Hello, I am a student in analytical chemistry, I am supposed to prepare samples, quality control, and calibration serial dilution for a forensic project which is working on larvae and flies (for quantification of benzodiazpines).
would you please correct what I wrote here even in terms of the specific volume and concentration?
Sample prep:
Collected sample with matrix is spiked with target analytes and RS (recovery standard)
Sample is extracted (prepared for analysis)
IS (internal standard is spiked before the analysis
Cal prep:
Calibration standards (mixture of target analytes and RS) are prepared with serial dilution
IS is added before the analysis
My only contribution is to say, don't use serial dilution for statistical reasons unless absolutely necessary and if you must monitor the accuracy.
Sample Preparation:
Collect the sample and add a known amount of the target analytes (benzodiazepines) and a recovery standard (RS) to the matrix.
Extract the sample to prepare it for analysis.
Spike an internal standard (IS) into the extracted sample before analysis.
Quality Control:
Prepare a series of quality control samples by spiking known amounts of the target analytes and RS into a matrix.
Extract the QC samples to prepare them for analysis.
Spike an IS into the extracted QC samples before analysis.
Calibration Preparation:
Prepare a series of calibration standards containing a known concentration of the target analytes and RS by serial dilution.
Spike an IS into the calibration standards before analysis.
Overall, the approach you have described seems appropriate for the quantification of benzodiazepines in larvae and flies. However, it is important to note that the specific details of the sample preparation, calibration, and quality control depend on the specific analytical method being used. It is also important to ensure that the sample, calibration, and QC matrices are appropriate and do not interfere with the analysis.
Mohammed Almajidi
I appreciate your response,
you wrote " Prepare a series of quality control samples by spiking known amounts of the target analytes and RS into a matrix. Extract the QC samples to prepare them for analysis"
I have some questions:
1) It seems the QC sample preparation is the same with the sample preparation, what is the difference exactly?
2) what do you mean by "series of QC samples" ?
my advisor told me the feature of QC samples is the fact that we can consider their recovery as 100%,, I thought it means we have to do the same process like the sample preparation BUT add the RS after the extraction process (because in this way we know that the QC recovery is 100%)
I dont know, maybe I am wrong. I am working with HPLC-ESI-mass
another question, you wrote I need to spike the RS into the calibration serial dilution too, is there any extraction process for calibration serial dilution?
waiting for your response, Zeinab.
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