Injector: Accuracy of injection volume

[LCFlo]

Dear all,

is anybody experienced in the verification of the accuracy of the injection volume ? We use an Acquity System (Waters UPLC).

Thank you for every hint

Florian

[Alfred88]

Dear Florian:
You don't have to check the injection volume as part of periodic PQ. This issue was discussed before.
However, you can fill an autosampler vial with water, and weigh it. Then, inject 10 times of the same volume (eg. 50uL), and weigh again after each injection.
W(n) - W(n+1) = Amount of (n+1)th injection.

[Hollow]

Dear Florian:
You don't have to check the injection volume as part of periodic PQ. This issue was discussed before.
However, you can fill an autosampler vial with water, and weigh it. Then, inject 10 times of the same volume (eg. 50uL), and weigh again after each injection.
W(n) - W(n+1) = Amount of (n+1)th injection.

don't think this works for the UPLC cause it's using a loop system, so the volume drawn from the sample is more than actually injected

The method from Alfred is ok for the older Waters injection systems like Alliance or 717 autosampler and is part of the regular Waters OQ/PQ.

Did you asked Waters? I think they can tell you how they do it as part of their OQs (if they perform this tests on the UPLC as well)

[bartjoosen]

For the Alliance system they use a calibration line: area vs different injection volumes.

The accuracy is the intercept divided by slope.


Bart