HP Data Explorer 4 Series User Manual

Page 263

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Converting to a Singly Charged Spectrum (Mariner Data Only)

Data Explorer

Software User’s Guide

5-59

5

5.10 Converting to a Singly Charged

Spectrum (Mariner Data Only)

NOTE: Single-charge conversion is not supported for
Mariner DAD data.

Description

The Single-Charge Conversion function generates a
theoretical, centroided, singly charged spectrum. This function
uses isotopic spacing in detected spectral peaks to generate
the theoretical spectrum.

For example, if you use this function on a spectrum that
includes +3 peaks, the software multiplies each mass by 3 and
removes the mass of two extra protons. The resulting
spectrum contains theoretical +1 species.

If more than one charge state is present, each charge state is
converted appropriately, and the total range of the converted
spectrum is approximately 1.2 times the m/z of the highest m/z
present.

Requirements

Use this function only on isotopically resolved data that is
labeled with the correct charge state. Peaks with low
signal-to-noise ratios may be labeled with incorrect charge
states. Set peak detection thresholds to disregard these peaks
before converting the spectrum.

If you use this function on a spectrum that is not correctly
labeled, the resulting spectrum may contain charge states
other than 1.

Converting

To convert a multiply charged spectrum to a singly charged
spectrum:

1.

Display the spectrum trace of interest.

2.

Examine the spectrum. Make sure peaks are labeled with
the correct charge state, and that no noise peaks are
labeled with a charge state. Adjust peak detection
parameters as needed.

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