Adjusting the Baseline

5.8.2 Using Baseline Correction

Description

When to use

The Baseline Correction function corrects for a curved baseline, including a DC-offset baseline, by eliminating broad artifacts from the data set.

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.

Correcting the baseline

Returning to the original spectrum

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.

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

5

with a BC trace label.

To return to the original trace, see “Returning to the original

 

spectrum” on page 5-3.

 

Data Explorer™ Software User’s Guide

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