spiked samples preparation [Bioanalytics]

posted by Ladi – Thailand, 2015-09-17 09:04 (3115 d 05:22 ago) – Posting: # 15413
Views: 7,864

Dear all BA/BE people,

This is my first time posting here. I am really glad to find this forum.

Would you please elucidate me the correct and most appropriate way to prepare spiked plasma samples for calibration curve and QC. First let me tell you how we usually do it.

For example, if we need 500 uL of study sample - we would use 450 or 480 uL of the blank plasma and add 50 uL or 20 uL of analyte solution (working solution) to make total volume of 500 uL (So that concentration is calculated from total volume of 500 uL). Our analyte solution is typically prepared in 50% methanol or acetonitrile. I understand that doing this way we have diluted the matrix in spiked samples and it won't be equivalent to study samples.

What I understand we should have done is actually used the same volume of blank plasma and study samples. For example, we could use 500 uL of blank plasma and then spike with 20 uL or 50 uL of analyte solution. Then, what we should do is add 20 uL or 50 uL of diluent to all study samples too.

Also I understand that the %solution spiked into plasma should not be more than 5% (not sure where this number is from) of total plasma volume. What i am not clear is 5% 'organic solvent' or 5% 'spiking solution'?

I really appreciate your kind suggestions,

Ladi

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