Waters ACQUITY UPC2, Обзор и руководство по обслуживанию, Страница: 17 / 84

Overview 13
If the Points Across Peak value for the narrowest peak of interest is less than
15, to improve peak integration reproducibility, specify a higher sampling rate
in the instrument method. If the value is greater than 100, specify a lower
sampling rate.
Set the sampling rate to the lowest value required to achieve 25 to 50 points
across the narrowest peak. Excessively high sampling rates increase baseline
noise and lead to very large data files.
Median baseline filter
The median baseline filter enhances the detector's baseline stability by
decreasing the baseline's curvature, facilitating the development of
integration methods. The filter's primary purpose is to reduce the effects of
mobile phase gradient separations that demonstrate gradual compositional
changes. Note that it should not be applied in cases where abrupt gradient
changes, such as steps, are evident.
Generally, the filter does not significantly change peak area, peak height,
width or retention times. Nevertheless, it can create baseline distortions
around very wide peaks, and these distortions can affect peak area. Therefore,
the filter is not recommended for situations where peak widths (measured at
5% height) are greater than 5% of run time.
In the ACQUITY UPC
2
PDA detector, the filter works with 2D channels only.
It cannot be applied to 3D or extracted 2D channels. When the MBF data
mode is selected for a channel, the presentation of the data in the real-time
data display plot is delayed by a percentage (~25%) of the run time. A
countdown clock in the instrument control panel indicates the length of the
delay.