中文摘要：

brassinosteroids， 28-homobrassinolide (28-h-BL ) 和 28-epihomobrassinolide (28-eh-BL ) 的二异构体的破碎小径，被双人脚踏车团 spectrometry 调查了(MS n， n = 1， 2， 3， 4 ) 与 electrospray 电离(ESI ) 来源。protonated 28-h-BL 和 28-eh-BL 的 ESI 集体度谱的破碎小径包括地被阐明，并且原则在这表明调查能潜在地被用来识别并且区分 brassinosteroids 和他们的异构体。

英文摘要：

The fragmentation pathways of two isomers of brassinosteroids, 28-homobrassinolide （28-h-BL） and 28-epihomobrassinolide （28-eh-BL）, have been investigated by tandem mass spectrometry （MSn, n = 1, 2, 3, 4） with the electrospray ionization （ESI） source. The ESI mass spectrometric fragmentation pathways of protonated 28-h-BL and 28-eh-BL were comprehensively elucidated, and the principles revealed in this investigation could potentially be used to identify and distinguish brassinosteroids and their isomers.