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- Posts: 83
- Joined: Sat Sep 26, 2009 9:54 am
Dear chromatographers,
We have observing a strange issue with injection of certain samples using SE-HPLC using Shimadzu LC2010 (with cooled autosampler at 4 degrees).
We use 1ml HPLC glass vials and inject 100ul, and we observed that the volume inserted in the vial affects the result: when the vial is filled with ~ 700-800ul we get higher results than when filled with 300ul. In both cases results are reproducible and even comparable with other 2 HPLC models (also higher fill volume showing higher results).
I have excluded that 300ul is too low volume for the tip of the needle by injecting a standard of known concentration with vial filled with both 700ul and 300ul and get 100% recovery.
If this is sample related, what could it be and are there autosampler settings to modify? The standard and sample are basically the same, but sample formulation buffer has one additional component (30mg/ml sucrose). Could this be increasing sample viscosity for example so I need to fill the vial, but it doesn't seem convincing? anyone had a similar experience?
We have observing a strange issue with injection of certain samples using SE-HPLC using Shimadzu LC2010 (with cooled autosampler at 4 degrees).
We use 1ml HPLC glass vials and inject 100ul, and we observed that the volume inserted in the vial affects the result: when the vial is filled with ~ 700-800ul we get higher results than when filled with 300ul. In both cases results are reproducible and even comparable with other 2 HPLC models (also higher fill volume showing higher results).
I have excluded that 300ul is too low volume for the tip of the needle by injecting a standard of known concentration with vial filled with both 700ul and 300ul and get 100% recovery.
If this is sample related, what could it be and are there autosampler settings to modify? The standard and sample are basically the same, but sample formulation buffer has one additional component (30mg/ml sucrose). Could this be increasing sample viscosity for example so I need to fill the vial, but it doesn't seem convincing? anyone had a similar experience?
