A new general method is developed for the optimization of
HPLC ternary or pseudo-quaternary mobile phases which are
represented by the trilinear coordinate system. This method can
predict the global optimum of the mobile phase composition. The
global optimum composition along each edge of the triangle and
the corresponding selectivity factor of the worst-separated peak
pair(s) are used in this method. This method is named the
weighted pattern comparison optimization method (WPCO) and is
applicable for both known and unknown samples. The WPCO
method is simpler than those currently in use. The WPCO method
was tested by using 68 literature data sets whose separation
response surfaces are different. Results of the WPCO method
agree with the results obtained by the minimum α plot method
and by the grid search method, and do so with substantially
fewer experimental measurements. Compared with the 5% (in
eluent composition) step size grid-search procedure, the WPCO
method using the same step size reduces the experimental work
by 75%.
For further reducing the experimental work, the original
WPCO method is simplified. In an ordinary HPLC separation, the
separation factor and resolution are approximately proportional
to the logarithm of the selectivity factor. Based on this, the
separation factor replaces the logarithm of selectivity factor in
the original WPCO method. This further reduces the experimental
work and avoids the error introduced in the measurement of the
column dead volume. The simplified WPCO method has been
tested in the normal-phase and reversed-phase chromatography
separation cases. The simplified WPCO method has been tested
by using 27 literature data sets whose separation response
surfaces are different. Results of the simplified and original
WPCO methods are nearly identical when the capacity factors of
the solutes of the worst-separated peak pairs are greater than 5.
When the capacity factors are less than 5, the simplified WPCO
method is satisfactory in less complex, less critical
applications.
Two new metabolites of nefopam have been separated from
greyhound urine. In the separation process, flash chromatography
is used for cleaning up and preseparating the samples in a single
step. Compared with other techniques, experimental work is
reduced. The structure of one of the newly discovered
metabolites is determined using MS and NMR. The most probable
structure of the other metabolite is determined using MS. The
main metabolic pathways at different doses in greyhounds are
studied. / Graduation date: 1991
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37317 |
| Date | 14 June 1990 |
| Creators | Chen, Hsiao, Chen, Xiao |
| Contributors | Piepmeier, Edward H., Craig, A. Morrie |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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