Technical data

Agilent 1290 Infinity LC System Manual and Quick Reference 129
Appendix
6
Setting Up a Method using Edit Entire Method
analysis stops before the end of the run defined in the pump. This can be
the case when a gradient equilibration ramp has been set at the end of the
gradient. For instance, the %B may rise to 95 % at 10 min and it is expected
that all peaks have eluted from the column so the run is essentially at an
end but an extra gradient segment is added which takes %B back down to
the initial value over two minutes to gently start the re-equilibration of the
column. No useful data is expected during this downwards ramp so the
detector Stop Time is set to 10 min and data collection stops while the
pump Stop Time is 12 min to allow the downwards ramp to complete. This
is a matter of user choice and some accept that the final minutes of the
chromatogram cannot contain useful data but record it anyway to avoid the
inconvenience of having a different Stop Time for the detector. The detector
Stop Time does not override the pump and cause the run to end as would
an earlier Stop Time in any other module hence the convenience of setting
Stop Times to As Pump.
• Timetable operates in the same way as other modules, that is, add a line,
select the function to be changed and enter the new values for that function.
The changes for the detector will take place immediately at the specified
time. The following functions can be changed during the run:
• Balance
• Change Signal
• Change Threshold
• Change Peak –detector Peakwidth
• Change Spectra Acquisition Mode
• Change Contacts
• Advanced - Spectrum
Spectra can be saved during the run on a continuous or peak-controlled
basis (This applies to the ChemStation software. Some software packages,
e.g. EZChrom, only support continuous collection of all spectra and the
peak-controlled options do not appear). Spectral collection and signal
collection are independent operations performed by the detector firmware
and are not dependent on the computer software extracting data from the
3D data matrix. The rate at which spectra are taken is determined by the
Peakwidth setting and eight spectra are taken during the time specified in
Peakwidth. The firmware does peak detection on signal A only to determine
when peak-controlled spectra should be saved. For multiple signals it may
be necessary to have signal A set as a broadband detector to ensure peak
spectra are available for all the different wavelength signals.