The application calculates noise in ICIS similar to how the INCOS algorithm calculates noise. The application estimates the baseline using the intensities of the scans that it counted to determine the INCOS noise. The application then takes the sum of the intensities of these scans and divides this value by the number of scans, as shown in this equation:

π‘π‘Žπ‘ π‘’π‘™π‘–π‘›π‘’=πΌπ‘›π‘›πœ–π‘›π‘œπ‘–π‘ π‘’π‘›πœ–π‘›π‘œπ‘–π‘ π‘’

The baseline correction works as follows:

  1. For each scan x in the chromatogram, the application determines whether the scan in question is a baseline scan or not (the first and last scan in the display area are always baseline scans).
  2. For the remaining x scans, a baseline scan is available if a line can be placed in the chromatogram at a point (scan x / intensity of scan x ). This way, the intensities of all neighboring scans lie above the straight line.
  3. After all baseline scans have been determined, the intensities between the baseline scans are corrected (an amount is deducted from the intensity values between the baseline scans, which results from the y-axis value of a straight line through the neighboring baseline scans at the scan (x) point.
  4. The intensities of all baseline scans are set to zero.
  5. After the (optional) smoothing and the baseline correction (optional in CHRO), the actual peak detection takes place.
  6. The criterion for peak detection is an intensity threshold ITR, which is determined as follows:
  • For baseline corrected chromatograms:
  • ITR= nm * Noise (nm=Noisemultiplier)
  • For uncorrected chromatograms:
  • ITR= baseline + nm * Noise