Extraction recovery and matrix effect of nine compounds and internal standard in rat plasma.

Data are expressed as means ± S.D. (n = 3).aNeat is the standard in injection solvent.bPost-spiked is the standard spiked in the prepared control plasma.cPre-spiked is the standard spiked into control plasma before prepared.dMatrix effect (%) calculated as [(b/a)×100]%.eRecovery (%) calculated as [(c/b)×100]%.