3.2.4. Extraction recovery and ionization
The mean extraction recoveries obtained for 6 replicates of the QC samples at different concentrations were 89.52 ± 4.35% (precision, 9.2%), 87.23 ± 5.17% (8.2%), and 90.41 ± 3.65% (8.2%) for RA, 85.46 ± 4.19% (6.60%), 88.23 ± 4.37% (7.60%), and 84.98 ± 5.14% (7.60%) for A1 and 92.18 ± 6.16% (6.60%) for the IS. These data were calculated with precision.
In terms of ionization, the peak area ratios of the two target compounds and IS after spiking the evaporated plasma samples at three concentration levels were 96.8-103.2% and 95.3-103.6% of the concentration levels of the neat standard solutions of RA and A1, respectively, which suggests that the method was free from matrix effects.