Chromatography-Free Ultrasensitive Profiling of Multiclass Plant Hormones via One-Pot Dual–Channel Derivatization Coupled with Acoustic Ejection Mass Spectrometry

Plant hormones regulate diverse physiological processes, but their simultaneous analysis is challenging due to structural diversity, low abundance, and complex matrices. Herein, we report a chromatography-free analytical platform integrating one-pot dual-channel derivatization with acoustic ejection mass spectrometry (AEMS). Using N,N-diethyl-1,2-ethanediamine for carboxyl-containing hormones and 2-methyl-4-phenylaminomethyl-benzeneboronic acid for cis-diol-containing brassinosteroids, 11 key phytohormones were rapidly derivatized (< 1 min) in a single reaction vessel. The derivatization enhanced sensitivity up to 183-fold, achieving femtogram-level limits of detection (3.9–22 fg). Coupled with AEMS, each sample was analyzed in ∼3 s without chromatography. Validation confirmed excellent linearity (R2 ≥ 0.9991), precision (RSD < 15.3%), accuracy (77.3–110.8% recovery), and minimal matrix effects (76.3–105.1%). The method successfully quantified endogenous plant hormones in Arabidopsis thaliana seeds, Brassica napus stamens, and Oryza sativa seeds, and captured dynamic hormone changes during rice germination. This high-throughput platform provides a promising tool for comprehensive plant hormone profiling.