| Towards
Rapid Open Tubular Liquid Chromatography |
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Objective: to develop rapid open tubular chromatographic systems
by enhancing the radial mass transport via moulding the tubes into serpentine
shape. A well known feature of the flows downstream of bends is the so-called
Prandtl's secondary flow generated as a result of competing inertia, centrifugal
forces and pressure. In general, the radial mixing improves with increasing
linear (tangential) velocity; thus the stationary phase has to withstand
large shear forces at phase boundaries. Novel chemistries are being developed
in order to facilitate bonding of stationary phases.
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Funded by: EPSRC.
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| Self Assembled
Ultrathin Organic Films as Stationary Phases for Chromatographic Separations |
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Aims: To produce highly uniform and well defined chromatographic
phases by the means of spontaneous self-assembly and controlled surface
polymerization, for use in both packed and open tubular columns. The phases
for packed columns are to be prepared by both controlled polymerization
of alkylchlorosilanes and spontaneous self-assembly of alkanethiols on
gold or silver atoms dispersed on the surface of suitable support (silica,
alumina, glass). The phases in open-tubular columns are to be prepared
in situ by chemically bonding directly to the walls of the capillaries,
whether metal, glass or silica.
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Sponsored by: Phase Sep and SmithKline-Beecham. Other funding applied
for.
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| The
Design, Construction and Evaluation of High Performance UV Detectors for
Capillary Liquid Phase Separations |
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Objective: to provide comprehensive insight into capillary-optimised
UV absorbance detectors. UV spectroscopy is the most widely used detection
mode. This can be attributed to its universality, relative technical ease
of implementation, low cost and ease of converting the existing HPLC detectors
with commercially available capillary cell assembly units. In fact, most
commercial CS instruments are sold equipped with the UV absorbance detector
as standard. However, the sensitivity of the UV absorbance detection in
the capillary cells is limited by short path lengths across the capillary
lumen, of the order of 100mm and less, and the
difficulties in obtaining high light throughput in the geometrically constrained
nanoliter-scale detection cells. The former limits the modulation of the
output signal; the latter controls the fundamental noise level. This work
describes a critical evaluation of the requirements for UV-absorbance detector
for capillary separation techniques followed by the design and construction
of the capillary-optimized optical interface and development of auxiliary
electronics and software for data acquisition.
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Funded by: EC TEMPUS, DTI
LINK Scheme and CVCP ORS Award.
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