Agilent InfinityLab LC Series Diode Array Detectors User Manual
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5
Optimizing the Detector
Optimizing the Detector Regarding to the System
Optimizing the Detector Regarding to the
System
Delay Volume and Extra-Column Volume
The
delay volume
is defined as the system volume between the point of mixing in
the pump and the front of the column.
The
extra-column volume
is defined as the volume between the injection point
and the detection point, excluding the volume in the column.
Extra-Column Volume
Extra-column volume is a source of peak dispersion that will reduce the
resolution of the separation and so should be minimized. Smaller diameter
columns require proportionally smaller extra-column volumes to keep peak
dispersion at a minimum.
In a liquid chromatograph the extra-column volume will depend on the
connection tubing between the autosampler, column and detector; and on the
volume of the flow cell in the detector. The extra-column volume is minimized
with the Agilent InfinityLab LC Series system due to the narrow-bore (0.12 mm
i.d.) tubing, the low-volume heat exchangers in the column compartment and the
flow cell in the detector.
How to Configure the Optimum Delay Volume
To maintain resolution in the Agilent 1290 Infinity II DAD/Agilent 1290 Infinity
DAD FS the 10 mm Max-Light cartridge cell has a low dispersion volume
(
volume 1.0 µL) and no further volume optimization is required. In situations
where the alternative 60 mm Max-Light high sensitivity cell is used to get higher
sensitivity the cell volume is optimized for the use with 3 mm and 4.6 mm inner
diameter columns.