Applied Biosystems Data Explorer 4 Series, User Manual

Page: 251 / 447

Adjusting the Baseline
Data Explorer
™
Software User’s Guide 5-47
5
5.8.2 Using Baseline Correction
Description
The Baseline Correction function corrects for a curved
baseline, including a DC-offset baseline, by eliminating broad
artifacts from the data set.
When to use
Baseline-correct if you are analyzing data:
• With a baseline that is not flat, and you are using the
%Base Peak Intensity parameter (intensity-based
thresholding) to screen out noise peaks. For best results,
apply Baseline Correction, then re-detect peaks.
If you use area-based thresholding (%Max Peak Area)
during peak detection, Baseline Correction is not typically
needed. %Max Peak Area compensates for a rising or
falling baseline.
• With a baseline that is not at 0. Some measurements (for
example, Centroid% peak detection value, or the Peak
Height % in the Resolution calculator), are derived from a
peak height measured from 0.
NOTE: If you are analyzing Mariner data, baseline
correction is typically not needed. If you baseline-correct
Mariner data, note that due to the shorter flight times and
fewer data points associated with Mariner data, baseline
correction may affect peak shape, which in turn affects
mass accuracy.
Correcting the
baseline
To correct the baseline:
1. Display the spectrum of interest.
2. Select Duplicate Active Trace from the Display menu to
keep the original data displayed after processing.
3. From the Process menu, select Baseline Correction.
The baseline is adjusted, and the trace is displayed
with a BC trace label.
Returning to the
original spectrum
To return to the original trace, see “Returning to the original
spectrum” on page 5-3.