Location:

Detection tab page
Report Variable (Detection Parameters)

Type:

Floating point number

Dimension:

Signal unit

Value Range:

0.0001 ... 10,000,000.0

Default:

Dynamical (= Noise value of the related chromatogram)

Related Parameters:

Always consider this parameter in combination with the Peak Slice

Description:

Together with the Peak Slice parameter, the Sensitivity parameter determines the granularity of the peak detection algorithm; i.e., when using small values, even the smallest signals are interpreted as peaks; for example, pump pulsation, whereas such signals are ignored when using higher values.

Function:

Peak recognition is performed using a rectangle formed by the granularity of the y-axis (Sensitivity) and the granularity of the x-axis (Peak Slice) (see figure a):

As shown in the picture, this rectangle is placed with its lower left corner on the first data point, and is duplicated by mirroring in the direction of negative y-values. As long as none of the subsequent data points is above or below the mirrored rectangle, the last data point will be used for positioning further rectangles (b). The measured signal is interpreted as noise.

If three successive data points are located above or below the rectangle (simplified!), the peak recognition algorithm will recognize a peak. When the signal difference of one data point to the next one becomes so small that they are within the bandwidth again, the peak end is indicated (c).

Manually Setting the Parameters Sensitivity and Peak Slice

You can manually modify the granularity of the peak recognition; that is, you can determine the size of the rectangle or the bandwidth. The larger the area, the lower the sensitivity of the system. Smaller peaks are likely to be interpreted as noise.

General Rule

If a specific peak shall "just" be interpreted as a peak and if this was not achieved via the Auto setting, specify a manual Sensitivity value of a third of the signal height of the peak.

 Notes:

This parameter refers directly to peak detection only and indirectly to integration. For area calculation, the original signal is used. (The parameter influences peak start and peak end. In this way, the peak area is influenced, also.)

Using the Sensitivity and Peak Slice variables is only necessary in case of chromatograms comprising very wide (many minutes) or very narrow (< 0.1 s) peaks. Under normal conditions, the default values should not be changed.

Sensitivity is always interpreted in the unit installed; for example, mAU.

Graphical definition is recommended above all for Sensitivity and Peak Slice. For more information, refer to  Modifying the Peak Recognition Algorithm.