Agilent Technologies 1100 Series Reference Manual page 278

8
Theory of Operation
Concentration Correction
For every measured spectrum, a certain time is required. During this time the
concentration within the flow cell may be changed. This can effect the spectra.
To avoid this distortion every spectra point is corrected with the
quasi-simultaneous measured concentration of the chromatographic
channel A. As point of reference the mid-point of each spectra is used.
Concentration correction is not done
• If the cuvette is used, e.g. fluorescence scan.
• If 'all spectra without signal' is used as spectra acquisition mode.
Peak Detector
The peak detector (PD) always uses signal A as the pilot signal. The PD is
adjusted by means of two setpoints: peakwidth and threshold. Both setpoints
are time-programmable. While the PD-threshold is a method parameter of its
own, the PD-peakwidth parameter is derived from the general peakwidth
(PKWD) parameter. At the start of the run, the value for the PD-peakwidth is
set equal to the PKWD setpoint. The peak detector recognizes changes in the
slope of this signal (upslope, apex, downslope and baseline) and stores spectra
according to the operator's instructions. During the run the PD-peakwidth
parameter can be changed by time-programming.
280 1100 Series FD Reference Manual