Figure 2.

Validation of bevacizumab LC-MRM assay. (A) Two transitions of the peptide STAYLQM(ox)NSLR ((M + 2H)²⁺ → y6⁺, (M + 2H)²⁺ → y5⁺) were used as qualifiers and one transition ((M+2H)²⁺ → y7⁺) was used as the quantifier. (B) Full STAYLQM(ox)NSLR calibration curve. NAT peptide was spiked at different concentrations into digested plasma, using SIS as constant normalizer, followed by H₂O₂ oxidation and LC-MRM. The linear range was from 14 to 1400 fmol NAT on-column. The curve was conducted in 5 independent replicates, yielding coefficients of variations <15.6% for all points except 14.6 fmol with a CV of 20.8% (Table 1).