Agilent Technologies 1100 Series Reference Manual page 34

2 How to optmize the Detector
increase in signal intensity was achieved by increasing the path length from 6 mm to 10
mm.
When increasing the path length, the cell volume usually increases — in our example
from 5 – 13 µl. Typically, this causes more peak dispersion. As
this did not affect the resolution in the gradient separation in our example.
As a rule-of-thumb the flow cell volume should be about 1/3 of the peak volume at half
height. To determine the volume of your peaks, take the peak width as reported in the
integration results multiply it by the flow rate and divide it by 3).
Figure 8
Traditionally LC analysis with UV detectors is based on comparing measurements with
internal or external standards. To check photometric accuracy of the Agilent 1100
DAD/MWD it is necessary to have more precise information on path lengths of the
flow cells.
The correct response is:
expected response * correction factor
Please find below the details of the Agilent 1100 DAD/MWD flow cells:
Table 5 Correction factors for Agilent 1100 DAD/MWD flow cells
Flow cell type
Standard flow cell
Semi-micro flow cell
34 1100 Series DAD and MWD Reference Manual
Time (min)
Influence of Cell Path Length on Signal Height
Cell volume Part number
13 µl G1315-60012
5 µl G1315-60011
Analysis of pesticide standard
6- mm optical path length
10- mm optical path length
Path length Path length
(nominal) (actual)
10 mm 9.80 ± 0.07 mm
6 mm 5.80 ± 0.07 mm
Figure 8 demonstrates,
Correction
factor
10/9.8
6/5.8