Good %RSD, bad retrieval rate??? [August 17, 2004]
Posted: Mon Aug 30, 2004 7:22 pm
By Anonymous on Tuesday, August 17, 2004 - 03:04 am:
Hello,
my %RSD of the actual method are <1%, but the retreival rate is sometimes up to 10-15%.
The calibration has good (0,995 - 0,999) linearity.
What could be the reason therefore?
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By Helmut on Friday, August 20, 2004 - 04:47 am:
The reason is simply that you don't have a good linearity at your calibration ! The number of 9's in the correlation factor is not an indicator for a good linearity !
There was a very good and informative article in LC-GC-Europe, March 2004 about linearity and calibration !
There you can read how to perform and control your linearity in a much better way than with the unefficient correlation factor !
Internet: www.lcgceurope.com
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By Mark on Friday, August 20, 2004 - 05:41 am:
I'm sorry for asking such a stupid question here, but what is meant by the retreival rate?
Regards,
Mark
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By Seppal on Thursday, August 26, 2004 - 02:40 am:
dont use R² for calibration check, do a response factor test, thats more interesting
Josef Maria
Hello,
my %RSD of the actual method are <1%, but the retreival rate is sometimes up to 10-15%.
The calibration has good (0,995 - 0,999) linearity.
What could be the reason therefore?
-------------------------------------------------------------------------------------------------------
By Helmut on Friday, August 20, 2004 - 04:47 am:
The reason is simply that you don't have a good linearity at your calibration ! The number of 9's in the correlation factor is not an indicator for a good linearity !
There was a very good and informative article in LC-GC-Europe, March 2004 about linearity and calibration !
There you can read how to perform and control your linearity in a much better way than with the unefficient correlation factor !
Internet: www.lcgceurope.com
-------------------------------------------------------------------------------------------------------
By Mark on Friday, August 20, 2004 - 05:41 am:
I'm sorry for asking such a stupid question here, but what is meant by the retreival rate?
Regards,
Mark
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By Seppal on Thursday, August 26, 2004 - 02:40 am:
dont use R² for calibration check, do a response factor test, thats more interesting
Josef Maria