Quantification of Carbon Nanotubes by Raman Analysis.

The increasing prevalence of carbon nanotubes (CNTs) in manufacturing and research environments, together with the potential exposure risks, necessitates development of reliable and accurate monitoring methods for these materials. We examined quantification of CNTs by two distinct methods based on Raman spectroscopy. First, as measured by the Raman peak intensity of aqueous CNT suspensions, and second, by Raman mapping of air filter surfaces onto which CNTs were collected as aerosols or applied as small-area (0.

Characterization of surface-confined ionic liquid stationary phases: impact of cation and anion identity on retention.

A series of surface-confined ionic liquid (SCIL) stationary phases for high-performance liquid chromatography were synthesized in-house. The synthesized phases were characterized by the linear solvation energy relationship (LSER) method to determine the effect of residual linking ligands and the role of the cation and the anion on retention. Statistical analysis was utilized to determine whether the system coefficients returned from multiple linear regression analysis of chromatographic retention data for a set of 28 neutral aromatic probe solutes were significantly different.

Characterization and performance of injection molded poly(methylmethacrylate) microchips for capillary electrophoresis.

Injection molded poly(methylmethacrylate) (IM-PMMA), chips were evaluated as potential candidates for capillary electrophoresis disposable chip applications. Mass production and usage of plastic microchips depends on chip-to-chip reproducibility and on analysis accuracy. Several important properties of IM-PMMA chips were considered: fabrication quality evaluated by environmental scanning electron microscope imaging, surface quality measurements, selected thermal/electrical properties as indicated by measurement of the current versus applied voltage (I-V) characteristic and the influence of channel surface treatments.

An online fiber-optic UV-visible detector for continuous free-flow electrophoresis.

A PC-controlled, scanning online UV detector for continuous free-flow electrophoresis (CFFE) was designed to allow for single UV wavelength monitoring across a 1-D array of 48 longitudinal flow cells interfaced to a CFFE apparatus. In the detection scheme, the UV light is sequentially passed through each of the flow cells. The design integrates online acquisition of absorbance spectra of components separated by CFFE.

Spectroelectrochemical sensing based on multimode selectivity simultaneously achievable in a single device. 11. Design and evaluation of a small portable sensor for the determination of ferrocyanide in Hanford waste samples.

A portable spectroelectrochemical sensor has been designed, evaluated, and demonstrated on a complex sample of radioactive waste. The sensor consisted of a black delrin sample compartment with a total internal sample volume of 800 microL, attached to an indium tin oxide coated glass multiple internal reflection optical element. Detection was by total internal reflection of light from a blue light emitting diode source.