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- Posts: 45
- Joined: Thu Nov 05, 2009 6:28 am
Good day, collegues!
My colleagues analyzed mycotoxins (ochratoxin A, aflatoxin B + G, vomitoxin) and met the following problem.
The analysis was performed on two systems (Agilent and Waters). Mobile phase: buffer. C18 type column (3 μm, 4.6 mm x 250 mm), or (3 μm, 4.6 mm x 125 mm). To comply with all the necessary conditions for the HPLC column conditioning time, thus the error in the preparation of a standard or mobile phase is not present. They do not see the expected peak.
They installed a new column and again prepared fresh mobile phase in the system. They do not see the expected peak.
They did a column washing procedure, put a new column. It does not solve the problem.
Some time later (HPLC washed overnight with 5% acetonitrile solution at a flow of 0.2 ml/min). Then again prepared standards and have begun to condition the column, at this moment all the peaks began to consistently go out one after another. They were as much as it was the previous standard injection time. The impression that they have accumulated somewhere.
I'm not sure that the problem is in the column. I think that there is some effect sorption/desorption of the compounds in HPLC. For the inter- action materials with surface capillaries or needles, can 6-port valve.
All systems have been checked by a service engineer, and all showed excellent condition.
Do you have any opinion, what's the problem?
Thank you, very much for your time!
With best regards
Dmitry
My colleagues analyzed mycotoxins (ochratoxin A, aflatoxin B + G, vomitoxin) and met the following problem.
The analysis was performed on two systems (Agilent and Waters). Mobile phase: buffer. C18 type column (3 μm, 4.6 mm x 250 mm), or (3 μm, 4.6 mm x 125 mm). To comply with all the necessary conditions for the HPLC column conditioning time, thus the error in the preparation of a standard or mobile phase is not present. They do not see the expected peak.
They installed a new column and again prepared fresh mobile phase in the system. They do not see the expected peak.
They did a column washing procedure, put a new column. It does not solve the problem.
Some time later (HPLC washed overnight with 5% acetonitrile solution at a flow of 0.2 ml/min). Then again prepared standards and have begun to condition the column, at this moment all the peaks began to consistently go out one after another. They were as much as it was the previous standard injection time. The impression that they have accumulated somewhere.
I'm not sure that the problem is in the column. I think that there is some effect sorption/desorption of the compounds in HPLC. For the inter- action materials with surface capillaries or needles, can 6-port valve.
All systems have been checked by a service engineer, and all showed excellent condition.
Do you have any opinion, what's the problem?
Thank you, very much for your time!
With best regards
Dmitry
When the path is over and passed successfully, it's nice to remember even the mistakes ...
