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RegisterAbnormal calibration curve [Bioanalytics]
@Ohlbe:
I prepare my working solutions once a week, but have confirmed the bad response with several batches of working solutions so I am sure they are not the problem. To tell the truth, adsorption seems a reasonable explanation.
Yes, I have seen a 40-70% decrease in the peak areas at higher concentration levels, compared to the response I had initially. I vented the instrument and cleaned some easily accessible components of the mass spectrometer (not as deep as the optics/mass analyzer though), but saw no improvement.
@Helmut:
I had to inject several hundreds of matrix extracts to optimize the method, so this could be the case. Contamination was one of the first scenarios that occured to me as well but when cleaning did not work, I focused in other scenarios.
Thank you very much for your suggestions, they were really valuable feedback! Any other possible causes that you may think would be of great help!
stdev
I prepare my working solutions once a week, but have confirmed the bad response with several batches of working solutions so I am sure they are not the problem. To tell the truth, adsorption seems a reasonable explanation.
Yes, I have seen a 40-70% decrease in the peak areas at higher concentration levels, compared to the response I had initially. I vented the instrument and cleaned some easily accessible components of the mass spectrometer (not as deep as the optics/mass analyzer though), but saw no improvement.
@Helmut:
I had to inject several hundreds of matrix extracts to optimize the method, so this could be the case. Contamination was one of the first scenarios that occured to me as well but when cleaning did not work, I focused in other scenarios.
Thank you very much for your suggestions, they were really valuable feedback! Any other possible causes that you may think would be of great help!
stdev
Complete thread:
- Abnormal calibration curve stdev 2012-09-11 22:00
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- Abnormal calibration curve ElMaestro 2012-09-12 10:47
- Abnormal calibration curve Helmut 2012-09-12 14:40
- Abnormal calibration curve stdev 2012-09-12 19:10
- Abnormal calibration curve Ohlbe 2012-09-12 19:21
- Abnormal calibration curvestdev 2012-09-12 21:58
- Abnormal calibration curve Ohlbe 2012-09-12 22:32
- Abnormal calibration curvestdev 2012-09-12 21:58
- Abnormal calibration curve Helmut 2012-09-12 19:26
- Abnormal calibration curve stdev 2012-09-13 16:45
- Abnormal calibration curve Ohlbe 2012-09-12 19:21
- Abnormal calibration curve stdev 2012-09-12 19:10
Ing. Helmut Schütz