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- Posts: 1
- Joined: Wed Jul 30, 2014 3:24 pm
I am a little bit desperate. The OQPQ for one of our systems was executed. Afterwards I checked the report. The report stated a delay volume about 0.26 ml. It is a 1290 quaternary system. My first guess was that the delay volume is the same thing as the dwell volume but agilent gives it a different name.
I checked the method which was used to determine the delay volume and noticed that the jetweaver with an internal volume of 350 µl was activated. This means it can not be the same as the dwell volume as the dwell volume has to be higher than 350 µl because the jetweaver is between the gradient proportioning valve and the detector. The OQ Report discloses the following equations for the delay and dwell volume
Delay Volume = ("calculated start of composition step" - "set start of composition step) x flow rate
Dwell Volume = ("set time of changing gradient mix" - "time to reach % of composiont) x flow rate
To be frank, I can't see any differences. Could anyone of you help me understanding the difference between the dwell volume and the delay volume. Another question that I have: Why is it useful to know the delay volume. I completely understand why it's important to know the dwell volume but after all those years of liquid chromatography experience I have never had to deal with such thing like the delay volume.
Many thanks for your support in advance.
barrelproof