Location:

Detection tab page
Report Variable (Detection Parameters)

Type:

Command

Dimension:

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Value range:

0.00 ... 100.00

Default:

10.00

Related Parameters:

Peak Purity Start/End Wavelength

Description:

The Peak Purity Threshold detection parameter determines the threshold for the signal height above which spectra comparison is performed for the UV and Mass Spectra. The parameter is important for the Peak Purity Analysis (PPA) and the Peak Ratio.

Peak Purity Analysis (PPA)

When determining the Peak Purity Index (PPI) or the Peak Purity Match Factor, the parameter defines the signal height above the baseline, from which the spectra are extracted for calculation.

Peak Ratio

For the Peak Ratio, the PPTrshold parameter defines the signal height above which the ratio is formed.

Function:

Peak Purity Analysis (PPA)

The value is stated in percent of the peak height, that is at the value 20%, only the spectra are used to determine the match factor for which the signal height of the peak is at least 20%.

The smaller the selected value, the wider the match factor curves. The calculation may include spectra that no longer have an optimum Signal-to-Noise Ratio. The match factor curve then has "fringes" at the margins (peak start and peak end). This can be avoided by a smaller threshold value.

Limiting the wavelength range that is used for calculating the center wavelength of the PPI is possible via the Peak Purity Start/End Wavelength detection parameters. A corresponding limitation to a specified mass range is not possible for the MS Peak Purity Match.

Peak Ratio

A value of 10% means that the signal ratio between two channels is only formed where the signal intensity exceeds 10% in two channels.