Supercritical fluids have found applications in a wide variety of fields, from solvents for reaction media to engineering of nanoparticles. They are also of interest in the analytical field for transferring non-volatile organic molecules into the gas phase for detection and deposition purposes. This work highlights the use of supercritical fluids as an analytical tool for the transfer of a grou...

A general approach for producing biodegradable nanoparticles for sustained nucleic acid release is presented. The nanoparticles are produced by precipitating a water-in-oil microemulsion in supercritical CO(2). The microemulsion consists of a transfer RNA aqueous solution (water phase), dichloromethane containing poly(l-lactic acid)-poly(ethylene glycol) (oil phase), the surfactant n-octyl β-D-...

Free radical polymerization of ethylene in an intermediate pressure and temperature range (P(ethylene) < 250 bar and 50 °C < T < 90 °C) in the presence of an organic solvent has been studied. Under selected conditions (P, T) and according to the amount of organic solvent added, either a supercritical monophasic or a biphasic medium is obtained. In the case of a biphasic medium, polymerization o...

At low pressure, ethylene gas consists of single translating and rotating molecules and behaves as an ideal gas. With decrease of free volume by compression, various rotating supramolecular particles are formed, which require less space for the movement: molecular pairs, bimolecules and oligomolecules. The appearance of a new kind of particles is manifested as a phase transition of the second o...

This work involves the determination of transport coefficients and equation of state of supercritical fluids by molecular dynamics (MD) simulations on parallel computers using the Green-Kubo formulae and the virial equation of state, respectively. The MD program uses an effective Lennard-Jones potential, linked cell lists for efficient sorting of molecules, periodic boundary conditions, and a m...

The electrochemical oxidation and reduction of decamethylferrocene is demonstrated in supercritical carbon dioxide at a macro gold disc electrode at 100 bar and 313 K. Fast mass transport effects were exhibited and the corresponding steady-state voltammetry was observed at high scan rates. A highly lipophilic room temperature ionic liquid that readily dissolved in supercritical CO(2) with aceto...

Abbreviations: AIBN, 2,20-azo-bis-isobutyronitrile; ASE, Accelerated solvent extraction; CAR, Carboxen; DAD, Diode-array detector; DI-SPME, Direct-immersion solid-phase extraction; DSPE, Dispersive solid-phase extraction; EGDMA, Ethylene glycol dimethacrylate; ESE, Enhanced solvent extraction; ESI, Electrospray ionization; FD, Fluorescence detection; FLD, Fluorimetric detection; GC, Gas chromat...

In rabbit depressor nerve fibers, an on-off firing pattern, period-1 firing, and integer multiple firing with quiescent state were observed as the static pressure level was increased. A bursting pattern with bursts at the systolic phase of blood pressure, continuous firing, and bursting with burst at diastolic phase and quiescent state at systolic phase were observed as the mean level of the dy...

The near infrared absorption of pure ethylene in the region of the second overtone of the C-H stretching fundamentals (8200 c m 1 to 9500 c m J ) was measured at supercritical temperatures {Tc = 9.5 °C) between 22 °C and 200 °C from 0.7 bar to 3000 bar. The density and temperature dependence of bandshape, maximum frequency and absorption intensity are reported and discussed. The bands observed ...

A revised phase diagram for water shows three distinct fluid phases. There is no continuity of liquid and gas, and no “critical point” on Gibbs’ density surface as hypothesized by van der Waals. A supercritical colloidal mesophase bounded by percolation transition loci separates supercritical liquid water and gas-phase steam. The water phase is bounded by a percolation transition (PA) of availa...