## Zero Sample Preparation [Bioanalytics]

Dear Scopy,

» Oops, sorry a typo on my end. I meant to write QC and not BC

OK, then I know what it is

» So my follow up question is this: What's the compositional or structural difference between a CC sample and BC sample.

None. Both are blank matrix spiked with known concentrations of analyte, then with IS when they are processed. The concentrations of the CC samples are established based on the expected range of concentrations to be measured; the concentrations of the QC samples are derived from that (LQC # 3 times the LLOQ, HQC at least 75 % of the ULOQ, MQC somewhere mid-range - the EMA guideline says 30-50 % of the range).

Regards
Ohlbe