Toevaluatetherecoveriesofallphytohormones,wesubjectedtheloadingsolvent 90% MeOH to the overall sample pretreatment process andspiked the eluting solutions with specific amounts of phytohormone stan-dards. After LC–MS/MS analysis, the peak areas of these compoundswere recorded as S 0 . Simultaneously the same amounts of phytohor-mones dissolved in 90% MeOH were also subjected to sample pretreat-ment and LC–MS/MS analysis to give a final peak area, S. The recoveryrate was calculated as S/S 0