Improved methodology for assaying brassinosteroids in plant tissues using magnetic hydrophilic material for both extraction and derivatization.
BACKGROUND
Brassinosteriods (BRs) are a group of important phytohormones that have major effects on plant growth and development. To fully elucidate the function of BRs, a sensitive BR assay is required. However, most of the previously reported methods are tedious and time-consuming due to multiple pretreatment steps. Therefore, it is of great significance to develop a method to increase the throughput and detection sensitivity of BR analysis.


RESULTS
We established a novel analytical method of BRs based on magnetic solid phase extraction (MSPE) combined with in situ derivatization (ISD). TiO2-coated magnetic hollow mesoporous silica spere(TiO2/MHMSS) was served as a double identity- a microextraction sorbent and "microreactor" for the capture and derivatization of BRs in sequence. BRs were first extracted onto TiO2/MHMSS through hydrophilic interaction. The BR-adsorbed TiO2/MHMSS was then employed as a "microreactor" for the derivatization of BRs with 4-(N,N-dimethyamino)phenylboronic acid (DMAPBA). The MSPE-ISD method was simple and fast, which could be accomplished within 10 min. Furthermore, the derivatives of BRs showed better MS response because they were incorporated with tertiary amino groups. Uniquely, endogenous BRs were detected in only 100 mg fresh weight plant tissue.


CONCLUSIONS
Our proposed MSPE-ISD method for the determination of endogenous BRs is rapid and sensitive. It can be applied to the analysis of endogenous BRs in 100 mg fresh plant tissue (Brassica napus L. (B. napus L)). The proposed strategy for plant sample preparation may be extended to develop analytical methods for determination of a wide range of analytes with poor MS response in other complex sample matrices.
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, 430072 China ; Chinese Acad Sci, Key Lab Plant Germplasm Enhancement & Specialty A, Wuhan Bot Garden, Wuhan, 430074 China.
Jun
J
Ding
College of Chemical Engineering, Wuhan Textile University, Wuhan, 430200 China.
Jian-Hong
JH
Wu
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, 430072 China.
Jiu-Feng
JF
Liu
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, 430072 China.
Bi-Feng
BF
Yuan
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, 430072 China.
Yu-Qi
YQ
Feng
Brassinosteroid; Hydrophilic interaction; In situ derivatization; Liquid chromatography-mass spectrometry; Magnetic solid phase extraction