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D Raftery

Publications and source records attributed to D Raftery.

10 recordsLinked to original sources
PubMed2001

Analysis of multiple samples using multiplex sample NMR: selective excitation and chemical shift imaging approaches.

Two improved approaches for the rapid analysis of multiple samples using multiplex sample NMR are described. In the first approach, frequency-selective 90 degrees radio frequency pulses and large pulsed field gradients are applied to excite and detect multiple samples in rapid succession. This method is advantageous for samples with relatively long longitudinal (T1) relaxation times. In the second approach, chemical shift imaging is applied to acquire both the spectral and spatial information of multiple samples simultaneously. Chemical shift imaging is more time-consuming than selective excitation; however, it is advantageous for detecting samples with short T1's and for signal averaging. Both approaches demonstrate the potential of multiplex sample NMR for carrying out high-throughput NMR detection.

Journal Article↗
PubMed2001

Characterization of surface and photooxidative properties of supported metal oxide photocatalysts using solid-state NMR.

In situ solid-state NMR (SSNMR) methodologies have been used to investigate the surface properties and photooxidative reactivities of a number of metal oxide photocatalysts. Adsorption of ethanol on single monolayers of TiO2, SnO2, V205, and WO3 supported on porous Vycor glass results in the formation of hydrogen-bonded ethanol species and metal-bound ethoxide species. The chemical shift of the metal-bound ethoxide species varies with the metal oxide catalyst while the chemical shift of the hydrogen-bonded species is independent of the metal oxide. X-ray powder diffraction, UV-VIS spectroscopy, and SSNMR investigations of ethanol adsorption show that increasing the number of monolayers of TiO2 on the Vycor surface changes the morphology of the catalyst from amorphous at a single monolayer coverage to anatase at a four monolayer coverage. The rate of photocatalytic oxidation of ethanol, acetone, and 2-propanol also increases with increasing TiO2 monolayer coverage.

2-Propanol↗
PubMed2001

Autonomous biomonitoring systems: towards ubiquitous sensing.

The future is a world embedded with sensor technology that constantly provides us with information about our environment and health. This article looks at some of the key enabling technologies driving sensor development and introduces the concept of autonomous biomonitoring systems.

Biosensing Techniques↗
PubMed1999

NMR probe for the simultaneous acquisition of multiple samples.

A dual channel probe for the simultaneous acquisition of NMR data from multiple samples has been developed. This multiplex probe consists of two noninteracting sample coils that are each capable of detecting NMR signals at the same resonant frequency with good sensitivity and resolution. 13C free induction decays for the two samples, methanol (13C, 99%) and carbon tetrachloride (13C, 99%), were acquired simultaneously at 75.44 MHz using a single transmitter pulse and separate NMR receivers. S/N measurements are comparable to those observed using single coils. No evidence of cross talk is evident in the spectra even after considerable signal averaging. The probe demonstrates the feasibility of significant parallelism in NMR, which will be of interest in situations where high throughput analysis is desired.

Carbon Tetrachloride↗