Chromatography Forum

We have a lot of method using 5uL. Is it too small? what is typical range of injection volume for Agilent 1200 and waters LCs?

Thanks,

The answer depends on the exact model and configuration of autosampler (A/S) you have. For example: Agilent offers several different models of 1200-series A/S with different injection volume ranges. They also offer several option kits which can extend these ranges as well. The Agilent "standard" G1313A or G1329A/B, A/S (similar to Waters and most other brands) offers an injection range of 0.1 to 100.0 ul and use a high pressure pump as the "syringe". With these models Agilent quotes precision as "<0.25% RSD from 5-100 µL, <1% from 1-5 µL, variable volume". Other available A/S versions have a range of 0.01 to 40 ul. Extended range versions go up to 1500 or 5000 ul volumes.

As a general rule, with high pressure pump style injectors (as used in the Agilent A/S's), try to stay between 10% and 90% of the total injection volume capacity of the system for best results. With traditional syringe based loop style injectors best results are achieved by choosing the exact sized loop volume needed and overfilling it ~ 3x.

Most of our cGMP-validated test methods utilize 5ul injections, on Agilent 1100 systems.

A few use 3ul, none smaller.