36
Viscometer Chromatogram
2,0
6,6
11,2
15,8
20,4
25,0
-25
-3
20
43
65
88
110
Retention Volume (ml)
Figure 14
DP
Chromatogram Showing Delay Volume Too Small
The third possibility is that the delay volume is too large, a situation that will result in
overlap of the breakthrough negative
DP
peak with the chromatogram of a subsequent injection.
This may always be prevented by delaying the start of the next injection, but at a loss in sample
throughput.
So it is important that the delay volume be matched to the chromatographic columns
being used for the separation. Viscotek provides two columns for this purpose: small (one to
two columns), and large (three to four columns). They are easily changed out whenever the
SEC columns are increased or decreased.
