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第2楼2008/02/18
Many analytical methods are based on liquid chromatography
and typically the only measure of system stability
is standards, injected repeatedly throughout the sequence.
In this paper, a novel approach is presented,
where the analytical run is treated as a process with the
chromatographic data as the product. It is postulated that
enhanced quality of the data can be obtained through
monitoring the process, i.e., the chromatographic system,
during the sequence. For this purpose, a liquid chromatography
process control (LCPC) system has been developed.
Here, several parameters, e.g., the pressure at the
column and the injection valve, are monitored. Chemometrics
is used for interpreting the data and producing
multivariate statistical process control (MSPC) charts. The
chromatographic run is divided into two parts: the
dynamic injection phase and the static elution phase. Two
principal component analysis (PCA) models, one for each
phase, are continuously created and upgraded as the data
are collected. The results of the PCA are shown in the
MSPC charts, and when an error detection limit is
exceeded, the analyst is promptly notified. LCPC, a
continuous system suitability test, provides better control
of the analysis, allowing a reduction in the number of
standards and replicates. Furthermore, troubleshooting
is facilitated.