Chemistry Commons^™

Ultimate Detectability Of Volatile Organic Compounds: How Much Further Can We Reduce Their Ambient Air Sample Volumes For Analysis?, Ki-Hyun Kim

Ki-Hyun Kim

To understand the ultimately lowest detection range of volatile organic compounds (VOCs) in air, application of a high sensitivity analytical system was investigated by coupling thermal desorption (TD) technique with gas chromatography (GC) and time of flight (TOF) mass spectrometry (MS). The performance of the TD-GC-TOF MS system was evaluated using liquid standards of 19 target VOCs prepared in the range of 35 pg to 2.79 ng per μL. Studies were carried out using both total ion chromatograms (TIC) and extracted ion chromatograms (EIC) mode. EIC mode was used for calibration to reduce background and to improve signal to noise. …

Ultraviolet Photoinitiated On-Fiber Copolymerization Of Ionic Liquid Sorbent Coatings For Headspace And Direct Immersion Solid-Phase Microextraction, Tien D. Ho, Honglian Yu, William T.S. Cole, Jared L. Anderson

Jared L. Anderson

A high-throughput method for the production of solid-phase microextraction (SPME) sorbent coatings via ultraviolet (UV) photoinitiated copolymerization of ionic liquid (IL) monomers on a fused silica support is described. The copolymerization of monocationic and dicationic IL cross-linkers was performed “on-fiber” using UV initiated free radical polymerization. Mixtures composed of various amounts of the IL cross-linker, UV initiator (DAROCUR 1173), and IL monomer were dip-coated onto an etched and derivatized fused silica support and placed in a high-capacity UV reactor. The method requires no organic dispersive solvent and is much more rapid compared to traditional methods in which polymeric ionic liquid …

Nontargeted Comprehensive Two-Dimensional Gas Chromatography/Time-Of-Flight Mass Spectrometry Method And Software For Inventorying Persistent And Bioaccumulative Contaminants In Marine Environments, Eunha Hoh, Nathan G. Dodder, Steven J. Lehotay, Kristin C. Pangallo, Christopher M. Reddy, Keith A. Maruya

Kristin Pangallo

Small Heat Shock Protein Activity Is Regulated By Variable Oligomeric Substructure, J. L. Benesch, M. Ayoub, C. V. Robinson, J. A. Aquilina

J. A. Aquilina

The alpha-crystallins are members of the small heat shock protein (sHSP) family of molecular chaperones which have evolved to minimize intracellular protein aggregation, however they are also implicated in a number of protein deposition diseases. In this study we have employed novel mass spectrometry techniques to investigate the changes in quaternary structure associated with this switch from chaperone to adjuvant of aggregation. We have replicated the oligomeric rearrangements observed for in vivo disease-related modifications, without altering the protein sequence, by refolding the alpha-crystallins in vitro. This refolding results in a loss of dimeric substructure concomitant with an augmentation of substrate …

Vaporization And Sublimation Enthalpies Of Acetanilide And Several Derivatives By Correlation Gas Chromatography, Patamaporn Umnahanant, James Chickos

James Chickos

No abstract provided.

Measuring Markers Of Liver Function Using A Micropatterned Paper Device Designed For Blood From A Fingerstick, Sarah J. Vella, Patrick Beattie, Rebecca Cademartiri, Anna Laromaine, Andres W. Martinez, Scott T. Phillips, Katherine A. Mirica, George M. Whitesides

Rebecca Cademartiri

This paper describes a paper-based microfluidic device that measures two enzymatic markers of liver function (alkaline phosphatase, ALP, and aspartate aminotransferase, AST) and total serum protein. A device consists of four components: (i) a top plastic sheet, (ii) a filter membrane, (iii) a patterned paper chip containing the reagents necessary for analysis, and (iv) a bottom plastic sheet. The device performs both the sample preparation (separating blood plasma from erythrocytes) and the assays; it also enables both qualitative and quantitative analysis of data. The data obtained from the paper-microfluidic devices show standard deviations in calibration runs and “spiked” standards that …

An Examination Of The Thermodynamics Of Fusion, Vaporization, And Sublimation Of (R,S)- And (R)-Flurbiprofen By Correlation Gas Chromatography, Patamaporn Umnahanant, Darrell Hasty, James Chickos

James Chickos

No abstract provided.

Nanocrystalline Amn2o4 (A = Co, Ni, Cu) Spinels For Remediation Of Volatile Organic Compounds—Synthesis, Characterization And Catalytic Performance, Ali Hosseini, Ali Niaei, Darioush Salari, Reza Nabavi

Seyed Reza nabavi

Nanocrystalline AMn2O4 (A = Co, Ni, Cu) manganite spinels were prepared by using the sol–gel auto combustion method under the same

synthesis conditions and their physico-chemical properties were studied by XRD, UV–vis DRS, SEM, BET and FTIR. Besides, the reducibility of

oxides was studied by temperature-programmed reduction (TPR). The relationship between the properties and activity of spinels in oxidation of 2-

propanol and toluene was investigated. Among all, nickel manganite exhibited the most promising activity, in which the completed conversion of 2-

propanol and toluene occurred at 250 and 350 8C, respectively. Higher activity of nickel manganite oxide was explained …

Bacterial Isolation By Lectin-Modified Microengines, Susana Campuzano, Jahir Orozco, Daniel Kagan, Maria Guix, Wei Gao, Sirilak Sattayasamitsathit, Jonathan C. Claussen, Arben Merkoci, Joseph Wang

Jonathan C. Claussen

New template-based self-propelled gold/nickel/polyaniline/platinum (Au/Ni/PANI/Pt) microtubular engines, functionalized with the Concanavalin A (ConA) lectin bioreceptor, are shown to be extremely useful for the rapid, real-time isolation of Escherichia coli (E. coli) bacteria from fuel-enhanced environmental, food, and clinical samples. These multifunctional microtube engines combine the selective capture of E. coli with the uptake of polymeric drug-carrier particles to provide an attractive motion-based theranostics strategy. Triggered release of the captured bacteria is demonstrated by movement through a low-pH glycine-based dissociation solution. The smaller size of the new polymer-metal microengines offers convenient, direct, and label-free optical visualization of the captured bacteria and …

Determination Of The Solubilizing Character Of 1-Methoxyethyl-1- Methylpiperidinium Tris(Pentafluoroethyl)Trifluorophosphate Based On The Abraham Solvation Parameter Model, Pamela Twu, Jared L. Anderson, Timothy W. Stephens, William E. Acree Jr., Michael H. Abraham

Jared L. Anderson

Chromatographic retention data were measured for a chemically diverse set of organic solutes on an anhydrous 1-methoxyethyl-1-methylpiperidinium tris(pentafluoroethyl)trifluorophosphate, ([MeoeMPip]+ [FAP]–), stationary phase at both 323 K and 353 K. The experimental retention factors were combined with previously published thermodynamic data and gas-to-water partition coefficient data to yield gas-to-anhydrous ionic liquid (IL) and water-to-anhydrous IL partition coefficients. The three sets of partition coefficient data were analyzed in accordance with the Abraham model. The Abraham model correlations that were determined in the present study describe the observed gas-to-([MeoeMPip]+[FAP]–) (log K) and water-to-([MeoeMPip]+[FAP]–) (log P) partition coefficient data to within average standard deviations …

Selective Recognition Of H2po4 By A Cholestane-Imidazole-Zinc Ensemble, Jyoti Ramesh Jadhav, Md Wasi Ahmad, Hong Seok Kim

Dr. Mohammad Wasi Ahmad (Md Wasi Ahmad)

A new facile amphiphile cholestane-based zinc complex 4 containing a 3-aminopropylimidazole moiety at the 3a and 7a positions of cholestane was designed and synthesized. Recognition selectivity of the new receptor 4 with various anions was assessed by 1H NMR titration. Dihydrogen phosphate showed the highest binding affinity among all the tested anions

Development Of Spectrophotometric Method For The Determination Of Perindopril Erbumine In Pharmaceutical Formulations Using 2, 4 Dinitrofluorobenzene, Habibur Rahman Dr.

Habibur Rahman

No abstract provided.