Dear alls,
my question in in the project of extraction of caffein from fresh leaves. Recovery studies were also carried out to verify the precision and accuracy.
There are five calibration standards are 10ug/ml, 20ug/ml, 30ug/ml, 40ug/ml, 50ug/ml.
When 1ml of extract A was analysed directly by HPLC under suitable conditions, I got the result that leaves A had caffein amount 35,11ug/ml at the retention time 7,4.
How do I perform Spike Recovery in this case? Please help me.
Thank you for your consider,
Nhu Nguyen
A spike-and-recovery experiment is designed to assess this difference in assay response. To perform a spike-and-recovery experiment, a known amount of analyte is added to the sample matrix and standard diluent, and the two sets of responses are compared based on values calculated from a standard curve.
Hope this will help
https://tools.thermofisher.com/content/sfs/brochures/TR0058-Spike-and-Recovery.pdf
Mrs/Miss Nguyen,
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[https://www.researchgate.net/post/How_can_we_fix_the_concentration_of_internal_standard_in_LCMS_analysis]
Dear Nhu,
You have to do a recovery procedure. The steps are:
1. A known amount of analyte is initially added (spiked) into the leaves. After, you make the caffein extraction procedure.
2. Then the assay is run to measure the response (recovery) of the spiked sample matrix compared to an identical spike in a sample matrix control.
3. For example, you spiked the leaves with 50 ng/ml, and when you analyze it at the equipment, you obtain a response of 28000 of recovery; and in the control (50ng/mL) you obtain a response of 31000. The percentage of recovery is as follows: Rec(%)=(28000*100)/31000= 90,32% of recovery.
I hope I have helped you. If you need any help, text me.
Bes regards, Alba
1. Check the leaves for caffeine first.
2. Select a leaf sample with the lowest concentration of caffeine (or no caffeine).
3. Add a known amount of caffeine to the selected matrix and mix well (choose in which form to add - dry or dissolved)
4. Next is the standard extraction procedure you use.
5. Analyze and find out what is the concentration of caffeine that you extracted after adding it.
6. Calculate recovery.
Do 5-10 repetitions.
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