorption tubes, and solvent extraction resins to establish robust sampling methods for emissions testing of e-cigarette emissions.

Qualitative Analysis of E-Liquid Emissions as a Function of Flavor Additives Using Two Aerosol Capture Methods

PubMed Central

Eddingsaas, Nathan; Pagano, Todd; Cummings, Cody; Rahman, Irfan; Robinson, Risa

2018-01-01

This work investigates emissions sampling methods employed for qualitative identification of compounds in e-liquids and their resultant aerosols to assess what capture methods may be sufficient to identify harmful and potentially harmful constituents present. Three popular e-liquid flavors (cinnamon, mango, vanilla) were analyzed using qualitative gas chromatography-mass spectrometry (GC-MS) in the un-puffed state. Each liquid was also machine-puffed under realistic-use flow rate conditions and emissions were captured using two techniques: filter pads and methanol impingers. GC-MS analysis was conducted on the emissions captured using both techniques from all three e-liquids. The e-liquid GC-MS analysis resulted in positive identification of 13 compounds from the cinnamon flavor e-liquid, 31 from mango, and 19 from vanilla, including a number of compounds observed in all e-liquid experiments. Nineteen compounds were observed in emissions which were not present in the un-puffed e-liquid. Qualitative GC-MS analysis of the emissions samples identify compounds observed in all three samples: e-liquid, impinge, and filter pads, and each subset thereof. A limited number of compounds were observed in emissions captured with impingers, but were not observed in emissions captured using filter pads; a larger number of compounds were observed on emissions collected from the filter pads, but not those captured with impingers. It is demonstrated that sampling methods have different sampling efficiencies and some compounds might be missed using only one method. It is recommended to investigate filter pads, impingers, thermal desorption tubes, and solvent extraction resins to establish robust sampling methods for emissions testing of e-cigarette emissions. PMID:29438289

Cryogenic Liquid Sample Acquisition System for Remote Space Applications

NASA Technical Reports Server (NTRS)

Mahaffy, Paul; Trainer, Melissa; Wegel, Don; Hawk, Douglas; Melek, Tony; Johnson, Christopher; Amato, Michael; Galloway, John

2013-01-01

There is a need to acquire autonomously cryogenic hydrocarbon liquid sample from remote planetary locations such as the lakes of Titan for instruments such as mass spectrometers. There are several problems that had to be solved relative to collecting the right amount of cryogenic liquid sample into a warmer spacecraft, such as not allowing the sample to boil off or fractionate too early; controlling the intermediate and final pressures within carefully designed volumes; designing for various particulates and viscosities; designing to thermal, mass, and power-limited spacecraft interfaces; and reducing risk. Prior art inlets for similar instruments in spaceflight were designed primarily for atmospheric gas sampling and are not useful for this front-end application. These cryogenic liquid sample acquisition system designs for remote space applications allow for remote, autonomous, controlled sample collections of a range of challenging cryogenic sample types. The design can control the size of the sample, prevent fractionation, control pressures at various stages, and allow for various liquid sample levels. It is capable of collecting repeated samples autonomously in difficult lowtemperature conditions often found in planetary missions. It is capable of collecting samples for use by instruments from difficult sample types such as cryogenic hydrocarbon (methane, ethane, and propane) mixtures with solid particulates such as found on Titan. The design with a warm actuated valve is compatible with various spacecraft thermal and structural interfaces. The design uses controlled volumes, heaters, inlet and vent tubes, a cryogenic valve seat, inlet screens, temperature and cryogenic liquid sensors, seals, and vents to accomplish its task.

Experimental research on rock fracture failure characteristics under liquid nitrogen cooling conditions

NASA Astrophysics Data System (ADS)

Gao, Feng; Cai, Chengzheng; Yang, Yugui

2018-06-01

As liquid nitrogen is injected into a wellbore as fracturing fluid, it can rapidly absorb heat from warmer rock and generate cryogenic condition in downhole region. This will alter the physical conditions of reservoir rocks and further affect rock failure characteristics. To investigate rock fracture failure characteristics under liquid nitrogen cooling conditions, the fracture features of four types of sandstones and one type of marble were tested on original samples (the sample without any treatment) and cryogenic samples (the samples just taken out from the liquid nitrogen), respectively. The differences between original samples and cryogenic samples in load-displacement curves, fracture toughness, energy evolution and the crack density of ruptured samples were compared and analyzed. The results showed that at elastic deformation stage, cryogenic samples presented less plastic deformation and more obvious brittle failure characteristics than original ones. The average fracture toughness of cryogenic samples was 10.47%-158.33% greater than that of original ones, indicating that the mechanical strength of rocks used were enhanced under cooling conditions. When the samples ruptured, the cryogenic ones were required to absorb more energy and reserve more elastic energy. In general, the fracture degree of cryogenic samples was higher than that of original ones. As the samples were entirely fractured, the crack density of cryogenic samples was about 536.67% at most larger than that of original ones. This indicated that under liquid nitrogen cooling conditions, the stimulation reservoir volume is expected to be improved during fracturing. This work could provide a reference to the research on the mechanical properties and fracture failure of rock during liquid nitrogen fracturing.

Organophosphate flame retardants in household dust before and after introduction of new furniture.

PubMed

Keimowitz, A R; Strunsky, N; Wovkulich, K

2016-04-01

Flame retardant compounds originating from household items collect in household dust, a reasonable proxy for human exposure. Contributions of specific items or behaviors to dust are difficult to separate. This study examined standardized college housing before and after the introduction of new, flame retardant couches in order to explore any effect that changing upholstered furniture may have on flame retardant concentrations in dust. Two contradictory hypotheses were posited: (1) that new furniture might increase flame retardant releases immediately after introduction due to initial off-gassing of new materials or (2) that older furniture would release more flame retardants due to mechanical breakdown of polyurethane foam. This study was designed to determine which of these processes dominated. Prior to the introduction of new furniture, TDCIPP was detected in 12/20 samples at a median concentration of 22 μg/g and TCEP was detected in 1/20 samples at a concentration of 16 μg/g. TDCIPP and TCEP were not detected in any samples (N = 29) after the introduction of new couches. TPHP was detected both before (in 11/20 samples) and after (in 5/29 samples) introduction of new couches; the median concentrations before and after were 63 ± 49 and 16 ± 11 μg/g (standard deviation shown). Introduced couches contained TDCIPP (and not TPHP) at ∼1.25% (w/w). These data support the second hypothesis and indicate that removal of older furniture decreases TDCIPP and TCEP concentrations in dust and may potentially reduce total flame retardant concentrations in dust, at least immediately after introduction of the new furniture. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pressure-assisted introduction of urine samples into a short capillary for electrophoretic separation with contactless conductivity and UV spectrometry detection.

PubMed

Makrlíková, Anna; Opekar, František; Tůma, Petr

2015-08-01

A computer-controlled hydrodynamic sample introduction method has been proposed for short-capillary electrophoresis. In the method, the BGE flushes sample from the loop of a six-way sampling valve and is carried to the injection end of the capillary. A short pressure impulse is generated in the electrolyte stream at the time when the sample zone is at the capillary, leading to injection of the sample into the capillary. Then the electrolyte flow is stopped and the separation voltage is turned on. This way of sample introduction does not involve movement of the capillary and both of its ends remain constantly in the solution during both sample injection and separation. The amount of sample introduced to the capillary is controlled by the duration of the pressure pulse. The new sample introduction method was tested in the determination of ammonia, creatinine, uric acid, and hippuric acid in human urine. The determination was performed in a capillary with an overall length of 10.5 cm, in two BGEs with compositions 50 mM MES + 5 mM NaOH (pH 5.1) and 1 M acetic acid + 1.5 mM crown ether 18-crown-6 (pH 2.4). A dual contactless conductivity/UV spectrometric detector was used for the detection. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development and Applications of Liquid Sample Desorption Electrospray Ionization Mass Spectrometry

NASA Astrophysics Data System (ADS)

Zheng, Qiuling; Chen, Hao

2016-06-01

Desorption electrospray ionization mass spectrometry (DESI-MS) is a recent advance in the field of analytical chemistry. This review surveys the development of liquid sample DESI-MS (LS-DESI-MS), a variant form of DESI-MS that focuses on fast analysis of liquid samples, and its novel analy-tical applications in bioanalysis, proteomics, and reaction kinetics. Due to the capability of directly ionizing liquid samples, liquid sample DESI (LS-DESI) has been successfully used to couple MS with various analytical techniques, such as microfluidics, microextraction, electrochemistry, and chromatography. This review also covers these hyphenated techniques. In addition, several closely related ionization methods, including transmission mode DESI, thermally assisted DESI, and continuous flow-extractive DESI, are briefly discussed. The capabilities of LS-DESI extend and/or complement the utilities of traditional DESI and electrospray ionization and will find extensive and valuable analytical application in the future.

Advanced in situ Spectroscopic Techniques And Their Applications In Environmental Biogeochemistry: Introduction To The Special Section

EPA Science Inventory

Understanding the molecular-scale complexities and interplay of chemical and biological processes of contaminants at solid, liquid, and gas interfaces is a fundamental and crucial element to enhance our understanding of anthropogenic environmental impacts. The ability to describ...

Genotoxicity of wastewaters used for irrigation of food crops.

PubMed

Ansari, Mohd Ikram; Malik, Abdul

2009-04-01

In most towns of India, wastewater coming from both industrial and domestic sources and without any treatment is used to irrigate the agricultural crops. This practice has been polluting the soil, and pollutants could possibly reach the food chain. For the above reasons, the wastewaters of Ghaziabad City (India), which is used for irrigation, were sampled (at two different sites) and monitored for the presence of genotoxic agents from January 2005 to June 2007. Gas chromatographic analysis showed the presence of certain OC (DDE, DDT, Dieldrin, Aldrin, and Endosulfan) and OP (Dimethoate, Malathion, Methlyparathion, and Chlorpyrifos) pesticides in both the sampling sites. Wastewater samples were concentrated using XAD resins (XAD-4 and XAD-8) and liquid-liquid extraction procedures, and the extracts were assayed for genotoxic potential by Ames Salmonella/microsome test, DNA repair defective mutants, and bacteriophage lambda systems. The test samples exhibited significant mutagenicity with TA98, TA97a, and TA100 strains with the probable role of contaminating pesticides in the wastewater. However, XAD-concentrated samples were more mutagenic in both sites as compared to liquid-liquid-extracted samples. The damage in the DNA repair defective mutants in the presence of XAD-concentrated water samples were also found to be higher to that of liquid-liquid-extracted water samples at the dose level of 20 muL/mL culture. All the mutants invariably exhibited significant decline in their colony-forming units as compared to their isogenic wild-type counterparts. The survival was decreased by 81.7 and 75.5% in polA(-) strain in site I, and 76.0 and 73.5% in site II in polA(-) under the same experimental conditions after 6 h of treatment with XAD-concentrated and liquid-liquid-extracted samples, respectively. A significant decrease in the survival of bacteriophage lambda was also observed when treated with the test samples. Copyright 2008 Wiley Periodicals, Inc.

Fluid sampling system

DOEpatents

Houck, Edward D.

1994-01-01

An fluid sampling system allows sampling of radioactive liquid without spillage. A feed tank is connected to a liquid transfer jet powered by a pumping chamber pressurized by compressed air. The liquid is pumped upwardly into a sampling jet of a venturi design having a lumen with an inlet, an outlet, a constricted middle portion, and a port located above the constricted middle portion. The liquid is passed under pressure through the constricted portion causing its velocity to increase and its pressure to decreased, thereby preventing liquid from escaping. A septum sealing the port can be pierced by a two pointed hollow needle leading into a sample bottle also sealed by a pierceable septum affixed to one end. The bottle is evacuated by flow through the sample jet, cyclic variation in the sampler jet pressure periodically leaves the evacuated bottle with lower pressure than that of the port, thus causing solution to pass into the bottle. The remaining solution in the system is returned to the feed tank via a holding tank.

Fluid sampling system

DOEpatents

Houck, E.D.

1994-10-11

An fluid sampling system allows sampling of radioactive liquid without spillage. A feed tank is connected to a liquid transfer jet powered by a pumping chamber pressurized by compressed air. The liquid is pumped upwardly into a sampling jet of a venturi design having a lumen with an inlet, an outlet, a constricted middle portion, and a port located above the constricted middle portion. The liquid is passed under pressure through the constricted portion causing its velocity to increase and its pressure to be decreased, thereby preventing liquid from escaping. A septum sealing the port can be pierced by a two pointed hollow needle leading into a sample bottle also sealed by a pierceable septum affixed to one end. The bottle is evacuated by flow through the sample jet, cyclic variation in the sampler jet pressure periodically leaves the evacuated bottle with lower pressure than that of the port, thus causing solution to pass into the bottle. The remaining solution in the system is returned to the feed tank via a holding tank. 4 figs.

Hexavalent chromium monitor

DOEpatents

Tao, Shiquan; Winstead, Christopher B.

2005-04-12

A monitor is provided for use in measuring the concentration of hexavalent chromium in a liquid, such as water. The monitor includes a sample cell, a light source, and a photodetector. The sample cell is in the form of a liquid-core waveguide, the sample cell defining an interior core and acting as a receiver for the liquid to be analyzed, the interior surface of the sample cell having a refractive index of less than 1.33. The light source is in communication with a first end of the sample cell for emitting radiation having a wavelength of about and between 350 to 390 nm into the interior core of the waveguide. The photodetector is in communication with a second end of the waveguide for measuring the absorption of the radiation emitted by the light source by the liquid in the sample cell. The monitor may also include a processor electronically coupled to the photodetector for receipt of an absorption signal to determine the concentration of hexavalent chromium in the liquid.

Heat Capacity of Hydrous Silicate Melts

NASA Astrophysics Data System (ADS)

Robert, G.; Whittington, A. G.; Stechern, A.; Behrens, H.

2015-12-01

We determined the heat capacities of four series of glasses and liquids of basaltic and basaltic andesite compositions including two natural remelts from Fuego volcano, Guatemala, and two Fe-free analogs. The samples are low-alkali, Ca- and Mg-rich aluminosilicates with non-bridging oxygen to tetrahedrally-coordinated cation ratios (NBO/T) ranging between 0.33 and 0.67. Differential scanning calorimetry measurements were performed at atmospheric pressure between room temperature and ≈100 K above the glass transition for hydrous samples and up to ≈1800 K for dry samples. The water contents investigated range up to 5.34 wt.% (16.4 mol%). Water does not measurably affect the heat capacity of glasses (T

Correction of a liquid lens for 3D imaging systems

NASA Astrophysics Data System (ADS)

Bower, Andrew J.; Bunch, Robert M.; Leisher, Paul O.; Li, Weixu; Christopher, Lauren A.

2012-06-01

3D imaging systems are currently being developed using liquid lens technology for use in medical devices as well as in consumer electronics. Liquid lenses operate on the principle of electrowetting to control the curvature of a buried surface, allowing for a voltage-controlled change in focal length. Imaging systems which utilize a liquid lens allow extraction of depth information from the object field through a controlled introduction of defocus into the system. The design of such a system must be carefully considered in order to simultaneously deliver good image quality and meet the depth of field requirements for image processing. In this work a corrective model has been designed for use with the Varioptic Arctic 316 liquid lens. The design is able to be optimized for depth of field while minimizing aberrations for a 3D imaging application. The modeled performance is compared to the measured performance of the corrected system over a large range of focal lengths.

Conformational energy calculations on polypeptides and proteins: use of a statistical mechanical procedure for evaluating structure and properties.

PubMed

Scheraga, H A; Paine, G H

1986-01-01

We are using a variety of theoretical and computational techniques to study protein structure, protein folding, and higher-order structures. Our earlier work involved treatments of liquid water and aqueous solutions of nonpolar and polar solutes, computations of the stabilities of the fundamental structures of proteins and their packing arrangements, conformations of small cyclic and open-chain peptides, structures of fibrous proteins (collagen), structures of homologous globular proteins, introduction of special procedures as constraints during energy minimization of globular proteins, and structures of enzyme-substrate complexes. Recently, we presented a new methodology for predicting polypeptide structure (described here); the method is based on the calculation of the probable and average conformation of a polypeptide chain by the application of equilibrium statistical mechanics in conjunction with an adaptive, importance sampling Monte Carlo algorithm. As a test, it was applied to Met-enkephalin.

Interfaces and thin films as seen by bound electromagnetic waves.

PubMed

Knoll, W

1998-01-01

This contribution summarizes the use of plasmon surface polaritons and guided optical waves for the characterization of interfaces and thin organic films. After a short introduction to the theoretical background of evanescent wave optics, examples are given that show how this interfacial "light" can be employed to monitor thin coatings at a solid/air or solid/liquid interface. Examples are given for a very sensitive thickness determination of samples ranging from self-assembled monolayers, to multilayer assemblies prepared by the Langmuir/Blodgett/Kuhn technique or by the alternate polyelectrolyte deposition. These are complemented by the demonstration of the potential of the technique to also monitor time-dependent processes in a kinetic mode. Here, we put an emphasis on the combination set-up of surface plasmon optics with electrochemical techniques, allowing for the on-line characterization of various surface functionalization strategies, e.g. for (bio-) sensor purposes.

Buprenorphine detection in hair samples by immunometric screening test: preliminary experience.

PubMed

Svaizer, Fiorenza; Lotti, Andrea; Gottardi, Massimo; Miozzo, Maria Pia

2010-03-20

The recent introduction of buprenorphine use by the Drug Addiction Services has induced toxicology laboratories to develop new qualitative or semiquantitative screening assay for its determination in hair samples. The aim of this preliminary study was to verify the correlation between the buprenorphine intake and the immunometric screening test results (VMA-T Comedical and buprenorphine CEDIA/Thermo-Fisher/Microgenics reagents) and therefore their comparison with the liquid chromatography coupled with mass spectrometry (LC/MS) results. Hair samples were obtained from 32 subjects without buprenorphine-therapy reported and 17 in treatment. In glass test tube with hermetic cap were weighed 33 mg of 49 finely cut hair samples, washed with 1 mL of SLV-VMA-T washing solution, which is then completely sucked and eliminated. The samples were extracted with 400 microL of VMA-T reagent for an hour at 100 degrees C. The extracts were analysed by immunometric screening test on ILab 650 chemistry analyser, using buprenorphine CEDIA reagent assay. From the 32 non-takers of drug, 30 semiquantitative results were less than 10 pg/mg and 2 were over 10 pg/mg; from the 17 subjects with therapy, all were over 10 pg/mg (range 13-50 pg/mg); no samples were false-negative. Results suggest that exist a good relationship between the administration of buprenorphine and its concentration in hair, detectable through this method and reagents line. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

A simple, rapid and novel method based on salting-out assisted liquid-liquid extraction for ochratoxin A determination in beer samples prior to ultra-high performance liquid chromatography coupled to tandem mass spectrometry.

PubMed

Mariño-Repizo, Leonardo; Goicoechea, Hector; Raba, Julio; Cerutti, Soledad

2018-06-07

A novel, simple, easy and cheap sample treatment strategy based on salting-out assisted liquid-liquid extraction (SALLE) for ochratoxin A (OTA) ultra-trace analysis in beer samples using ultra-high performance liquid chromatography-tandem mass spectrometry determination was developed. The factors involved in the efficiency of pretreatment were studied employing factorial design in the screening phase and the optimal conditions of the significant variables on the analytical response were evaluated using a central composite face-centred design (CCF). Consequently, the amount of salt ((NH 4 ) 2 SO 4 ), together with the volumes of sample, hydrophilic (acetone) and nonpolar (toluene) solvents, and times of vortexing and centrifugation were optimized. Under optimized conditions, the limits of detection (LOD) and quantification (LOQ) were 0.02 µg l -1 and 0.08 µg l -1 respectively. OTA extraction recovery by SALLE was approximately 90% (0.2 µg l -1 ). Furthermore, the methodology was in agreement with EU Directive requirements and was successfully applied for analysis of beer samples.

Fast, simple and efficient salting-out assisted liquid-liquid extraction of naringenin from fruit juice samples prior to their enantioselective determination by liquid chromatography.

PubMed

Magiera, Sylwia; Kwietniowska, Ewelina

2016-11-15

In this study, an easy, simple and efficient method for the determination of naringenin enantiomers in fruit juices after salting-out-assisted liquid-liquid extraction (SALLE) and high-performance liquid chromatography (HPLC) with diode-array detection (DAD) was developed. The sample treatment is based on the use of water-miscible acetonitrile as the extractant and acetonitrile phase separation under high-salt conditions. After extraction, juice samples were incubated with hydrochloric acid in order to achieve hydrolysis of naringin to naringenin. The hydrolysis parameters were optimized by using a half-fraction factorial central composite design (CCD). After sample preparation, chromatographic separation was obtained on a Chiralcel® OJ-RH column using the mobile phase consisting of 10mM aqueous ammonium acetate:methanol:acetonitrile (50:30:20; v/v/v) with detection at 288nm. The average recovery of the analyzed compounds ranged from 85.6 to 97.1%. The proposed method was satisfactorily used for the determination of naringenin enantiomers in various fruit juices samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ionic liquid-based microwave-assisted dispersive liquid-liquid microextraction and derivatization of sulfonamides in river water, honey, milk, and animal plasma.

PubMed

Xu, Xu; Su, Rui; Zhao, Xin; Liu, Zhuang; Zhang, Yupu; Li, Dan; Li, Xueyuan; Zhang, Hanqi; Wang, Ziming

2011-11-30

The ionic liquid-based microwave-assisted dispersive liquid-liquid microextraction (IL-based MADLLME) and derivatization was applied for the pretreatment of six sulfonamides (SAs) prior to the determination by high-performance liquid chromatography (HPLC). By adding methanol (disperser), fluorescamine solution (derivatization reagent) and ionic liquid (extraction solvent) into sample, extraction, derivatization, and preconcentration were continuously performed. Several experimental parameters, such as the type and volume of extraction solvent, the type and volume of disperser, amount of derivatization reagent, microwave power, microwave irradiation time, pH of sample solution, and ionic strength were investigated and optimized. When the microwave power was 240 W, the analytes could be derivatized and extracted simultaneously within 90 s. The proposed method was applied to the analysis of river water, honey, milk, and pig plasma samples, and the recoveries of analytes obtained were in the range of 95.0-110.8, 95.4-106.3, 95.0-108.3, and 95.7-107.7, respectively. The relative standard deviations varied between 1.5% and 7.3% (n=5). The results showed that the proposed method was a rapid, convenient and feasible method for the determination of SAs in liquid samples. Copyright © 2011 Elsevier B.V. All rights reserved.

The effects of a liquid ethanol diet on nutritional status and fluid balance in the rat.

PubMed

Piano, M R; Artwohl, J; Kim, S D; Gass, G

2001-01-01

The liquid ethanol diet is a widely used method of ethanol administration. The purpose of this study was to evaluate fluid balance using a multitude of physiological parameters (electrolytes, osmolality, total serum proteins, fluid intake/output and body weight), during and after the introduction of liquid ethanol diet. Animals were randomized into four different dietary protocols (two control and two ethanol groups) and were placed in metabolic cages for 16 days. Serum electrolytes, as well as the above parameters, were measured before, during and 1 week after the introduction of 9% (v/v) ethanol-containing diet (Lieber-DeCarli: LD). After the first night on 9% (v/v) ethanol LD, animals had significantly decreased diet consumption, urine output and body weight. However, a major finding of this study was that, during the habituation phase, the electrolyte values remained within the normal range for rats and, in particular, serum sodium was not altered at any time point measured in this study. Based upon the findings from this study, it is recommended that body weight be carefully monitored as a measure of the animal's equilibration and physiological adaptation during the initiation of a liquid ethanol diet, since neither the serum sodium nor calculated osmolality values were changed. Our results also highlight the need to offer water to animals during the habituation phase of ethanol consumption. This is because ethanol rats that were offered water ad libitum lost less weight than groups that did not receive water ad libitum, despite consuming the same amount of LD diet.

Combining Laser Ablation/Liquid Phase Collection Surface Sampling and High-Performance Liquid Chromatography Electrospray Ionization Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ovchinnikova, Olga S; Kertesz, Vilmos; Van Berkel, Gary J

This paper describes the coupling of ambient pressure transmission geometry laser ablation with a liquid phase sample collection method for surface sampling and ionization with subsequent mass spectral analysis. A commercially available autosampler was adapted to produce a liquid droplet at the end of the syringe injection needle while in close proximity to the surface to collect the sample plume produced by laser ablation. The sample collection was followed by either flow injection or a high performance liquid chromatography (HPLC) separation of the extracted components and detection with electrospray ionization mass spectrometry (ESI-MS). To illustrate the analytical utility of thismore » coupling, thin films of a commercial ink sample containing rhodamine 6G and of mixed isobaric rhodamine B and 6G dyes on glass microscope slides were analyzed. The flow injection and HPLC/ESI-MS analysis revealed successful laser ablation, capture and, with HPLC, the separation of the two compounds. The ablated circular area was about 70 m in diameter for these experiments. The spatial sampling resolution afforded by the laser ablation, as well as the ability to use sample processing methods like HPLC between the sample collection and ionization steps, makes this combined surface sampling/ionization technique a highly versatile analytical tool.« less

Occurrence of Campylobacter in commercially broken liquid egg in Japan.

PubMed

Sato, Miki; Sashihara, Nobuhiro

2010-03-01

Samples of unpasteurized liquid egg (whole egg, egg yolk, and egg white) and pasteurized liquid whole egg were collected from egg-breaking facilities in Japan and were tested for the presence of Campylobacter. Isolates recovered were tested for freeze-thaw response, sensitivity to antimicrobials, and heat resistance. Campylobacter was isolated from 27.9% of unpasteurized liquid whole egg samples and 36.0% of unpasteurized liquid egg yolk samples. No Campylobacter was isolated from unpasteurized liquid egg white or pasteurized liquid whole egg samples. The contamination levels of Campylobacter ranged from <3 to 240/100 ml. Freeze-thaw response was tested by freezing and thawing liquid whole egg and egg yolk to examine whether those conditions influenced the survival rate. It was shown that freezing and thawing reduced Campylobacter counts. Sensitivity to all antimicrobials used in this study was observed in 47.6% of the isolates. The most predominant antibiotic resistance profile was similar to that of isolates from chicken. D(55 degrees C)-values of 0.16 to 0.38 min and 0.47 to 0.84 min were determined for Campylobacter isolates in liquid whole egg and egg yolk, respectively. These values were lower than those reported for Salmonella. The very weak heat tolerance of Campylobacter indicated that it could be eliminated at the current legal pasteurization condition. There is no safety concern for commercially broken pasteurized liquid egg pertaining to Campylobacter contamination.

Cavity ring-down spectroscopy in the liquid phase

NASA Astrophysics Data System (ADS)

Xu, Shucheng; Sha, Guohe; Xie, Jinchun

2002-02-01

A new application for cavity ring-down spectroscopic (CRDS) technique using a pulsed polarized light source has been developed in the absorption measurement of liquids for "colorless" organic compounds using both a single sample cell and double sample cells inserted in an optical cavity at Brewster angle. At present an experimental capability of measuring absorption coefficients as small as 2-5×10-7 cm-1 has been demonstrated by measurement of the absorption baselines. The first spectra for CRDS in the liquid phase, the C-H stretching fifth vibrational overtones of benzene in the pure liquid and hexane solution are obtained. The optical absorption length for liquids in both a single sample cell and double sample cells of 1 cm length is up to 900 cm due to multipass of light within an optical cavity. Compared to the thermal lens and optoacoustic spectroscopic techniques, the sensitivity for CRDS mainly depends on the optical absorption path of the sample (single passing path of the sample times multipass times), is not determined by the laser power and the length of the sample cell. The absolute absorption coefficient and band intensity for the sample are determined directly by the spectroscopy.

Do-It-Yourself Device for Recovery of Cryopreserved Samples Accidentally Dropped into Cryogenic Storage Tanks

PubMed Central

Mehta, Rohini; Baranova, Ancha; Birerdinc, Aybike

2012-01-01

Liquid nitrogen is colorless, odorless, extremely cold (-196 °C) liquid kept under pressure. It is commonly used as a cryogenic fluid for long term storage of biological materials such as blood, cells and tissues 1,2. The cryogenic nature of liquid nitrogen, while ideal for sample preservation, can cause rapid freezing of live tissues on contact - known as 'cryogenic burn'2, which may lead to severe frostbite in persons closely involved in storage and retrieval of samples from Dewars. Additionally, as liquid nitrogen evaporates it reduces the oxygen concentration in the air and might cause asphyxia, especially in confined spaces2. In laboratories, biological samples are often stored in cryovials or cryoboxes stacked in stainless steel racks within the Dewar tanks1. These storage racks are provided with a long shaft to prevent boxes from slipping out from the racks and into the bottom of Dewars during routine handling. All too often, however, boxes or vials with precious samples slip out and sink to the bottom of liquid nitrogen filled tank. In such cases, samples could be tediously retrieved after transferring the liquid nitrogen into a spare container or discarding it. The boxes and vials can then be relatively safely recovered from emptied Dewar. However, the cryogenic nature of liquid nitrogen and its expansion rate makes sunken sample retrieval hazardous. It is commonly recommended by Safety Offices that sample retrieval be never carried out by a single person. Another alternative is to use commercially available cool grabbers or tongs to pull out the vials3. However, limited visibility within the dark liquid filled Dewars poses a major limitation in their use. In this article, we describe the construction of a Cryotolerant DIY retrieval device, which makes sample retrieval from Dewar containing cryogenic fluids both safe and easy. PMID:22617806

Do-It-Yourself device for recovery of cryopreserved samples accidentally dropped into cryogenic storage tanks.

PubMed

Mehta, Rohini; Baranova, Ancha; Birerdinc, Aybike

2012-05-11

Liquid nitrogen is colorless, odorless, extremely cold (-196 °C) liquid kept under pressure. It is commonly used as a cryogenic fluid for long term storage of biological materials such as blood, cells and tissues (1,2). The cryogenic nature of liquid nitrogen, while ideal for sample preservation, can cause rapid freezing of live tissues on contact - known as 'cryogenic burn' (2), which may lead to severe frostbite in persons closely involved in storage and retrieval of samples from Dewars. Additionally, as liquid nitrogen evaporates it reduces the oxygen concentration in the air and might cause asphyxia, especially in confined spaces (2). In laboratories, biological samples are often stored in cryovials or cryoboxes stacked in stainless steel racks within the Dewar tanks (1). These storage racks are provided with a long shaft to prevent boxes from slipping out from the racks and into the bottom of Dewars during routine handling. All too often, however, boxes or vials with precious samples slip out and sink to the bottom of liquid nitrogen filled tank. In such cases, samples could be tediously retrieved after transferring the liquid nitrogen into a spare container or discarding it. The boxes and vials can then be relatively safely recovered from emptied Dewar. However, the cryogenic nature of liquid nitrogen and its expansion rate makes sunken sample retrieval hazardous. It is commonly recommended by Safety Offices that sample retrieval be never carried out by a single person. Another alternative is to use commercially available cool grabbers or tongs to pull out the vials (3). However, limited visibility within the dark liquid filled Dewars poses a major limitation in their use. In this article, we describe the construction of a Cryotolerant DIY retrieval device, which makes sample retrieval from Dewar containing cryogenic fluids both safe and easy.

Recent progress of task-specific ionic liquids in chiral resolution and extraction of biological samples and metal ions.

PubMed

Wu, Datong; Cai, Pengfei; Zhao, Xiaoyong; Kong, Yong; Pan, Yuanjiang

2018-01-01

Ionic liquids have been functionalized for modern applications. The functional ionic liquids are also called task-specific ionic liquids. Various task-specific ionic liquids with certain groups have been constructed and exploited widely in the field of separation. To take advantage of their properties in separation science, task-specific ionic liquids are generally used in techniques such as liquid-liquid extraction, solid-phase extraction, gas chromatography, high-performance liquid chromatography, and capillary electrophoresis. This review mainly covers original research papers published in the last five years, and we will focus on task-specific ionic liquids as the chiral selectors in chiral resolution and as extractant or sensor for biological samples and metal ion purification. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantitative determination of atmospheric hydroperoxyl radical

DOEpatents

Springston, Stephen R.; Lloyd, Judith; Zheng, Jun

2007-10-23

A method for the quantitative determination of atmospheric hydroperoxyl radical comprising: (a) contacting a liquid phase atmospheric sample with a chemiluminescent compound which luminesces on contact with hydroperoxyl radical; (b) determining luminescence intensity from the liquid phase atmospheric sample; and (c) comparing said luminescence intensity from the liquid phase atmospheric sample to a standard luminescence intensity for hydroperoxyl radical. An apparatus for automating the method is also included.

Determination of dissolved-phase pesticides in surface water from the Yakima River basin, Washington, using the Goulden large-sample extractor and gas chromatography/mass spectrometer

USGS Publications Warehouse

Foster, Gregory D.; Gates, Paul M.; Foreman, William T.; McKenzie, Stuart W.; Rinella, Frank A.

1993-01-01

Concentrations of pesticides in the dissolved phase of surface water samples from the Yakima River basin, WA, were determined using preconcentration in the Goulden large-sample extractor (GLSE) and gas chromatography/mass spectrometry (GC/MS) analysis. Sample volumes ranging from 10 to 120 L were processed with the GLSE, and the results from the large-sample analyses were compared to those derived from 1-L continuous liquid-liquid extractions Few of the 40 target pesticides were detected in 1-L samples, whereas large-sample preconcentration in the GLSE provided detectable levels for many of the target pesticides. The number of pesticides detected in GLSE processed samples was usually directly proportional to sample volume, although the measured concentrations of the pesticides were generally lower at the larger sample volumes for the same water source. The GLSE can be used to provide lower detection levels relative to conventional liquid-liquid extraction in GC/MS analysis of pesticides in samples of surface water.

Chemical Composition and Evaluation of Nicotine, Tobacco Alkaloids, pH and Selected Flavors in e-Cigarette Cartridges and Refill Solutions

PubMed Central

Lisko, Joseph G.; Tran, Hang; Stanfill, Stephen B.; Blount, Benjamin C.; Watson, Clifford H.

2015-01-01

Introduction Electronic cigarette (e-cigarette) use is increasing dramatically in developed countries, but little is known about these rapidly evolving products. This study analyzed and evaluated the chemical composition including nicotine, tobacco alkaloids, pH and flavors in 36 e-liquids brands from four manufacturers. Methods We determined the concentrations of nicotine, alkaloids, and select flavors and measured pH in solutions used in e-cigarettes. E-cigarette products were chosen based upon favorable consumer approval ratings from online review websites. Quantitative analyses were performed using strict quality assurance/quality control (QC) validated methods previously established by our lab for the measurement of nicotine, alkaloids, pH and flavors. Results Three-quarters of the products contained lower measured nicotine levels than the stated label values (6% - 42% by concentration). The pH for e-liquids ranged from 5.1 – 9.1. Minor tobacco alkaloids were found in all samples containing nicotine, and their relative concentrations varied widely among manufacturers. A number of common flavor compounds were analyzed in all e-liquids. Conclusions Free nicotine levels calculated from the measurement of pH correlated with total nicotine content. The direct correlation between the total nicotine concentration and pH suggests that the alkalinity of nicotine drives the pH of e-cigarette solutions. A higher percentage of nicotine exists in the more absorbable free form as total nicotine concentration increases. A number of products contained tobacco alkaloids at concentrations that exceed U.S. Pharmacopeia limits for impurities in nicotine used in pharmaceutical and food products. PMID:25636907

Halo-shaped Flowing Atmospheric Pressure Afterglow – a Heavenly New Design for Simplified Sample Introduction and Improved Ionization in Ambient Mass Spectrometry

PubMed Central

Pfeuffer, Kevin P.; Schaper, J. Niklas; Shelley, Jacob T.; Ray, Steven J.; Chan, George C.-Y.; Bings, Nicolas H.; Hieftje, Gary M.

2013-01-01

The flowing atmospheric pressure afterglow (FAPA) is a promising new source for atmospheric pressure, ambient desorption/ionization mass spectrometry. However, problems exist with reproducible sample introduction into the FAPA source. To overcome this limitation, a new FAPA geometry has been developed in which concentric tubular electrodes are utilized to form a halo-shaped discharge; this geometry has been termed the halo-FAPA or h-FAPA. With this new geometry, it is still possible to achieve direct desorption and ionization from a surface; however, sample introduction through the inner capillary is also possible and improves interaction between the sample material (solution, vapor, or aerosol) and the plasma to promote desorption and ionization. The h-FAPA operates with a helium gas flow of 0.60 L/min outer, 0.30 L/min inner, applied current of 30 mA at 200 V for 6 watts of power. In addition, separation of the discharge proper and sample material prevents perturbations to the plasma. Optical-emission characterization and gas rotational temperatures reveal that the temperature of the discharge is not significantly affected (< 3% change at 450K) by water vapor during solution-aerosol sample introduction. The primary mass-spectral background species are protonated water clusters, and the primary analyte ions are protonated molecular ions (M+H+). Flexibility of the new ambient sampling source is demonstrated by coupling it with a laser ablation unit, a concentric nebulizer and a droplet-on-demand system for sample introduction. A novel arrangement is also presented in which the central channel of the h-FAPA is used as the inlet to a mass spectrometer. PMID:23808829

Halo-shaped flowing atmospheric pressure afterglow: a heavenly design for simplified sample introduction and improved ionization in ambient mass spectrometry.

PubMed

Pfeuffer, Kevin P; Schaper, J Niklas; Shelley, Jacob T; Ray, Steven J; Chan, George C-Y; Bings, Nicolas H; Hieftje, Gary M

2013-08-06

The flowing atmospheric-pressure afterglow (FAPA) is a promising new source for atmospheric-pressure, ambient desorption/ionization mass spectrometry. However, problems exist with reproducible sample introduction into the FAPA source. To overcome this limitation, a new FAPA geometry has been developed in which concentric tubular electrodes are utilized to form a halo-shaped discharge; this geometry has been termed the halo-FAPA or h-FAPA. With this new geometry, it is still possible to achieve direct desorption and ionization from a surface; however, sample introduction through the inner capillary is also possible and improves interaction between the sample material (solution, vapor, or aerosol) and the plasma to promote desorption and ionization. The h-FAPA operates with a helium gas flow of 0.60 L/min outer, 0.30 L/min inner, and applied current of 30 mA at 200 V for 6 W of power. In addition, separation of the discharge proper and sample material prevents perturbations to the plasma. Optical-emission characterization and gas rotational temperatures reveal that the temperature of the discharge is not significantly affected (<3% change at 450 K) by water vapor during solution-aerosol sample introduction. The primary mass-spectral background species are protonated water clusters, and the primary analyte ions are protonated molecular ions (M + H(+)). Flexibility of the new ambient sampling source is demonstrated by coupling it with a laser ablation unit, a concentric nebulizer, and a droplet-on-demand system for sample introduction. A novel arrangement is also presented in which the central channel of the h-FAPA is used as the inlet to a mass spectrometer.

APPLICATION OF A SPRAY DEPOSITION METHOD FOR REVERSED PHASE LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY

EPA Science Inventory

Four coal gasification wastewater samples were analyzed for nonvolatile and polar organics by liquid chromatography-mass spectrometry (LC/MS). Samples were separated on a reverse phase liquid chromatographic column using an aqueous solvent as the eluant. A special spray depositio...

Combined liquid chromatography-mass spectrometry for trace analysis of pharmaceuticals

NASA Astrophysics Data System (ADS)

Schmidt, Lothar; Danigel, Harald; Jungclas, Hartmut

1982-07-01

A 252Cf-plasma desorption mass spectrometer (PDMS) for the analysis of thin layers from nonvolatile organic samples has been set up to be combined with a liquid chromatograph. A novel interface performs the direct inlet of the liquid sample through a capillary into the vacuum system of the spectrometer. Samples of drugs are periodically collected, transferred to the ion source and analysed using a rotating disk. This on-line sample preparation has been tested for three antiarrhythmic drugs using various solvents and mixtures.

Images reveal that atmospheric particles can undergo liquid-liquid phase separations.

PubMed

You, Yuan; Renbaum-Wolff, Lindsay; Carreras-Sospedra, Marc; Hanna, Sarah J; Hiranuma, Naruki; Kamal, Saeid; Smith, Mackenzie L; Zhang, Xiaolu; Weber, Rodney J; Shilling, John E; Dabdub, Donald; Martin, Scot T; Bertram, Allan K

2012-08-14

A large fraction of submicron atmospheric aerosol particles contains both organic material and inorganic salts. As the relative humidity cycles in the atmosphere and the water content of the particles correspondingly changes, these mixed particles can undergo a range of phase transitions, possibly including liquid-liquid phase separation. If liquid-liquid phase separation occurs, the gas-particle partitioning of atmospheric semivolatile organic compounds, the scattering and absorption of solar radiation, and the reactive uptake of gas species on atmospheric particles may be affected, with important implications for climate predictions. The actual occurrence of liquid-liquid phase separation within individual atmospheric particles has been considered uncertain, in large part because of the absence of observations for real-world samples. Here, using optical and fluorescence microscopy, we present images that show the coexistence of two noncrystalline phases for real-world samples collected on multiple days in Atlanta, GA as well as for laboratory-generated samples under simulated atmospheric conditions. These results reveal that atmospheric particles can undergo liquid-liquid phase separations. To explore the implications of these findings, we carried out simulations of the Atlanta urban environment and found that liquid-liquid phase separation can result in increased concentrations of gas-phase NO(3) and N(2)O(5) due to decreased particle uptake of N(2)O(5).

Microbial flora of in-use soap products.

PubMed Central

McBride, M E

1984-01-01

A comparison has been made of the in-use bacterial load of two bar soaps with and without antibacterials and two liquid soaps in five different locations over a 1-week period. Of the 25 samples taken from each soap, 92 to 96% of samples from bar soaps were culture positive as compared to 8% of those from liquid soaps. Bacterial populations ranged from 0 to 3.8 log CFU per sample for bar soaps and from 0 to 2.0 log CFU per sample for liquid soaps. The mean bacterial populations per sample were 1.96 and 2.47 log CFU for the two bar soaps, and 0.08 and 0.12 log CFU for the two liquid soaps. The difference in bacterial population between bar soaps and liquid soaps was statistically significant (P = 0.005). Staphylococcus aureus was isolated on three occasions from bar soaps but not from liquid soaps. S. aureus was isolated twice from the exterior of the plastic dispensers of liquid soap but not from the soap itself. Gram-negative bacteria were cultured only from soaps containing antibacterials. Bacterial populations on bar soaps were not high compared with bacterial populations on hands, and the flora was continually changing without evidence of a carrier state. PMID:6486782

Screening of commercial and pecan shell-extracted liquid smoke agents as natural antimicrobials against foodborne pathogens.

PubMed

Van Loo, Ellen J; Babu, D; Crandall, Philip G; Ricke, Steven C

2012-06-01

Liquid smoke extracts have traditionally been used as flavoring agents, are known to possess antioxidant properties, and serve as natural alternatives to conventional antimicrobials. The antimicrobial efficacies of commercial liquid smoke samples may vary depending on their source and composition and the methods used to extract and concentrate the smoke. We investigated the MICs of eight commercial liquid smoke samples against Salmonella Enteritidis, Staphylococcus aureus, and Escherichia coli . The commercial liquid smoke samples purchased were supplied by the manufacturer as water-based or concentrated extracts of smoke from different wood sources. The MICs of the commercial smokes to inhibit the growth of foodborne pathogens ranged from 0.5 to 6.0% for E. coli, 0.5 to 8.0% for Salmonella, and 0.38 to 6% for S. aureus. The MIC for each liquid smoke sample was similar in its effect on both E. coli and Salmonella. Solvent-extracted antimicrobials prepared using pecan shells displayed significant differences between their inhibitory concentrations depending on the type of solvent used for extraction. The results indicated that the liquid smoke samples tested in this study could serve as effective natural antimicrobials and that their inhibitory effects depended more on the solvents used for extraction than the wood source.

Exclusive Liquid Repellency: An Open Multi-Liquid-Phase Technology for Rare Cell Culture and Single-Cell Processing.

PubMed

Li, Chao; Yu, Jiaquan; Schehr, Jennifer; Berry, Scott M; Leal, Ticiana A; Lang, Joshua M; Beebe, David J

2018-05-23

The concept of high liquid repellency in multi-liquid-phase systems (e.g., aqueous droplets in an oil background) has been applied to areas of biomedical research to realize intrinsic advantages not available in single-liquid-phase systems. Such advantages have included minimizing analyte loss, facile manipulation of single-cell samples, elimination of biofouling, and ease of use regarding loading and retrieving of the sample. In this paper, we present generalized design rules for predicting the wettability of solid-liquid-liquid systems (especially for discrimination between exclusive liquid repellency (ELR) and finite liquid repellency) to extend the applications of ELR. We then apply ELR to two model systems with open microfluidic design in cell biology: (1) in situ underoil culture and combinatorial coculture of mammalian cells in order to demonstrate directed single-cell multiencapsulation with minimal waste of samples as compared to stochastic cell seeding and (2) isolation of a pure population of circulating tumor cells, which is required for certain downstream analyses including sequencing and gene expression profiling.

Optimization of chemical and instrumental parameters in hydride generation laser-induced breakdown spectrometry for the determination of arsenic, antimony, lead and germanium in aqueous samples.

PubMed

Yeşiller, Semira Unal; Yalçın, Serife

2013-04-03

A laser induced breakdown spectrometry hyphenated with on-line continuous flow hydride generation sample introduction system, HG-LIBS, has been used for the determination of arsenic, antimony, lead and germanium in aqueous environments. Optimum chemical and instrumental parameters governing chemical hydride generation, laser plasma formation and detection were investigated for each element under argon and nitrogen atmosphere. Arsenic, antimony and germanium have presented strong enhancement in signal strength under argon atmosphere while lead has shown no sensitivity to ambient gas type. Detection limits of 1.1 mg L(-1), 1.0 mg L(-1), 1.3 mg L(-1) and 0.2 mg L(-1) were obtained for As, Sb, Pb and Ge, respectively. Up to 77 times enhancement in detection limit of Pb were obtained, compared to the result obtained from the direct analysis of liquids by LIBS. Applicability of the technique to real water samples was tested through spiking experiments and recoveries higher than 80% were obtained. Results demonstrate that, HG-LIBS approach is suitable for quantitative analysis of toxic elements and sufficiently fast for real time continuous monitoring in aqueous environments. Copyright © 2013 Elsevier B.V. All rights reserved.

In-Line Reactions and Ionizations of Vaporized Diphenylchloroarsine and Diphenylcyanoarsine in Atmospheric Pressure Chemical Ionization Mass Spectrometry

NASA Astrophysics Data System (ADS)

Okumura, Akihiko; Takada, Yasuaki; Watanabe, Susumu; Hashimoto, Hiroaki; Ezawa, Naoya; Seto, Yasuo; Takayama, Yasuo; Sekioka, Ryoji; Yamaguchi, Shintaro; Kishi, Shintaro; Satoh, Takafumi; Kondo, Tomohide; Nagashima, Hisayuki; Nagoya, Tomoki

2016-07-01

We propose detecting a fragment ion (Ph2As+) using counter-flow introduction atmospheric pressure chemical ionization ion trap mass spectrometry for sensitive air monitoring of chemical warfare vomiting agents diphenylchloroarsine (DA) and diphenylcyanoarsine (DC). The liquid sample containing of DA, DC, and bis(diphenylarsine)oxide (BDPAO) was heated in a dry air line, and the generated vapor was mixed into the humidified air flowing through the sampling line of a mass spectrometer. Humidity effect on the air monitoring was investigated by varying the humidity of the analyzed air sample. Evidence of the in-line conversion of DA and DC to diphenylarsine hydroxide (DPAH) and then BDPAO was obtained by comparing the chronograms of various ions from the beginning of heating. Multiple-stage mass spectrometry revealed that the protonated molecule (MH+) of DA, DC, DPAH, and BDPAO could produce Ph2As+ through their in-source fragmentation. Among the signals of the ions that were investigated, the Ph2As+ signal was the most intense and increased to reach a plateau with the increased air humidity, whereas the MH+ signal of DA decreased. It was suggested that DA and DC were converted in-line into BDPAO, which was a major source of Ph2As+.

Pathologists and liquid biopsies: to be or not to be?

PubMed

Hofman, Paul; Popper, Helmut H

2016-12-01

Recently, the advent of therapies targeting genomic alterations has improved the care of patients with certain types of cancer. While molecular targets were initially detected in nucleic acid samples extracted from tumor tissue, detection of nucleic acids in circulating blood has allowed the development of what has become known as liquid biopsies, which provide a complementary and alternative sample source allowing identification of genomic alterations that might be addressed by targeted therapy. Consequently, liquid biopsies might rapidly revolutionize oncology practice in allowing administration of more effective treatments. Liquid biopsies also provide an approach towards short-term monitoring of metastatic cancer patients to evaluate efficacy of treatment and/or early detection of secondary mutations responsible for resistance to treatment. In this context, pathologists, who have already been required in recent years to take interest in the domain of molecular pathology of cancer, now face new challenges. The attitude of pathologists to and level of involvement in the practice of liquid biopsies, including mastering the methods employed in molecular analysis of blood samples, need close attention. Regardless of the level of involvement of pathologists in this new field, it is mandatory that oncologists, biologists, geneticists, and pathologists work together to coordinate the pre-analytical, analytical, and post-analytical phases of molecular assessment of tissue and liquid samples of individual cancer patients. The challenges include (1) implementation of effective and efficient procedures for reception and analysis of liquid and tissue samples for histopathological and molecular evaluation and (2) assuring short turn-around times to facilitate rapid optimization of individual patient treatment. In this paper, we will review the following: (1) recent data concerning the concept of liquid biopsies in oncology and its development for patient care, (2) advantages and limitations of molecular analyses performed on blood samples compared to those performed on tissue samples, and (3) short-term challenges facing pathologists in dealing with liquid biopsies of cancer patients and new strategies to early detect metastatic tumor cell clones.

An interface for the direct coupling of small liquid samples to AMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ognibene, T. J.; Thomas, A. T.; Daley, P. F.

We describe the moving wire interface attached to the 1-MV AMS system at LLNL’s Center for Accelerator Mass Spectrometry for the analysis of nonvolatile liquid samples as either discrete drops or from the direct output of biochemical separatory instrumentation, such as high-performance liquid chromatography (HPLC). Discrete samples containing at least a few 10 s of nanograms of carbon and as little as 50 zmol 14C can be measured with a 3–5% precision in a few minutes. The dynamic range of our system spans approximately 3 orders in magnitude. Sample to sample memory is minimized by the use of fresh targetsmore » for each discrete sample or by minimizing the amount of carbon present in a peak generated by an HPLC containing a significant amount of 14C. As a result, liquid sample AMS provides a new technology to expand our biomedical AMS program by enabling the capability to measure low-level biochemicals in extremely small samples that would otherwise be inaccessible.« less

An interface for the direct coupling of small liquid samples to AMS

DOE PAGES

Ognibene, T. J.; Thomas, A. T.; Daley, P. F.; ...

2015-05-28

We describe the moving wire interface attached to the 1-MV AMS system at LLNL’s Center for Accelerator Mass Spectrometry for the analysis of nonvolatile liquid samples as either discrete drops or from the direct output of biochemical separatory instrumentation, such as high-performance liquid chromatography (HPLC). Discrete samples containing at least a few 10 s of nanograms of carbon and as little as 50 zmol 14C can be measured with a 3–5% precision in a few minutes. The dynamic range of our system spans approximately 3 orders in magnitude. Sample to sample memory is minimized by the use of fresh targetsmore » for each discrete sample or by minimizing the amount of carbon present in a peak generated by an HPLC containing a significant amount of 14C. As a result, liquid sample AMS provides a new technology to expand our biomedical AMS program by enabling the capability to measure low-level biochemicals in extremely small samples that would otherwise be inaccessible.« less

Electro-focusing liquid extractive surface analysis (EF-LESA) coupled to mass spectrometry.

PubMed

Brenton, A Gareth; Godfrey, A Ruth

2014-04-01

Analysis of the chemical composition of surfaces by liquid sampling devices interfaced to mass spectrometry is attractive as the sample stream can be continuously monitored at good sensitivity and selectivity. A sampling probe has been constructed that takes discrete liquid samples (typically <100 nL) of a surface. It incorporates an electrostatic lens system, comprising three electrodes, to which static and pulsed voltages are applied to form a conical "liquid tip", employed to dissolve analytes at a surface. A prototype system demonstrates spatial resolution of 0.093 mm(2). Time of contact between the liquid tip and the surface is controlled to standardize extraction. Calibration graphs of different analyte concentrations on a stainless surface have been measured, together with the probe's reproducibility, carryover, and recovery. A leucine enkephalin-coated surface demonstrated good linearity (R(2) = 0.9936), with a recovery of 90% and a limit of detection of 38 fmol per single spot sampled. The probe is compact and can be fitted into automated sample analysis equipment having potential for rapid analysis of surfaces at a good spatial resolution.

Electro-Focusing Liquid Extractive Surface Analysis (EF-LESA) Coupled to Mass Spectrometry

PubMed Central

2014-01-01

Analysis of the chemical composition of surfaces by liquid sampling devices interfaced to mass spectrometry is attractive as the sample stream can be continuously monitored at good sensitivity and selectivity. A sampling probe has been constructed that takes discrete liquid samples (typically <100 nL) of a surface. It incorporates an electrostatic lens system, comprising three electrodes, to which static and pulsed voltages are applied to form a conical “liquid tip”, employed to dissolve analytes at a surface. A prototype system demonstrates spatial resolution of 0.093 mm2. Time of contact between the liquid tip and the surface is controlled to standardize extraction. Calibration graphs of different analyte concentrations on a stainless surface have been measured, together with the probe’s reproducibility, carryover, and recovery. A leucine enkephalin-coated surface demonstrated good linearity (R2 = 0.9936), with a recovery of 90% and a limit of detection of 38 fmol per single spot sampled. The probe is compact and can be fitted into automated sample analysis equipment having potential for rapid analysis of surfaces at a good spatial resolution. PMID:24597530

An enhanced droplet-based liquid microjunction surface sampling system coupled with HPLC-ESI-MS/MS for spatially resolved analysis

DOE PAGES

Van Berkel, Gary J.; Weiskittel, Taylor M.; Kertesz, Vilmos

2014-11-07

Droplet-based liquid microjunction surface sampling coupled with high-performance liquid chromatography (HPLC)-electrospray ionization (ESI)-tandem mass spectrometry (MS/MS) for spatially resolved analysis provides the possibility of effective analysis of complex matrix samples and can provide a greater degree of chemical information from a single spot sample than is typically possible with a direct analysis of an extract. Described here is the setup and enhanced capabilities of a discrete droplet liquid microjunction surface sampling system employing a commercially available CTC PAL autosampler. The system enhancements include incorporation of a laser distance sensor enabling unattended analysis of samples and sample locations of dramatically disparatemore » height as well as reliably dispensing just 0.5 μL of extraction solvent to make the liquid junction to the surface, wherein the extraction spot size was confined to an area about 0.7 mm in diameter; software modifications improving the spatial resolution of sampling spot selection from 1.0 to 0.1 mm; use of an open bed tray system to accommodate samples as large as whole-body rat thin tissue sections; and custom sample/solvent holders that shorten sampling time to approximately 1 min per sample. Lastly, the merit of these new features was demonstrated by spatially resolved sampling, HPLC separation, and mass spectral detection of pharmaceuticals and metabolites from whole-body rat thin tissue sections and razor blade (“crude”) cut mouse tissue.« less

An enhanced droplet-based liquid microjunction surface sampling system coupled with HPLC-ESI-MS/MS for spatially resolved analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Berkel, Gary J.; Weiskittel, Taylor M.; Kertesz, Vilmos

Droplet-based liquid microjunction surface sampling coupled with high-performance liquid chromatography (HPLC)-electrospray ionization (ESI)-tandem mass spectrometry (MS/MS) for spatially resolved analysis provides the possibility of effective analysis of complex matrix samples and can provide a greater degree of chemical information from a single spot sample than is typically possible with a direct analysis of an extract. Described here is the setup and enhanced capabilities of a discrete droplet liquid microjunction surface sampling system employing a commercially available CTC PAL autosampler. The system enhancements include incorporation of a laser distance sensor enabling unattended analysis of samples and sample locations of dramatically disparatemore » height as well as reliably dispensing just 0.5 μL of extraction solvent to make the liquid junction to the surface, wherein the extraction spot size was confined to an area about 0.7 mm in diameter; software modifications improving the spatial resolution of sampling spot selection from 1.0 to 0.1 mm; use of an open bed tray system to accommodate samples as large as whole-body rat thin tissue sections; and custom sample/solvent holders that shorten sampling time to approximately 1 min per sample. Lastly, the merit of these new features was demonstrated by spatially resolved sampling, HPLC separation, and mass spectral detection of pharmaceuticals and metabolites from whole-body rat thin tissue sections and razor blade (“crude”) cut mouse tissue.« less

Optimizing separations in online comprehensive two‐dimensional liquid chromatography

PubMed Central

Gargano, Andrea F.G.; Schoenmakers, Peter J.

2017-01-01

Abstract Online comprehensive two‐dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two‐dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two‐dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass spectrometry (e.g. high‐molecular‐weight polymers), providing important information on the distribution of the sample components along chemical dimensions (molecular weight, charge, lipophilicity, stereochemistry, etc.). Also, in comparison with conventional one‐dimensional liquid chromatography, two‐dimensional liquid chromatography provides a greater separation power (peak capacity). Because of the additional selectivity and higher peak capacity, the combination of two‐dimensional liquid chromatography with mass spectrometry allows for simpler mixtures of compounds to be introduced in the ion source at any given time, improving quantitative analysis by reducing matrix effects. In this review, we summarize the rationale and principles of two‐dimensional liquid chromatography experiments, describe advantages and disadvantages of combining different selectivities and discuss strategies to improve the quality of two‐dimensional liquid chromatography separations. PMID:29027363

[Determination of fatty acid esters of chloropropanediols in diet samples by gas chromatography-mass spectrometry coupled with solid-supported liquid-liquid extraction].

PubMed

Gao, Jie; Liu, Qing; Han, Feng; Miao, Hong; Zhao, Yunfeng; Wu, Yongning

2014-05-01

To establish a method for the determination of fatty acid esters of 3-monochloropropane-1, 2-diol (3-MCPD) and 2-monochloropropane-1, 3-diol (2-MCPD) in diet samples by gas chromatography-mass spectrometry (GC-MS) with solid-supported liquid-liquid extraction (SLE). Diet samples were ultrasonically extracted by hexane, followed by ester cleavage reaction with sodium methylate in methanol, and then purified by solid-supported liquid-liquid extraction. (SLE) using diatomaceous earth as the sorbent. After derivatization with heptafluorobutyrylimidazole, the analytes were detected by GC-MS and quantified by the deuterated internal standards. The limits of detection (LODs) of 3-MCPD esters and 2-MCPD esters in different diet samples were 0.002 - 0.005 mg/kg and 0.002 - 0.006 mg/kg. The average recoveries of 3-MCPD esters and 2-MCPD esters at the spiking levels of 0.05 and 0.1 mg/kg in the diet samples were in the range of 65.9% - 104.2% and 75.4% - 118.0%, respectively, with the relative standard deviations in the range of 2.2% - 14.2% and 0.8% - .13.9%. The method is simple, accurate and rugged for the determination of fatty acid esters of 3-MCPD and 2-MCPD in diet samples.

Flame Temperatures and Internal Pressures of Pyrotechnic Igniters Used in Liquid Propellant Gun Firings

DTIC Science & Technology

1982-03-01

IP AT 655 ~~I . . . . . 45 7 I. INTRODUCTION The lack of quantitative ignition design criteria in liquid propellant gun firings requires the...Meeting~ CPIA PubUaation No. :300~ VoZ . I, AppUed Physias Laboratory~ SiZver Spring~ MD~ p. :39:3 (19?9). 26 REFERENCES 1. J. D. Knapton, I. C. Stobie...T9E6 Igniter and a Booster Charge of M30 and Eimite !I I ll[[l 1!13 IP -111 .. Sll tiiiiML I RRX-P.D. !1252 I ~· s 1: 31~ 211 z II Figure B2

Comparison of alternate fuels for aircraft

NASA Technical Reports Server (NTRS)

Witcofski, R. D.

1979-01-01

A comparison of candidate alternate fuels for aircraft is presented. The fuels discussed include liquid hydrogen, liquid methane, and synthetic aviation kerosene. Each fuel is evaluated from the standpoint of production, transmission, airport storage and distribution facilities, and use in aircraft. Technology deficient areas for cryogenic fuels, which should be advanced prior to the introduction of the fuels into the aviation industry, are identified, as are the cost and energy penalties associated with not achieving those advances. Environmental emissions and safety aspects of fuel selection are discussed. A detailed description of the various fuel production and liquefaction processes and their efficiencies and economics is given.

Colloquium: Zoo of quantum-topological phases of matter

NASA Astrophysics Data System (ADS)

Wen, Xiao-Gang

2017-10-01

What are topological phases of matter? First, they are phases of matter at zero temperature. Second, they have a nonzero energy gap for the excitations above the ground state. Third, they are disordered liquids that seem to have no feature. But those disordered liquids actually can have rich patterns of many-body entanglement representing new kinds of order. This Colloquium gives a simple introduction and a brief survey of topological phases of matter. First topological phases with topological order (i.e., with long-range entanglement) are discussed. Then topological phases without topological order (i.e., with short-range entanglement) are covered.

AM363 martensitic stainless steel: A multiphase equation of state

NASA Astrophysics Data System (ADS)

De Lorenzi-Venneri, Giulia; Crockett, Scott D.

2017-01-01

A multiphase equation of state for stainless steel AM363 has been developed within the Opensesame approach and has been entered as material 4295 in the LANL-SESAME Library. Three phases were constructed separately: the low pressure martensitic phase, the austenitic phase and the liquid. Room temperature data and the explicit introduction of a magnetic contribution to the free energy determined the martensitic phase, while shock Hugoniot data was used to determine the austenitic phase and the phase boundaries. More experimental data or First Principles calculations would be useful to better characterize the liquid.

Analysis of trimethoprim, lincomycin, sulfadoxin and tylosin in swine manure using laser diode thermal desorption-atmospheric pressure chemical ionization-tandem mass spectrometry.

PubMed

Solliec, Morgan; Massé, Daniel; Sauvé, Sébastien

2014-10-01

A new extraction method coupled to a high throughput sample analysis technique was developed for the determination of four veterinary antibiotics. The analytes belong to different groups of antibiotics such as chemotherapeutics, sulfonamides, lincosamides and macrolides. Trimethoprim (TMP), sulfadoxin (SFX), lincomycin (LCM) and tylosin (TYL) were extracted from lyophilized manure using a sonication extraction. McIlvaine buffer and methanol (MeOH) were used as extraction buffers, followed by cation-exchange solid phase extraction (SPE) for clean-up. Analysis was performed by laser diode thermal desorption-atmospheric pressure chemical-ionization (LDTD-APCI) tandem mass spectrometry (MS/MS) with selected reaction monitoring (SRM) detection. The LDTD is a high throughput sample introduction method that reduces total analysis time to less than 15s per sample, compared to minutes when using traditional liquid chromatography (LC). Various SPE parameters were optimized after sample extraction: the stationary phase, the extraction solvent composition, the quantity of sample extracted and sample pH. LDTD parameters were also optimized: solvent deposition, carrier gas, laser power and corona discharge. The method limit of detection (MLD) ranged from 2.5 to 8.3 µg kg(-1) while the method limit of quantification (MLQ) ranged from 8.3 to 28µgkg(-1). Calibration curves in the manure matrix showed good linearity (R(2)≥ 0.996) for all analytes and the interday and intraday coefficients of variation were below 14%. Recoveries of analytes from manure ranged from 53% to 69%. The method was successfully applied to real manure samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of dispersive liquid-liquid microextraction for the preconcentration of eight parabens in real samples and their determination by high-performance liquid chromatography.

PubMed

Shen, Xiong; Liang, Jian; Zheng, Luxia; Lv, Qianzhou; Wang, Hong

2017-11-01

A simple and sensitive method for the simultaneous determination of eight parabens in human plasma and urine samples was developed. The samples were preconcentrated using dispersive liquid-liquid microextraction based on the solidification of floating organic drops and determined by high-performance liquid chromatography with ultraviolet detection. The influence of variables affecting the extraction efficiency was investigated and optimized using Placket-Burman design and Box-Behnken design. The optimized values were: 58 μL of 1-decanol (as extraction solvent), 0.65 mL methanol (as disperser solvent), 1.5% w/v NaCl in 5.0 mL of sample solution, pH 10.6, and 4.0 min centrifugation at 4000 rpm. The extract was injected into the high-performance liquid chromatography system for analysis. Under the optimum conditions, the linear ranges for eight parabens in plasma and urine were 1.0-1000 ng/mL, with correlation coefficients above 0.994. The limit of detection was 0.2-0.4 and 0.1-0.4 ng/mL for plasma and urine samples, respectively. Relative recoveries were between 80.3 and 110.7%, while relative standard deviations were less than 5.4%. Finally, the method was applied to analyze the parabens in 98 patients of primary breast cancer. Results showed that parabens existed widely, at least one paraben detected in 96.9% (95/98) of plasma samples and 98.0% (96/98) of urine samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An assessment of the liquid-gas partitioning behavior of major wastewater odorants using two comparative experimental approaches: liquid sample-based vaporization vs. impinger-based dynamic headspace extraction into sorbent tubes.

PubMed

Iqbal, Mohammad Asif; Kim, Ki-Hyun; Szulejko, Jan E; Cho, Jinwoo

2014-01-01

The gas-liquid partitioning behavior of major odorants (acetic acid, propionic acid, isobutyric acid, n-butyric acid, i-valeric acid, n-valeric acid, hexanoic acid, phenol, p-cresol, indole, skatole, and toluene (as a reference)) commonly found in microbially digested wastewaters was investigated by two experimental approaches. Firstly, a simple vaporization method was applied to measure the target odorants dissolved in liquid samples with the aid of sorbent tube/thermal desorption/gas chromatography/mass spectrometry. As an alternative method, an impinger-based dynamic headspace sampling method was also explored to measure the partitioning of target odorants between the gas and liquid phases with the same detection system. The relative extraction efficiency (in percent) of the odorants by dynamic headspace sampling was estimated against the calibration results derived by the vaporization method. Finally, the concentrations of the major odorants in real digested wastewater samples were also analyzed using both analytical approaches. Through a parallel application of the two experimental methods, we intended to develop an experimental approach to be able to assess the liquid-to-gas phase partitioning behavior of major odorants in a complex wastewater system. The relative sensitivity of the two methods expressed in terms of response factor ratios (RFvap/RFimp) of liquid standard calibration between vaporization and impinger-based calibrations varied widely from 981 (skatole) to 6,022 (acetic acid). Comparison of this relative sensitivity thus highlights the rather low extraction efficiency of the highly soluble and more acidic odorants from wastewater samples in dynamic headspace sampling.

Ionic Liquid-Doped Gel Polymer Electrolyte for Flexible Lithium-Ion Polymer Batteries

PubMed Central

Zhang, Ruisi; Chen, Yuanfen; Montazami, Reza

2015-01-01

Application of gel polymer electrolytes (GPE) in lithium-ion polymer batteries can address many shortcomings associated with liquid electrolyte lithium-ion batteries. Due to their physical structure, GPEs exhibit lower ion conductivity compared to their liquid counterparts. In this work, we have investigated and report improved ion conductivity in GPEs doped with ionic liquid. Samples containing ionic liquid at a variety of volume percentages (vol %) were characterized for their electrochemical and ionic properties. It is concluded that excess ionic liquid can damage internal structure of the batteries and result in unwanted electrochemical reactions; however, samples containing 40–50 vol % ionic liquid exhibit superior ionic properties and lower internal resistance compared to those containing less or more ionic liquids.

In-situ ionic liquid dispersive liquid-liquid microextraction using a new anion-exchange reagent combined Fe3O4 magnetic nanoparticles for determination of pyrethroid pesticides in water samples.

PubMed

Fan, Chen; Liang, You; Dong, Hongqiang; Ding, Guanglong; Zhang, Wenbing; Tang, Gang; Yang, Jiale; Kong, Dandan; Wang, Deng; Cao, Yongsong

2017-07-04

In this work, in-situ ionic liquid dispersive liquid-liquid microextraction combined ultrasmall Fe 3 O 4 magnetic nanoparticles was developed as a kind of pretreatment method to detect pyrethroid pesticides in water samples. New anion-exchange reagents including Na[DDTC] and Na[N(CN) 2 ] were optimized for in-situ extraction pyrethroids, which showed enhanced microextraction performance. Pyrethroids were enriched by hydrophilic ionic liquid [P 4448 ][Br] (aqueous solution, 200 μL, 0.2 mmol mL -1 ) reaction in-situ with anion-exchange reagent Na[N(CN) 2 ] (aqueous solution, 300 μL, 0.2 mmol mL -1 ) forming hydrophobic ionic liquid as extraction agent in water sample (10 mL). Ultrasmall superparamagnetic iron oxide nanoparticles (30 mg) were used to collect the mixture of ionic liquid and pyrethroids followed by elution with acetonitrile. The extraction of ionic liquid strategies was unique and efficiently fulfilled with high enrichment factors (176-213) and good recoveries (80.20-117.31%). The method was successively applied to the determination of pyrethroid pesticides in different kinds of water samples with the limits of detection ranged from 0.16 to 0.21 μg L -1 . The proposed method is actually nanometer-level microextraction (average size 80 nm) with the advantages of simplicity, rapidity, and sensitivity. Copyright © 2017 Elsevier B.V. All rights reserved.

Designing testing service at baristand industri Medan’s liquid waste laboratory

NASA Astrophysics Data System (ADS)

Kusumawaty, Dewi; Napitupulu, Humala L.; Sembiring, Meilita T.

2018-03-01

Baristand Industri Medan is a technical implementation unit under the Industrial and Research and Development Agency, the Ministry of Industry. One of the services often used in Baristand Industri Medan is liquid waste testing service. The company set the standard of service is nine working days for testing services. At 2015, 89.66% on testing services liquid waste does not meet the specified standard of services company because of many samples accumulated. The purpose of this research is designing online services to schedule the coming the liquid waste sample. The method used is designing an information system that consists of model design, output design, input design, database design and technology design. The results of designing information system of testing liquid waste online consist of three pages are pages to the customer, the recipient samples and laboratory. From the simulation results with scheduled samples, then the standard services a minimum of nine working days can be reached.

Concentric micro-nebulizer for direct sample insertion

DOEpatents

Fassel, V.A.; Rice, G.W.; Lawrence, K.E.

1984-03-06

A concentric micro-nebulizer and method for introducing liquid samples into a plasma established in a plasma torch including a first tube connected to a source of plasma gas. The concentric micro-nebulizer has inner and outer concentric tubes extending upwardly within the torch for connection to a source of nebulizer gas and to a source of liquid solvent and to a source of sample liquid. The inner tube is connected to the source of liquid solvent and to the source of sample liquid and the outer tube is connected to the source of nebulizer gas. The outer tube has an orifice positioned slightly below the plasma when it is established, with the inner and outer tubes forming an annulus therebetween with the annular spacing between the tubes at said orifice being less than about 0.05mm. The dead volume of the inner tube is less than about 5 microliters.

Concentric micro-nebulizer for direct sample insertion

DOEpatents

Fassel, Velmer A.; Rice, Gary W.; Lawrence, Kimberly E.

1986-03-11

A concentric micro-nebulizer and method for introducing liquid samples into a plasma established in a plasma torch including a first tube connected to a source of plasma gas. The concentric micro-nebulizer has inner and outer concentric tubes extending upwardly within the torch for connection to a source of nebulizer gas and to a source of liquid solvent and to a source of sample liquid. The inner tube is connected to the source of liquid solvent and to the source of sample liquid and the outer tube is connected to the source of nebulizer gas. The outer tube has an orifice positioned slightly below the plasma when it is established, with the inner and outer tubes forming an annulus therebetween with the annular spacing between the tubes at said orifice being less than about 0.05 mm. The dead volume of the inner tube is less than about 5 microliters.

Modeling of nanoscale liquid mixture transport by density functional hydrodynamics

NASA Astrophysics Data System (ADS)

Dinariev, Oleg Yu.; Evseev, Nikolay V.

2017-06-01

Modeling of multiphase compositional hydrodynamics at nanoscale is performed by means of density functional hydrodynamics (DFH). DFH is the method based on density functional theory and continuum mechanics. This method has been developed by the authors over 20 years and used for modeling in various multiphase hydrodynamic applications. In this paper, DFH was further extended to encompass phenomena inherent in liquids at nanoscale. The new DFH extension is based on the introduction of external potentials for chemical components. These potentials are localized in the vicinity of solid surfaces and take account of the van der Waals forces. A set of numerical examples, including disjoining pressure, film precursors, anomalous rheology, liquid in contact with heterogeneous surface, capillary condensation, and forward and reverse osmosis, is presented to demonstrate modeling capabilities.

Crystalline liquids: the blue phases

NASA Astrophysics Data System (ADS)

Wright, David C.; Mermin, N. David

1989-04-01

The blue phases of cholesteric liquid crystals are liquids that exhibit orientational order characterized by crystallographic space-group symmetries. We present here a pedagogical introduction to the current understanding of the equilibrium structure of these phases accompanied by a general overview of major experimental results. Using the Ginzburg-Landau free energy appropriate to the system, we first discuss in detail the character and stability of the usual helical phase of cholesterics, showing that for certain parameter ranges the helical phase is unstable to the appearance of one or more blue phases. The two principal models for the blue phases are two limiting cases of the Ginzburg-Landau theory. We explore each limit and conclude with some general considerations of defects in both models and an exact minimization of the free energy in a curved three-dimensional space.

Advances in display technology III; Proceedings of the Meeting, Los Angeles, CA, January 18, 19, 1983

NASA Astrophysics Data System (ADS)

Schlam, E.

1983-01-01

Human factors in visible displays are discussed, taking into account an introduction to color vision, a laser optometric assessment of visual display viewability, the quantification of color contrast, human performance evaluations of digital image quality, visual problems of office video display terminals, and contemporary problems in airborne displays. Other topics considered are related to electroluminescent technology, liquid crystal and related technologies, plasma technology, and display terminal and systems. Attention is given to the application of electroluminescent technology to personal computers, electroluminescent driving techniques, thin film electroluminescent devices with memory, the fabrication of very large electroluminescent displays, the operating properties of thermally addressed dye switching liquid crystal display, light field dichroic liquid crystal displays for very large area displays, and hardening military plasma displays for a nuclear environment.

State of the art of environmentally friendly sample preparation approaches for determination of PBDEs and metabolites in environmental and biological samples: A critical review.

PubMed

Berton, Paula; Lana, Nerina B; Ríos, Juan M; García-Reyes, Juan F; Altamirano, Jorgelina C

2016-01-28

Green chemistry principles for developing methodologies have gained attention in analytical chemistry in recent decades. A growing number of analytical techniques have been proposed for determination of organic persistent pollutants in environmental and biological samples. In this light, the current review aims to present state-of-the-art sample preparation approaches based on green analytical principles proposed for the determination of polybrominated diphenyl ethers (PBDEs) and metabolites (OH-PBDEs and MeO-PBDEs) in environmental and biological samples. Approaches to lower the solvent consumption and accelerate the extraction, such as pressurized liquid extraction, microwave-assisted extraction, and ultrasound-assisted extraction, are discussed in this review. Special attention is paid to miniaturized sample preparation methodologies and strategies proposed to reduce organic solvent consumption. Additionally, extraction techniques based on alternative solvents (surfactants, supercritical fluids, or ionic liquids) are also commented in this work, even though these are scarcely used for determination of PBDEs. In addition to liquid-based extraction techniques, solid-based analytical techniques are also addressed. The development of greener, faster and simpler sample preparation approaches has increased in recent years (2003-2013). Among green extraction techniques, those based on the liquid phase predominate over those based on the solid phase (71% vs. 29%, respectively). For solid samples, solvent assisted extraction techniques are preferred for leaching of PBDEs, and liquid phase microextraction techniques are mostly used for liquid samples. Likewise, green characteristics of the instrumental analysis used after the extraction and clean-up steps are briefly discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Apparatus for Sampling Surface Contamination

NASA Technical Reports Server (NTRS)

Wells, Mark

2008-01-01

An apparatus denoted a swab device has been developed as a convenient means of acquiring samples of contaminants from surfaces and suspending the samples in liquids. (Thereafter, the liquids can be dispensed, in controlled volumes, into scientific instruments for analysis of the contaminants.) The swab device is designed so as not to introduce additional contamination and to facilitate, simplify, and systematize the dispensing of controlled volumes of liquid into analytical instruments. The swab device is a single apparatus into which are combined all the equipment and materials needed for sampling surface contamination. The swab device contains disposable components stacked together on a nondisposable dispensing head. One of the disposable components is a supply cartridge holding a sufficient volume of liquid for one complete set of samples. (The liquid could be clean water or another suitable solvent, depending on the application.) This supply of liquid is sealed by Luer valves. At the beginning of a sampling process, the user tears open a sealed bag containing the supply cartridge. A tip on the nondisposable dispensing head is engaged with a Luer valve on one end of the supply cartridge and rotated, locking the supply cartridge on the dispensing head and opening the valve. The swab tip includes a fabric swab that is wiped across the surface of interest to acquire a sample. A sealed bag containing a disposable dispensing tip is then opened, and the swab tip is pushed into the dispensing tip until seated. The dispensing head contains a piston that passes through a spring-loaded lip seal. The air volume displaced by this piston forces the liquid out of the supply cartridge, over the swab, and into the dispensing tip. The piston is manually cycled to enforce oscillation of the air volume and thereby to cause water to flow to wash contaminants from the swab and cause the resulting liquid suspension of contaminants to flow into the dispensing tip. After several cycles to ensure adequate mixing, liquid containing the suspended contaminant sample is dispensed. The disposable components are then removed from the dispensing head, which may then be reused with a fresh set of disposable components.

Laser ablation inductively coupled plasma mass spectrometry measurement of isotope ratios in depleted uranium contaminated soils.

PubMed

Seltzer, Michael D

2003-09-01

Laser ablation of pressed soil pellets was examined as a means of direct sample introduction to enable inductively coupled plasma mass spectrometry (ICP-MS) screening of soils for residual depleted uranium (DU) contamination. Differentiation between depleted uranium, an anthropogenic contaminant, and naturally occurring uranium was accomplished on the basis of measured 235U/238U isotope ratios. The amount of sample preparation required for laser ablation is considerably less than that typically required for aqueous sample introduction. The amount of hazardous laboratory waste generated is diminished accordingly. During the present investigation, 235U/238U isotope ratios measured for field samples were in good agreement with those derived from gamma spectrometry measurements. However, substantial compensation was required to mitigate the effects of impaired pulse counting attributed to sample inhomogeneity and sporadic introduction of uranium analyte into the plasma.

The Quality of Selected Essential Medicines Sold in Accredited Drug Dispensing Outlets and Pharmacies in Tanzania

PubMed Central

Manyanga, Vicky; Chambuso, Mhina; Liana, Jafary; Rutta, Edmund; Embrey, Martha; Layloff, Thomas; Johnson, Keith

2016-01-01

Introduction The purpose of this study was to investigate the quality of a select group of medicines sold in accredited drug dispensing outlets (ADDOs) and pharmacies in different regions of Tanzania as part of an in-depth cross-sectional assessment of community access to medicines and community use of medicines. Methods We collected 242 samples of amoxicillin trihydrate, artemether-lumefantrine (ALu), co-trimoxazole, ergometrine maleate, paracetamol, and quinine from selected ADDOs and pharmacies in Mbeya, Morogoro, Singida, and Tanga regions. The analysis included physical examination and testing with validated analytical techniques. Assays for eight of nine products were conducted using high-performance thin-layer chromatography (HPTLC). For ALu tablets, we used a two-tiered approach, where tier 1 was a semi-quantitative Global Pharma Health Fund-Minilab® method and tier 2 was high-performance liquid chromatography (HPLC) as described in The International Pharmacopoeia’s monograph for artemether-lumefantrine. Results and Discussion The physical examination of samples revealed no defects in the solid and oral liquid dosage forms, but unusual discoloration in an injectable solution, ergometrine maleate. For ALu, the results showed that of 38 samples, 31 (81.6%) passed tier 1 testing and 7 (18.4%) gave inconclusive drug content results. The inconclusive ALu samples were submitted for tier 2 testing and all met the quality standards. The pass rate using the HPTLC and TLC/HPLC assays was 93.8%; the failures were the ergometrine maleate samples purchased from both ADDOs and pharmacies. The disintegration testing of the solid dosage forms was conducted in accordance with US Pharmacopeia monographs. Only two samples of paracetamol, 1.2% of the solid dosage forms, failed to comply to standards. The study revealed a high overall rate of 92.6% of samples that met the quality standards. Although the overall failure rate was 7.4%, it is important to note that this was largely limited to one product and likely due to poor distribution and storage rather than poor manufacturing practices. Conclusions Over 90% of the medicines sold in ADDOs and pharmacies met quality standards. Policy makers need to reconsider ergometrine maleate’s place on the list of medicines that ADDOs are allowed to dispense, by either substituting a more temperature-stable therapeutically equivalent product or requiring those sites to have refrigerators, which is not a feasible option for rural Tanzania. PMID:27846216

Group extraction of organic compounds present in liquid samples

NASA Technical Reports Server (NTRS)

Jahnsen, Vilhelm J. (Inventor)

1976-01-01

An extraction device is disclosed comprising a tube containing a substantially inert, chemically non-reactive packing material with a large surface area to volume ratio. A sample which consists of organic compounds dissolved in a liquid, is introduced into the tube. As the sample passes through the packing material it spreads over the material's large surface area to form a thin liquid film which is held on the packing material in a stationary state. A particular group or family of compounds is extractable from the sample by passing a particular solvent system consisting of a solvent and selected reagents through the packing material. The reagents cause optimum conditions to exist for the compounds of the particular family to pass through the phase boundary between the sample liquid and the solvent of the solvent system. Thus, the compounds of the particular family are separated from the sample liquid and become dissolved in the solvent of the solvent system. The particular family of compounds dissolved in the solvent, representing an extract, exits the tube together with the solvent through the tube's nozzle, while the rest of the sample remains on the packing material in a stationary state. Subsequently, a different solvent system may be passed through the packing material to extract another family of compounds from the remaining sample on the packing material.

DWPF DECON FRIT SUPERNATE ANALYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, D.; Crawford, C.

2010-09-22

The Savannah River National Laboratory (SRNL) has been requested to perform analyses on samples of the Defense Waste Processing Facility (DWPF) decon frit slurry (i.e., supernate samples and sump solid samples). Four 1-L liquid slurry samples were provided to SRNL by Savannah River Remediation (SRR) from the 'front-end' decon activities. Additionally, two 1-L sump solids samples were provided to SRNL for compositional and physical analysis. This report contains the results of the supernate analyses, while the solids (sump and slurry) results will be reported in a supplemental report. The analytical data from the decon frit supernate indicate that all ofmore » the radionuclide, organic, and inorganic concentrations met the limits in Revision 4 of the Effluent Treatment Plant (ETP) Waste Acceptance Criteria (WAC) with the exception of boron. The ETP WAC limit for boron is 15.0 mg/L while the average measured concentration (based on quadruplicate analysis) was 15.5 mg/L. The measured concentrations of Li, Na, and Si were also relatively high in the supernate analysis. These results are consistent with the relatively high measured value of B given the compositional make-up of Frit 418. Given these results, it was speculated that either (a) Frit 418 was dissolving into the supernate or aqueous fraction and/or (b) fine frit particulates were carried forward to the analytical instrument based on the sampling procedure used (i.e., the supernate samples were not filtered - only settled with the liquid fraction being transferred with a pipette). To address this issue, a filtered supernate sample (using a 0.45 um filter) was prepared and submitted for analysis. The results of the filtered sample were consistent with 'unfiltered or settled' sample - relatively high values of B, Li, Na, and Si were found. This suggests that Frit 418 is dissolving in the liquid phase which could be enhanced by the high surface area of the frit fines or particulates in suspension. Based on the results of this study, it is recommended that DWPF re-evaluate the technical basis for the B WAC limit (the only component that exceeds the ETP WAC limit from the supernate analyses) or assess if a waiver or exception can be obtained for exceeding this limit. Given the possible dissolution of B, Li, Na, and Si into the supernate (due to dissolution of frit), DWPF may need to assess if the release of these frit components into the supernate are a concern for the disposal options being considered. It should be noted that the results of this study may not be representative of future decon frit solutions or sump/slurry solids samples. Therefore, future DWPF decisions regarding the possible disposal pathways for either the aqueous or solid portions of the Decon Frit system need to factor in the potential differences. More specifically, introduction of a different frit or changes to other DWPF flowsheet unit operations (e.g., different sludge batch or coupling with other process streams) may impact not only the results but also the conclusions regarding acceptability with respect to the ETF WAC limits.« less

Magnetical hollow fiber bar collection of extract in homogenous ionic liquid microextraction of triazine herbicides in water samples.

PubMed

Wang, Kun; Jiang, Jia; Kang, Mingqin; Li, Dan; Zang, Shuang; Tian, Sizhu; Zhang, Hanqi; Yu, Aimin; Zhang, Ziwei

2017-04-01

The homogeneous ionic liquid microextraction combined with magnetical hollow fiber bar collection was developed for extracting triazine herbicides from water samples. These analytes were separated and determined by high performance liquid chromatography. The triazines were quickly extracted into ionic liquid microdroplets dispersed in solution, and then these microdroplets were completely collected with magnetical hollow fiber bars; the pores of which were impregnated with hydrophobic ionic liquid, which makes the phase separation simplified with no need of centrifugation. Some experimental parameters, such as the type of ionic liquid, ultrasonic immersion time of hollow fiber, pH of sample solution, volume of hydrophilic ionic liquid, amount of ion-pairing agent NH 4 PF 6 , NaCl concentration, number of magnetical hollow fiber bar, stirring rate, and collection time were investigated and optimized. When the present method was applied to the analysis of real water samples, the precision and recoveries of six triazine herbicides vary from 0.1 to 9.2% and 73.4 to 118.5%, respectively. The detection limits for terbumeton, ametryn, prometryn, terbutryn, trietazine, and dimethametryn were 0.48, 0.15, 0.15, 0.14, 0.35, and 0.16 μg L -1 , respectively.

SORPTION OF NONIONIC SURFACTANT OLIGOMERS TO SEDIMENT AND PCE DNAPL: EFFECTS ON PCE DISTRIBUTION BETWEEN WATER AND SEDIMENT. (R826650)

EPA Science Inventory

Introduction of surfactant mixtures to the subsurface for the purpose of
surfactant-enhanced aquifer remediation requires consideration of the effects of
surfactant sorption to sediment and nonaqueous phase liquids. These effects
include alteration of the solubiliz...

Mechanochemical hydrogenation of coal

DOEpatents

Yang, Ralph T.; Smol, Robert; Farber, Gerald; Naphtali, Leonard M.

1981-01-01

Hydrogenation of coal is improved through the use of a mechanical force to reduce the size of the particulate coal simultaneously with the introduction of gaseous hydrogen, or other hydrogen donor composition. Such hydrogen in the presence of elemental tin during this one-step size reduction-hydrogenation further improves the yield of the liquid hydrocarbon product.

Rethinking the Introduction of Particle Theory: A Substance-Based Framework

ERIC Educational Resources Information Center

Johnson, Philip; Papageorgiou, George

2010-01-01

In response to extensive research exposing students' poor understanding of the particle theory of matter, this article argues that the conceptual framework within which the theory is introduced could be a limiting factor. The standard school particle model is characterized as operating within a "solids, liquids, and gases" framework.…

General introduction: Liquid and solid (materials, main properties and applications …)

NASA Astrophysics Data System (ADS)

Zabler, Simon

2014-10-01

A general introduction about the diversity of foam structures is given with focus onto the structural, mechanical and dynamical properties at hand. Two classes of materials are addressed: liquid and semi-solid foams, on the one hand, solid foams, on the other hand. The latter can be subdivided into metallic, ceramic and organic foams, depending on the nature of the solid skeleton that supports the overall cell structure. Solid foams generally stem from the concept of mechanical light-weight structures, but they can just as well be employed for their large surface area as well as for their acoustic and thermal properties. Modern biomaterials use tailored ceramic or organo-ceramic foams as bone scaffolds, whereas hierarchically micro- and nanoporous structures are being used by chemistry to control catalytic reactions. Future materials design and development is going to rely increasingly on natural and synthetic foam structures and properties, be it food, thermal insulators or car frames, thus giving a promising outlook onto the foam research and development that is about to come. xml:lang="fr"

The injection of microorganisms into an atmospheric pressure rf-driven microplasma

NASA Astrophysics Data System (ADS)

Maguire, P. D.; Mahony, C. M. O.; Diver, D.; Mariotti, D.; Bennet, E.; Potts, H.; McDowell, D. A.

2013-09-01

The introduction of living organisms, such as bacteria, into atmospheric pressure microplasmas offers a unique means to study certain physical mechanisms in individual microorganisms and also help understand the impact of macroscopic entities and liquid droplets on plasma characteristics. We present the characterization of an RF-APD operating at 13.56 MHz and containing microorganisms in liquid droplets emitted from a nebulizer, with the spray entrained in a gas flow by a gas shroud and passed into the plasma source. We report successful microorganism injection and transmission through the plasma with stable plasma operation of at least one hour. Diagnostics include RF electrical characterization, optical emission spectrometry and electrostatic deflection to investigate microorganism charging. A close-coupled Impedans Octiv VI probe indicates source efficiencies of 10 to 15%. The introduction of the droplets/microorganisms results in increased plasma conductivity and reduced capacitance, due to their impact on electron density and temperature. An electrical model will be presented based on diagnostic data and deflection studies with input from simulations of charged aerosol diffusion and evaporation. Engineering and Physical Sciences Research Council EP/K006088, EP/K006142.

Assessment of total arsenic and arsenic species stability in alga samples and their aqueous extracts.

PubMed

García Salgado, S; Quijano Nieto, M A; Bonilla Simón, M M

2008-05-30

In order to achieve reliable information on speciation analysis, it is necessary to assess previously the species stability in the sample to analyse. Furthermore, in those cases where the sample treatment for species extraction is time-consuming, an assessment of the species integrity in the extracts is of paramount importance. Thus, the present paper reports total arsenic and arsenic species stability in alga samples (Sargassum fulvellum and Hizikia fusiformis), as well as in their aqueous extracts, which were stored in amber glass and polystyrene containers at different temperatures. Total arsenic determination was carried out by inductively coupled plasma atomic emission spectroscopy (ICP-AES), after sample acid digestion in a microwave oven, while arsenic speciation was conducted by anion exchange high performance liquid chromatography on-line coupled to ICP-AES, with and without sample introduction by hydride generation (HPLC-ICP-AES and HPLC-HG-ICP-AES), after aqueous microwave-assisted extraction. The results obtained for solid alga samples showed that total arsenic (for Hijiki alga) and arsenic species present (As(V) for Hijiki and NIES No. 9 Sargasso) are stable for at least 12 months when samples are stored in polystyrene containers at +20 degrees C. On the other hand, a different behaviour was observed in the stability of total arsenic and As(V) species in aqueous extracts for both samples, being the best storage conditions for Sargasso extracts a temperature of -18 degrees C and polystyrene containers, under which they are stable for at least 15 days, while Hijiki extracts must be stored in polystyrene containers at +4 degrees C in order to ensure the stability for 10 days.

Spatial and Temporal Analysis of Populations of the Sudden Oak Death Pathogen in Oregon Forests.

PubMed

Kamvar, Z N; Larsen, M M; Kanaskie, A M; Hansen, E M; Grünwald, N J

2015-07-01

Sudden oak death caused by the oomycete Phytophthora ramorum was first discovered in California toward the end of the 20th century and subsequently emerged on tanoak forests in Oregon before its first detection in 2001 by aerial surveys. The Oregon Department of Forestry has since monitored the epidemic and sampled symptomatic tanoak trees from 2001 to the present. Populations sampled over this period were genotyped using microsatellites and studied to infer the population genetic history. To date, only the NA1 clonal lineage is established in this region, although three lineages exist on the North American west coast. The original introduction into the Joe Hall area eventually spread to several regions: mostly north but also east and southwest. A new introduction into Hunter Creek appears to correspond to a second introduction not clustering with the early introduction. Our data are best explained by both introductions originating from nursery populations in California or Oregon and resulting from two distinct introduction events. Continued vigilance and eradication of nursery populations of P. ramorum are important to avoid further emergence and potential introduction of other clonal lineages.

Highly concentrated, ring-shaped phase conversion laser-induced breakdown spectroscopy technology for liquid sample analysis.

PubMed

Lin, Qingyu; Wei, Zhimei; Guo, Hongli; Wang, Shuai; Guo, Guangmeng; Zhang, Zhi; Duan, Yixiang

2017-06-10

A highly concentrated, ring-shaped phase conversion (RSPC) method was developed for liquid sample analysis using the laser-induced breakdown spectroscopy (LIBS) technique. In this work, test samples were prepared by mixing the metal particles with polyvinyl alcohol (PVA) supporter in liquid phase. With heat, the PVA solution solidified inside a modified glass petri dish, forming a metal-enriched polymer ring film. Distinguished from other traditional liquid-to-solid conversing methods, the proposed new method takes advantage of enhanced homogeneity for the target elements inside the ring film. The modified glass petri dish was used to control the ring-shaped concentration. Due to the specially designed circular groove at the bottom of this dish, where the PVA solution and liquid sample mixture accumulated, the target elements were concentrated in this small ring, which is beneficial for enhancing and stabilizing the plasma signals compared to the direct liquid sample analysis using LIBS. The limits of detection for Ag, Cu, Cr, and Ba obtained with the RSPC-LIBS technology were 0.098  μg·mL -1 , 0.18  μg·mL -1 , 0.83  μg·mL -1 , and 0.046  μg·mL -1 , respectively, which provided greater improvement than the direct bulk liquid analysis using LIBS.

Simulation of a Novel Single-column Cryogenic Air Separation Process Using LNG Cold Energy

NASA Astrophysics Data System (ADS)

Jieyu, Zheng; Yanzhong, Li; Guangpeng, Li; Biao, Si

In this paper, a novel single-column air separation process is proposed with the implementation of heat pump technique and introduction of LNG coldenergy. The proposed process is verifiedand optimized through simulation on the Aspen Hysys® platform. Simulation results reveal that thepower consumption per unit mass of liquid productis around 0.218 kWh/kg, and the total exergy efficiency of the systemis 0.575. According to the latest literatures, an energy saving of 39.1% is achieved compared with those using conventional double-column air separation units.The introduction of LNG cold energy is an effective way to increase the system efficiency.

Liquid-liquid extraction assisted by a carbon nanoparticles interface. Electrophoretic determination of atrazine in environmental samples.

PubMed

Caballero-Díaz, Encarnación; Simonet, Bartolomé; Valcárcel, Miguel

2013-10-21

A novel method for the determination of atrazine, using liquid-liquid extraction assisted by a nanoparticles film formed in situ and composed of organic solvent stabilized-carbon nanoparticles, is described. The presence of nanoparticles located at the liquid-liquid interface reinforced the extraction of analyte from matrix prior to capillary electrophoresis (CE) analysis. Some influential experimental variables were optimized in order to enhance the extraction efficiency. The developed procedure confirmed that carbon nanoparticles, especially multi-walled carbon nanotubes, are suitable to be used in sample treatment processes introducing new mechanisms of interaction with the analyte. The application of the proposed preconcentration method followed by CE detection enabled the determination of atrazine in spiked river water providing acceptable RSD values (11.6%) and good recoveries (about 87.0-92.0%). Additionally, a similar extraction scheme was tested in soil matrices with a view to further applications in real soil samples.

Modeling selected emulsions and double emulsions as memristive systems.

PubMed

Spasic, Aleksandar M; Jovanovic, Jovan M; Jovanovic, Mica

2012-06-15

The recent development in basic and applied science and engineering of finely dispersed systems is presented in general, but more attention has been paid to the liquid-liquid finely dispersed systems or to the particular emulsions and double emulsions. The selected systems for theoretical and experimental research were emulsions and double emulsions that appeared in the pilot plant for extraction of uranium from wet phosphoric acid. The objective of this research was to try to provide a new or different approach to elaborate the complex phenomena that occur at developed liquid-liquid interfaces. New concepts were introduced, the first is a concept of an entity, and the corresponding classification of finely dispersed systems and the second concept consider the introduction of an almost forgotten basic electrodynamics element memristor, and the corresponding memristive systems. Based on these concepts a theory of electroviscoelasticity was proposed and experimentally corroborated using the selected representative liquid-liquid system. Also, it is shown that the droplet, and/or droplet-film structure, that is, selected emulsion and/or double emulsion may be considered as the particular example of memristive systems. Copyright © 2012 Elsevier B.V. All rights reserved.

Determination of metal ions in tea samples using task-specific ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction coupled to liquid chromatography with ultraviolet detection.

PubMed

Werner, Justyna

2016-04-01

Task-specific ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction was used for the preconcentration of cadmium(II), cobalt(II), and lead(II) ions in tea samples, which were subsequently analyzed by liquid chromatography with UV detection. The proposed method of preconcentration is free of volatile organic compounds, which are often used as extractants and dispersing solvents in classic techniques of microextraction. A task-specific ionic liquid trioctylmethylammonium thiosalicylate was used as an extractant and a chelating agent. Ultrasound was used to disperse the ionic liquid. After microextraction, the phases were separated by centrifugation, and the ionic liquid phase was solubilized in methanol and directly injected into the liquid chromatograph. Selected microextraction parameters, such as the volume of ionic liquid, the pH of the sample, the duration of ultrasound treatment, the speed and time of centrifugation, and the effect of ionic strength, were optimized. Under optimal conditions an enrichment factor of 200 was obtained for each analyte. The limits of detection were 0.002 mg/kg for Cd(II), 0.009 mg/kg for Co(II), and 0.013 mg/kg for Pb(II). The accuracy of the proposed method was evaluated by an analysis of the Certified Reference Materials (INCT-TL-1, INCT-MPH-2) with the recovery values in the range of 90-104%. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of cryopreserved human sperm in vapor and liquid phases of liquid nitrogen: effect on motility parameters, morphology, and sperm function.

PubMed

Punyatanasakchai, Piyaphan; Sophonsritsuk, Areephan; Weerakiet, Sawaek; Wansumrit, Surapee; Chompurat, Deonthip

2008-11-01

To compare the effects of cryopreserved sperm in vapor and liquid phases of liquid nitrogen on sperm motility, morphology, and sperm function. Experimental study. Andrology laboratory at Ramathibodi Hospital, Thailand. Thirty-eight semen samples with normal motility and sperm count were collected from 38 men who were either patients of an infertility clinic or had donated sperm for research. Each semen sample was divided into two aliquots. Samples were frozen with static-phase vapor cooling. One aliquot was plunged into liquid nitrogen (-196 degrees C), and the other was stored in vapor-phase nitrogen (-179 degrees C) for 3 days. Thawing was performed at room temperature. Motility was determined by using computer-assisted semen analysis, sperm morphology was determined by using eosin-methylene blue staining, and sperm function was determined by using a hemizona binding test. Most of the motility parameters of sperm stored in the vapor phase were not significantly different from those stored in the liquid phase of liquid nitrogen, except in amplitude of lateral head displacement. The percentages of normal sperm morphology in both vapor and liquid phases also were not significantly different. There was no significant difference in the number of bound sperm in hemizona between sperm cryopreserved in both vapor and liquid phases of liquid nitrogen. Cryopreservation of human sperm in a vapor phase of liquid nitrogen was comparable to cryopreservation in a liquid phase of liquid nitrogen.

Hyperbaric hydrothermal atomic force microscope

DOEpatents

Knauss, Kevin G.; Boro, Carl O.; Higgins, Steven R.; Eggleston, Carrick M.

2002-01-01

A hyperbaric hydrothermal atomic force microscope (AFM) is provided to image solid surfaces in fluids, either liquid or gas, at pressures greater than normal atmospheric pressure. The sample can be heated and its surface imaged in aqueous solution at temperatures greater than 100.degree. C. with less than 1 nm vertical resolution. A gas pressurized microscope base chamber houses the stepper motor and piezoelectric scanner. A chemically inert, flexible membrane separates this base chamber from the sample cell environment and constrains a high temperature, pressurized liquid or gas in the sample cell while allowing movement of the scanner. The sample cell is designed for continuous flow of liquid or gas through the sample environment.

Hyperbaric Hydrothermal Atomic Force Microscope

DOEpatents

Knauss, Kevin G.; Boro, Carl O.; Higgins, Steven R.; Eggleston, Carrick M.

2003-07-01

A hyperbaric hydrothermal atomic force microscope (AFM) is provided to image solid surfaces in fluids, either liquid or gas, at pressures greater than normal atmospheric pressure. The sample can be heated and its surface imaged in aqueous solution at temperatures greater than 100.degree. C. with less than 1 nm vertical resolution. A gas pressurized microscope base chamber houses the stepper motor and piezoelectric scanner. A chemically inert, flexible membrane separates this base chamber from the sample cell environment and constrains a high temperature, pressurized liquid or gas in the sample cell while allowing movement of the scanner. The sample cell is designed for continuous flow of liquid or gas through the sample environment.

Determination of preservatives in cosmetics, cleaning agents and pharmaceuticals using fast liquid chromatography.

PubMed

Baranowska, Irena; Wojciechowska, Iwona; Solarz, Natalia; Krutysza, Ewa

2014-01-01

This paper reports the development of a method for simultaneously determining five preservatives in cosmetics, cleaning agents and pharmaceuticals by fast liquid chromatography. Methylisothiazolinone, methylchloroisothiazolinone, benzyl alcohol, sodium benzoate and methylparaben were separated on a Chromolith Fast Gradient reversed-phase 18e column using gradient elution with acetonitrile and a 0.1% aqueous solution of formic acid, with a run time of 3 min. The preparation of solid and liquid samples included ultrasonic extraction with methanol with recoveries ranging from 69 to 119%. The developed method was used to analyze samples of cosmetics (66 samples), cleaning agents (five samples) and pharmaceutical industry products (17 samples).

Optimizing separations in online comprehensive two-dimensional liquid chromatography.

PubMed

Pirok, Bob W J; Gargano, Andrea F G; Schoenmakers, Peter J

2018-01-01

Online comprehensive two-dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two-dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two-dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass spectrometry (e.g. high-molecular-weight polymers), providing important information on the distribution of the sample components along chemical dimensions (molecular weight, charge, lipophilicity, stereochemistry, etc.). Also, in comparison with conventional one-dimensional liquid chromatography, two-dimensional liquid chromatography provides a greater separation power (peak capacity). Because of the additional selectivity and higher peak capacity, the combination of two-dimensional liquid chromatography with mass spectrometry allows for simpler mixtures of compounds to be introduced in the ion source at any given time, improving quantitative analysis by reducing matrix effects. In this review, we summarize the rationale and principles of two-dimensional liquid chromatography experiments, describe advantages and disadvantages of combining different selectivities and discuss strategies to improve the quality of two-dimensional liquid chromatography separations. © 2017 The Authors. Journal of Separation Science published by WILEY-VCH Verlag GmbH & Co. KGaA.

Automated position control of a surface array relative to a liquid microjunction surface sampler

DOEpatents

Van Berkel, Gary J.; Kertesz, Vilmos; Ford, Michael James

2007-11-13

A system and method utilizes an image analysis approach for controlling the probe-to-surface distance of a liquid junction-based surface sampling system for use with mass spectrometric detection. Such an approach enables a hands-free formation of the liquid microjunction used to sample solution composition from the surface and for re-optimization, as necessary, of the microjunction thickness during a surface scan to achieve a fully automated surface sampling system.

A regulator for pressure-controlled total-liquid ventilation.

PubMed

Robert, Raymond; Micheau, Philippe; Avoine, Olivier; Beaudry, Benoit; Beaulieu, Alexandre; Walti, Hervé

2010-09-01

Total-liquid ventilation (TLV) is an innovative experimental method of mechanical-assisted ventilation in which lungs are totally filled and then ventilated with a tidal volume of perfluorochemical liquid by using a dedicated liquid ventilator. Such a novel medical device must resemble other conventional ventilators: it must be able to conduct controlled-pressure ventilation. The objective was to design a robust controller to perform pressure-regulated expiratory flow and to implement it on our latest liquid-ventilator prototype (Inolivent-4). Numerical simulations, in vitro experiments, and in vivo experiments in five healthy term newborn lambs have demonstrated that it was efficient to generate expiratory flows while avoiding collapses. Moreover, the in vivo results have demonstrated that our liquid ventilator can maintain adequate gas exchange, normal acid-base equilibrium, and achieve greater minute ventilation, better oxygenation and CO2 extraction, while nearing flow limits. Hence, it is our suggestion to perform pressure-controlled ventilation during expiration with minute ventilation equal or superior to 140 mL x min(-1) x kg(-1) in order to ensure PaCO2 below 55 mmHg. From a clinician's point of view, pressure-controlled ventilation greatly simplifies the use of the liquid ventilator, which will certainly facilitate its introduction in intensive care units for clinical applications.

Automated Liquid Microjunction Surface Sampling-HPLC-MS/MS Analysis of Drugs and Metabolites in Whole-Body Thin Tissue Sections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kertesz, Vilmos; Van Berkel, Gary J

A fully automated liquid extraction-based surface sampling system utilizing a commercially available autosampler coupled to high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) detection is reported. Discrete spots selected for droplet-based sampling and automated sample queue generation for both the autosampler and MS were enabled by using in-house developed software. In addition, co-registration of spatially resolved sampling position and HPLC-MS information to generate heatmaps of compounds monitored for subsequent data analysis was also available in the software. The system was evaluated with whole-body thin tissue sections from propranolol dosed rat. The hands-free operation of the system was demonstrated by creating heatmapsmore » of the parent drug and its hydroxypropranolol glucuronide metabolites with 1 mm resolution in the areas of interest. The sample throughput was approximately 5 min/sample defined by the time needed for chromatographic separation. The spatial distributions of both the drug and its metabolites were consistent with previous studies employing other liquid extraction-based surface sampling methodologies.« less

Quantitative analysis of polyhexamethylene guanidine (PHMG) oligomers via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with an ionic-liquid matrix.

PubMed

Yoon, Donhee; Lee, Dongkun; Lee, Jong-Hyeon; Cha, Sangwon; Oh, Han Bin

2015-01-30

Quantifying polymers by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) with a conventional crystalline matrix generally suffers from poor sample-to-sample or shot-to-shot reproducibility. An ionic-liquid matrix has been demonstrated to mitigate these reproducibility issues by providing a homogeneous sample surface, which is useful for quantifying polymers. In the present study, we evaluated the use of an ionic liquid matrix, i.e., 1-methylimidazolium α-cyano-4-hydroxycinnamate (1-MeIm-CHCA), to quantify polyhexamethylene guanidine (PHMG) samples that impose a critical health hazard when inhaled in the form of droplets. MALDI-TOF mass spectra were acquired for PHMG oligomers using a variety of ionic-liquid matrices including 1-MeIm-CHCA. Calibration curves were constructed by plotting the sum of the PHMG oligomer peak areas versus PHMG sample concentration with a variety of peptide internal standards. Compared with the conventional crystalline matrix, the 1-MeIm-CHCA ionic-liquid matrix had much better reproducibility (lower standard deviations). Furthermore, by using an internal peptide standard, good linear calibration plots could be obtained over a range of PMHG concentrations of at least 4 orders of magnitude. This study successfully demonstrated that PHMG samples can be quantitatively characterized by MALDI-TOFMS with an ionic-liquid matrix and an internal standard. Copyright © 2014 John Wiley & Sons, Ltd.

Rapid and sensitive analysis of polychlorinated biphenyls and acrylamide in food samples using ionic liquid-based in situ dispersive liquid-liquid microextraction coupled to headspace gas chromatography.

PubMed

Zhang, Cheng; Cagliero, Cecilia; Pierson, Stephen A; Anderson, Jared L

2017-01-20

A simple and rapid ionic liquid (IL)-based in situ dispersive liquid-liquid microextraction (DLLME) method was developed and coupled to headspace gas chromatography (HS-GC) employing electron capture (ECD) and mass spectrometry (MS) detection for the analysis of polychlorinated biphenyls (PCBs) and acrylamide at trace levels from milk and coffee samples. The chemical structures of the halide-based ILs were tailored by introducing various functional groups to the cations to evaluate the effect of different structural features on the extraction efficiency of the target analytes. Extraction parameters including the molar ratio of IL to metathesis reagent and IL mass were optimized. The effects of HS oven temperature and the HS sample vial volume on the analyte response were also evaluated. The optimized in situ DLLME method exhibited good analytical precision, good linearity, and provided detection limits down to the low ppt level for PCBs and the low ppb level for acrylamide in aqueous samples. The matrix-compatibility of the developed method was also established by quantifying acrylamide in brewed coffee samples. This method is much simpler and faster compared to previously reported GC-MS methods using solid-phase microextraction (SPME) for the extraction/preconcentration of PCBs and acrylamide from complex food samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Method and apparatus for processing a test sample to concentrate an analyte in the sample from a solvent in the sample

DOEpatents

Turner, Terry D.; Beller, Laurence S.; Clark, Michael L.; Klingler, Kerry M.

1997-01-01

A method of processing a test sample to concentrate an analyte in the sample from a solvent in the sample includes: a) boiling the test sample containing the analyte and solvent in a boiling chamber to a temperature greater than or equal to the solvent boiling temperature and less than the analyte boiling temperature to form a rising sample vapor mixture; b) passing the sample vapor mixture from the boiling chamber to an elongated primary separation tube, the separation tube having internal sidewalls and a longitudinal axis, the longitudinal axis being angled between vertical and horizontal and thus having an upper region and a lower region; c) collecting the physically transported liquid analyte on the internal sidewalls of the separation tube; and d) flowing the collected analyte along the angled internal sidewalls of the separation tube to and pass the separation tube lower region. The invention also includes passing a turbulence inducing wave through a vapor mixture to separate physically transported liquid second material from vaporized first material. Apparatus are also disclosed for effecting separations. Further disclosed is a fluidically powered liquid test sample withdrawal apparatus for withdrawing a liquid test sample from a test sample container and for cleaning the test sample container.

Method and apparatus for processing a test sample to concentrate an analyte in the sample from a solvent in the sample

DOEpatents

Turner, T.D.; Beller, L.S.; Clark, M.L.; Klingler, K.M.

1997-10-14

A method of processing a test sample to concentrate an analyte in the sample from a solvent in the sample includes: (a) boiling the test sample containing the analyte and solvent in a boiling chamber to a temperature greater than or equal to the solvent boiling temperature and less than the analyte boiling temperature to form a rising sample vapor mixture; (b) passing the sample vapor mixture from the boiling chamber to an elongated primary separation tube, the separation tube having internal sidewalls and a longitudinal axis, the longitudinal axis being angled between vertical and horizontal and thus having an upper region and a lower region; (c) collecting the physically transported liquid analyte on the internal sidewalls of the separation tube; and (d) flowing the collected analyte along the angled internal sidewalls of the separation tube to and pass the separation tube lower region. The invention also includes passing a turbulence inducing wave through a vapor mixture to separate physically transported liquid second material from vaporized first material. Apparatus is also disclosed for effecting separations. Further disclosed is a fluidically powered liquid test sample withdrawal apparatus for withdrawing a liquid test sample from a test sample container and for cleaning the test sample container. 8 figs.

A simple liquid extraction protocol for overcoming the ion suppression of triacylglycerols by phospholipids in liquid chromatography mass spectrometry studies.

PubMed

Araujo, Pedro; Tilahun, Ephrem; Breivik, Joar Fjørtoft; Abdulkader, Bashir M; Frøyland, Livar; Zeng, Yingxu

2016-02-01

It is well-known that triacylglycerol (TAG) ions are suppressed by phospholipid (PL) ions in regiospecific analysis of TAG by mass spectrometry (MS). Hence, it is essential to remove the PL during sample preparation prior to MS analysis. The present article proposes a cost-effective liquid-liquid extraction (LLE) method to remove PL from TAG in different kinds of biological samples by using methanol, hexane and water. High performance thin layer chromatography confirmed the lack of PL in krill oil and salmon liver samples, submitted to the proposed LLE protocol, and liquid chromatography tandem MS confirmed that the identified TAG ions were highly enhanced after implementing the LLE procedure. Copyright © 2015 Elsevier B.V. All rights reserved.

Flow through electrode with automated calibration

DOEpatents

Szecsody, James E [Richland, WA; Williams, Mark D [Richland, WA; Vermeul, Vince R [Richland, WA

2002-08-20

The present invention is an improved automated flow through electrode liquid monitoring system. The automated system has a sample inlet to a sample pump, a sample outlet from the sample pump to at least one flow through electrode with a waste port. At least one computer controls the sample pump and records data from the at least one flow through electrode for a liquid sample. The improvement relies upon (a) at least one source of a calibration sample connected to (b) an injection valve connected to said sample outlet and connected to said source, said injection valve further connected to said at least one flow through electrode, wherein said injection valve is controlled by said computer to select between said liquid sample or said calibration sample. Advantages include improved accuracy because of more frequent calibrations, no additional labor for calibration, no need to remove the flow through electrode(s), and minimal interruption of sampling.

Detection of boldenone, its conjugates and androstadienedione, as well as five corticosteroids in bovine bile through a unique immunoaffinity column clean-up and two validated liquid chromatography-tandem mass spectrometry analyses.

PubMed

Chiesa, L; Nobile, M; Panseri, S; Sgoifo Rossi, C A; Pavlovic, R; Arioli, F

2014-12-10

The presence of β-boldenone II phase metabolites and prednisolone in urine samples, owing to endogenous or natural origin or illicit treatment, is under debate within the European Union. The detection of β-boldenone conjugates, α-boldenone conjugates at concentrations higher than 2 ng mL(-1) and prednisolone above the cut-off level of 5 ng mL(-1) in urine have been, until now, critical in deciding if illegal drug use has occurred. The use of urine sometimes is not entirely satisfactory, especially when the drug is administrated at low doses or when its metabolic conversion is very fast. This subsequently would hamper its detection in urine. The introduction of a new, advantageous matrix where the illicit treatment can be investigated would be highly appreciated. In this study, we have developed and validated a simple and unique immunoaffinity clean-up procedure, which was applied to bovine bile samples, followed by two different analytical liquid chromatography-electrospray-tandem mass spectrometry methods. The first method tests androstadienedione, α- and β-boldenone sulphate, glucuronate and related free forms, while the other method assays prednisolone, prednisone, dexamethasone, cortisone, and cortisol. The methods were validated according to European Commission Decision 2002/657/EC. The evaluated parameters were linearity, specificity, precision (repeatability and intra-laboratory reproducibility), recovery, decision limit and detection capability. The decision limits (CCα) were between 0.38 and 0.45 ng mL(-1) for anabolic steroids, and 0.13 and 0.15 ng mL(-1) as far as corticosteroids were concerned. Intra- and inter-day repeatability was below 15.8 and 19.9% for all analytes, respectively. The methods were applied to the analysis of some bile samples collected from untreated young bulls in order to investigate the presence of the studied steroids in this matrix. Copyright © 2014 Elsevier B.V. All rights reserved.

A low-cost gradient system for high-performance liquid chromatography. Quantitation of complex pharmaceutical raw materials.

PubMed

Erni, F; Frei, R W

1976-09-29

A device is described that makes use of an eight-port motor valve to generate step gradients on the low-pressure side of a piston pump with a low dead volume. Such a gradient device with an automatic control unit, which also permits repetition of previous steps, can be built for about half the cost of a gradient system with two pumps. Applications of this gradient unit to the separation of complex mixtures of glycosides and alkaloids are discussed and compared with separations systems using two high-pressure pumps. The gradients that are used on reversed-phase material with solvent mixtures of water and completely miscible organic solvents are suitable for quantitative routine control of pharmaceutical products. The reproducibility of retention data is excellent over several months and, with the use of loop injectors, major components can be determined quantitatively with a reproducibility of better than 2% (relative standard deviation). The step gradient selector valve can also be used as an introduction system for very large sample volumes. Up to 11 can be injected and samples with concentrations of less than 1 ppb can be determined with good reproducibilities.

Constituents of smoke from cigarettes made from diverted nicotine replacement therapy patches.

PubMed

Morrissey, Hana; Ball, Patrick; Boland, Martin; Hefler, Marita; Thomas, David P

2016-03-01

Anecdotes of nicotine replacement therapy patch misuse associated with the introduction of smoke-free prisons have been reported by media internationally, including Canada in 2006, New Zealand in 2011 and Australia in 2014. This study identifies chemical compounds released through diverted nicotine replacement therapy patches when they are smoked. Two samples were produced: (i) shredded 21 mg nicotine replacement therapy patches rolled with tea leaves into a cigarette; and (ii) patches boiled in water and tea leaves, and then dried tea leaves rolled into a cigarette. The smoke was tested for nicotine, caffeine and toxins. High-performance liquid chromatography, mass spectrometry and spectrophotometry were used to detect the presence and quantity of nicotine and caffeine. A specialised laboratory was contracted to test the presence of toxins. Nicotine was liberated when the two samples were burnt but not if the nicotine replacement therapy patches were boiled in water alone. High concentrations of formaldehyde, acetaldehyde, acrolein, toluene, xylene and heavy metals were also released. Nicotine is released when diverted nicotine replacement therapy patches are smoked, as are caffeine and harmful toxins. These toxins have the potential to cause short- and long-term health damage. © 2015 Australasian Professional Society on Alcohol and other Drugs.

Microfluidic Lab-on-a-Chip Platforms: Requirements, Characteristics and Applications

NASA Astrophysics Data System (ADS)

Mark, D.; Haeberle, S.; Roth, G.; Von Stetten, F.; Zengerle, R.

This review summarizes recent developments in microfluidic platform approaches. In contrast to isolated application-specific solutions, a microfluidic platform provides a set of fluidic unit operations, which are designed for easy combination within a well-defined fabrication technology. This allows the implementation of different application-specific (bio-) chemical processes, automated by microfluidic process integration [1]. A brief introduction into technical advances, major market segments and promising applications is followed by a detailed characterization of different microfluidic platforms, comprising a short definition, the functional principle, microfluidic unit operations, application examples as well as strengths and limitations. The microfluidic platforms in focus are lateral flow tests, linear actuated devices, pressure driven laminar flow, microfluidic large scale integration, segmented flow microfluidics, centrifugal microfluidics, electro-kinetics, electrowetting, surface acoustic waves, and systems for massively parallel analysis. The review concludes with the attempt to provide a selection scheme for microfluidic platforms which is based on their characteristics according to key requirements of different applications and market segments. Applied selection criteria comprise portability, costs of instrument and disposable, sample throughput, number of parameters per sample, reagent consumption, precision, diversity of microfluidic unit operations and the flexibility in programming different liquid handling protocols.

BetaNMR Experiments on Liquid Samples

NASA Astrophysics Data System (ADS)

Gottberg, A.; Stachura, M.; Hemmingsen, L.; Macfarlane, W. A.; Bio-Beta-Nmr Collaboration; Collaps Collaboration

2016-09-01

In 2012 betaNMR spectroscopy was successfully applied on liquid samples; an achievement which opens new opportunities in the fields of chemistry and biochemistry. This project was motivated by the need for finding a new experimental approach to directly study biologically highly relevant metal ions, such as Mg(II), Cu(I), Ca(II), and Zn(II), which are silent in most spectroscopic techniques. The resonance spectrum recorded for Mg-31 implanted into an ionic liquid sample showed two resonances which originate from Mg ions occupying two different coordination geometries, illustrating that this technique can discriminate between different structures. This proof-of-principle result lays the foundation for studies of these metal ions at low concentrations and in environments of biological relevance where other methods are silent. The prototype chamber for bio-betaNMR allows for experiments not only on different samples such as: liquids, gels and solids, but also operates at different vacuum environments. In order to exploit the potential of betaNMR on liquid samples, tests with polarized beams of Mg-29 and Mg-31 have recently been performed at the ISAC facility at TRIUMF.

Fully-automated in-syringe dispersive liquid-liquid microextraction for the determination of caffeine in coffee beverages.

PubMed

Frizzarin, Rejane M; Maya, Fernando; Estela, José M; Cerdà, Víctor

2016-12-01

A novel fully-automated magnetic stirring-assisted lab-in-syringe analytical procedure has been developed for the fast and efficient dispersive liquid-liquid microextraction (DLLME) of caffeine in coffee beverages. The procedure is based on the microextraction of caffeine with a minute amount of dichloromethane, isolating caffeine from the sample matrix with no further sample pretreatment. Selection of the relevant extraction parameters such as the dispersive solvent, proportion of aqueous/organic phase, pH and flow rates have been carefully evaluated. Caffeine quantification was linear from 2 to 75mgL(-1), with detection and quantification limits of 0.46mgL(-1) and 1.54mgL(-1), respectively. A coefficient of variation (n=8; 5mgL(-1)) of a 2.1% and a sampling rate of 16h(-1), were obtained. The procedure was satisfactorily applied to the determination of caffeine in brewed, instant and decaf coffee samples, being the results for the sample analysis validated using high-performance liquid chromatography. Copyright © 2016 Elsevier Ltd. All rights reserved.

Application of allflex conservation buffer in illumina genotyping.

PubMed

de Groot, M; Ras, T; van Haeringen, W A

2016-12-01

This experiment was designed to study if liquid conservation buffer used in the novel Tissue Sampling Technology (TST) from Allflex can be used for Illumina BeadChip genotyping. Ear punches were collected from 6 bovine samples, using both the Tissue Sampling Unit (TSU) as well as the Total Tagger Universal (TTU) collection system. The stability of the liquid conservation buffer was tested by genotyping samples on Illumina BeadChips, incubated at 0, 3, 15, 24, 48, 72, 168, 336, 720 h after sample collection. Additionally, a replenishment study was designed to test how often the liquid conservation buffer could be completely replenished before a significant call rate drop could be observed. Results from the stability study showed an average call rate of 0.993 for samples collected with the TSU system and 0.953 for samples collected with the TTU system, both exceeding the inclusion threshold call rate of 0.85. As an additional control, the identity of the individual animals was confirmed using the International Society of Animal Genetics (ISAG) recommended SNP panel. The replenishment study revealed a slight drop in the sample call rate after replenishing the conservation buffer for the fourth time for the TSU as well as the TTU samples. In routine analysis, this application allows for multiple experiments to be performed on the liquid conservation buffer, while maintaining the tissue samples for future use. The data collected in this study shows that the liquid conservation buffer used in the TST system can be used for Illumina BeadChip genotyping applications.

Headspace solid-phase microextraction (HS-SPME) and liquid-liquid extraction (LLE): comparison of the performance in classification of ecstasy tablets. Part 2.

PubMed

Bonadio, Federica; Margot, Pierre; Delémont, Olivier; Esseiva, Pierre

2008-11-20

Headspace solid-phase microextraction (HS-SPME) is assessed as an alternative to liquid-liquid extraction (LLE) currently used for 3,4-methylenedioxymethampethamine (MDMA) profiling. Both methods were compared evaluating their performance in discriminating and classifying samples. For this purpose 62 different seizures were analysed using both extraction techniques followed by gas chromatography-mass spectroscopy (GC-MS). A previously validated method provided data for HS-SPME, whereas LLE data were collected applying a harmonized methodology developed and used in the European project CHAMP. After suitable pre-treatment, similarities between sample pairs were studied using the Pearson correlation. Both methods enable to distinguish between samples coming from the same pre-tabletting batches and samples coming from different pre-tabletting batches. This finding emphasizes the use of HS-SPME as an effective alternative to LLE, with additional advantages such as sample preparation and a solvent-free process.

Ionic liquid based dispersive liquid-liquid microextraction for the extraction of pesticides from bananas.

PubMed

Ravelo-Pérez, Lidia M; Hernández-Borges, Javier; Asensio-Ramos, María; Rodríguez-Delgado, Miguel Angel

2009-10-23

This paper describes a dispersive liquid-liquid microextraction (DLLME) procedure using room temperature ionic liquids (RTILs) coupled to high-performance liquid chromatography with diode array detection capable of quantifying trace amounts of eight pesticides (i.e. thiophanate-methyl, carbofuran, carbaryl, tebuconazole, iprodione, oxyfluorfen, hexythiazox and fenazaquin) in bananas. Fruit samples were first homogenized and extracted (1g) with acetonitrile and after suitable evaporation and reconstitution of the extract in 10 mL of water, a DLLME procedure using 1-hexyl-3-methylimidazolium hexafluorophosphate ([C(6)MIM][PF(6)]) as extraction solvent was used. Experimental conditions affecting the DLLME procedure (sample pH, sodium chloride percentage, ionic liquid amount and volume of disperser solvent) were optimized by means of an experimental design. In order to determine the presence of a matrix effect, calibration curves for standards and fortified banana extracts (matrix matched calibration) were studied. Mean recovery values of the extraction of the pesticides from banana samples were in the range of 69-97% (except for thiophanate-methyl and carbofuran, which were 53-63%) with a relative standard deviation lower than 8.7% in all cases. Limits of detection achieved (0.320-4.66 microg/kg) were below the harmonized maximum residue limits established by the European Union (EU). The proposed method, was also applied to the analysis of this group of pesticides in nine banana samples taken from the local markets of the Canary Islands (Spain). To the best of our knowledge, this is the first application of RTILs as extraction solvents for DLLME of pesticides from samples different than water.

Multiple functional ionic liquids based dispersive liquid-liquid microextraction combined with high performance chromatography for the determination of phenolic compounds in water samples.

PubMed

Sun, Jian-Nan; Chen, Juan; Shi, Yan-Ping

2014-07-01

A new mode of ionic liquid based dispersive liquid-liquid microextraction (IL-DLLME) is developed. In this work, [C6MIm][PF6] was chosen as the extraction solvent, and two kinds of hydrophilic ionic liquids, [EMIm][BF4] and [BSO3HMIm][OTf], functioned as the dispersive solvent. So in the whole extraction procedure, no organic solvent was used. With the aid of SO3H group, the acidic compound was extracted from the sample solution without pH adjustment. Two phenolic compounds, namely, 2-naphthol and 4-nitrophenol were chosen as the target analytes. Important parameters affecting the extraction efficiency, such as the type of hydrophilic ionic liquids, the volume ratio of [EMIm][BF4] to [BSO3HMIm][OTf], type and volume of extraction solvent, pH value of sample solution, sonication time, extraction time and centrifugation time were investigated and optimized. Under the optimized extraction conditions, the method exhibited good sensitivity with the limits of detection (LODs) at 5.5 μg L(-1)and 10.0 μg L(-1) for 4-nitrophenol and 2-naphthol, respectively. Good linearity over the concentration ranges of 24-384 μg L(-1) for 4-nitrophenol and 28-336 μg L(-1) for 2-naphthol was obtained with correlation coefficients of 0.9998 and 0.9961, respectively. The proposed method can directly extract acidic compound from environmental sample or even more complex sample matrix without any pH adjustment procedure. Copyright © 2014 Elsevier B.V. All rights reserved.

Dispersive liquid-liquid microextraction based on solidification of floating organic droplet followed by high-performance liquid chromatography with ultraviolet detection and liquid chromatography-tandem mass spectrometry for the determination of triclosan and 2,4-dichlorophenol in water samples.

PubMed

Zheng, Cao; Zhao, Jing; Bao, Peng; Gao, Jin; He, Jin

2011-06-24

A novel, simple and efficient dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO) technique coupled with high-performance liquid chromatography with ultraviolet detection (HPLC-UV) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of triclosan and its degradation product 2,4-dichlorophenol in real water samples. The extraction solvent used in this work is of low density, low volatility, low toxicity and proper melting point around room temperature. The extractant droplets can be collected easily by solidifying it at a lower temperature. Parameters that affect the extraction efficiency, including type and volume of extraction solvent and dispersive solvent, salt effect, pH and extraction time, were investigated and optimized in a 5 mL sample system by HPLC-UV. Under the optimum conditions (extraction solvent: 12 μL of 1-dodecanol; dispersive solvent: 300 of μL acetonitrile; sample pH: 6.0; extraction time: 1 min), the limits of detection (LODs) of the pretreatment method combined with LC-MS/MS were in the range of 0.002-0.02 μg L(-1) which are lower than or comparable with other reported approaches applied to the determination of the same compounds. Wide linearities, good precisions and satisfactory relative recoveries were also obtained. The proposed technique was successfully applied to determine triclosan and 2,4-dichlorophenol in real water samples. Copyright © 2011 Elsevier B.V. All rights reserved.

Application of liquid-liquid-liquid microextraction and high-performance liquid chromatography for the determination of alkylphenols and bisphenol-A in water.

PubMed

Lin, Che-Yi; Fuh, Ming-Ren; Huang, Shang-Da

2011-02-01

A method termed liquid-liquid-liquid microextraction (LLLME) was utilized to extract 4-t-butylphenol, 4-t-octylphenol, 4-n-nonylphenol, and bisphenol-A from water. The extracted target analytes were separated and quantified by high-performance liquid chromatography using a fluorescence detector. In LLLME, the donor phase (i.e. water sample) was made weakly acidic by adding monobasic potassium phosphate (KH(2) PO(4)); the organic phase adopted was 4-chlorotoluene; the acceptor phase (i.e. enriched extract) was 0.2 M tetraethylammonium hydroxide dissolved in ethylene glycol. This study solves a problem associated with the surface activity of long-chain alkylphenolate ions, permitting LLLME to extract long-chain alkylphenols. Experimental conditions such as acceptor phase composition, organic phase identity, acceptor phase volume, sample agitation, extraction time, and salt addition were optimized. The relative standard deviation (RSD, 2.0-5.8%), coefficient of determination (r(2) 0.9977-0.9999), and detection limit (0.017-0.0048 ng/mL) of the proposed method were achieved under the selected optimized conditions. The method was successfully applied to analyses of lake and tap water samples, and the relative recoveries of target analytes from the spiked lake and tap water samples were 92.8-106.3 and 93.6-105.6%, respectively. The results obtained with the proposed method confirm this microextraction technique to be reliable for the monitoring of alkylphenols and bisphenol-A in water samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Developmental Testing of Liquid and Gaseous/Vaporous Decontamination on Bacterial Spores and Other Biological Warfare Agents on Military Relevant Surfaces

DTIC Science & Technology

2016-02-11

process ( gas /vapor or liquid ), sampling will be conducted as soon as possible. Samples will be incubated for 12 to 48 hours (depending on the...Final 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Test Operations Procedure (TOP) 08-2-065 Developmental Testing of Liquid and Gaseous...biological decontamination protocol to analyze the efficacy of liquid and gaseous/vaporous decontaminants on military-relevant surfaces. The

Rapid analysis of aflatoxins B1, B2, and ochratoxin A in rice samples using dispersive liquid-liquid microextraction combined with HPLC.

PubMed

Lai, Xian-Wen; Sun, Dai-Li; Ruan, Chun-Qiang; Zhang, He; Liu, Cheng-Lan

2014-01-01

A novel, simple, and rapid method is presented for the analysis of aflatoxin B1, aflatoxin B2, and ochratoxin A in rice samples by dispersive liquid-liquid microextraction combined with LC and fluorescence detection. After extraction of the rice samples with a mixture of acetonitrile/water/acetic acid, mycotoxins were rapidly partitioned into a small volume of organic solvent (chloroform) by dispersive liquid-liquid microextraction. The three mycotoxins were simultaneously determined by LC with fluorescence detection after precolumn derivatization for aflatoxin B1 and B2. Parameters affecting both extraction and dispersive liquid-liquid microextraction procedures, including the extraction solvent, the type and volume of extractant, the volume of dispersive solvent, the addition of salt, the pH and the extraction time, were optimized. The optimized protocol provided an enrichment factor of approximately 1.25 and with detection of limits (0.06-0.5 μg/kg) below the maximum levels imposed by current regulations for aflatoxins and ochratoxin A. The mean recovery of three mycotoxins ranged from 82.9-112%, with a RSD less than 7.9% in all cases. The method was successfully applied to measure mycotoxins in commercial rice samples collected from local supermarkets in China. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of atenolol in human plasma using ionic-liquid-based ultrasound-assisted in situ solvent formation microextraction followed by high-performance liquid chromatography.

PubMed

Zeeb, Mohsen; Farahani, Hadi; Papan, Mohammad Kazem

2016-06-01

An efficient analytical method called ionic-liquid-based ultrasound-assisted in situ solvent formation microextraction followed by high-performance liquid chromatography was developed for the determination of atenolol in human plasma. A hydrophobic ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) was formed by the addition of a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) to a sample solution containing an ion-pairing agent during microextraction. The analyte was extracted into the ionic liquid phase while the microextraction solvent was dispersed throughout the sample by utilizing ultrasound. The sample was then centrifuged, and the extracting phase retracted into the microsyringe and injected to liquid chromatography. After optimization, the calibration curve showed linearity in the range of 2-750 ng/mL with the regression coefficient corresponding to 0.998. The limits of detection (S/N = 3) and quantification (S/N = 10) were 0.5 and 2 ng/mL, respectively. A reasonable relative recovery range of 90-96.7% and satisfactory intra-assay (4.8-5.1%, n = 6) and interassay (5.0-5.6%, n = 9) precision along with a substantial sample clean-up demonstrated good performance of the procedure. It was applied for the determination of atenolol in human plasma after oral administration and some pharmacokinetic data were obtained. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid pretreatment and determination of bisphenol A in water samples based on vortex-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with fluorescence detection.

PubMed

Yang, Xiao; Diao, Chun-Peng; Sun, Ai-Ling; Liu, Ren-Min

2014-10-01

A method for the rapid pretreatment and determination of bisphenol A in water samples based on vortex-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with fluorescence detection was proposed in this paper. A simple apparatus consisting of a test tube and a cut-glass dropper was designed and applied to collect the floating extraction drop in liquid-liquid microextraction when low-density organic solvent was used as the extraction solvent. Solidification and melting steps that were tedious but necessary once the low-density organic solvent used as extraction solvent could be avoided by using this apparatus. Bisphenol A was selected as model pollutant and vortex-assisted liquid-liquid microextraction was employed to investigate the usefulness of the apparatus. High-performance liquid chromatography with fluorescence detection was selected as the analytical tool for the detection of bisphenol A. The linear dynamic range was from 0.10 to 100 μg/L for bisphenol A, with good squared regression coefficient (r(2) = 0.9990). The relative standard deviation (n = 7) was 4.7% and the limit of detection was 0.02 μg/L. The proposed method had been applied to the determination of bisphenol A in natural water samples and was shown to be economical, fast, and convenient. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simulation of elution profiles in liquid chromatography - II: Investigation of injection volume overload under gradient elution conditions applied to second dimension separations in two-dimensional liquid chromatography.

PubMed

Stoll, Dwight R; Sajulga, Ray W; Voigt, Bryan N; Larson, Eli J; Jeong, Lena N; Rutan, Sarah C

2017-11-10

An important research direction in the continued development of two-dimensional liquid chromatography (2D-LC) is to improve the detection sensitivity of the method. This is especially important in applications where injection of large volumes of effluent from the first dimension ( 1 D) column into the second dimension ( 2 D) column leads to severe 2 D peak broadening and peak shape distortion. For example, this is common when coupling two reversed-phase columns and the organic solvent content of the 1 D mobile phase overwhelms the 2 D column with each injection of 1 D effluent, leading to low resolution in the second dimension. In a previous study we validated a simulation approach based on the Craig distribution model and adapted from the work of Czok and Guiochon [1] that enabled accurate simulation of simple isocratic and gradient separations with very small injection volumes, and isocratic separations with mismatched injection and mobile phase solvents [2]. In the present study we have extended this simulation approach to simulate separations relevant to 2D-LC. Specifically, we have focused on simulating 2 D separations where gradient elution conditions are used, there is mismatch between the sample solvent and the starting point in the gradient elution program, injection volumes approach or even exceed the dead volume of the 2 D column, and the extent of sample loop filling is varied. To validate this simulation we have compared results from simulations and experiments for 101 different conditions, including variation in injection volume (0.4-80μL), loop filling level (25-100%), and degree of mismatch between sample organic solvent and the starting point in the gradient elution program (-20 to +20% ACN). We find that that the simulation is accurate enough (median errors in retention time and peak width of -1.0 and -4.9%, without corrections for extra-column dispersion) to be useful in guiding optimization of 2D-LC separations. However, this requires that real injection profiles obtained from 2D-LC interface valves are used to simulate the introduction of samples into the 2 D column. These profiles are highly asymmetric - simulation using simple rectangular pulses leads to peak widths that are far too narrow under many conditions. We believe the simulation approach developed here will be useful for addressing practical questions in the development of 2D-LC methods. Copyright © 2017 Elsevier B.V. All rights reserved.

Corrosion Behavior of Ceramic Cup of Blast Furnace Hearth by Liquid Iron and Slag

NASA Astrophysics Data System (ADS)

Li, Yanglong; Cheng, Shusen; Wang, Zhifeng

2016-10-01

Three kinds of sample bricks of ceramic cups for blast furnace hearth were studied by dynamic corrosion tests based on different corrosion systems, i.e., liquid iron system, liquid slag system and liquid iron-slag system. Considering the influence of temperature and sample rotational speed, the corrosion profiles and mass loss of the samples were analyzed. In addition, the microstructure of the corroded samples was observed by optical microscope (OM) and scanning electron microscope (SEM). It was found that the corrosion profiles could be divided into iron corrosion region, slag corrosion region and iron-slag corrosion region via corrosion degree after iron-slag corrosion experiment. The most serious corrosion occurred in iron-slag corrosion region. This is due to Marangoni effect, which promotes a slag film formed between liquid iron and ceramic cup and results in local corrosion. The corrosion of the samples deepened with increasing temperature of liquid iron and slag from 1,623 K to 1,823 K. The variation of slag composition had greater influence on the erosion degree than that of rotational speed in this experiment. Taking these results into account the ceramic cup composition should be close to slag composition to decrease the chemical reaction. A microporous and strong material should be applied for ceramic cup.

Simultaneous Determination of 13 Priority Polycyclic Aromatic Hydrocarbons in Tehran’s Tap Water and Water for Injection Samples Using Dispersive Liquid-Liquid Micro Extraction Method and Gas Chromatography-Mass Spectrometry

PubMed Central

Sadeghi, Ramezan; Kobarfard, Farzad; Yazdanpanah, Hassan; Eslamizad, Samira; Bayate, Mitra

2016-01-01

Polycyclic aromatic hydrocarbons (PAHs) are classified as persistent and carcinogenic organic pollutants. PAHs contamination has been reported in water. Many of relevant regulatory bodies such as EU and EPA have regulated the limit levels for PAHs in drinking water. In this study, 13 priority polycyclic aromatic hydrocarbons (PAHs) were determined in tap water samples of Tehran and water for injection. Dispersive liquid-liquid microextraction procedure combined with gas chromatography-mass spectrometry was used for the extraction and determination of PAHs in the samples. Under the optimized conditions, the range of extraction recoveries and relative standard deviations (RSDs) of PAHs in water using internal standard (anthracene-d10) were in the range of 71-90% and 4-16%, respectively. Limit of detection for different PAHs were between 0.03 and 0.1 ngmL-1. The concentration of PAHs in all tap water as well as water for injection samples were lower than the limit of quantification of PAHs. This is the first study addressing the occurrence of PAHs in water for injection samples in Iran using dispersive liquid-liquid micro extraction procedure combined with gas chromatography-mass spectrometry. PMID:27642318

[Health technology assessment report. Use of liquid-based cytology for cervical cancer precursors screening].

PubMed

Ronco, Guglielmo; Confortini, Massimo; Maccallini, Vincenzo; Naldoni, Carlo; Segnan, Nereo; Sideri, Mario; Zappa, Marco; Zorzi, Manuel; Calvia, Maria; Giorgi Rossi, Paolo

2012-01-01

OBJECTIVE OF THE PROJECT: Purpose of this Report is to evaluate the impact of the introduction of liquid-based cytology (LBC) in cervical cancer screening in terms of efficacy, undesired effects, costs and implications for organisation. EFFICACY AND UNDESIRED EFFECTS: LBC WITH MANUAL INTERPRETATION: The estimates of cross-sectional accuracy for high-grade intraepithelial neoplasia (CIN2 or more severe and CIN3 or more severe) obtained by a systematic review and meta-analysis published in 2008 were used. This review considered only studies in which all women underwent colposcopy or randomised controlled trials (RCTs) with complete verification of test positives. A systematic search of RCTs published thereafter was performed. Three RCTs were identified. One of these studies was conducted in 6 Italian regions and was of large size (45,174 women randomised); a second one was conducted in another Italian region (Abruzzo) and was of smaller size (8,654 women randomised); a third RCT was conducted in the Netherlands and was of large size (89,784 women randomised). No longitudinal study was available. There is currently no clear evidence that LBC increases the sensitivity of cytology and even less that its introduction increases the efficacy of cervical screening in preventing invasive cancers. The Italian randomised study NTCC showed a decrease in specificity, which was not observed in the other two RCTs available. In addition, the 2008 meta-analysis observed a reduction - even if minimal - in specificity just at the ASC-US cytological cut-off, but also a remarkable heterogeneity between studies. These results suggest that the effect of LBC on specificity is variable and plausibly related to the local style of cytology interpretation. There is evidence that LBC reduces the proportion of unsatisfactory slides, although the size of this effect varies remarkably. LBC WITH COMPUTER-ASSISTED INTERPRETATION: An Australian study, based on double testing, showed a statistically significant increase of the sensitivity for CIN2 or more of LBC with computer-assisted interpretation vs. conventional cytology with manual interpretation. However, an English RCT estimated that LBC with computer-assisted interpretation has a lower sensitivity than LBC with manual interpretation. COST AND ECONOMIC EVALUATION: In the current Italian situation the use of liquid-based cytology for primary screening is estimated to increase the costs of cytological screening. Liquid-based cytology needs shorter time for interpretation than conventional cytology. However, in the Italian situation, savings obtained from this time reduction and from the decreased number of repeats due to unsatisfactory slides are not currently sufficient to compensate the cost increase due to the prices currently applied by producers and to a possible greater number of colposcopies caused by LBC. In any case, at current prices, cost is estimated to increase even when assuming a referral rate to colposcopy with LBC similar or slightly lower than that with conventional cytology. For the costs of computer-assisted interpretation of liquid-based cytology, readers are referred to the relative HTA report (Epidemiol Prev 2012;36(5) Suppl 3:e1-43). ORGANISATIONAL AND ETHICAL ASPECTS: Ethical, legal and communication problems are judged to remain unchanged when compared to screening with conventional cytology. After having used the test for some time, interpreters prefer liquid-based to conventional cytology. Reduced time for interpretation makes the adoption of LBC a possible approach to deal with shortenings of cytology interpreters which is happening in Italy. However, alternative solutions, such as computer-assisted interpretation of cytology and the use of HPV as primary screening test, should be considered. Liquid-based cytology allows performing molecular tests, in particular the HPV test. This property allows triaging women with borderline or mild cytology by "reflex" molecular or immunocytochemical tests with no need to recall them. LBC sampling can be used also if HPV is applied as the primary screening test, allowing "reflex" triaging of HPV positive women by cytology with no need to recall them nor to take two samples, one for HPV testing and one for conventional cytology. This represents a remarkable advantage in terms of organization. However, costs are high because only 5-7% of women screened with this approach need interpretation of cytology. In addition, HPV testing with the Hybrid Capture assay on material preserved in LBC transport media needs a preliminary conversion phase, which limits the use of LBC for triaging HPV positive women. It is advisable that in the near future industry develops sampling/transport systems that allow performing both the HPV test and cytology or other validated triage tests without additional manipulations and at sustainable costs.

Preservation of Liquid Biological Samples

NASA Technical Reports Server (NTRS)

Putcha, Lakshmi (Inventor); Nimmagudda, Ramalingeshwara (Inventor)

2004-01-01

The present invention related to the preservation of a liquid biological sample. The biological sample is exposed to a preservative containing at least about 0.15 g of sodium benzoate and at least about 0.025 g of citric acid per 100 ml of sample. The biological sample may be collected in a vessel or an absorbent mass. The biological sample may also be exposed to a substrate and/or a vehicle.

40 CFR 761.269 - Sampling liquid PCB remediation waste.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Sampling liquid PCB remediation waste. 761.269 Section 761.269 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC..., AND USE PROHIBITIONS Cleanup Site Characterization Sampling for PCB Remediation Waste in Accordance...

40 CFR 761.269 - Sampling liquid PCB remediation waste.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Sampling liquid PCB remediation waste. 761.269 Section 761.269 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC..., AND USE PROHIBITIONS Cleanup Site Characterization Sampling for PCB Remediation Waste in Accordance...

40 CFR 761.269 - Sampling liquid PCB remediation waste.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Sampling liquid PCB remediation waste. 761.269 Section 761.269 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC..., AND USE PROHIBITIONS Cleanup Site Characterization Sampling for PCB Remediation Waste in Accordance...

40 CFR 761.269 - Sampling liquid PCB remediation waste.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Sampling liquid PCB remediation waste. 761.269 Section 761.269 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC..., AND USE PROHIBITIONS Cleanup Site Characterization Sampling for PCB Remediation Waste in Accordance...

Analytical instrument with apparatus and method for sample concentrating

DOEpatents

Zaromb, S.

1986-08-04

A system for analysis of trace concentrations of contaminants in air includes a portable liquid chromatograph and a preconcentrator for the contaminants to be analyzed. The preconcentrator includes a sample bag having an inlet valve and an outlet valve for collecting an air sample. When the sample is collected the sample bag is connected in series with a sorbing apparatus in a recirculation loop. The sorbing apparatus has an inner gas-permeable container containing a sorbent material and an outer gas-impermeable container. The sample is circulated through the outer container and around the inner container for trapping and preconcentrating the contaminants in the sorbent material. The sorbent material may be a liquid having the same composition as the mobile phase of the chromatograph for direct injection thereinto. Alternatively, the sorbent material may be a porous, solid body, to which mobile phase liquid is added after preconcentration of the contaminants for dissolving the contaminants, the liquid solution then being withdrawn for injection into the chromatograph.

Analytical instrument with apparatus for sample concentrating

DOEpatents

Zaromb, Solomon

1989-01-01

A system for analysis of trace concentrations of contaminants in air includes a portable liquid chromatograph and a preconcentrator for the contaminants to be analyzed. The preconcentrator includes a sample bag having an inlet valve and an outlet valve for collecting an air sample. When the sample is collected the sample bag is connected in series with a sorbing apparatus in a recirculation loop. The sorbing apparatus has an inner gas-permeable container containing a sorbent material and an outer gas-impermeable container. The sample is circulated through the outer container and around the inner container for trapping and preconcentrating the contaminants in the sorbent material. The sorbent material may be a liquid having the same composition as the mobile phase of the chromatograph for direct injection thereinto. Alternatively, the sorbent material may be a porous, solid body, to which mobile phase liquid is added after preconcentration of the contaminants for dissolving the contaminants, the liquid solution then being withdrawn for injection into the chromatograph.

Method for preconcentrating a sample for subsequent analysis

DOEpatents

Zaromb, Solomon

1990-01-01

A system for analysis of trace concentration of contaminants in air includes a portable liquid chromatograph and a preconcentrator for the contaminants to be analyzed. The preconcentrator includes a sample bag having an inlet valve and an outlet valve for collecting an air sample. When the sample is collected the sample bag is connected in series with a sorbing apparatus in a recirculation loop. The sorbing apparatus has an inner gas-permeable container containing a sorbent material and an outer gas-impermeable container. The sample is circulated through the outer container and around the inner container for trapping and preconcentrating the contaminants in the sorbent material. The sorbent material may be a liquid having the same composition as the mobile phase of the chromatograph for direct injection thereinto. Alternatively, the sorbent material may be a porous, solid body, to which mobile phase liquid is added after preconcentration of the contaminants for dissolving the contaminants, the liquid solution then being withdrawn for injection into the chromatograph.

On the reduction of splash-back

NASA Astrophysics Data System (ADS)

Dickerson, Andrew; Stephen, Jeremy

2017-11-01

The reduction of splash height following the impact of a solid body on a liquid surface is relevant to multiple sectors including military missile entry, industrial processing, and visits to public restrooms. While most studies have viewed splashes in the context of control of impactor shape and surface properties, we here consider the effects of splash height following modification of a liquid surface by surfactants and thin fabrics. Smooth, hydrophilic, free-falling spheres are allowed to impact a quiescent liquid surface of modified surface conditions while filmed with a high-speed camera. We measure splash heights and cavity depths formed by impacting spheres across Froude numbers 3 - 6.5. As expected, lowering the surface tension of the liquid increased splash height with respect to pure water. The introduction of fabric to the surface has an more unpredictable effect. With respect to unaltered impact conditions, ample inclusion of fabric on the surface reduces splash height, while a meager amount of fabric amplifies splashing due to the augmentation of cavity formation preceding a Worthington jet.

Modification of the rheological properties of screen printing ceramic paints containing gold

NASA Astrophysics Data System (ADS)

Izak, P.; Mastalska-Poplawska, J.; Lis, J.; Stempkowska, A.

2017-01-01

This work presents the results of modification of rheological properties of screen printing paints containing gold. 15 wt% glossy gold paste and 15 wt% glossy liquid gold were used as modifiers containing gold. The study showed that the gold paint for screen printing can be obtained by evaporation of the 15 wt% liquid gold and the golden luster. The compaction process of liquid gold by evaporation is slow and easy to perform in industrial conditions. The second way to adapt the 15 wt% gold ceramic paint for screen printing application depended on adding the aniseed oil and the pine oil. The course of the flow curve of the gold paste without modification indicates that it is shear thinning and shows the desired effect of thixotropy, and even anti-thixotropy, at low shear rates (<50-1 s-1). The introduction of the essential oils eliminates this phenomenon and the paste converts itself from the non-rheostable to the rheostable liquid.

Modification of the fluorescent antibody virus neutralisation test--elimination of the cytotoxic effect for the detection of rabies virus neutralising antibodies.

PubMed

Bedeković, Tomislav; Lemo, Nina; Lojkić, Ivana; Mihaljević, Zeljko; Jungić, Andreja; Cvetnić, Zeljko; Cač, Zeljko; Hostnik, Peter

2013-04-01

The virus neutralisation test is used for the quantitation of specific antibodies in serum samples. However, the success of the test depends on the quality of samples. In the case of poor quality samples, a cytotoxic effect can be observed and the results of the test can be compromised. Additionally, the cytotoxic effect limits the use of different substances, such as muscle extract or liquid from thoracic cavity (thoracic liquid), as a sample for the detection of rabies virus neutralising antibodies in the follow-up of fox oral vaccination campaigns. To eliminate the cytotoxic effect, a modified fluorescent antibody virus neutralisation (mFAVN) test was developed and evaluated. In the mFAVN test, inocula were removed after a 1h and the cytotoxic effect was prevented. According to the results obtained, the specificity of the mFAVN test compared to the FAVN test was 88.8% and the sensitivity was 94.4%. The diagnostic validity of the test was 0.99 (CI=0.98-1.00). To evaluate the possibility of using muscle extract and thoracic liquid as samples for the virus neutralisation test, 102 sera, muscle extract and thoracic liquid samples of dog origin were tested with the mFAVN test. The correlation between sera and muscle extracts was 87.9% (r=0.88, p<0.001). The correlation between sera and thoracic liquid was 94.2% (r=0.94, p<0.001). These findings indicated that both muscle extract and thoracic liquid could be used as samples for detection of rabies virus neutralising antibodies in the follow-up of oral vaccination campaigns. To evaluate the level of elimination of the cytotoxic effect, the 102 samples of sera, muscle extracts and thoracic liquid of dog origin were also tested in parallel using the mFAVN and FAVN tests. In the mFAVN test, no instance of cytotoxic effect was observed in the cells. In the FAVN test, two sera (1.9%), 35 muscle extracts (34.3%) and 56 thoracic liquid samples (54.9%) showed cytotoxic effect. The results of this study strongly suggest that cytotoxic effect can be eliminated completely from the rabies virus neutralising antibody detection tests used in the follow-up of oral vaccination campaigns and that very poor quality samples, such as muscle extract and thoracic liquid, can be used. Copyright © 2013 Elsevier B.V. All rights reserved.

Determination of Niacinamide in Lotions and Creams Using Liquid-Liquid Extraction and High-Performance Liquid Chromatography

ERIC Educational Resources Information Center

Usher, Karyn M.; Simmons, Carolyn R.; Keating, Daniel W.; Rossi, Henry F., III

2015-01-01

Chemical separations are an important part of an undergraduate chemistry curriculum. Sophomore students often get experience with liquid-liquid extraction in organic chemistry classes, but liquid-liquid extraction is not as often introduced as a quantitative sample preparation method in honors general chemistry or quantitative analysis classes.…

Restructured low-fat cooked ham containing liquid whey fortified with lactulose.

PubMed

Oliveira, Cristiane A; Massingue, Armando A; Moura, Ana Paula R; Fontes, Paulo Rogério; Ramos, Alcinéia Ls; Ramos, Eduardo M

2018-01-01

Current health concerns have driven consumers to request products with nutritional and physiological advantages, which can be achieved by using prebiotic ingredients. Lactulose is a prebiotic with excellent functional properties and can be easily incorporated into meat products through the addition of liquid whey. This study investigated the technological and sensorial quality of restructured cooked ham elaborated without liquid whey added (control) and with liquid whey containing different contents (0, 30, 60 and 100 g kg -1 ) of lactulose. Liquid whey did not change any technological or sensorial characteristics of the product, but the general acceptability decreased due to addition of lactulose. Samples with higher lactulose concentrations had lower moisture content, pH and refreezing loss and increased carbohydrate content. Control and whey added samples had higher lightness and lower intense color than samples with lactulose. Liquid whey additions with higher lactulose content increased hardness and chewiness of the samples. Restructured cooked hams formulated with liquid whey and 30 g kg -1 of lactulose had minimal effects on the technological properties and sensory characteristics and, due to the possible benefits conferred by the prebiotic, is a potential alternative to provide meat products with prebiotic activity. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Sensory characteristics of liquids thickened with commercial thickeners to levels specified in the International Dysphagia Diet Standardization Initiative (IDDSI) framework.

PubMed

Ong, Jane Jun-Xin; Steele, Catriona M; Duizer, Lisa M

2018-06-01

Sensory characteristics are important for the acceptance of thickened liquids, but those of liquids thickened to the new standards put forth by the International Dysphagia Diet Standardization Initiative (IDDSI) are unknown. This research sought to identify and rate the perception of important sensory properties of liquids thickened to levels specified in the IDDSI framework. Samples were made with water, with and without added barium sulfate, and were thickened with a cornstarch or xanthan gum based thickener. Samples were characterized using projective mapping/ultra-flash profiling to identify important sample attributes, and then with trained descriptive analysis panels to characterize those attributes in non-barium and barium thickened liquids. Three main groups of attributes were observed. Taste and flavor attributes decreased in intensity with increasing thickener. Thickener specific attributes included graininess and chalkiness for the cornstarch thickened samples, and slipperiness for the xanthan gum samples. Within the same type of thickener, ratings of thickness-related attributes (perceived viscosity, adhesiveness, manipulation, and swallowing) at different IDDSI levels were significantly different from each other. However, in non-barium samples, cornstarch samples were perceived as thicker than xanthan gum samples even though they had similar apparent viscosities at 50 s -1 . On the other hand, the two thickeners had similar perceived thickness in the barium samples even though the apparent viscosities of cornstarch samples were higher than those of the xanthan gum samples. In conclusion, IDDSI levels can be distinguished based on sensory properties, but these properties may be affected by the type of thickener and medium being thickened.

Nicotine Levels and Presence of Selected Tobacco-Derived Toxins in Tobacco Flavoured Electronic Cigarette Refill Liquids

PubMed Central

Farsalinos, Konstantinos E.; Gillman, I. Gene; Melvin, Matt S.; Paolantonio, Amelia R.; Gardow, Wendy J.; Humphries, Kathy E.; Brown, Sherri E.; Poulas, Konstantinos; Voudris, Vassilis

2015-01-01

Background. Some electronic cigarette (EC) liquids of tobacco flavour contain extracts of cured tobacco leaves produced by a process of solvent extraction and steeping. These are commonly called Natural Extract of Tobacco (NET) liquids. The purpose of the study was to evaluate nicotine levels and the presence of tobacco-derived toxins in tobacco-flavoured conventional and NET liquids. Methods. Twenty-one samples (10 conventional and 11 NET liquids) were obtained from the US and Greek market. Nicotine levels were measured and compared with labelled values. The levels of tobacco-derived chemicals were compared with literature data on tobacco products. Results. Twelve samples had nicotine levels within 10% of the labelled value. Inconsistency ranged from −21% to 22.1%, with no difference observed between conventional and NET liquids. Tobacco-specific nitrosamines (TSNAs) were present in all samples at ng/mL levels. Nitrates were present almost exclusively in NET liquids. Acetaldehyde was present predominantly in conventional liquids while formaldehyde was detected in almost all EC liquids at trace levels. Phenols were present in trace amounts, mostly in NET liquids. Total TSNAs and nitrate, which are derived from the tobacco plant, were present at levels 200–300 times lower in 1 mL of NET liquids compared to 1 gram of tobacco products. Conclusions. NET liquids contained higher levels of phenols and nitrates, but lower levels of acetaldehyde compared to conventional EC liquids. The lower levels of tobacco-derived toxins found in NET liquids compared to tobacco products indicate that the extraction process used to make these products did not transfer a significant amount of toxins to the NET. Overall, all EC liquids contained far lower (by 2–3 orders of magnitude) levels of the tobacco-derived toxins compared to tobacco products. PMID:25811768

Nicotine levels and presence of selected tobacco-derived toxins in tobacco flavoured electronic cigarette refill liquids.

PubMed

Farsalinos, Konstantinos E; Gillman, I Gene; Melvin, Matt S; Paolantonio, Amelia R; Gardow, Wendy J; Humphries, Kathy E; Brown, Sherri E; Poulas, Konstantinos; Voudris, Vassilis

2015-03-24

Some electronic cigarette (EC) liquids of tobacco flavour contain extracts of cured tobacco leaves produced by a process of solvent extraction and steeping. These are commonly called Natural Extract of Tobacco (NET) liquids. The purpose of the study was to evaluate nicotine levels and the presence of tobacco-derived toxins in tobacco-flavoured conventional and NET liquids. Twenty-one samples (10 conventional and 11 NET liquids) were obtained from the US and Greek market. Nicotine levels were measured and compared with labelled values. The levels of tobacco-derived chemicals were compared with literature data on tobacco products. Twelve samples had nicotine levels within 10% of the labelled value. Inconsistency ranged from -21% to 22.1%, with no difference observed between conventional and NET liquids. Tobacco-specific nitrosamines (TSNAs) were present in all samples at ng/mL levels. Nitrates were present almost exclusively in NET liquids. Acetaldehyde was present predominantly in conventional liquids while formaldehyde was detected in almost all EC liquids at trace levels. Phenols were present in trace amounts, mostly in NET liquids. Total TSNAs and nitrate, which are derived from the tobacco plant, were present at levels 200-300 times lower in 1 mL of NET liquids compared to 1 gram of tobacco products. NET liquids contained higher levels of phenols and nitrates, but lower levels of acetaldehyde compared to conventional EC liquids. The lower levels of tobacco-derived toxins found in NET liquids compared to tobacco products indicate that the extraction process used to make these products did not transfer a significant amount of toxins to the NET. Overall, all EC liquids contained far lower (by 2-3 orders of magnitude) levels of the tobacco-derived toxins compared to tobacco products.

Measuring Vapor Pressure with an Isoteniscope: A Hands-on Introduction to Thermodynamic Concepts

ERIC Educational Resources Information Center

Chen, Wenqian; Haslam, Andrew J.; Macey, Andrew; Shah, Umang V.; Brechtelsbauer, Clemens

2016-01-01

Characterization of the vapor pressure of a volatile liquid or azeotropic mixture, and its fluid phase diagram, can be achieved with an isoteniscope and an industrial grade digital pressure sensor using the experimental method reported in this study. We describe vapor-pressure measurements of acetone and n-hexane and their azeotrope, and how the…

77 FR 15405 - Self-Regulatory Organizations; EDGA Exchange, Inc.; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-15

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Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-20

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Simultaneous determination of dextromethorphan, dextrorphan, and guaifenesin in human plasma using semi-automated liquid/liquid extraction and gradient liquid chromatography tandem mass spectrometry.

PubMed

Eichhold, Thomas H; McCauley-Myers, David L; Khambe, Deepa A; Thompson, Gary A; Hoke, Steven H

2007-01-17

A method for the simultaneous determination of dextromethorphan (DEX), dextrorphan (DET), and guaifenesin (GG) in human plasma was developed, validated, and applied to determine plasma concentrations of these compounds in samples from six clinical pharmacokinetic (PK) studies. Semi-automated liquid handling systems were used to perform the majority of the sample manipulation including liquid/liquid extraction (LLE) of the analytes from human plasma. Stable-isotope-labeled analogues were utilized as internal standards (ISTDs) for each analyte to facilitate accurate and precise quantification. Extracts were analyzed using gradient liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Use of semi-automated LLE with LC-MS/MS proved to be a very rugged and reliable approach for analysis of more than 6200 clinical study samples. The lower limit of quantification was validated at 0.010, 0.010, and 1.0 ng/mL of plasma for DEX, DET, and GG, respectively. Accuracy and precision of quality control (QC) samples for all three analytes met FDA Guidance criteria of +/-15% for average QC accuracy with coefficients of variation less than 15%. Data from the thorough evaluation of the method during development, validation, and application are presented to characterize selectivity, linearity, over-range sample analysis, accuracy, precision, autosampler carry-over, ruggedness, extraction efficiency, ionization suppression, and stability. Pharmacokinetic data are also provided to illustrate improvements in systemic drug and metabolite concentration-time profiles that were achieved by formulation optimization.

Use of radioimmunoassay as a screen for antibiotics in confined animal feeding operations and confirmation by liquid chromatography/mass spectrometry

USGS Publications Warehouse

Meyer, M.T.; Bumgarner, J.E.; Varns, J.L.; Daughtridge, J.V.; Thurman, E.M.; Hostetler, K.A.

2000-01-01

Approximately one-half of the 50 000000 lb of antibiotics produced in the USA are used in agriculture. Because of the intensive use of antibiotics in the management of confined livestock operations, the potential exists for the transport of these compounds and their metabolites into our nation's water resources. A commercially available radioimmunoassay method, developed as a screen for tetracycline antibiotics in serum, urine, milk, and tissue, was adapted to analyze water samples at a detection level of approximately 1.0 ppb and a semiquantitative analytical range of 1-20 ppb. Liquid waste samples were obtained from 13 hog lagoons in three states and 52 surface- and ground-water samples were obtained primarily from areas associated with intensive swine and poultry production in seven states. These samples were screened for the tetracycline antibiotics by using the modified radioimmunoassay screening method. The radioimmunoassay tests yielded positive results for tetracycline antibiotics in samples from all 13 of the hog lagoons. Dilutions of 10-100-fold of the hog lagoon samples indicated that tetracycline antibiotic concentrations ranged from approximately 5 to several hundred parts per billion in liquid hog lagoon waste. Of the 52 surface- and ground-water samples collected all but two tested negative and these two samples contained tetracycline antibiotic concentrations less than 1 ppb. A new liquid chromatography/mass spectrometry method was used to confirm the radioimmunoassay results in 9 samples and also to identify the tetracycline antibiotics to which the radioimmunoassay test was responding. The new liquid chromatography/mass spectrometry method with online solid-phase extraction and a detection level of 0.5 ??g/l confirmed the presence of chlorotetracycline in the hog lagoon samples and in one of the surface-water samples. The concentrations calculated from the radioimmunoassay were a factor of 1-5 times less than those calculated by the liquid chromatography/mass spectrometry concentrations for chlorotetracycline. Copyright (C) 2000 Elsevier Science B.V.

Sample processor for the automatic extraction of families of compounds from liquid samples and/or homogenized solid samples suspended in a liquid

NASA Technical Reports Server (NTRS)

Jahnsen, Vilhelm J. (Inventor); Campen, Jr., Charles F. (Inventor)

1980-01-01

A sample processor and method for the automatic extraction of families of compounds, known as extracts, from liquid and/or homogenized solid samples are disclosed. The sample processor includes a tube support structure which supports a plurality of extraction tubes, each containing a sample from which families of compounds are to be extracted. The support structure is moveable automatically with respect to one or more extraction stations, so that as each tube is at each station a solvent system, consisting of a solvent and reagents, is introduced therein. As a result an extract is automatically extracted from the tube. The sample processor includes an arrangement for directing the different extracts from each tube to different containers, or to direct similar extracts from different tubes to the same utilization device.

[Dynamics of genome changes in Rauwolfia serpentina callus tissue upon the switch to conditions of submerged cultivation].

PubMed

Spiridonova, E V; Adnof, D M; Andreev, I O; Kunakh, V A

2008-01-01

Genome of Rauwolfia serpentina callus cells was found to fail undergo the noticeable changes for several early passages upon the switch from surface to submerged cultivation in the liquid medium of special composition. After subsequent 4-6 passages in submerged culture RAPD spectra polymorphism was revealed which may reflect the changes in DNA sequence as well as in the structure of cell population that forms the strain. Introduction of the intermediary passage on the agar-solidified medium of more simple composition prior to transfer into liquid medium appeared not to affect essentially the level and the pattern of genome changes.

Isolated Liquid Droplet Combustion: Inhibition and Extinction Studies

NASA Technical Reports Server (NTRS)

Dryer, F. L.; Kroenlein, K. G.; Kazakov, A.; Williams, F. A.; Nayagam, V.

2004-01-01

Introduction of fire suppressants to the ambient environment surrounding a heterogeneous diffusion flame may be an inefficient technique for fire safety in systems without buoyant flows. Carbon dioxide substitution for nitrogen diluent leads to significant modifications of the sphero-symmetric burning behavior of isolated n-heptane droplets, partly through increased heat capacity within the gaseous diffusion flame, but mostly because of modifications in spectral radiative coupling in the gas phase. Effects of longer time scale phenomena such as sooting and slow gas-phase/droplet convection remain to be determined. Similar methodologies can be applied to evaluate the effects and efficacy of chemical inhibitors in the liquid and gas phases.

Theoretical Performance of Hydrogen-Oxygen Rocket Thrust Chambers

NASA Technical Reports Server (NTRS)

Sievers, Gilbert K.; Tomazic, William A.; Kinney, George R.

1961-01-01

Data are presented for liquid-hydrogen-liquid-oxygen thrust chambers at chamber pressures from 15 to 1200 pounds per square inch absolute, area ratios to approximately 300, and percent fuel from about 8 to 34 for both equilibrium and frozen composition during expansion. Specific impulse in vacuum, specific impulse, combustion-chamber temperature, nozzle-exit temperature, characteristic velocity, and the ratio of chamber-to-nozzle-exit pressure are included. The data are presented in convenient graphical forms to allow quick calculation of theoretical nozzle performance with over- or underexpansion, flow separation, and introduction of the propellants at various initial conditions or heat loss from the combustion chamber.

Optimal sampling strategies for detecting zoonotic disease epidemics.

PubMed

Ferguson, Jake M; Langebrake, Jessica B; Cannataro, Vincent L; Garcia, Andres J; Hamman, Elizabeth A; Martcheva, Maia; Osenberg, Craig W

2014-06-01

The early detection of disease epidemics reduces the chance of successful introductions into new locales, minimizes the number of infections, and reduces the financial impact. We develop a framework to determine the optimal sampling strategy for disease detection in zoonotic host-vector epidemiological systems when a disease goes from below detectable levels to an epidemic. We find that if the time of disease introduction is known then the optimal sampling strategy can switch abruptly between sampling only from the vector population to sampling only from the host population. We also construct time-independent optimal sampling strategies when conducting periodic sampling that can involve sampling both the host and the vector populations simultaneously. Both time-dependent and -independent solutions can be useful for sampling design, depending on whether the time of introduction of the disease is known or not. We illustrate the approach with West Nile virus, a globally-spreading zoonotic arbovirus. Though our analytical results are based on a linearization of the dynamical systems, the sampling rules appear robust over a wide range of parameter space when compared to nonlinear simulation models. Our results suggest some simple rules that can be used by practitioners when developing surveillance programs. These rules require knowledge of transition rates between epidemiological compartments, which population was initially infected, and of the cost per sample for serological tests.

Sample preparation combined with electroanalysis to improve simultaneous determination of antibiotics in animal derived food samples.

PubMed

da Silva, Wesley Pereira; de Oliveira, Luiz Henrique; Santos, André Luiz Dos; Ferreira, Valdir Souza; Trindade, Magno Aparecido Gonçalves

2018-06-01

A procedure based on liquid-liquid extraction (LLE) and phase separation using magnetically stirred salt-induced high-temperature liquid-liquid extraction (PS-MSSI-HT-LLE) was developed to extract and pre-concentrate ciprofloxacin (CIPRO) and enrofloxacin (ENRO) from animal food samples before electroanalysis. Firstly, simple LLE was used to extract the fluoroquinolones (FQs) from animal food samples, in which dilution was performed to reduce interference effects to below a tolerable threshold. Then, adapted PS-MSSI-HT-LLE protocols allowed re-extraction and further pre-concentration of target analytes in the diluted acid samples for simultaneous electrochemical quantification at low concentration levels. To improve the peak separation, in simultaneous detection, a baseline-corrected second-order derivative approach was processed. These approaches allowed quantification of target FQs from animal food samples spiked at levels of 0.80 to 2.00 µmol L -1 in chicken meat, with recovery values always higher than 80.5%, as well as in milk samples spiked at 4.00 µmol L -1 , with recovery values close to 70.0%. Copyright © 2018 Elsevier Ltd. All rights reserved.

Improved hydrostatic pressure sample injection by tilting the microchip towards the disposable miniaturized CE device.

PubMed

Wang, Wei; Zhou, Fang; Zhao, Liang; Zhang, Jian-Rong; Zhu, Jun-Jie

2008-02-01

A simple method of hydrostatic pressure sample injection towards a disposable microchip CE device was developed. The liquid level in the sample reservoir was higher than that in the sample waste reservoir (SWR) by tilting microchip and hydrostatic pressure was generated, the sample was driven to pass through injection channel into SWR. After sample loading, the microchip was levelled for separation under applied high separation voltage. Effects of tilted angle, initial liquid height and injection duration on electrophoresis were investigated. With enough injection duration, the injection result was little affected by tilted angle and initial liquid heights in the reservoirs. Injection duration for obtaining a stable sample plug was mainly dependent on the tilted angle rather than the initial height of liquid. Experimental results were consistent with theoretical prediction. Fluorescence observation and electrochemical detection of dopamine and catechol were employed to verify the feasibility of tilted microchip hydrostatic pressure injection. Good reproducibility of this injection method was obtained. Because the instrumentation was simplified and no additional hardware was needed in this technology, the proposed method would be potentially useful in disposable devices.

Detection of Organophosphorus Pesticides in Wheat by Ionic Liquid-Based Dispersive Liquid-Liquid Microextraction Combined with HPLC

PubMed Central

Quan, Ji; Hu, Zeshu

2018-01-01

Food safety issues closely related to human health have always received widespread attention from the world society. As a basic food source, wheat is the fundamental support of human survival; therefore, the detection of pesticide residues in wheat is very necessary. In this work, the ultrasonic-assisted ionic liquid-dispersive liquid-liquid microextraction (DLLME) method was firstly proposed, and the extraction and analysis of three organophosphorus pesticides were carried out by combining high-performance liquid chromatography (HPLC). The extraction efficiencies of three ionic liquids with bis(trifluoromethylsulfonyl)imide (Tf2N) anion were compared by extracting organophosphorus in wheat samples. It was found that the use of 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([OMIM][Tf2N]) had both high enrichment efficiency and appropriate extraction recovery. Finally, the method was used for the determination of three wheat samples, and the recoveries of them were 74.8–112.5%, 71.8–104.5%, and 83.8–115.5%, respectively. The results show that the method proposed is simple, fast, and efficient, which can be applied to the extraction of organic matters in wheat samples. PMID:29854562

Vortex-assisted liquid-liquid microextraction for the rapid screening of short-chain chlorinated paraffins in water.

PubMed

Chang, Chia-Yu; Chung, Wu-Hsun; Ding, Wang-Hsien

2016-01-01

The rapid screening of trace levels of short-chain chlorinated paraffins in various aqueous samples was performed by a simple and reliable procedure based on vortex-assisted liquid-liquid microextraction combined with gas chromatography and electron capture negative ionization mass spectrometry. The optimal vortex-assisted liquid-liquid microextraction conditions for 20 mL water sample were as follows: extractant 400 μL of dichloromethane; vortex extraction time of 1 min at 2500 × g; centrifugation of 3 min at 5000 × g; and no ionic strength adjustment. Under the optimum conditions, the limit of quantitation was 0.05 μg/L. Precision, as indicated by relative standard deviations, was less than 9% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was above 91%. The vortex-assisted liquid-liquid microextraction with gas chromatography and electron capture negative ionization mass spectrometry method was successfully applied to quantitatively extract short-chain chlorinated paraffins from samples of river water and the effluent of a wastewater treatment plant, and the concentrations ranged from 0.8 to 1.6 μg/L. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simple, multiplexed, PCR-based barcoding of DNA enables sensitive mutation detection in liquid biopsies using sequencing.

PubMed

Ståhlberg, Anders; Krzyzanowski, Paul M; Jackson, Jennifer B; Egyud, Matthew; Stein, Lincoln; Godfrey, Tony E

2016-06-20

Detection of cell-free DNA in liquid biopsies offers great potential for use in non-invasive prenatal testing and as a cancer biomarker. Fetal and tumor DNA fractions however can be extremely low in these samples and ultra-sensitive methods are required for their detection. Here, we report an extremely simple and fast method for introduction of barcodes into DNA libraries made from 5 ng of DNA. Barcoded adapter primers are designed with an oligonucleotide hairpin structure to protect the molecular barcodes during the first rounds of polymerase chain reaction (PCR) and prevent them from participating in mis-priming events. Our approach enables high-level multiplexing and next-generation sequencing library construction with flexible library content. We show that uniform libraries of 1-, 5-, 13- and 31-plex can be generated. Utilizing the barcodes to generate consensus reads for each original DNA molecule reduces background sequencing noise and allows detection of variant alleles below 0.1% frequency in clonal cell line DNA and in cell-free plasma DNA. Thus, our approach bridges the gap between the highly sensitive but specific capabilities of digital PCR, which only allows a limited number of variants to be analyzed, with the broad target capability of next-generation sequencing which traditionally lacks the sensitivity to detect rare variants. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Simultaneous determination of tyramine and tryptamine and their precursor amino acids by micellar liquid chromatography and pulsed amperometric detection in wines.

PubMed

Gil-Agustí, M; Carda-Broch, S; Monferrer-Pons, Ll; Esteve-Romero, J

2007-07-13

Two biogenic amines, tryptamine and tyramine, and their precursors, tryptophan and tyrosine, were determined by a liquid chromatographic procedure. A hybrid micellar mobile phase of sodium dodecyl sulphate (SDS) and 1-propanol, a C18 column and electrochemical detection were used. A pH study in the range of 3-9 was performed and pH 3 was finally selected in accordance with resolution and analysis time. Oxidation potential was also checked in the range 0.6-0.9V: the maximum area obtained in all those potentials was at 0.8V, which was selected to carry out the analysis using a sequence of pulsed amperometric detection waveform. The four compounds were resolved using a mobile phase of 0.15M SDS-5% 1-propanol with an analysis time of 16 min. Repeatabilities and intermediate precision were evaluated at three different concentrations for each compound with RSD values lower than 2.6 and 4.8%, respectively. Limits of detection and quantification were also obtained within the 10-40 and 33-135 ng/ml ranges, respectively. Finally, the applicability of the procedure was tested in several types of wine and no matrix effect was observed. The possibility of direct sample introduction simplifies and greatly expedites the treatments with reduced cost, improving the accuracy of the procedures.

Thermal Characterization, Using the Photopyroelectric Technique, of Liquids Used in the Automobile Industry

NASA Astrophysics Data System (ADS)

Cervantes-Espinosa, L. M.; Castillo-Alvarado, F. de L.; Lara-Hernández, G.; Cruz-Orea, A.; Mendoza-Alvarez, J. G.; Valcárcel, J. P.; García-Quiroz, A.

2012-11-01

Thermal properties of liquids used in the automobile industry such as engine oil, antifreeze, and a liquid for windshield wipers were obtained using the photopyroelectric (PPE) technique. The inverse PPE configuration was used in order to obtain the thermal effusivity of the liquid samples. The theoretical equation for the PPE signal in this configuration, as a function of the incident light modulation frequency, was fitted to the experimental data in order to obtain the thermal effusivity of these samples. Also, the back PPE configuration was used to obtain the thermal diffusivity of these liquids; this thermal parameter was obtained by fitting the theoretical equation for this configuration, as a function of the sample thickness (called the thermal wave resonator cavity), to the experimental data. All measurements were done at room temperature. A complete thermal characterization of these liquids used in the automobile industry was achieved by the relationship between the obtained thermal diffusivities and thermal effusivities with their thermal conductivities and volumetric heat capacities. The obtained results are compared with the thermal properties of similar liquids.

Ultrasound-assisted ionic liquid dispersive liquid-liquid microextraction combined with graphite furnace atomic absorption spectrometric for selenium speciation in foods and beverages.

PubMed

Tuzen, Mustafa; Pekiner, Ozlem Zeynep

2015-12-01

A rapid and environmentally friendly ultrasound assisted ionic liquid dispersive liquid liquid microextraction (USA-IL-DLLME) was developed for the speciation of inorganic selenium in beverages and total selenium in food samples by using graphite furnace atomic absorption spectrometry. Some analytical parameters including pH, amount of complexing agent, extraction time, volume of ionic liquid, sample volume, etc. were optimized. Matrix effects were also investigated. Enhancement factor (EF) and limit of detection (LOD) for Se(IV) were found to be 150 and 12 ng L(-1), respectively. The relative standard deviation (RSD) was found 4.2%. The accuracy of the method was confirmed with analysis of LGC 6010 Hard drinking water and NIST SRM 1573a Tomato leaves standard reference materials. Optimized method was applied to ice tea, soda and mineral water for the speciation of Se(IV) and Se(VI) and some food samples including beer, cow's milk, red wine, mixed fruit juice, date, apple, orange, grapefruit, egg and honey for the determination of total selenium. Copyright © 2015 Elsevier Ltd. All rights reserved.

Extraction of ranitidine and nizatidine with using imidazolium ionic liquids prior spectrophotometric and chromatographic detection.

PubMed

Kiszkiel, Ilona; Starczewska, Barbara; Leśniewska, Barbara; Późniak, Patrycja

2015-03-15

A new extraction medium was proposed for liquid-liquid extraction of the histamine H2 receptor antagonists ranitidine (RNT) and nizatidine (NZT). The ionic liquids with low vapor pressure and favorable solvating properties for a range of compounds such as 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C4mim][Tf2N] were tested for isolation of analytes. The extraction parameters of RNT and NZT, namely, amount of ionic liquid, pH of sample solution, shaking and centrifugation time were optimized. The isolation processes were performed with 1 mL of the ionic liquids. The extracted samples (pH values near 4) were shaken at 1750 rpm. The influence of interfering substances on the efficiency of extraction process was also studied. Methods for the histamine H2 receptor antagonists (ranitidine and nizatidine) determination after their separation using imidazolium ionic liquids by high performance liquid chromatography (HPLC) combined with UV spectrophotometry were developed. The application of ionic liquids in extraction step allows for selective isolation of analytes from aqueous matrices and their preconcentration. The above methods were applied to the determination of RNT and NZT in environmental samples (river water and wastewater after treatment). Copyright © 2014 Elsevier B.V. All rights reserved.

Magnetomotive room temperature dicationic ionic liquid: a new concept toward centrifuge-less dispersive liquid-liquid microextraction.

PubMed

Beiraghi, Asadollah; Shokri, Masood; Seidi, Shahram; Godajdar, Bijan Mombani

2015-01-09

A new centrifuge-less dispersive liquid-liquid microextraction technique based on application of magnetomotive room temperature dicationic ionic liquid followed by electrothermal atomic absorption spectrometry (ETAAS) was developed for preconcentration and determination of trace amount of gold and silver in water and ore samples, for the first time. Magnetic ionic liquids not only have the excellent properties of ionic liquids but also exhibit strong response to an external magnetic field. These properties provide more advantages and potential application prospects for magnetic ionic liquids than conventional ones in the fields of extraction processes. In this work, thio-Michler's ketone (TMK) was used as chelating agent to form Ag/Au-TMK complexes. Several important factors affecting extraction efficiency including extraction time, rate of vortex agitator, pH of sample solution, concentration of the chelating agent, volume of ionic liquid as well as effects of interfering species were investigated and optimized. Under the optimal conditions, the limits of detection (LOD) were 3.2 and 7.3ngL(-1) with the preconcentration factors of 245 and 240 for Au and Ag, respectively. The precision values (RSD%, n=7) were 5.3% and 5.8% at the concentration level of 0.05μgL(-1) for Au and Ag, respectively. The relative recoveries for the spiked samples were in the acceptable range of 96-104.5%. The results demonstrated that except Hg(2+), no remarkable interferences are created by other various ions in the determination of Au and Ag, so that the tolerance limits (WIon/WAu or Ag) of major cations and anions were in the range of 250-1000. The validated method was successfully applied for the analysis of Au and Ag in some water and ore samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Cryopreservation of human sperm: efficacy and use of a new nitrogen-free controlled rate freezer versus liquid nitrogen vapour freezing.

PubMed

Creemers, E; Nijs, M; Vanheusden, E; Ombelet, W

2011-12-01

Preservation of spermatozoa is an important aspect of assisted reproductive medicine. The aim of this study was to investigate the efficacy and use of a recently developed liquid nitrogen and cryogen-free controlled rate freezer and this compared with the classical liquid nitrogen vapour freezing method for the cryopreservation of human spermatozoa. Ten patients entering the IVF programme donated semen samples for the study. Samples were analysed according to the World Health Organization guidelines. No significant difference in total sperm motility after freeze-thawing between the new technique and classical technique was demonstrated. The advantage of the new freezing technique is that it uses no liquid nitrogen during the freezing process, hence being safer to use and clean room compatible. Investment costs are higher for the apparatus but running costs are only 1% in comparison with classical liquid nitrogen freezing. In conclusion, post-thaw motility of samples frozen with the classical liquid nitrogen vapour technique was comparable with samples frozen with the new nitrogen-free freezing technique. This latter technique can thus be a very useful asset to the sperm cryopreservation laboratory. © 2011 Blackwell Verlag GmbH.

Alternative solvent-based methyl benzoate vortex-assisted dispersive liquid-liquid microextraction for the high-performance liquid chromatographic determination of benzimidazole fungicides in environmental water samples.

PubMed

Santaladchaiyakit, Yanawath; Srijaranai, Supalax

2014-11-01

Vortex-assisted dispersive liquid-liquid microextraction using methyl benzoate as an alternative extraction solvent for extracting and preconcentrating three benzimidazole fungicides (i.e., carbendazim, thiabendazole, and fluberidazole) in environmental water samples before high-performance liquid chromatographic analysis has been developed. The selected microextraction conditions were 250 μL of methyl benzoate containing 300 μL of ethanol, 1.0% w/v sodium acetate, and vortex agitation speed of 2100 rpm for 30 s. Under optimum conditions, preconcentration factors were 14.5-39.0 for the target fungicides. Limits of detection were obtained in the range of 0.01-0.05 μg/L. The proposed method was then applied to surface water samples and the recovery evaluations at three spiked concentration levels of 5, 30, and 50 μg/L were obtained in the range of 77.4-110.9% with the relative standard deviation <7.4%. The present method was simple, rapid, low cost, sensitive, environmentally friendly, and suitable for the trace analysis of the studied fungicides in environmental water samples. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application and optimization of microwave-assisted extraction and dispersive liquid-liquid microextraction followed by high-performance liquid chromatography for sensitive determination of polyamines in turkey breast meat samples.

PubMed

Bashiry, Moein; Mohammadi, Abdorreza; Hosseini, Hedayat; Kamankesh, Marzieh; Aeenehvand, Saeed; Mohammadi, Zaniar

2016-01-01

A novel method based on microwave-assisted extraction and dispersive liquid-liquid microextraction (MAE-DLLME) followed by high-performance liquid chromatography (HPLC) was developed for the determination of three polyamines from turkey breast meat samples. Response surface methodology (RSM) based on central composite design (CCD) was used to optimize the effective factors in DLLME process. The optimum microextraction efficiency was obtained under optimized conditions. The calibration graphs of the proposed method were linear in the range of 20-200 ng g(-1), with the coefficient determination (R(2)) higher than 0.9914. The relative standard deviations were 6.72-7.30% (n = 7). The limits of detection were in the range of 0.8-1.4 ng g(-1). The recoveries of these compounds in spiked turkey breast meat samples were from 95% to 105%. The increased sensitivity in using the MAE-DLLME-HPLC-UV has been demonstrated. Compared with previous methods, the proposed method is an accurate, rapid and reliable sample-pretreatment method. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

Performance of VITEK® MS V3.0 for the Identification of Mycobacterium species from Patient Samples using Automated Liquid Media Systems.

PubMed

Miller, Eric; Cantrell, Christopher; Beard, Melodie; Derylak, Andrew; Babady, N Esther; McMillen, Tracy; Miranda, Edwin; Body, Barbara; Tang, Yi-Wei; Vasireddy, Ravikiran; Vasireddy, Sruthi; Smith, Terry; Iakhiaeva, Elena; Wallace, Richard J; Brown-Elliott, Barbara A; Moreno, Erik; Totty, Heather; Deol, Parampal

2018-06-06

The accuracy and robustness of the VITEK® MS V3.0 matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) system was evaluated by identifying mycobacteria from automated liquid media systems using patient samples. This is the first report demonstrating that proteins within the liquid media, its supplements, and decontamination reagents for non-sterile patient samples do not generate misidentification or false positive results when using the VITEK MS V3.0 system. Prior to testing with patient samples, a seeded study was conducted to challenge the accuracy of the VITEK MS to identify mycobacteria from liquid media through mimicking a clinical workflow. A total of 77 Mycobacterium strains representing 21 species, seeded in simulated sputum, were decontaminated and inoculated into BACT/ALERT®MP liquid culture medium, incubated until positivity, and identified using VITEK MS. A total of 383 liquid cultures were tested of which 379 (99%) identified correctly to the species/complex/group; four (1%) obtained a No Identification, and no misidentifications were observed. Following the simulated sputum study, a total of 73 smear-positive liquid medium cultures detected using BD BBL™ MGIT™ and VersaTREK® MYCO liquid media were identified by VITEK MS. Sixty-four (87.7%) correctly identified to the species/complex/group level; seven (9.6%) resulted as No Identification, and two (2.7%) misidentified at the species level. These results indicate the VITEK MS V3.0 is an accurate tool for routine diagnostics of Mycobacterium species isolated from liquid cultures. Copyright © 2018 American Society for Microbiology.

The Indicating FTA Elute Cartridge

PubMed Central

de Bie, Roosmarie P.; Schmeink, Channa E.; Bakkers, Judith M.J.E.; Snijders, Peter J.F.; Quint, Wim G.V.; Massuger, Leon F.A.G.; Bekkers, Ruud L.M.; Melchers, Willem J.G.

2011-01-01

The clinically validated high-risk human papillomavirus (hrHPV) Hybrid Capture 2 (HC2) and GP5+/6+-PCR assays were analyzed on an Indicating FTA Elute cartridge (FTA cartridge). The FTA cartridge is a solid dry carrier that allows safe transport of cervical samples. FTA cartridge samples were compared with liquid-based samples for hrHPV and high-grade cervical intraepithelial neoplasia (CIN) detection. One cervical sample was collected in a liquid-based medium, and one was applied to the FTA cartridge. DNA was eluted directly from the FTA cartridge by a simple elution step. HC2 and GP5+/6+-PCR assays were performed on both the liquid-based and the FTA-eluted DNA of 88 women. Overall agreement between FTA and liquid-based samples for the presence of hrHPV was 90.9% with GP5+/6+-PCR and 77.3% with HC2. The sensitivity for high-grade CIN of hrHPV testing on the FTA cartridges was 84.6% with GP5+/6+-PCR and only 53.8% with HC2. By comparison, these sensitivities on liquid-based samples were 92.3% and 100% for GP5+/6+-PCR and HC2, respectively. Therefore, the FTA cartridge shows reasonably good overall agreement for hrHPV detection with liquid-based media when using GP5+/6+-PCR but not HC2 testing. Even with GP5+/6+-PCR, the FTA cartridge is not yet capable of detecting all high-grade CIN lesions. PMID:21704269

Analytical methods for the assessment of endocrine disrupting chemical exposure during human fetal and lactation stages: a review.

PubMed

Jiménez-Díaz, I; Vela-Soria, F; Rodríguez-Gómez, R; Zafra-Gómez, A; Ballesteros, O; Navalón, A

2015-09-10

In the present work, a review of the analytical methods developed in the last 15 years for the determination of endocrine disrupting chemicals (EDCs) in human samples related with children, including placenta, cord blood, amniotic fluid, maternal blood, maternal urine and breast milk, is proposed. Children are highly vulnerable to toxic chemicals in the environment. Among these environmental contaminants to which children are at risk of exposure are EDCs -substances able to alter the normal hormone function of wildlife and humans-. The work focuses mainly on sample preparation and instrumental techniques used for the detection and quantification of the analytes. The sample preparation techniques include, not only liquid-liquid extraction (LLE) and solid-phase extraction (SPE), but also modern microextraction techniques such as extraction with molecular imprinted polymers (MIPs), stir-bar sorptive extraction (SBSE), hollow-fiber liquid-phase microextraction (HF-LPME), dispersive liquid-liquid microextraction (DLLME), matrix solid phase dispersion (MSPD) or ultrasound-assisted extraction (UAE), which are becoming alternatives in the analysis of human samples. Most studies focus on minimizing the number of steps and using the lowest solvent amounts in the sample treatment. The usual instrumental techniques employed include liquid chromatography (LC), gas chromatography (GC) mainly coupled to tandem mass spectrometry. Multiresidue methods are being developed for the determination of several families of EDCs with one extraction step and limited sample preparation. Copyright © 2015 Elsevier B.V. All rights reserved.

46 CFR 153.935a - Storage of cargo samples.

Code of Federal Regulations, 2011 CFR

2011-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations General Vessel Safety...: (1) A designated and ventilated space in the cargo area of the vessel; or (2) An area approved by the... to the cargo samples; and (3) Apart from other sample bottles containing incompatible liquids (See...

46 CFR 153.935a - Storage of cargo samples.

Code of Federal Regulations, 2010 CFR

2010-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations General Vessel Safety...: (1) A designated and ventilated space in the cargo area of the vessel; or (2) An area approved by the... to the cargo samples; and (3) Apart from other sample bottles containing incompatible liquids (See...

46 CFR 153.935a - Storage of cargo samples.

Code of Federal Regulations, 2012 CFR

2012-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations General Vessel Safety...: (1) A designated and ventilated space in the cargo area of the vessel; or (2) An area approved by the... to the cargo samples; and (3) Apart from other sample bottles containing incompatible liquids (See...

46 CFR 153.935a - Storage of cargo samples.

Code of Federal Regulations, 2013 CFR

2013-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations General Vessel Safety...: (1) A designated and ventilated space in the cargo area of the vessel; or (2) An area approved by the... to the cargo samples; and (3) Apart from other sample bottles containing incompatible liquids (See...

Spectro-microscopic Characterization of Physical Properties and Phase Separations in Individual Atmospheric Particles

NASA Astrophysics Data System (ADS)

OBrien, R. E.; Wang, B.; Neu, A.; Kelly, S. T.; Lundt, N.; Epstein, S. A.; MacMillan, A.; You, Y.; Laskin, A.; Nizkorodov, S.; Bertram, A. K.; Moffet, R.; Gilles, M.

2013-12-01

The phase state and liquid-liquid phase separations of ambient and laboratory generated aerosol particles were investigated using (1) scanning transmission x-ray microscopy/near-edge x-ray absorption fine structure spectroscopy (STXM/NEXAFS) coupled to a relative humidity (RH) controlled in-situ chamber and (2) environmental scanning electron microscopy (ESEM). The phase states of the particles were determined from measurements of their size and optical density. A comparison is made between the observed phase states of ambient samples and of laboratory generated aerosols to determine how well laboratory samples represent the phase of ambient samples. In addition, liquid-liquid phase separations in laboratory generated particles were investigated. Preliminary results showing that liquid-liquid phase separations occur at RH's between the deliquescence and efflorescence points and that the organic phase surrounds the inorganic phase will be presented. The STXM/NEXAFS technique provides insight into the degree of mixing at the deliquescence point and the degree of phase separation for particles of atmospherically relevant sizes.

Sensitive spectrophotometric determination of Co(II) using dispersive liquid-liquid micro-extraction method in soil samples.

PubMed

Hasanpour, Foroozan; Hadadzadeh, Hassan; Taei, Masoumeh; Nekouei, Mohsen; Mozafari, Elmira

2016-05-01

Analytical performance of conventional spectrophotometer was developed by coupling of effective dispersive liquid-liquid micro-extraction method with spectrophotometric determination for ultra-trace determination of cobalt. The method was based on the formation of Co(II)-alpha-benzoin oxime complex and its extraction using a dispersive liquid-liquid micro-extraction technique. During the present work, several important variables such as pH, ligand concentration, amount and type of dispersive, and extracting solvent were optimized. It was found that the crucial factor for the Co(II)-alpha benzoin oxime complex formation is the pH of the alkaline alcoholic medium. Under the optimized condition, the calibration graph was linear in the ranges of 1.0-110 μg L(-1) with the detection limit (S/N = 3) of 0.5 μg L(-1). The preconcentration operation of 25 mL of sample gave enhancement factor of 75. The proposed method was applied for determination of Co(II) in soil samples.

Determination of some organophosphorus pesticides in water and watermelon samples by microextraction prior to high-performance liquid chromatography.

PubMed

Wang, Chun; Wu, Qiuhua; Wu, Chunxia; Wang, Zhi

2011-11-01

A novel method based on simultaneous liquid-liquid microextraction and carbon nanotube reinforced hollow fiber microporous membrane solid-liquid phase microextraction has been developed for the determination of six organophosphorus pesticides, i.e. isocarbophos, phosmet, parathion-methyl, triazophos, fonofos and phoxim, in water and watermelon samples prior to high-performance liquid chromatography (HPLC). Under the optimum conditions, the method shows a good linearity within a range of 1-200 ng/mL for water samples and 5-200 ng/g for watermelon samples, with the correlation coefficients (r) varying from 0.9990 to 0.9997 and 0.9986 to 0.9995, respectively. The limits of detection (LODs) were in the range between 0.1 and 0.3 ng/mL for water samples and between 1.0 and 1.5 ng/g for watermelon samples. The recoveries of the method at spiking levels of 5.0 and 50.0 ng/mL for water samples were between 85.4 and 100.8%, and at spiking levels of 5.0 and 50.0 ng/g for watermelon samples, they were between 82.6 and 92.4%, with the relative standard deviations (RSDs) varying from 4.5-6.9% and 5.2-7.4%, respectively. The results suggested that the developed method represents a simple, low-cost, high analytes preconcentration and excellent sample cleanup procedure for the determination of organophosphorus pesticides in water and watermelon samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hollow fiber supported ionic liquid membrane microextraction for determination of sulfonamides in environmental water samples by high-performance liquid chromatography.

PubMed

Tao, Yong; Liu, Jing-Fu; Hu, Xia-Lin; Li, Hong-Cheng; Wang, Thanh; Jiang, Gui-Bin

2009-08-28

By using ionic liquid as membrane liquid and tri-n-octylphosphine oxide (TOPO) as additive, hollow fiber supported liquid phase microextraction (HF-LPME) was developed for the determination of five sulfonamides in environmental water samples by high-performance liquid chromatography with ultraviolet detection The extraction solvent and the parameters affecting the extraction enrichment factor such as the type and amount of carrier, pH and volume ratio of donor phase and acceptor phase, extraction time, salt-out effect and matrix effect were optimized. Under the optimal extraction conditions (organic liquid membrane phase: [C(8)MIM][PF(6)] with 14% TOPO (w/v); donor phase: 4mL, pH 4.5 KH(2)PO(4) with 2M Na(2)SO(4); acceptor phase: 25microL, pH 13 NaOH; extraction time: 8 h), low detection limits (0.1-0.4microg/L, RSDor=0.999) were obtained for all the analytes. The presence of humic acid (0-25mg/L dissolved organic carbon) and bovine serum albumin (0-100microg/mL) had no significant effect on the extraction efficiency. Good spike recoveries over the range of 82.2-103.2% were obtained when applying the proposed method on five real environmental water samples. These results indicated that this present method was very sensitive and reliable with good repeatabilities and excellent clean-up in water samples. The proposed method confirmed hollow fiber supported ionic liquid membrane based LPME to be robust to monitoring trace levels of sulfadiazine, sulfamerazine, sulfamethazine, sulfadimethoxine and sulfamethoxazole in aqueous samples.

Liquid Microjunction Surface Sampling Coupled with High-Pressure Liquid Chromatography-Electrospray Ionization-Mass Spectrometry for Analysis of Drugs and Metabolites in Whole-Body Thin Tissue Sections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kertesz, Vilmos; Van Berkel, Gary J

2010-01-01

In this work, a commercially available autosampler was adapted to perform direct liquid microjunction (LMJ) surface sampling followed by a high-pressure liquid chromatography (HPLC) separation of the extract components and detection with electrospray ionization mass spectrometry (ESI-MS). To illustrate the utility of coupling a separation with this direct liquid extraction based surface sampling approach, four different organs (brain, lung, kidney, and liver) from whole-body thin tissue sections of propranolol dosed and control mice were examined. The parent drug was observed in the chromatograms of the surface sampling extracts from all the organs of the dosed mouse examined. In addition, twomore » isomeric phase II metabolites of propranolol (an aliphatic and an aromatic hydroxypropranolol glucuronide) were observed in the chromatograms of the extracts from lung, kidney, and liver. Confirming the presence of one or the other or both of these glucuronides in the extract from the various organs was not possible without the separation. These drug and metabolite data obtained using the LMJ surface sampling/HPLC-MS method and the results achieved by analyzing similar samples by conventional extraction of the tissues and subsequent HPLC-MS analysis were consistent.« less

Immunoassay of paralytic shellfish toxins by moving magnetic particles in a stationary liquid-phase lab-on-a-chip.

PubMed

Kim, Myoung-Ho; Choi, Suk-Jung

2015-04-15

In this study, we devised a stationary liquid-phase lab-on-a-chip (SLP LOC), which was operated by moving solid-phase magnetic particles in the stationary liquid phase. The SLP LOC consisted of a sample chamber to which a sample and reactants were added, a detection chamber containing enzyme substrate solution, and a narrow channel connecting the two chambers and filled with buffer. As a model system, competitive immunoassays of saxitoxin (STX), a paralytic shellfish toxin, were conducted in the SLP LOC using protein G-coupled magnetic particles (G-MPs) as the solid phase. Anti-STX antibodies, STX-horseradish peroxidase conjugate, G-MPs, and a STX sample were added to the sample chamber and reacted by shaking. While liquids were in the stationary state, G-MPs were transported from the sample chamber to the detection chamber by moving a magnet below the LOC. After incubation to allow the enzymatic reaction to occur, the absorbance of the detection chamber solution was found to be reciprocally related to the STX concentration of the sample. Thus, the SLP LOC may represent a novel, simple format for point-of-care testing applications of enzyme-linked immunosorbent assays by eliminating complicated liquid handling steps. Copyright © 2014 Elsevier B.V. All rights reserved.

Development of a new multi-residue laser diode thermal desorption atmospheric pressure chemical ionization tandem mass spectrometry method for the detection and quantification of pesticides and pharmaceuticals in wastewater samples.

PubMed

Boisvert, Michel; Fayad, Paul B; Sauvé, Sébastien

2012-11-19

A new solid phase extraction (SPE) method coupled to a high throughput sample analysis technique was developed for the simultaneous determination of nine selected emerging contaminants in wastewater (atrazine, desethylatrazine, 17β-estradiol, ethynylestradiol, norethindrone, caffeine, carbamazepine, diclofenac and sulfamethoxazole). We specifically included pharmaceutical compounds from multiple therapeutic classes, as well as pesticides. Sample pre-concentration and clean-up was performed using a mixed-mode SPE cartridge (Strata ABW) having both cation and anion exchange properties, followed by analysis by laser diode thermal desorption atmospheric pressure chemical ionization coupled to tandem mass spectrometry (LDTD-APCI-MS/MS). The LDTD interface is a new high-throughput sample introduction method, which reduces total analysis time to less than 15s per sample as compared to minutes with traditional liquid-chromatography coupled to tandem mass spectrometry (LC-MS/MS). Several SPE parameters were evaluated in order to optimize recovery efficiencies when extracting analytes from wastewater, such as the nature of the stationary phase, the loading flow rate, the extraction pH, the volume and composition of the washing solution and the initial sample volume. The method was successfully applied to real wastewater samples from the primary sedimentation tank of a municipal wastewater treatment plant. Recoveries of target compounds from wastewater ranged from 78% to 106%, the limit of detection ranged from 30 to 122ng L(-1) while the limit of quantification ranged from 90 to 370ng L(-1). Calibration curves in the wastewater matrix showed good linearity (R(2)≥0.991) for all target analytes and the intraday and interday coefficient of variation was below 15%, reflecting a good precision. Copyright © 2012 Elsevier B.V. All rights reserved.

Salting-out assisted liquid-liquid extraction combined with capillary HPLC for the determination of sulfonylurea herbicides in environmental water and banana juice samples.

PubMed

Gure, Abera; Lara, Francisco J; Moreno-González, David; Megersa, Negussie; del Olmo-Iruela, Monsalud; García-Campaña, Ana M

2014-09-01

A salting-out assisted liquid-liquid extraction (SALLE) combined with capillary high performance liquid chromatography with diode array detector (capillary HPLC-DAD) was proposed for extraction and determination of residues of nine sulfonylurea herbicides (SUHs) in environmental water and banana juice samples. Various parameters affecting the extraction process such as the type and volume of the organic solvent, sample volume, type and amount of salt, pH of the sample and vortex time were optimized. Under optimum conditions, matrix matched calibration curves were established using river water and banana juice samples. Good linear relationships as well as low limits of detection, LODs (0.4-1.3 and 3-13 µg/L) and quantification, LOQs (1.3-4.3 and 10-43 µg/L) were obtained in water and banana juice samples, respectively. The precision (intra- and inter-day) of the peak areas expressed as relative standard deviations (%, RSD), at two concentration levels were below 10 % in both matrices. Recoveries obtained from spiked environmental waters (river water and groundwater) and banana juice samples, at two concentration levels, ranged from 72 to 115%. The results of the analysis revealed that the proposed SALLE-capillary HPLC method is simple, rapid, cheap and environmentally friendly, being successfully applicable for the determination of SUH residues in waters and banana juices. Copyright © 2014 Elsevier B.V. All rights reserved.

Direct sample introduction-gas chromatography-mass spectrometry for the determination of haloanisole compounds in cork stoppers.

PubMed

Cacho, J I; Nicolás, J; Viñas, P; Campillo, N; Hernández-Córdoba, M

2016-12-02

A solventless analytical method is proposed for analyzing the compounds responsible for cork taint in cork stoppers. Direct sample introduction (DSI) is evaluated as a sample introduction system for the gas chromatography-mass spectrometry (GC-MS) determination of four haloanisoles (HAs) in cork samples. Several parameters affecting the DSI step, including desorption temperature and time, gas flow rate and other focusing parameters, were optimized using univariate and multivariate approaches. The proposed method shows high sensitivity and minimises sample handling, with detection limits of 1.6-2.6ngg -1 , depending on the compound. The suitability of the optimized procedure as a screening method was evaluated by obtaining decision limits (CCα) and detection capabilities (CCβ) for each analyte, which were found to be in 6.9-11.8 and 8.7-14.8ngg -1 , respectively, depending on the compound. Twenty-four cork samples were analysed, and 2,4,6-trichloroanisole was found in four of them at levels between 12.6 and 53ngg -1 . Copyright © 2016 Elsevier B.V. All rights reserved.

Method of retrieving a liquid sample, a suction lysimeter, a portable suction lysimeter, a lysimeter system, and a deep lysimeter

DOEpatents

Hubbell, Joel M.; Sisson, James B.

2003-08-26

A method of retrieving a liquid sample comprises providing a portable lysimeter including a semi-permeable membrane and a chamber in fluid communication with the semi-permeable membrane; making a hole at a site from which a liquid sample is desired; evacuating the chamber by applying a vacuum to the chamber; lowering the portable lysimeter into the hole; obtaining a sample in the chamber; and retrieving the lysimeter from the bore; wherein it is not necessary to backfill the bore. A portable lysimeter includes a semi-permeable member and a chamber in fluid communication with the semi-permeable membrane.

Dual liquid and gas chromatograph system

DOEpatents

Gay, D.D.

A chromatographic system is described that utilizes one detection system for gas chromatographic and micro-liquid chromatographic determinations. The detection system is a direct-current, atmospheric-pressure, helium plasma emission spectrometer. The detector utilizes a nontransparent plasma source unit which contains the plasma region and two side-arms which receive effluents from the micro-liquid chromatograph and the gas chromatograph. The dual nature of this chromatographic system offers: (1) extreme flexibility in the samples to be examined; (2) extreme low sensitivity; (3) element selectivity; (4) long-term stability; (5) direct correlation of data from the liquid and gas samples; (6) simpler operation than with individual liquid and gas chromatographs, each with different detection systems; and (7) cheaper than a commercial liquid chromatograph and a gas chromatograph.

Dual liquid and gas chromatograph system

DOEpatents

Gay, Don D.

1985-01-01

A chromatographic system that utilizes one detection system for gas chromatographic and micro-liquid chromatographic determinations. The detection system is a direct-current, atmospheric-pressure, helium plasma emission spectrometer. The detector utilizes a non-transparent plasma source unit which contains the plasma region and two side-arms which receive effluents from the micro-liquid chromatograph and the gas chromatograph. The dual nature of this chromatographic system offers: (1) extreme flexibility in the samples to be examined; (2) extremely low sensitivity; (3) element selectivity; (4) long-term stability; (5) direct correlation of data from the liquid and gas samples; (6) simpler operation than with individual liquid and gas chromatographs, each with different detection systems; and (7) cheaper than a commercial liquid chromatograph and a gas chromatograph.

Comparison of green sample preparation techniques in the analysis of pyrethrins and pyrethroids in baby food by liquid chromatography-tandem mass spectrometry.

PubMed

Petrarca, Mateus Henrique; Ccanccapa-Cartagena, Alexander; Masiá, Ana; Godoy, Helena Teixeira; Picó, Yolanda

2017-05-12

A new selective and sensitive liquid chromatography triple quadrupole mass spectrometry method was developed for simultaneous analysis of natural pyrethrins and synthetic pyrethroids residues in baby food. In this study, two sample preparation methods based on ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) and salting-out assisted liquid-liquid extraction (SALLE) were optimized, and then, compared regarding the performance criteria. Appropriate linearity in solvent and matrix-based calibrations, and suitable recoveries (75-120%) and precision (RSD values≤16%) were achieved for selected analytes by any of the sample preparation procedures. Both methods provided the analytical selectivity required for the monitoring of the insecticides in fruit-, cereal- and milk-based baby foods. SALLE, recognized by cost-effectiveness, and simple and fast execution, provided a lower enrichment factor, consequently, higher limits of quantification (LOQs) were obtained. Some of them too high to meet the strict legislation regarding baby food. Nonetheless, the combination of ultrasound and DLLME also resulted in a high sample throughput and environmental-friendly method, whose LOQs were lower than the default maximum residue limit (MRL) of 10μgkg -1 set by European Community for baby foods. In the commercial baby foods analyzed, cyhalothrin and etofenprox were detected in different samples, demonstrating the suitability of proposed method for baby food control. Copyright © 2017 Elsevier B.V. All rights reserved.

Combination of saponification and dispersive liquid-liquid microextraction for the determination of tocopherols and tocotrienols in cereals by reversed-phase high-performance liquid chromatography.

PubMed

Shammugasamy, Balakrishnan; Ramakrishnan, Yogeshini; Ghazali, Hasanah M; Muhammad, Kharidah

2013-07-26

A simple sample preparation technique coupled with reversed-phase high-performance liquid chromatography was developed for the determination of tocopherols and tocotrienols in cereals. The sample preparation procedure involved a small-scale hydrolysis of 0.5g cereal sample by saponification, followed by the extraction and concentration of tocopherols and tocotrienols from saponified extract using dispersive liquid-liquid microextraction (DLLME). Parameters affecting the DLLME performance were optimized to achieve the highest extraction efficiency and the performance of the developed DLLME method was evaluated. Good linearity was observed over the range assayed (0.031-4.0μg/mL) with regression coefficients greater than 0.9989 for all tocopherols and tocotrienols. Limits of detection and enrichment factors ranged from 0.01 to 0.11μg/mL and 50 to 73, respectively. Intra- and inter-day precision were lower than 8.9% and the recoveries were around 85.5-116.6% for all tocopherols and tocotrienols. The developed DLLME method was successfully applied to cereals: rice, barley, oat, wheat, corn and millet. This new sample preparation approach represents an inexpensive, rapid, simple and precise sample cleanup and concentration method for the determination of tocopherols and tocotrienols in cereals. Copyright © 2013 Elsevier B.V. All rights reserved.

A fast method for bisphenol A and six analogues (S, F, Z, P, AF, AP) determination in urine samples based on dispersive liquid-liquid microextraction and liquid chromatography-tandem mass spectrometry.

PubMed

Rocha, Bruno Alves; da Costa, Bruno Ruiz Brandão; de Albuquerque, Nayara Cristina Perez; de Oliveira, Anderson Rodrigo Moraes; Souza, Juliana Maria Oliveira; Al-Tameemi, Maha; Campiglia, Andres Dobal; Barbosa, Fernando

2016-07-01

In this study, a novel method combining dispersive liquid-liquid microextraction (DLLME) and fast liquid chromatography coupled to mass spectrometry (LC-MS/MS) was developed and validated for the extraction and determination of bisphenol A (BPA) and six bisphenol analogues, namely bisphenol S (BPS), bisphenol F (BPF), bisphenol P (BPP), bisphenol Z (BPZ), bisphenol AP (BPAP) and bisphenol AF (BPAF) in human urine samples. Type and volume of extraction and disperser solvents, pH sample, ionic strength, and agitation were evaluated. The matrix-matched calibration curves of all analytes were linear with correlation coefficients higher than 0.99 in the range level of 0.5-20.0ngmL(-1). The relative standard deviation (RSD), precision, at three concentrations (1.0, 8.0 and 15.0ngmL(-1)) was lower than 15% with accuracy ranging from 90 to 112%. The biomonitoring capability of the new method was confirmed with the analysis of 50 human urine samples randomly collected from Brazilians. BPA was detected in 92% of the analyzed samples at concentrations ranging

Modified electrokinetic sample injection method in chromatography and electrophoresis analysis

DOEpatents

Davidson, J. Courtney; Balch, Joseph W.

2001-01-01

A sample injection method for horizontal configured multiple chromatography or electrophoresis units, each containing a number of separation/analysis channels, that enables efficient introduction of analyte samples. This method for loading when taken in conjunction with horizontal microchannels allows much reduced sample volumes and a means of sample stacking to greatly reduce the concentration of the sample. This reduction in the amount of sample can lead to great cost savings in sample preparation, particularly in massively parallel applications such as DNA sequencing. The essence of this method is in preparation of the input of the separation channel, the physical sample introduction, and subsequent removal of excess material. By this method, sample volumes of 100 nanoliter to 2 microliters have been used successfully, compared to the typical 5 microliters of sample required by the prior separation/analysis method.

Automation of nanoflow liquid chromatography-tandem mass spectrometry for proteome analysis by using a strong cation exchange trap column.

PubMed

Jiang, Xiaogang; Feng, Shun; Tian, Ruijun; Han, Guanghui; Jiang, Xinning; Ye, Mingliang; Zou, Hanfa

2007-02-01

An approach was developed to automate sample introduction for nanoflow LC-MS/MS (microLC-MS/MS) analysis using a strong cation exchange (SCX) trap column. The system consisted of a 100 microm id x 2 cm SCX trap column and a 75 microm id x 12 cm C18 RP analytical column. During the sample loading step, the flow passing through the SCX trap column was directed to waste for loading a large volume of sample at high flow rate. Then the peptides bound on the SCX trap column were eluted onto the RP analytical column by a high salt buffer followed by RP chromatographic separation of the peptides at nanoliter flow rate. It was observed that higher performance of separation could be achieved with the system using SCX trap column than with the system using C18 trap column. The high proteomic coverage using this approach was demonstrated in the analysis of tryptic digest of BSA and yeast cell lysate. In addition, this system was also applied to two-dimensional separation of tryptic digest of human hepatocellular carcinoma cell line SMMC-7721 for large scale proteome analysis. This system was fully automated and required minimum changes on current microLC-MS/MS system. This system represented a promising platform for routine proteome analysis.

Graphical Interface for the Study of Gas-Phase Reaction Kinetics: Cyclopentene Vapor Pyrolysis

NASA Astrophysics Data System (ADS)

Marcotte, Ronald E.; Wilson, Lenore D.

2001-06-01

The undergraduate laboratory experiment on the pyrolysis of gaseous cyclopentene has been modernized to improve safety, speed, and precision and to better reflect the current practice of physical chemistry. It now utilizes virtual instrument techniques to create a graphical computer interface for the collection and display of experimental data. An electronic pressure gauge has replaced the mercury manometer formerly needed in proximity to the 500 °C pyrolysis oven. Students have much better real-time information available to them and no longer require multiple lab periods to get rate constants and acceptable Arrhenius parameters. The time saved on manual data collection is used to give the students a tour of the computer interfacing hardware and software and a hands-on introduction to gas-phase reagent preparation using a research-grade high-vacuum system. This includes loading the sample, degassing it by the freeze-pump-thaw technique, handling liquid nitrogen and working through the logic necessary for each reconfiguration of the diffusion pump section and the submanifolds.

Pollution pathways of pharmaceutical residues in the aquatic environment on the island of Mallorca, Spain.

PubMed

Rodríguez-Navas, Carlos; Björklund, Erland; Bak, Søren A; Hansen, Martin; Krogh, Kristine A; Maya, Fernando; Forteza, Rafael; Cerdà, Víctor

2013-07-01

This work determines the principal environmental pollution pathways of pharmaceuticals on the island of Mallorca (Spain). The evaluation was made on the basis of the quantification of pharmaceutical residues by liquid chromatography-tandem mass spectrometry in several environmental water samples, including wastewater-treatment plant effluents, municipal solid waste landfill leachates, groundwater (GW), and marine water. An overall set of 19 pharmaceuticals has been identified in the environment of the 27 human pharmaceuticals investigated in this study. WWTP effluents are the main source of discharge of the pharmaceuticals into the aquatic environment. The data indicate that reuse of treated domestic wastewater for irrigation (which supplies some 30 % of the total water demand in Mallorca) contributes to the contamination of GW. In addition, leaching from landfills is identified as another, but minor, possible source of introduction of pharmaceuticals to GW aquifers. Finally, WWTP effluents ending in the Mediterranean Sea, primarily highly urbanized coastal areas, cause pharmaceutical residues to occur in marine water bodies.

Human Papillomavirus Prevalence and Herd Immunity after Introduction of Vaccination Program, Scotland, 2009–2013

PubMed Central

Kavanagh, Kimberley; Pan, Jiafeng; Love, John; Cuschieri, Kate; Robertson, Chris; Ahmed, Syed; Palmer, Timothy; Pollock, Kevin G.J.

2016-01-01

In 2008, a national human papillomavirus (HPV) immunization program using a bivalent vaccine against HPV types 16 and 18 was implemented in Scotland along with a national surveillance program designed to determine the longitudinal effects of vaccination on HPV infection at the population level. Each year during 2009–2013, the surveillance program conducted HPV testing on a proportion of liquid-based cytology samples from women undergoing their first cervical screening test for precancerous cervical disease. By linking vaccination, cervical screening, and HPV testing data, over the study period we found a decline in HPV types 16 and 18, significant decreases in HPV types 31, 33, and 45 (suggesting cross-protection), and a nonsignificant increase in HPV 51. In addition, among nonvaccinated women, HPV types 16 and 18 infections were significantly lower in 2013 than in 2009. Our results preliminarily indicate herd immunity and sustained effectiveness of the bivalent vaccine on virologic outcomes at the population level. PMID:26692336

Human Papillomavirus Prevalence and Herd Immunity after Introduction of Vaccination Program, Scotland, 2009-2013.

PubMed

Cameron, Ross L; Kavanagh, Kimberley; Pan, Jiafeng; Love, John; Cuschieri, Kate; Robertson, Chris; Ahmed, Syed; Palmer, Timothy; Pollock, Kevin G J

2016-01-01

In 2008, a national human papillomavirus (HPV) immunization program using a bivalent vaccine against HPV types 16 and 18 was implemented in Scotland along with a national surveillance program designed to determine the longitudinal effects of vaccination on HPV infection at the population level. Each year during 2009-2013, the surveillance program conducted HPV testing on a proportion of liquid-based cytology samples from women undergoing their first cervical screening test for precancerous cervical disease. By linking vaccination, cervical screening, and HPV testing data, over the study period we found a decline in HPV types 16 and 18, significant decreases in HPV types 31, 33, and 45 (suggesting cross-protection), and a nonsignificant increase in HPV 51. In addition, among nonvaccinated women, HPV types 16 and 18 infections were significantly lower in 2013 than in 2009. Our results preliminarily indicate herd immunity and sustained effectiveness of the bivalent vaccine on virologic outcomes at the population level.

Mode-mismatched confocal thermal-lens microscope with collimated probe beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cabrera, Humberto, E-mail: hcabrera@ictp.it; Centro Multidisciplinartio de Ciencias, Instituto Venezolano de Investigaciones Científicas; Korte, Dorota

2015-05-15

We report a thermal lens microscope (TLM) based on an optimized mode-mismatched configuration. It takes advantage of the coaxial counter propagating tightly focused excitation and collimated probe beams, instead of both focused at the sample, as it is in currently known TLM setups. A simple mathematical model that takes into account the main features of the instrument is presented. The confocal detection scheme and the introduction of highly collimated probe beam allow enhancing the versatility, limit of detection (LOD), and sensitivity of the instrument. The theory is experimentally verified measuring ethanol’s absorption coefficient at 532.8 nm. Additionally, the presented techniquemore » is applied for detection of ultra-trace amounts of Cr(III) in liquid solution. The achieved LOD is 1.3 ppb, which represents 20-fold enhancement compared to transmission mode spectrometric techniques and a 7.5-fold improvement compared to previously reported methods for Cr(III) based on thermal lens effect.« less

Petrology, chemistry, and chronology of 14078 - Chemical constraints on the origin of KREEP

NASA Technical Reports Server (NTRS)

Mckay, G. A.; Nyquist, L. E.; Wiesmann, H.; Wooden, J. L.; Bansal, B. M.

1978-01-01

Petrographic, chemical and isotopic similarities between 14078 and other Apollo-14 KREEP basalts suggest that these samples were derived from the same parent liquid and possibly from the same cooling unit. The liquid was probably generated via meteorite impact. Subtle differences are noted in the shapes of REE patterns of KREEP-rich samples from different landing sites; the origin of these differences is not well understood. Calculated Ti/Sm values in liquids parental to primitive cumulate samples are similar to values proposed for the whole moon.

Graphene Microcapsule Arrays for Combinatorial Electron Microscopy and Spectroscopy in Liquids

DOE PAGES

Yulaev, Alexander; Guo, Hongxuan; Strelcov, Evgheni; ...

2017-04-27

Atomic-scale thickness, molecular impermeability, low atomic number, and mechanical strength make graphene an ideal electron-transparent membrane for material characterization in liquids and gases with scanning electron microscopy and spectroscopy. Here in this paper, we present a novel sample platform made of an array of thousands of identical isolated graphene-capped microchannels with high aspect ratio. A combination of a global wide field of view with high resolution local imaging of the array allows for high throughput in situ studies as well as for combinatorial screening of solutions, liquid interfaces, and immersed samples. We demonstrate the capabilities of this platform by studyingmore » a pure water sample in comparison with alkali halide solutions, a model electrochemical plating process, and beam-induced crystal growth in liquid electrolyte. Spectroscopic characterization of liquid interfaces and immersed objects with Auger and X-ray fluorescence analysis through the graphene membrane are also demonstrated.« less

Estimated content percentages of volatile liquids and fat extractables in ready-to-eat foods.

PubMed

Daft, J L; Cline, J K; Palmer, R E; Sisk, R L; Griffitt, K R

1996-01-01

Content percentages of volatile liquids and fat extractables in 340 samples of ready-to-eat foods were determined gravimetrically. Volatile liquids were determined by drying samples in a microwave oven with a self-contained balance; results were printed out automatically. Fat extractables were extracted from the samples with mixed ethers; extracts were dried and weighed manually. The samples, 191 nonfat and 149 fatty (containing ca 2% or more fat) foods, represent about 5000 different food items and include infant and toddler, ethnic, fast, and imported items. Samples were initially prepared for screening of essential and toxic elements and chemical contamination by chopping and mixing into homogenous composites. Content determinations were then made on separate portions from each composite. Content results were put into a database for evaluation. Overall, mean results from both determinations agree with published data for moisture and fat contents of similar food items. Coefficients of variation, however, were lower for determination of volatile liquids than for that of fat extractables.

Ionic liquid-based ultrasound-assisted emulsification microextraction coupled with high performance liquid chromatography for the determination of four fungicides in environmental water samples.

PubMed

Liang, Pei; Wang, Fang; Wan, Qin

2013-02-15

A highly efficient and environmentally friendly sample preparation method termed ionic liquid-based ultrasound-assisted emulsification microextraction (IL-USAEME) combined with high performance liquid chromatography has been developed for the determination of four fungicides (azoxystrobin, diethofencarb, pyrimethanil and kresoxim-methyl) in water samples. In this novel approach, ionic liquid (IL) was used as extraction solvent in place of the organic solvent used in conventional USAEME assay, and there is no need for using organic dispersive solvent which is typically required in the common dispersive liquid-liquid microextraction method. Various parameters that affect the extraction efficiency, such as the kind and volume of IL, ultrasound emulsification time, extraction temperature and salt addition were investigated and optimized. Under the optimum extraction condition, the linearities of calibration curves were in the range from 3 to 5000 ng mL(-1) for target analytes with the correlation coefficient higher than 0.9992. The enrichment factors and the limits of detection were in the range of 88-137 and 0.73-2.2 ng mL(-1), depending on the analytes. The environmental water samples were successfully analyzed using the proposed method, and the relative recoveries at fortified levels of 50 and 100 ng mL(-1) were in the range of 83.9%-116.2%. Copyright © 2012 Elsevier B.V. All rights reserved.

Vortex-assisted magnetic β-cyclodextrin/attapulgite-linked ionic liquid dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography for the fast determination of four fungicides in water samples.

PubMed

Yang, Miyi; Xi, Xuefei; Wu, Xiaoling; Lu, Runhua; Zhou, Wenfeng; Zhang, Sanbing; Gao, Haixiang

2015-02-13

A novel microextraction technique combining magnetic solid-phase microextraction (MSPME) with ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) to determine four fungicides is presented in this work for the first time. The main factors affecting the extraction efficiency were optimized by the one-factor-at-a-time approach and the impacts of these factors were studied by an orthogonal design. Without tedious clean-up procedure, analytes were extracted from the sample to the adsorbent and organic solvent and then desorbed in acetonitrile prior to chromatographic analysis. Under the optimum conditions, good linearity and high enrichment factors were obtained for all analytes, with correlation coefficients ranging from 0.9998 to 1.0000 and enrichment factors ranging 135 and 159 folds. The recoveries for proposed approach were between 98% and 115%, the limits of detection were between 0.02 and 0.04 μg L(-1) and the RSDs changed from 2.96 to 4.16. The method was successfully applied in the analysis of four fungicides (azoxystrobin, chlorothalonil, cyprodinil and trifloxystrobin) in environmental water samples. The recoveries for the real water samples ranged between 81% and 109%. The procedure proved to be a time-saving, environmentally friendly, and efficient analytical technique. Copyright © 2015 Elsevier B.V. All rights reserved.

Class-conditional feature modeling for ignitable liquid classification with substantial substrate contribution in fire debris analysis.

PubMed

Lopatka, Martin; Sigman, Michael E; Sjerps, Marjan J; Williams, Mary R; Vivó-Truyols, Gabriel

2015-07-01

Forensic chemical analysis of fire debris addresses the question of whether ignitable liquid residue is present in a sample and, if so, what type. Evidence evaluation regarding this question is complicated by interference from pyrolysis products of the substrate materials present in a fire. A method is developed to derive a set of class-conditional features for the evaluation of such complex samples. The use of a forensic reference collection allows characterization of the variation in complex mixtures of substrate materials and ignitable liquids even when the dominant feature is not specific to an ignitable liquid. Making use of a novel method for data imputation under complex mixing conditions, a distribution is modeled for the variation between pairs of samples containing similar ignitable liquid residues. Examining the covariance of variables within the different classes allows different weights to be placed on features more important in discerning the presence of a particular ignitable liquid residue. Performance of the method is evaluated using a database of total ion spectrum (TIS) measurements of ignitable liquid and fire debris samples. These measurements include 119 nominal masses measured by GC-MS and averaged across a chromatographic profile. Ignitable liquids are labeled using the American Society for Testing and Materials (ASTM) E1618 standard class definitions. Statistical analysis is performed in the class-conditional feature space wherein new forensic traces are represented based on their likeness to known samples contained in a forensic reference collection. The demonstrated method uses forensic reference data as the basis of probabilistic statements concerning the likelihood of the obtained analytical results given the presence of ignitable liquid residue of each of the ASTM classes (including a substrate only class). When prior probabilities of these classes can be assumed, these likelihoods can be connected to class probabilities. In order to compare the performance of this method to previous work, a uniform prior was assumed, resulting in an 81% accuracy for an independent test of 129 real burn samples. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Micropyrolyzer for chemical analysis of liquid and solid samples

DOEpatents

Mowry, Curtis D.; Morgan, Catherine H.; Manginell, Ronald P.; Frye-Mason, Gregory C.

2006-07-18

A micropyrolyzer has applications to pyrolysis, heated chemistry, and thermal desorption from liquid or solid samples. The micropyrolyzer can be fabricated from semiconductor materials and metals using standard integrated circuit technologies. The micropyrolyzer enables very small volume samples of less than 3 microliters and high sample heating rates of greater than 20.degree. C. per millisecond. A portable analyzer for the field analysis of liquid and solid samples can be realized when the micropyrolyzer is combined with a chemical preconcentrator, chemical separator, and chemical detector. Such a portable analyzer can be used in a variety of government and industrial applications, such as non-proliferation monitoring, chemical and biological warfare detection, industrial process control, water and air quality monitoring, and industrial hygiene.

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...

Stability of dolasetron in two oral liquid vehicles.

PubMed

Johnson, Cary E; Wagner, Deborah S; Bussard, Wendy E

2003-11-01

The stability of dolasetron 10 mg/mL over 90 days when prepared as an oral liquid formulation from commercially available tablets in both strawberry syrup and a sugar-free vehicle was studied. A liquid suspension of dolasetron mesylate 10 mg/mL was prepared from commercially available dolasetron tablets, OraPlus, and Ora-Sweet or strawberry syrup. Six samples of each formulation were prepared and stored in amber plastic bottles. Three samples of each formulation were refrigerated (3-5 degrees C) and three were stored at room temperature (23-25 degrees C). A 1-mL sample was withdrawn from each of the 12 bottles immediately and after 7, 14, 30, 60, and 90 days. After further dilution to an expected concentration of 10 micrograms/mL with sample diluent, the solutions were assayed in duplicate using high-performance liquid chromatography. The samples were also inspected for color and odor changes, and the pH of each sample was determined. The stability-indicating capability of the dolasetron assay was determined by forced degradation of four separate 10-mg/mL samples exposed to direct sunlight for 90 days. There were no detectable changes in color, odor, or taste and no visible microbial growth in any sample. At least 98% of the initial dolasetron concentration remained throughout the 90-day study period for all samples. An extemporaneously compounded oral liquid preparation of dolasetron mesylate 10 mg/mL in a 1:1 mixture of Ora-Plus and strawberry syrup or Ora-Sweet was stable for at least 90 days when stored at 3-5 or 23-25 degrees C.

Comparative evaluation of ICP sample introduction systems to be used in the metabolite profiling of chlorine-containing pharmaceuticals via HPLC-ICP-MS.

PubMed

Klencsár, Balázs; Sánchez, Carlos; Balcaen, Lieve; Todolí, José; Lynen, Frederic; Vanhaecke, Frank

2018-05-10

A systematic evaluation of four different ICP sample introduction systems to be used in the context of metabolite profiling of chlorine-containing pharmaceuticals via HPLC-ICP-MS was carried out using diclofenac and its major metabolite, 4'-hydroxy-diclofenac, as model compounds. The strict requirements for GMP validation of chromatographic methods in the pharmaceutical industry were adhered to in this context. The final aim of this investigation is an extension of the applicability and validatability of HPLC-ICP-MS in the field of pharmaceutical R&D. Five different gradient programmes were tested while the baseline peak width (w b ), peak capacity (P), USP tailing factor (A s ) and USP signal-to-noise ratio (USP S/N) were determined as major indicators of the chromatographic performance and the values obtained were compared to the corresponding FDA recommendations (if applicable). Four different ICP-MS sample introductions systems were investigated involving two units typically working at higher flow rates (∼1.0 mL min -1 ) and another two systems working at lower flow rates (∼0.1 mL min -1 ). Optimal conditions with potential for applicability under GMP conditions were found at a mobile phase flow rate of 1.0 mL min -1 by using a pneumatic micro-flow LC nebulizer mounted onto a Peltier-cooled cyclonic spray chamber cooled to -1 °C for sample introduction. Under these conditions, HPLC-ICP-MS provided a chromatographic performance similar to that of HPLC with UV detection. The peak shape (USP tailing factor = 1.1-1.4) was significantly improved compared to that obtained with the Peltier-cooled Scott-type spray chamber. Two alternative sample introduction systems - a POINT ® and a High-Temperature Torch-Integrated Sample Introduction System (hTISIS) - were also tested at a flow rate of 0.1 mL min -1 using a chromatographic column with 1.0 mm ID. Although these systems allowed the peak shape to be improved compared to that obtained with the traditional Scott-type spray chamber, the limits of detection and of quantification achievable were strongly compromised due to the significantly lower sensitivity observed for Cl. In addition to a comparison of the aforementioned sample introduction systems, also the effect of spray chamber temperature was evaluated and it was demonstrated that proper temperature control plays an essential role in the optimization of HPLC-ICP-MS methods. Copyright © 2018 Elsevier B.V. All rights reserved.

Nebulization reflux concentrator

NASA Technical Reports Server (NTRS)

Collins, V. G.; Cofer, W. R., III

1986-01-01

A nebulization reflux concentrator for removing trace gas contaminants from a sample gas is described. Sample gas from a gas supply is drawn by a suction source into a vessel. The gas enters the vessel through an atomizing nozzle, thereby atomizing and entraining a scrubbing liquid solvent drawn through a siphon tube from a scrubbing liquid reservoir. The gas and entrained liquid rise through a concentrator and impinge upon a solvent phobic filter, whereby purified gas exits through the filter housing and contaminated liquid coalesces on the solvent phobic filter and falls into the reservoir.

Device and technique for in-process sampling and analysis of molten metals and other liquids presenting harsh sampling conditions

DOEpatents

Alvarez, Joseph L.; Watson, Lloyd D.

1989-01-01

An apparatus and method for continuously analyzing liquids by creating a supersonic spray which is shaped and sized prior to delivery of the spray to a analysis apparatus. The gas and liquid are mixed in a converging-diverging nozzle where the liquid is sheared into small particles which are of a size and uniformly to form a spray which can be controlled through adjustment of pressures and gas velocity. The spray is shaped by a concentric supplemental flow of gas.

Pharmacokinetic Studies of Chinese Medicinal Herbs Using an Automated Blood Sampling System and Liquid Chromatography-mass Spectrometry.

PubMed

Wu, Yu-Tse; Wu, Ming-Tsang; Lin, Chia-Chun; Chien, Chao-Feng; Tsai, Tung-Hu

2012-01-01

The safety of herbal products is one of the major concerns for the modernization of traditional Chinese medicine, and pharmacokinetic data of medicinal herbs guide us to design the rational use of the herbal formula. This article reviews the advantages of the automated blood sampling (ABS) systems for pharmacokinetic studies. In addition, three commonly used sample preparative methods, protein precipitation, liquid-liquid extraction and solid-phase extraction, are introduced. Furthermore, the definition, causes and evaluation of matrix effects in liquid chromatography-mass spectrometry (LC/MS) analysis are demonstrated. Finally, we present our previous works as practical examples of the application of ABS systems and LC/MS for the pharmacokinetic studies of Chinese medicinal herbs.

Determination of endocrine-disrupting chemicals in human milk by dispersive liquid-liquid microextraction.

PubMed

Vela-Soria, Fernando; Jiménez-Díaz, Inmaculada; Díaz, Caridad; Pérez, José; Iribarne-Durán, Luz María; Serrano-López, Laura; Arrebola, Juan Pedro; Fernández, Mariana Fátima; Olea, Nicolás

2016-09-01

Human populations are widely exposed to numerous so-called endocrine-disrupting chemicals, exogenous compounds able to interfere with the endocrine system. This exposure has been associated with several health disorders. New analytical procedures are needed for biomonitoring these xenobiotics in human matrices. A quick and inexpensive methodological procedure, based on sample treatment by dispersive liquid-liquid microextraction, is proposed for the determination of bisphenols, parabens and benzophenones in samples. LOQs ranged from 0.4 to 0.7 ng ml(-1) and RSDs from 4.3 to 14.8%. This methodology was satisfactorily applied in the simultaneous determination of a wide range of endocrine-disrupting chemicals in human milk samples and is suitable for application in biomonitoring studies.

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

PubMed Central

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. Images PMID:970947

Development of an automated high-temperature valveless injection system for online gas chromatography

NASA Astrophysics Data System (ADS)

Kreisberg, N. M.; Worton, D. R.; Zhao, Y.; Isaacman, G.; Goldstein, A. H.; Hering, S. V.

2014-12-01

A reliable method of sample introduction is presented for online gas chromatography with a special application to in situ field portable atmospheric sampling instruments. A traditional multi-port valve is replaced with a valveless sample introduction interface that offers the advantage of long-term reliability and stable sample transfer efficiency. An engineering design model is presented and tested that allows customizing this pressure-switching-based device for other applications. Flow model accuracy is within measurement accuracy (1%) when parameters are tuned for an ambient-pressure detector and 15% accurate when applied to a vacuum-based detector. Laboratory comparisons made between the two methods of sample introduction using a thermal desorption aerosol gas chromatograph (TAG) show that the new interface has approximately 3 times greater reproducibility maintained over the equivalent of a week of continuous sampling. Field performance results for two versions of the valveless interface used in the in situ instrument demonstrate typically less than 2% week-1 response trending and a zero failure rate during field deployments ranging up to 4 weeks of continuous sampling. Extension of the valveless interface to dual collection cells is presented with less than 3% cell-to-cell carryover.

Transport Powder and Liquid Samples by Surface Acoustic Waves

NASA Technical Reports Server (NTRS)

Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Louyeh, Sahar

2009-01-01

Sample transport is an important requirement for In-situ analysis of samples in NASA planetary exploration missions. Tests have shown that powders or liquid drops on a surface can be transported by surface acoustic waves (SAW) that are generated on the surface using interdigital transducers. The phenomena were investigated experimentally and to generate SAWs interdigital electrodes were deposited on wafers of 128 deg rotated Y-cut LiNbO?. Transporting capability of the SAW device was tested using particles of various sizes and drops of various viscosities liquids. Because of different interaction mechanisms with the SAWs, the powders and the liquid drops were observed to move in opposite directions. In the preliminary tests, a speed of 180 mm/s was achieved for powder transportation. The detailed experimental setup and results are presented in this paper. The transporting mechanism can potentially be applied to miniaturize sample analysis system or " lab-on-chip" devices.

Ionic liquid-based reagents improve the stability of midterm fecal sample storage.

PubMed

Hao, Lilan; Xia, Zhongkui; Yang, Huanming; Wang, Jian; Han, Mo

2017-08-01

Fecal samples are widely used in metagenomic research, which aims to elucidate the relationship between human health and the intestinal microbiota. However, the best conditions for stable and reliable storage and transport of these samples at room temperature are still unknown, and whether samples stored at room temperature for several days will maintain their microbiota composition is still unknown. Here, we established and tested a preservation method using reagents containing imidazolium- or pyridinium-based ionic liquids. We stored human fecal samples in these reagents for up to 7 days at different temperatures. Subsequently, all samples were sequenced and compared with fresh samples and/or samples treated under other conditions. The 16S rRNA sequencing results suggested that ionic liquid-based reagents could stabilize the composition of the microbiota in fecal samples during a 7-day storage period, particularly when stored at room temperature. Thus, this method may have implications in the storage of fecal samples for metagenomic research. Copyright © 2017 Elsevier B.V. All rights reserved.

Biodegradation of Dense Non-Aqueous Phase Liquids (DNAPLs) Through Bioaugmentation of Source Areas Dover National Test Site, Dover, Delaware

DTIC Science & Technology

2007-05-01

Bioaugmentation of Source Areas Dover National Test Site, Dover, Delaware ESTCP Project Number ER-0008 May 2007 Revision 3.0 ER0008 ii...2007.05.24 Revision 3.0 TABLE OF CONTENTS Page 1. INTRODUCTION...ER0008 iii 2007.05.24 Revision 3.0 3.5 Testing and Evaluation Plan

Frustration and curvature - Glasses and the cholesteric blue phase

NASA Technical Reports Server (NTRS)

Sethna, J. P.

1983-01-01

An analogy is drawn between continuum elastic theories of the blue phase of cholesteric liquid crystals and recent theories of frustration in configurational glasses. Both involve the introduction of a lattice of disclination lines to relieve frustration; the frustration is due to an intrinsic curvature in the natural form of parallel transport. A continuum theory of configurational glasses is proposed.

An Introduction to Controller Performance Assessment in Process Control Class through Stiction in Control Valves

ERIC Educational Resources Information Center

Srinivasan, Ranganathan; Rengaswamy, Raghunathan; Harris, Sandra

2007-01-01

In this paper, we discuss a simple liquid level experiment that can be used to teach nonlinear phenomena in process control through stiction in control valves. This experiment can be used to introduce the undergraduate students to the area of Controller Performance Assessment (CPA). The experiment is very easy to set-up and demonstrate. While…

The indicating FTA elute cartridge a solid sample carrier to detect high-risk HPV and high-grade cervical lesions.

PubMed

de Bie, Roosmarie P; Schmeink, Channa E; Bakkers, Judith M J E; Snijders, Peter J F; Quint, Wim G V; Massuger, Leon F A G; Bekkers, Ruud L M; Melchers, Willem J G

2011-07-01

The clinically validated high-risk human papillomavirus (hrHPV) Hybrid Capture 2 (HC2) and GP5+/6+-PCR assays were analyzed on an Indicating FTA Elute cartridge (FTA cartridge). The FTA cartridge is a solid dry carrier that allows safe transport of cervical samples. FTA cartridge samples were compared with liquid-based samples for hrHPV and high-grade cervical intraepithelial neoplasia (CIN) detection. One cervical sample was collected in a liquid-based medium, and one was applied to the FTA cartridge. DNA was eluted directly from the FTA cartridge by a simple elution step. HC2 and GP5+/6+-PCR assays were performed on both the liquid-based and the FTA-eluted DNA of 88 women. Overall agreement between FTA and liquid-based samples for the presence of hrHPV was 90.9% with GP5+/6+-PCR and 77.3% with HC2. The sensitivity for high-grade CIN of hrHPV testing on the FTA cartridges was 84.6% with GP5+/6+-PCR and only 53.8% with HC2. By comparison, these sensitivities on liquid-based samples were 92.3% and 100% for GP5+/6+-PCR and HC2, respectively. Therefore, the FTA cartridge shows reasonably good overall agreement for hrHPV detection with liquid-based media when using GP5+/6+-PCR but not HC2 testing. Even with GP5+/6+-PCR, the FTA cartridge is not yet capable of detecting all high-grade CIN lesions. Copyright © 2011 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

Analysis and Design of the NASA Langley Cryogenic Pressure Box

NASA Technical Reports Server (NTRS)

Glass, David E.; Stevens, Jonathan C.; Vause, R. Frank; Winn, Peter M.; Maguire, James F.; Driscoll, Glenn C.; Blackburn, Charles L.; Mason, Brian H.

1999-01-01

A cryogenic pressure box was designed and fabricated for use at NASA Langley Research Center (LaRC) to subject 72 in. x 60 in. curved panels to cryogenic temperatures and biaxial tensile loads. The cryogenic pressure box is capable of testing curved panels down to -423 F (20K) with 54 psig maximum pressure on the concave side, and elevated temperatures and atmospheric pressure on the convex surface. The internal surface of the panel is cooled by high pressure helium as that is cooled to -423 F by liquid helium heat exchangers. An array of twelve independently controlled fans circulate the high pressure gaseous helium to provide uniform cooling on the panel surface. The load introduction structure, consisting of four stainless steel load plates and numerous fingers attaching the load plates to the test panel, is designed to introduce loads into the test panel that represent stresses that will he observed in the actual tank structure. The load plates are trace cooled with liquid nitrogen to reduce thermal gradients that may result in bending the load plates, and thus additional stresses in the test panel. The design of the cryogenic systems, load introduction structure, and control system are discussed in this report.

Comparison of rumen bacteria distribution in original rumen digesta, rumen liquid and solid fractions in lactating Holstein cows.

PubMed

Ji, Shoukun; Zhang, Hongtao; Yan, Hui; Azarfar, Arash; Shi, Haitao; Alugongo, Gibson; Li, Shengli; Cao, Zhijun; Wang, Yajing

2017-01-01

Original rumen digesta, rumen liquid and solid fractions have been frequently used to assess the rumen bacterial community. However, bacterial profiles in rumen original digesta, liquid and solid fractions vary from each other and need to be better established. To compare bacterial profiles in each fraction, samples of rumen digesta from six cows fed either a high fiber diet (HFD) or a high energy diet (HED) were collected via rumen fistulas. Rumen digesta was then squeezed through four layers of cheesecloth to separate liquid and solid fractions. The bacterial profiles of rumen original digesta, liquid and solid fractions were analyzed with High-throughput sequencing technique. Rumen bacterial diversity was mainly affected by diet and individual cow ( P  > 0.05) rather than rumen fraction. Bias distributed bacteria were observed in solid and liquid fractions of rumen content using Venn diagram and LEfSe analysis. Fifteen out of 16 detected biomarkers (using LEfSe analysis) were found in liquid fraction, and these 15 biomarkers contributed the most to the bacterial differences among rumen content fractions. Similar results were found when using samples of original rumen digesta, rumen liquid or solid fractions to assess diversity of rumen bacteria; however, more attention should be draw onto bias distributed bacteria in different ruminal fractions, especially when liquid fraction has been used as a representative sample for rumen bacterial study.

Development of an ionic liquid-based ultrasonic-assisted liquid-liquid microextraction method for sensitive determination of biogenic amines: application to the analysis of octopamine, tyramine and phenethylamine in beer samples.

PubMed

Huang, Ke-Jing; Jin, Chun-Xue; Song, Shi-Lin; Wei, Cai-Yun; Liu, Yan-Ming; Li, Jing

2011-03-15

A simple and efficient method, ionic liquid-based ultrasound-assisted liquid-liquid microextraction, has been developed for the determination of three biogenic amines including octopamine (OCT), tyramine (TYR) and phenethylamine (PHE). Fluorescence probe 2,6-dimethyl-4-quinolinecarboxylic acid N-hydroxysuccinimide ester was applied for derivatization of biogenic amines and high-performance liquid chromatography coupled with fluorescence detection was used for the determination of the derivatives. The factors affecting the extraction efficiency, such as the type and volume of ionic liquid, ultrasonication time and centrifugation time have been investigated in detail. Under the optimum conditions, linearity of the method was observed in the range of 0.5-50 μgmL(-1) for OCT and TYR, and 0.025-2.5 μgmL(-1) for PHE, respectively, with correlation coefficients (γ)>0.996. The limits of detection ranged from 0.25-50 ngmL(-1) (S/N=3). The spiked recoveries of three target compounds in beer samples were in the range of 90.2-114%. As a result, this method has been successfully applied for the sensitive determination of OCT, TYR and PHE in beer samples. Copyright © 2011 Elsevier B.V. All rights reserved.

Electrolysis of a molten semiconductor

PubMed Central

Yin, Huayi; Chung, Brice; Sadoway, Donald R.

2016-01-01

Metals cannot be extracted by electrolysis of transition-metal sulfides because as liquids they are semiconductors, which exhibit high levels of electronic conduction and metal dissolution. Herein by introduction of a distinct secondary electrolyte, we reveal a high-throughput electro-desulfurization process that directly converts semiconducting molten stibnite (Sb2S3) into pure (99.9%) liquid antimony and sulfur vapour. At the bottom of the cell liquid antimony pools beneath cathodically polarized molten stibnite. At the top of the cell sulfur issues from a carbon anode immersed in an immiscible secondary molten salt electrolyte disposed above molten stibnite, thereby blocking electronic shorting across the cell. As opposed to conventional extraction practices, direct sulfide electrolysis completely avoids generation of problematic fugitive emissions (CO2, CO and SO2), significantly reduces energy consumption, increases productivity in a single-step process (lower capital and operating costs) and is broadly applicable to a host of electronically conductive transition-metal chalcogenides. PMID:27553525

Electrolysis of a molten semiconductor.

PubMed

Yin, Huayi; Chung, Brice; Sadoway, Donald R

2016-08-24

Metals cannot be extracted by electrolysis of transition-metal sulfides because as liquids they are semiconductors, which exhibit high levels of electronic conduction and metal dissolution. Herein by introduction of a distinct secondary electrolyte, we reveal a high-throughput electro-desulfurization process that directly converts semiconducting molten stibnite (Sb2S3) into pure (99.9%) liquid antimony and sulfur vapour. At the bottom of the cell liquid antimony pools beneath cathodically polarized molten stibnite. At the top of the cell sulfur issues from a carbon anode immersed in an immiscible secondary molten salt electrolyte disposed above molten stibnite, thereby blocking electronic shorting across the cell. As opposed to conventional extraction practices, direct sulfide electrolysis completely avoids generation of problematic fugitive emissions (CO2, CO and SO2), significantly reduces energy consumption, increases productivity in a single-step process (lower capital and operating costs) and is broadly applicable to a host of electronically conductive transition-metal chalcogenides.

Electrolysis of a molten semiconductor

NASA Astrophysics Data System (ADS)

Yin, Huayi; Chung, Brice; Sadoway, Donald R.

2016-08-01

Metals cannot be extracted by electrolysis of transition-metal sulfides because as liquids they are semiconductors, which exhibit high levels of electronic conduction and metal dissolution. Herein by introduction of a distinct secondary electrolyte, we reveal a high-throughput electro-desulfurization process that directly converts semiconducting molten stibnite (Sb2S3) into pure (99.9%) liquid antimony and sulfur vapour. At the bottom of the cell liquid antimony pools beneath cathodically polarized molten stibnite. At the top of the cell sulfur issues from a carbon anode immersed in an immiscible secondary molten salt electrolyte disposed above molten stibnite, thereby blocking electronic shorting across the cell. As opposed to conventional extraction practices, direct sulfide electrolysis completely avoids generation of problematic fugitive emissions (CO2, CO and SO2), significantly reduces energy consumption, increases productivity in a single-step process (lower capital and operating costs) and is broadly applicable to a host of electronically conductive transition-metal chalcogenides.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Y.; Fan, A.; Fiorillo, G.

Rare event search experiments, such as those searching for dark matter and observations of neutrinoless double beta decay, require ultra low levels of radioactive background for unmistakable identification. In order to reduce the radioactive background of detectors used in these types of event searches, low background photosensors are required, as the physical size of these detectors become increasing larger, and hence the number of such photosensors used also increases rapidly. Considering that most dark matter and neutrinoless double beta decay experiments are turning towards using noble liquids as the target choice, liquid xenon and liquid argon for instance, photosensors thatmore » can work well at cryogenic temperatures are required, 165 K and 87 K for liquid xenon and liquid argon, respectively. The Silicon Geiger Hybrid Tube (SiGHT) is a novel photosensor designed specifically for use in ultra low background experiments operating at cryogenic temperatures. It is based on the proven photocathode plus silicon photomultiplier (SiPM) hybrid technology and consists of very few other, but also ultra radio-pure, materials like fused silica and silicon for the SiPM. Lastly, the introduction of the SiGHT concept, as well as a feasibility study for its production, is reported in this article.« less

Jet-mixing of initially-stratified liquid-liquid pipe flows: experiments and numerical simulations

NASA Astrophysics Data System (ADS)

Wright, Stuart; Ibarra-Hernandes, Roberto; Xie, Zhihua; Markides, Christos; Matar, Omar

2016-11-01

Low pipeline velocities lead to stratification and so-called 'phase slip' in horizontal liquid-liquid flows due to differences in liquid densities and viscosities. Stratified flows have no suitable single point for sampling, from which average phase properties (e.g. fractions) can be established. Inline mixing, achieved by static mixers or jets in cross-flow (JICF), is often used to overcome liquid-liquid stratification by establishing unstable two-phase dispersions for sampling. Achieving dispersions in liquid-liquid pipeline flows using JICF is the subject of this experimental and modelling work. The experimental facility involves a matched refractive index liquid-liquid-solid system, featuring an ETFE test section, and experimental liquids which are silicone oil and a 51-wt% glycerol solution. The matching then allows the dispersed fluid phase fractions and velocity fields to be established through advanced optical techniques, namely PLIF (for phase) and PTV or PIV (for velocity fields). CFD codes using the volume of a fluid (VOF) method are then used to demonstrate JICF breakup and dispersion in stratified pipeline flows. A number of simple jet configurations are described and their dispersion effectiveness is compared with the experimental results. Funding from Cameron for Ph.D. studentship (SW) gratefully acknowledged.

An evaluation of sucrose as a possible contaminant in e-liquids for electronic cigarettes by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

PubMed

Kubica, Paweł; Wasik, Andrzej; Kot-Wasik, Agata; Namieśnik, Jacek

2014-05-01

The influence of sucrose combustion products on smoking and nicotine addiction is still controversial because the presence of the sucrose may be treated as a source of aldehydes and organic acids. In e-liquids used as refills for electronic cigarettes, which are made primarily of poly(propylene glycol), glycerine and ethanol, sucrose may be present at trace levels, and its impact on mainstream smoke formation, and hence on human health and smoking/nicotine addiction is unknown. An analytical method was developed where high-performance liquid chromatography in hydrophilic interaction liquid chromatography mode and tandem mass spectrometry were used for fast and simple determination of sucrose and other saccharides in e-liquids for electronic cigarettes. Minimal effort was required in the sample preparation step, and satisfactory results were obtained, and the sample matrix had an insignificant impact. The chromatographic separation was done using an Ascentis Express OH5 column (150 mm × 2.1 mm, 2.7 μm). The coefficients of variation for within-day precision for three concentrations were 2.4 %, 1.6 % and 2.3 %, and the between-day coefficients of variation for a single concentration were 2.1 %, 2.5 % and 1.7 % measured on the next 3 days. The detection limit was 0.73 μg/g, and the sucrose content in e-liquids ranged from 0.76 to 72.93 μg/g among 37 samples. Moreover, with the method presented it is possible to determine the presence of other saccharides such as fructose, glucose, maltose and lactose. However, only sucrose was found in all samples of e-liquids. The proposed method is rapid, simple and reliable in terms of high-performance liquid chromatography coupled with tandem mass spectrometry.

Electronic Cigarette Refill Liquids: Child-Resistant Packaging, Nicotine Content, and Sales to Minors.

PubMed

Buettner-Schmidt, Kelly; Miller, Donald R; Balasubramanian, Narayanaganesh

2016-01-01

To determine the accuracy of the labeled quantity of the nicotine content of the e-liquids sold in unlicensed vape stores, whether the packaging of e-liquids sold within the vape stores was child-resistant, whether minors were present within vape stores, and whether sales to minors occurred. This study was conducted across North Dakota prior to implementation of a new e-cigarette state law and provided a baseline assessment before enactment of the new legal requirements. We tested samples of e-liquids and performed observations in 16 stores that were selling e-cigarettes but were not legally required to be licensed for tobacco retail. The e-liquids were analyzed for nicotine content using a validated high-performance liquid chromatography method for nicotine analysis. Of the 70 collected e-liquid samples that claimed to contain nicotine, 17% contained more than the labeled quantity and 34% contained less than the labeled quantity by 10% or more, with one sample containing 172% more than the labeled quantity. Of the 94 e-liquid containers sampled, only 35% were determined to be child-resistant. Minors were present in stores, although no sales to minors occurred. Mislabeling of nicotine in e-liquids is common and exposes the user to the harmful effects of nicotine. The lack of child-resistant packaging for this potentially toxic substance is a serious public health problem. E-cigarettes should be included in the legal definition of tobacco products, child-resistant packaging and nicotine labeling laws should be enacted and strictly enforced, and vape stores should be licensed by states. Copyright © 2016 Elsevier Inc. All rights reserved.

Electronic Cigarette Refill Liquids: Child-Resistant Packaging, Nicotine Content, and Sales to Minors2

PubMed Central

Buettner-Schmidt, Kelly; Miller, Donald R.; Balasubramanian, Narayanaganesh

2016-01-01

Purpose To determine the accuracy of the labeled quantity of the nicotine content of the e-liquids sold in unlicensed vape stores, whether the packaging of e-liquids sold within the vape stores was child-resistant, whether minors were present within vape stores, and whether sales to minors occurred. This study was conducted across North Dakota prior to implementation of a new e-cigarette state law and provided a baseline assessment before enactment of the new legal requirements. Design and Methods We tested samples of e-liquids and performed observations in 16 stores that were selling e-cigarettes but were not legally required to be licensed for tobacco retail. The e-liquids were analyzed for nicotine content using a validated high-performance liquid chromatography method for nicotine analysis. Results Of the 70 collected e-liquid samples that claimed to contain nicotine, 17% contained more than the labeled quantity and 34% contained less than the labeled quantity by 10% or more, with one sample containing 172% more than the labeled quantity. Of the 94 e-liquid containers sampled, only 35% were determined to be child-resistant. Minors were present in stores, although no sales to minors occurred. Conclusions Mislabeling of nicotine in e-liquids is common and exposes the user to the harmful effects of nicotine. The lack of child-resistant packaging for this potentially toxic substance is a serious public health problem. E-cigarettes should be included in the legal definition of tobacco products, child-resistant packaging and nicotine labeling laws should be enacted and strictly enforced, and vape stores should be licensed by states. PMID:27079973

Deep eutectic solvent-based ultrasound-assisted dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography for the determination of ultraviolet filters in water samples.

PubMed

Wang, Huazi; Hu, Lu; Liu, Xinya; Yin, Shujun; Lu, Runhua; Zhang, Sanbing; Zhou, Wenfeng; Gao, Haixiang

2017-09-22

In the present study, a simple and rapid sample preparation method designated ultrasound-assisted dispersive liquid-liquid microextraction based on a deep eutectic solvent (DES) followed by high-performance liquid chromatography with ultraviolet (UV) detection (HPLC-UVD) was developed for the extraction and determination of UV filters from water samples. The model analytes were 2,4-dihydroxybenzophenone (BP-1), benzophenone (BP) and 2-hydroxy-4-methoxybenzophenone (BP-3). The hydrophobic DES was prepared by mixing trioctylmethylammonium chloride (TAC) and decanoic acid (DecA). Various influencing factors (selection of the extractant, amount of DES, ultrasound duration, salt addition, sample volume, sample pH, centrifuge rate and duration) on UV filter recovery were systematically investigated. Under optimal conditions, the proposed method provided good recoveries in the range of 90.2-103.5% and relative standard deviations (inter-day and intra-day precision, n=5) below 5.9%. The enrichment factors for the analytes ranged from 67 to 76. The limits of detection varied from 0.15 to 0.30ngmL -1 , depending on the analytes. The linearities were between 0.5 and 500ngmL -1 for BP-1 and BP and between 1 and 500ngmL -1 for BP-3, with coefficients of determination greater than 0.99. Finally, the proposed method was applied to the determination of UV filters in swimming pool and river water samples, and acceptable relative recoveries ranging from 82.1 to 106.5% were obtained. Copyright © 2017. Published by Elsevier B.V.

Multi-residue method for determination of 58 pesticides, pharmaceuticals and personal care products in water using solvent demulsification dispersive liquid-liquid microextraction combined with liquid chromatography-tandem mass spectrometry.

PubMed

Caldas, Sergiane Souza; Rombaldi, Caroline; Arias, Jean Lucas de Oliveira; Marube, Liziane Cardoso; Primel, Ednei Gilberto

2016-01-01

A rapid and efficient sample pretreatment using solvent-based de-emulsification dispersive liquid-liquid microextraction (SD-DLLME) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was studied for the extraction of 58 pharmaceuticals and personal care products (PPCPs) and pesticides from water samples. Type and volume of extraction and disperser solvents, pH, salt addition, amount of salt and type of demulsification solvent were evaluated. Limits of quantification (LOQ) in the range from 0.0125 to 1.25 µg L(-1) were reached, and linearity was in the range from the LOQ of each compound to 25 μg L(-1). Recoveries ranged from 60% to 120% for 84% of the compounds, with relative standard deviations lower than 29%. The proposed method demonstrated, for the first time, that sample preparation by SD-DLLME with determination by LC-MS/MS can be successfully used for the simultaneous extraction of 32 pesticides and 26 PPCPs from water samples. The entire procedure, including the extraction of 58 organic compounds from the aqueous sample solution and the breaking up of the emulsion after extraction with water, rather than with an organic solvent, was environmentally friendly. In addition, this technique was less expensive and faster than traditional techniques. Finally, the analytical method under study was successfully applied to the analysis of all 58 pesticides and PPCPs in surface water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Antimicrobial-Resistant Bacterial Populations and Antimicrobial Resistance Genes Obtained from Environments Impacted by Livestock and Municipal Waste

PubMed Central

Durso, Lisa M.; Harhay, Dayna M.; Schmidt, John W.

2015-01-01

This study compared the populations of antimicrobial-resistant bacteria and the repertoire of antimicrobial resistance genes in four environments: effluent of three municipal wastewater treatment facilities, three cattle feedlot runoff catchment ponds, three swine waste lagoons, and two “low impact” environments (an urban lake and a relict prairie). Multiple liquid and solid samples were collected from each environment. The prevalences and concentrations of antimicrobial-resistant (AMR) Gram-negative (Escherichia coli and Salmonella enterica) and Gram-positive (enterococci) bacteria were determined from individual samples (n = 174). The prevalences of 84 antimicrobial resistance genes in metagenomic DNA isolated from samples pooled (n = 44) by collection date, location, and sample type were determined. The prevalences and concentrations of AMR E. coli and Salmonella were similar among the livestock and municipal sample sources. The levels of erythromycin-resistant enterococci were significantly higher in liquid samples from cattle catchment ponds and swine waste lagoons than in liquid samples from municipal wastewater treatment facilities, but solid samples from these environments did not differ significantly. Similarly, trimethoprim/sulfamethoxazole-resistant E. coli concentrations were significantly higher in swine liquid than in municipal liquid samples, but there was no difference in solid samples. Multivariate analysis of the distribution of antimicrobial resistance genes using principal coordinate analysis showed distinct clustering of samples with livestock (cattle and swine), low impact environment and municipal samples forming three separate clusters. The numbers of class A beta-lactamase, class C beta-lactamase, and fluoroquinolone resistance genes detected were significantly higher (P < 0.05) in municipal samples than in cattle runoff or swine lagoon samples. In conclusion, we report that AMR is a very widespread phenomenon and that similar prevalences and concentrations of antimicrobial-resistant bacteria and antimicrobial resistance genes exist in cattle, human, and swine waste streams, but a higher diversity of antimicrobial resistance genes are present in treated human waste discharged from municipal wastewater treatment plants than in livestock environments. PMID:26197056

Antimicrobial-Resistant Bacterial Populations and Antimicrobial Resistance Genes Obtained from Environments Impacted by Livestock and Municipal Waste.

PubMed

Agga, Getahun E; Arthur, Terrance M; Durso, Lisa M; Harhay, Dayna M; Schmidt, John W

2015-01-01

This study compared the populations of antimicrobial-resistant bacteria and the repertoire of antimicrobial resistance genes in four environments: effluent of three municipal wastewater treatment facilities, three cattle feedlot runoff catchment ponds, three swine waste lagoons, and two "low impact" environments (an urban lake and a relict prairie). Multiple liquid and solid samples were collected from each environment. The prevalences and concentrations of antimicrobial-resistant (AMR) Gram-negative (Escherichia coli and Salmonella enterica) and Gram-positive (enterococci) bacteria were determined from individual samples (n = 174). The prevalences of 84 antimicrobial resistance genes in metagenomic DNA isolated from samples pooled (n = 44) by collection date, location, and sample type were determined. The prevalences and concentrations of AMR E. coli and Salmonella were similar among the livestock and municipal sample sources. The levels of erythromycin-resistant enterococci were significantly higher in liquid samples from cattle catchment ponds and swine waste lagoons than in liquid samples from municipal wastewater treatment facilities, but solid samples from these environments did not differ significantly. Similarly, trimethoprim/sulfamethoxazole-resistant E. coli concentrations were significantly higher in swine liquid than in municipal liquid samples, but there was no difference in solid samples. Multivariate analysis of the distribution of antimicrobial resistance genes using principal coordinate analysis showed distinct clustering of samples with livestock (cattle and swine), low impact environment and municipal samples forming three separate clusters. The numbers of class A beta-lactamase, class C beta-lactamase, and fluoroquinolone resistance genes detected were significantly higher (P < 0.05) in municipal samples than in cattle runoff or swine lagoon samples. In conclusion, we report that AMR is a very widespread phenomenon and that similar prevalences and concentrations of antimicrobial-resistant bacteria and antimicrobial resistance genes exist in cattle, human, and swine waste streams, but a higher diversity of antimicrobial resistance genes are present in treated human waste discharged from municipal wastewater treatment plants than in livestock environments.

Apparatus and method for comparing corresponding acoustic resonances in liquids

DOEpatents

Sinha, Dipen N.

1999-01-01

Apparatus and method for comparing corresponding acoustic resonances in liquids. The present invention permits the measurement of certain characteristics of liquids which affect the speed of sound therein. For example, a direct correlation between the octane rating of gasoline and the speed of sound in a gasoline sample has been experimentally observed. Therefore, changes in the speed of sound therein can be utilized as a sensitive parameter for determining changes in composition of a liquid sample. The present apparatus establishes interference patterns inside of a liquid without requiring the use of very thin, rigorously parallel ceramic discs, but rather uses readily available piezoelectric transducers attached to the outside surface of the usual container for the liquid and located on the same side thereof in the vicinity of one another. That is, various receptacle geometries may be employed, and the driving and receiving transducers may be located on the same side of the receptacle. The cell may also be constructed of any material that is inert to the liquid under investigation. A single-transducer embodiment, where the same transducer provides the excitation to the sample container and receives signals impressed therein, is also described.

Apparatus and method for comparing corresponding acoustic resonances in liquids

DOEpatents

Sinha, D.N.

1999-03-23

Apparatus and method are disclosed for comparing corresponding acoustic resonances in liquids. The present invention permits the measurement of certain characteristics of liquids which affect the speed of sound therein. For example, a direct correlation between the octane rating of gasoline and the speed of sound in a gasoline sample has been experimentally observed. Therefore, changes in the speed of sound therein can be utilized as a sensitive parameter for determining changes in composition of a liquid sample. The present apparatus establishes interference patterns inside of a liquid without requiring the use of very thin, rigorously parallel ceramic discs, but rather uses readily available piezoelectric transducers attached to the outside surface of the usual container for the liquid and located on the same side thereof in the vicinity of one another. That is, various receptacle geometries may be employed, and the driving and receiving transducers may be located on the same side of the receptacle. The cell may also be constructed of any material that is inert to the liquid under investigation. A single-transducer embodiment, where the same transducer provides the excitation to the sample container and receives signals impressed therein, is also described. 5 figs.

Ambient Mass Spectrometry Imaging Using Direct Liquid Extraction Techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laskin, Julia; Lanekoff, Ingela

2015-11-13

Mass spectrometry imaging (MSI) is a powerful analytical technique that enables label-free spatial localization and identification of molecules in complex samples.1-4 MSI applications range from forensics5 to clinical research6 and from understanding microbial communication7-8 to imaging biomolecules in tissues.1, 9-10 Recently, MSI protocols have been reviewed.11 Ambient ionization techniques enable direct analysis of complex samples under atmospheric pressure without special sample pretreatment.3, 12-16 In fact, in ambient ionization mass spectrometry, sample processing (e.g., extraction, dilution, preconcentration, or desorption) occurs during the analysis.17 This substantially speeds up analysis and eliminates any possible effects of sample preparation on the localization of moleculesmore » in the sample.3, 8, 12-14, 18-20 Venter and co-workers have classified ambient ionization techniques into three major categories based on the sample processing steps involved: 1) liquid extraction techniques, in which analyte molecules are removed from the sample and extracted into a solvent prior to ionization; 2) desorption techniques capable of generating free ions directly from substrates; and 3) desorption techniques that produce larger particles subsequently captured by an electrospray plume and ionized.17 This review focuses on localized analysis and ambient imaging of complex samples using a subset of ambient ionization methods broadly defined as “liquid extraction techniques” based on the classification introduced by Venter and co-workers.17 Specifically, we include techniques where analyte molecules are desorbed from solid or liquid samples using charged droplet bombardment, liquid extraction, physisorption, chemisorption, mechanical force, laser ablation, or laser capture microdissection. Analyte extraction is followed by soft ionization that generates ions corresponding to intact species. Some of the key advantages of liquid extraction techniques include the ease of operation, ability to analyze samples in their native environments, speed of analysis, and ability to tune the extraction solvent composition to a problem at hand. For example, solvent composition may be optimized for efficient extraction of different classes of analytes from the sample or for quantification or online derivatization through reactive analysis. In this review, we will: 1) introduce individual liquid extraction techniques capable of localized analysis and imaging, 2) describe approaches for quantitative MSI experiments free of matrix effects, 3) discuss advantages of reactive analysis for MSI experiments, and 4) highlight selected applications (published between 2012 and 2015) that focus on imaging and spatial profiling of molecules in complex biological and environmental samples.« less

Direct Analysis of Organic Compounds in Liquid Using a Miniature Photoionization Ion Trap Mass Spectrometer with Pulsed Carrier-Gas Capillary Inlet.

PubMed

Lu, Xinqiong; Yu, Quan; Zhang, Qian; Ni, Kai; Qian, Xiang; Tang, Fei; Wang, Xiaohao

2017-08-01

A miniature ion trap mass spectrometer with capillary direct sampling and vacuum ultraviolet photoionization source was developed to conduct trace analysis of organic compounds in liquids. Self-aspiration sampling is available where the samples are drawn into the vacuum chamber through a capillary with an extremely low flow rate (less than 1 μL/min), which minimizes sample consumption in each analysis to tens of micrograms. A pulsed gas-assisted inlet was designed and optimized to promote sample transmission in the tube and facilitate the cooling of ions, thereby improving instrument sensitivity. A limit of detection of 2 ppb could be achieved for 2,4-dimethylaniline in a methanol solution. The sampling system described in the present study is specifically suitable for a miniature photoionization ion trap mass spectrometer that can perform rapid and online analysis for liquid samples. Graphical Abstract ᅟ.

Direct Analysis of Organic Compounds in Liquid Using a Miniature Photoionization Ion Trap Mass Spectrometer with Pulsed Carrier-Gas Capillary Inlet

NASA Astrophysics Data System (ADS)

Lu, Xinqiong; Yu, Quan; Zhang, Qian; Ni, Kai; Qian, Xiang; Tang, Fei; Wang, Xiaohao

2017-08-01

A miniature ion trap mass spectrometer with capillary direct sampling and vacuum ultraviolet photoionization source was developed to conduct trace analysis of organic compounds in liquids. Self-aspiration sampling is available where the samples are drawn into the vacuum chamber through a capillary with an extremely low flow rate (less than 1 μL/min), which minimizes sample consumption in each analysis to tens of micrograms. A pulsed gas-assisted inlet was designed and optimized to promote sample transmission in the tube and facilitate the cooling of ions, thereby improving instrument sensitivity. A limit of detection of 2 ppb could be achieved for 2,4-dimethylaniline in a methanol solution. The sampling system described in the present study is specifically suitable for a miniature photoionization ion trap mass spectrometer that can perform rapid and online analysis for liquid samples.

99. LIQUID OXYGEN LINE AND SAMPLING VALVE FOR RAPIDLOAD ON ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

99. LIQUID OXYGEN LINE AND SAMPLING VALVE FOR RAPID-LOAD ON WEST SIDE OF SKID 9A - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Application of dispersion-solidification liquid-liquid microextraction for the determination of triazole fungicides in environmental water samples by high-performance liquid chromatography.

PubMed

Wang, Chun; Wu, Qiuhua; Wu, Chunxia; Wang, Zhi

2011-01-15

A simple, rapid and environmentally friendly method has been developed for the determination of four triazole fungicides (myclobutanil, tebuconazole, triadimenol, hexaconazole) in water samples by dispersion-solidification liquid-liquid microextraction coupled with high performance liquid chromatography-diode array detection. Several variables that affect the extraction efficiencies, including the type and volume of the extraction solvent and dispersive solvent, extraction time, effect of pH and salt addition, were investigated and optimized. Under the optimum conditions, the proposed method is sensitive and shows a good linearity within a range of 0.5-200 ng mL(-1), with the correlation coefficients (r) varying from 0.9992 to 0.9998. High enrichment factors were achieved ranging from 190 to 450. The recoveries of the target analytes from water samples at spiking levels of 1.0, 5.0 and 50.0 ng mL(-1) were between 84.8% and 110.2%. The limits of detection (LODs) for the analytes were ranged in 0.06-0.1 ng mL(-1), and the relative standard deviations (RSD) varied from 3.9% to 5.7%. The proposed method has been successfully applied for the determination of the triazole fungicides in real water samples. Copyright © 2010 Elsevier B.V. All rights reserved.

Trace determination of organophosphate esters in white wine, red wine, and beer samples using dispersive liquid-liquid microextraction combined with ultra-high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Pang, Long; Yang, Huiqiang; Yang, Peijie; Zhang, Hongzhong; Zhao, Jihong

2017-08-15

In this study, dispersive liquid-liquid microextraction coupled with ultra-high-performance liquid chromatography-tandem mass spectrometry was developed for the analysis of five representative organophosphate esters (OPEs) in wine samples. Under optimized conditions, the proposed method resulted in good linearity (R 2 >0.9933) over the range of 0.1-100μgL -1 , with limits of detection (LODs, S/N =3) and quantification (LOQs, S/N =10) in the ranges of 0.48-18.8ngL -1 and 1.58-62.5ngL -1 , respectively. Inter- and intra-assay precisions of RSD% ranged from 3.21% to 6.13% and from 1.69% to 7.63%, respectively. The spiked recoveries of target OPEs from white wine, red wine, and beer samples were in the ranges of 80-122%, 76-120%, and 76-110%, respectively, at two different concentration levels. The total concentrations of five OPEs found in white wine, red wine, and beer samples were in the ranges of 0.29-0.85μgL -1 , 1.00-3.05μgL -1 , and 0.86-1.47μgL -1 , respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

One-step displacement dispersive liquid-liquid microextraction coupled with graphite furnace atomic absorption spectrometry for the selective determination of methylmercury in environmental samples.

PubMed

Liang, Pei; Kang, Caiyan; Mo, Yajun

2016-01-01

A novel method for the selective determination of methylmercury (MeHg) was developed by one-step displacement dispersive liquid-liquid microextraction (D-DLLME) coupled with graphite furnace atomic absorption spectrometry. In the proposed method, Cu(II) reacted with diethyldithiocarbamate (DDTC) to form Cu-DDTC complex, which was used as the chelating agent instead of DDTC for the dispersive liquid-liquid microextraction (DLLME) of MeHg. Because the stability of MeHg-DDTC is higher than that of Cu-DDTC, MeHg can displace Cu from the Cu-DDTC complex and be preconcentrated in a single DLLME procedure. MeHg could be extracted into the extraction solvent phase at pH 6 while Hg(II) remained in the sample solution. Potential interference from co-existing metal ions with lower DDTC complex stability was largely eliminated without the need of any masking reagent. Under the optimal conditions, the limit of detection of this method was 13.6ngL(-1) (as Hg), and an enhancement factor of 81 was achieved with a sample volume of 5.0mL. The proposed method was successfully applied for the determination of trace MeHg in some environmental samples with satisfactory results. Copyright © 2015 Elsevier B.V. All rights reserved.

2-Naphthalenthiol derivatization followed by dispersive liquid-liquid microextraction as an efficient and sensitive method for determination of acrylamide in bread and biscuit samples using high-performance liquid chromatography.

PubMed

Faraji, Mohammad; Hamdamali, Mohammadrezza; Aryanasab, Fezzeh; Shabanian, Meisam

2018-07-13

In this research, an ultrasonic-assisted extraction followed by 2-naphthalenthiol derivatization and dispersive liquid-liquid microextraction of acrylamide (AA) was developed as simple and sensitive sample preparation method for AA in bread and biscuit samples using high performance liquid chromatography. Influence of derivatization and microextraction parameters were evaluated and optimized. Results showed that the derivatization of AA leads to improve its hydrophobicity and chromatographic behavior. Under optimum conditions of derivatization and microextraction, the method yielded a linear calibration curve ranging from 10 to 1000 μg L -1 with a determination coefficient (R 2 ) of 0.9987. Limit of detection (LOD) and limit of quantification (LOQ) were 3.0 and 9.0 μg L -1 , respectively. Intra-day (n = 6) and inter-day (n = 3) precisions based on relative standard deviation percent (RSD%) for extraction and determination of AA at 50 and 500 μg L -1 levels were less than 9.0%. Finally, the performance of proposed method was investigated for determination of AA in some bread and biscuit samples, and satisfactory results were obtained (relative recovery ≥ 90%). Copyright © 2018. Published by Elsevier B.V.

Simultaneous determination of six synthetic phenolic antioxidants in edible oils using dispersive liquid-liquid microextraction followed by high-performance liquid chromatography with diode array detection.

PubMed

Xu, Shuangjiao; Liu, Liangliang; Wang, Yanqin; Zhou, Dayun; Kuang, Meng; Fang, Dan; Yang, Weihua; Wei, Shoujun; Xiao, Aiping; Ma, Lei

2016-08-01

A simple, rapid, organic-solvent- and sample-saving pretreatment technique, called dispersive liquid-liquid microextraction, was developed for the determination of six synthetic phenolic antioxidants from edible oils before high-performance liquid chromatography with diode array detection. The entire procedure was composed of a two-step microextraction and a centrifugal process and could be finished in about 5 min, only consuming only 25 mg of sample and 1 mL of the organic solvent for each extraction. The influences of several important parameters on the microextraction efficiency were thoroughly investigated. Recovery assays for oil samples were spiked at three concentration levels, 50, 100 and 200 mg/kg, and provided recoveries in the 86.3-102.5% range with a relative standard deviation below 3.5%. The intra-day and inter-day precisions for the analysis were less than 3.8%. The proposed method was successfully applied for the determination of synthetic phenolic antioxidants in different oil samples, and satisfactory results were obtained. Thus, the developed method represents a viable alternative for the quality control of synthetic phenolic antioxidant concentrations in edible oils. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination of four synthesized metabolites of mequindox in urine samples using ultrasound-assisted dispersive liquid-liquid microextraction combined with high-performance liquid chromatography.

PubMed

Zhang, Jiaheng; Gao, Haixiang; Peng, Bing; Li, Yubo; Li, Songqing; Zhou, Zhiqiang

2012-01-15

A novel pretreatment method termed ultrasound-assisted dispersive liquid-liquid microextraction (UADLLME) coupled with high-performance liquid chromatography-ultraviolet detector (HPLC-UV) was applied for the detection of four synthesized metabolites of mequindox in pig urine samples. A total volume of 200 μL of methanol (dispersant) and 60 μL of 1,1,2,2-tetrachloroethane (extract) were injected into 5.0 mL of urine sample and then emulsified by ultrasound treatment for 4 min to form a cloudy solution. The effect of several factors on the recovery of each metabolite was investigated by a fitting derivation method for the first time. Under optimum conditions, the method yields a linear calibration curve in the concentration range from 0.5 to 500 μg/L and a limit of detection (LOD) of 0.16-0.28 μg/L for target analytes. The recoveries ranged from 72.0% to 91.3% with a relative standard deviation (RSD) of less than 5.2%. The enrichment factors for the four compounds ranged from 75 to 95. Two pig urine samples were successfully analyzed using the proposed method. Copyright © 2011 Elsevier B.V. All rights reserved.

Pesticide extraction from table grapes and plums using ionic liquid based dispersive liquid-liquid microextraction.

PubMed

Ravelo-Pérez, Lidia M; Hernández-Borges, Javier; Herrera-Herrera, Antonio V; Rodríguez-Delgado, Miguel Angel

2009-12-01

Room temperature ionic liquids (RTILs) have been used as extraction solvents in dispersive liquid-liquid microextraction (DLLME) for the determination of eight multi-class pesticides (i.e. thiophanate-methyl, carbofuran, carbaryl, tebuconazole, iprodione, oxyfluorfen, hexythiazox, and fenazaquin) in table grapes and plums. The developed method involves the combination of DLLME and high-performance liquid chromatography with diode array detection. Samples were first homogenized and extracted with acetonitrile. After evaporation and reconstitution of the extract in water containing sodium chloride, a quick DLLME procedure that used the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate ([C(6)MIM][PF(6)]) and methanol was developed. The RTIL dissolved in a very small volume of acetonitrile was directed injected in the chromatographic system. The comparison between the calibration curves obtained from standards and from spiked sample extracts (matrix-matched calibration) showed the existence of a strong matrix effect for most of the analyzed pesticides. A recovery study was also developed with five consecutive extractions of the two types of fruits spiked at three concentration levels. Mean recovery values were in the range of 72-100% for table grapes and 66-105% for plum samples (except for thiophanate-methyl and carbofuran, which were 64-75% and 58-66%, respectively). Limits of detection (LODs) were in the range 0.651-5.44 microg/kg for table grapes and 0.902-6.33 microg/kg for plums, representing LODs below the maximum residue limits (MRLs) established by the European Union in these fruits. The potential of the method was demonstrated by analyzing 12 commercial fruit samples (six of each type).

Thermal Design, Analysis, and Testing of the Quench Module Insert Bread Board

NASA Technical Reports Server (NTRS)

Breeding Shawn; Khodabandeh, Julia; Turner, Larry D. (Technical Monitor)

2001-01-01

The science requirements for materials processing is to provide the desired PI requirements of thermal gradient, solid/liquid interface front velocity for a given processing temperature desired by the PI. Processing is performed by translating the furnace with the sample in a stationary position to minimize any disturbances to the solid/liquid interface front during steady state processing. Typical sample materials for this metals and alloys furnace are lead-tin alloys, lead-antimony alloys, and aluminum alloys. Samples must be safe to process and therefore typically are contained with hermetically sealed cartridge tubes (gas tight) with inner ceramic liners (liquid tight) to prevent contamination and/or reaction of the sample material with the cartridge tube.

An assessment of the potential of laser-induced breakdown spectroscopy (LIBS) for the analysis of cesium in liquid samples of biological origin.

PubMed

Metzinger, Anikó; Kovács-Széles, Eva; Almási, István; Galbács, Gábor

2014-01-01

The present study describes the development of an analytical method for the determination of cesium in biological fluid samples (human urine and blood samples) by laser-induced breakdown spectroscopy (LIBS). The developed method is based on sample presentation by liquid-to-solid conversion, enhancing the emission signal by drying the liquid into small "pockets" created in a metal support (zinc plate), and allows the analysis to be carried out on as little as 1 μL of sample volume, in a closed sample cell. Absolute detection limits on the Cs I 852.1 nm spectral line were calculated by the IUPAC 3σ method to be 6 ng in the urine sample and 27 ng in the blood serum sample. It is estimated that LIBS may be used to detect highly elevated concentration levels of Cs in fluid samples taken from people potentially exposed to surges of Cs from non-natural sources.

Determination of the chromatic dispersion of liquids based on the liquid-prism SPR configuration in angular and spectral interrogations

NASA Astrophysics Data System (ADS)

Lan, Guoqiang; Liu, Shugang; Wang, Yuxiao; Zhang, Xueru; Song, Yinglin

2015-10-01

In this work, we use the liquid-prism SPR sensing configuration to determine the chromatic dispersion of different liquids, since the condition of SPR is sensitive to the refractive index of the liquid prism. We use the glass slide coated with 50 nm Au film as the sensing chip, and use AvaLight - HAL (360 nm - 2500 nm) light source as the broaden band light source in our experiments. We adopt the deionized water as the standard sample to determine the chromatic dispersion of different liquid samples (ethanol and n-hexane), and we implement the experiment through the SPR sensing configuration in angular and spectral interrogations. According to the experimental data, the chromatic dispersions of ethanol and n-hexane are obtained. The proposed technique provides a new high sensitive method for the determination of chromatic dispersion of liquids.

Sub-nanometer Resolution Imaging with Amplitude-modulation Atomic Force Microscopy in Liquid

PubMed Central

Farokh Payam, Amir; Piantanida, Luca; Cafolla, Clodomiro; Voïtchovsky, Kislon

2016-01-01

Atomic force microscopy (AFM) has become a well-established technique for nanoscale imaging of samples in air and in liquid. Recent studies have shown that when operated in amplitude-modulation (tapping) mode, atomic or molecular-level resolution images can be achieved over a wide range of soft and hard samples in liquid. In these situations, small oscillation amplitudes (SAM-AFM) enhance the resolution by exploiting the solvated liquid at the surface of the sample. Although the technique has been successfully applied across fields as diverse as materials science, biology and biophysics and surface chemistry, obtaining high-resolution images in liquid can still remain challenging for novice users. This is partly due to the large number of variables to control and optimize such as the choice of cantilever, the sample preparation, and the correct manipulation of the imaging parameters. Here, we present a protocol for achieving high-resolution images of hard and soft samples in fluid using SAM-AFM on a commercial instrument. Our goal is to provide a step-by-step practical guide to achieving high-resolution images, including the cleaning and preparation of the apparatus and the sample, the choice of cantilever and optimization of the imaging parameters. For each step, we explain the scientific rationale behind our choices to facilitate the adaptation of the methodology to every user's specific system. PMID:28060262

Use of the Keele injector for sample introduction for gas chromatographic analysis of vinclozolin in lettuces.

PubMed

Shim, J H; Lee, Y S; Kim, M R; Lee, C J; Kim, I S

2003-10-10

We examined a Keele injector for sample introduction for gas chromatographic analysis of vinclozolin treated in lettuces. Samples in milligram quantity were introduced into a glass tube in a Keele injector at a gas chromatograph injection port. The glass tube was then crushed to allow the sample to carry onto a capillary column in a normal manner. The standard calibration curve for quantitative detection of vinclozolin was obtained by determining vinclozolin spiked in samples at variable concentrations. The calibration curve showed a linear response to vinclozolin ranging from 0.05 to 1.0 microg/g, giving a slope value of 174.8, the y-intercept value of -2.8146 and the mean r2-value of 0.9994. Limit of quantification for vinclozolin was 0.05 microg/g by this method, comparable to 0.01 microg/g by a normal injector. When samples treated previously with vinclozolin were determined by the Keele injector, vinclozolin was found to be about 30% lower as compared to a normal method, suggesting about 70% recovery of the spiked vinclozolin by the Keele injector. From these results, the Keele injector was suggested to be potential for sample introduction in gas chromatographic analysis of vinclozolin in lettuce samples.

Liquid Biopsy and its Potential for Management of Hepatocellular Carcinoma.

PubMed

Zhou, Jian; Huang, Ao; Yang, Xin-Rong

2016-06-01

We summarized the recent findings of liquid biopsy in cancer field and discussed its potential utility in hepatocellular carcinoma. Literature published in MEDLINE, EMBASE, and Science Direct electronic databases was searched and reviewed. Liquid biopsy specially referred to the detection of nucleic acids (circulating cell-free DNA, cfDNA) and circulating tumor cells (CTCs) in the blood of cancer patients. Compared to conventional single-site sampling or biopsy method, liquid biopsy had the advantages such as non-invasiveness, dynamic monitoring, and the most important of all, overcoming the limit of spatial and temporal heterogeneity. The genomic information of cancer could be profiled by genotyping cfDNA/CTC and subsequently applied to make molecular classification, targeted therapy guidance, and unveil drug resistance mechanisms. The serial sampling feature of liquid biopsy made it possible to monitor treatment response in a real-time manner and predict tumor metastasis/recurrence in advance. Liquid biopsy is a non-invasive, dynamic, and informative sampling method with important clinical translational significance in cancer research and practice. Much work needs to be done before it is used in the management of HCC.

Determination of spirocyclic tetronic/tetramic acid derivatives and neonicotinoid insecticides in fruits and vegetables by liquid chromatography and mass spectrometry after dispersive liquid-liquid microextraction.

PubMed

Pastor-Belda, Marta; Garrido, Isabel; Campillo, Natalia; Viñas, Pilar; Hellín, Pilar; Flores, Pilar; Fenoll, José

2016-07-01

Dispersive liquid-liquid microextraction was used to preconcentrate three spirocyclic tetronic/tetramic acid derivatives (spirotetramat, spiromesifen and spirodiclofen) and five neonicotinoid (thiamethoxam, chlotianidin, imidacloprid, acetamiprid and thiacloprid) insecticides previously extracted from fruit and vegetable matrices with acetonitrile. The organic enriched phase was evaporated, reconstituted in 25μL acetonitrile and analyzed by reversed-phase liquid chromatography with tandem mass spectrometry using a triple quadrupole in selected reaction monitoring mode. Enrichment factors in the 15-100 range were obtained. A matrix effect was observed, the detection limits varying between 0.025 and 0.5ngg(-1), depending on the compound and the sample matrix. The developed method was applied to the analysis of 25 samples corresponding to five different fruit and vegetable matrices. Only thiamethoxam was detected in a lemon sample at a concentration close to the quantification limit, and spiromesifen and spirotetramat at concentrations between 11.6 and 54.5ngg(-1). Copyright © 2016 Elsevier Ltd. All rights reserved.

Cold-stage microscopy system for fast-frozen liquids.

PubMed

Talmon, Y; Davis, H T; Scriven, L E; Thomas, E L

1979-06-01

The least artifact-laden fixation technique for examining colloidal suspensions, microemulsions, and other microstructured liquids in the electron microscope appears to be thermal fixation, i.e., ultrafast freezing of the liquid specimen. For rapid-enough cooling and for observation in TEM/STEM a thin sample is needed. The need is met by trapping a thin layer ( approximately 100 nm) of liquid between two polyimide films ( approximately 40 nm thickness) mounted on copper grids and immersing the resulting sandwich in liquid nitrogen at its melting point. For liquids containing water, polyimides films are used since this polymer is far less susceptible to the electron beam damage observed for the commonly used polymer films such as Formvar and collodion in contact with ice. Transfer of the frozen sample into the microscope column without deleterious frost deposition and warming is accomplished with a new transfer module for the cooling stage of the JEOL JEM-100CX microscope, which makes a true cold stage out of a device originally intended for cooling specimens inside the column. Sample results obtained with the new fast-freeze, cold-stage microscopy system are given.

Determination of diflubenzuron and chlorbenzuron in fruits by combining acetonitrile-based extraction with dispersive liquid-liquid microextraction followed by high-performance liquid chromatography.

PubMed

Ruan, Chunqiang; Zhao, Xiang; Liu, Chenglan

2015-09-01

In this study, a simple and low-organic-solvent-consuming method combining an acetonitrile-partitioning extraction procedure followed by "quick, easy, cheap, effective, rugged and safe" cleanup with ionic-liquid-based dispersive liquid-liquid microextraction and high-performance liquid chromatography with diode array detection was developed for the determination of diflubenzuron and chlorbenzuron in grapes and pears. Ionic-liquid-based dispersive liquid-liquid microextraction was performed using the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate as the extractive solvent and acetonitrile extract as the dispersive solvent. The main factors influencing the efficiency of the dispersive liquid-liquid microextraction were evaluated, including the extractive solvent type and volume and the dispersive solvent volume. The validation parameters indicated the suitability of the method for routine analyses of benzoylurea insecticides in a large number of samples. The relative recoveries at three spiked levels ranged between 98.6 and 109.3% with relative standard deviations of less than 5.2%. The limit of detection was 0.005 mg/kg for the two insecticides. The proposed method was successfully used for the rapid determination of diflubenzuron and chlorbenzuron residues in real fruit samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Q-controlled amplitude modulation atomic force microscopy in liquids: An analysis

NASA Astrophysics Data System (ADS)

Hölscher, H.; Schwarz, U. D.

2006-08-01

An analysis of amplitude modulation atomic force microscopy in liquids is presented with respect to the application of the Q-Control technique. The equation of motion is solved by numerical and analytic methods with and without Q-Control in the presence of a simple model interaction force adequate for many liquid environments. In addition, the authors give an explicit analytical formula for the tip-sample indentation showing that higher Q factors reduce the tip-sample force. It is found that Q-Control suppresses unwanted deformations of the sample surface, leading to the enhanced image quality reported in several experimental studies.