Brassinosteroids (BRs) are regarded as the sixth plant hormone that is widely distributed in the plant kingdom. Sensitive quantification of BRs will be greatly benefit to illuminate the detail mechanisms about how BRs play crucial role in plant developmental processes such as cell division, cell expansion, cytodifferentiation, seed germination, vegetative growth and resisting biological or abiotic stress. In the current study, we developed a method for rapid and sensitive determination of endogenous BRs in plant tissues by combining LC–MS and a novel sample preparation strategy, in which the plant tissue extract was supplied to solid phase boronate affinity labeling and extraction, followed by desorption and salt-induced phase transition extraction for further purification. Under the optimized conditions, good linearity was obtained for 6 BR with correlation coefficients (r) ranging from 0.9988 to 0.9999. The limits of detection (LODs, S/N = 3) ranged from 1.4 to 2.8 pg mL⁻¹. The recoveries were between 93.4% and 116.2% with the relative standard deviations (RSDs) ranging from 2.8% to 15.8%. Finally, the developed method was successfully applied to the analysis of 6 endogenous BR in various plant tissues including 20 mg FW Oryza sativa shoot, 10 mg FW Oryza sativa root, 20 mg FW Arabidopsis thaliana shoot, 4 Arabidopsis thaliana flowers (2.8 mg) and one Brassica napus stamen (3.0 mg) with concentration ranging from 0.26 to 157.28 ng g⁻¹ FW.

油菜素类固醇（BRs）被认为是在植物界广泛分布的第六种植物激素。BR的灵敏定量将有助于阐明BR在植物发育过程中如何发挥关键作用的详细机制，例如细胞分裂，细胞扩增，细胞分化，种子萌发，营养生长以及抵抗生物或非生物胁迫。在当前的研究中，我们通过结合LC-MS和新颖的样品前处理策略，开发了一种快速，灵敏地测定植物组织中内源BR的方法，该方法将植物组织提取物用于固相硼酸酯亲和标记和提取，然后通过解吸和盐诱导的相变萃取进行进一步纯化。在优化的条件下，r）介于0.9988至0.9999之间。检测限（LOD，S / N = 3）在1.4至2.8 pg mL ^{-1的范围内}。回收率在93.4％至116.2％之间，相对标准偏差（RSD）在2.8％至15.8％之间。最后，所提出的方法被成功地应用于各种植物组织6内源性BR包括20毫克FW的分析稻芽，10毫克FW稻根，20毫克FW拟南芥拍摄，4个拟南芥花（2.8毫克）和1个甘蓝型油菜雄蕊（3.0 mg），浓度范围为0.26至157.28 ng g ^-1  FW。