Determination of jasmonic acid in bark extracts from Hevea brasiliensis by capillary electrophoresis with laser-induced fluorescence detection

A simple and sensitive method is described for determination of jasmonic acid (JA) in plant tissues. The method is based on derivatization of JA with 5-bromomethylfluorescein (5-BMF) and separation and quantification of the resulting 5-BMF-JA derivative by capillary electrophoresis coupled to laser-induced fluorescence detection (CE-LIF). The derivatization conditions were studied in detail. Our results indicated that 5-BMF-labeled JA could be well separated from other plant hormones present in the sample by use of 20 mmol L-1 borate buffer (pH 8.5). The response to JA was a linear function of concentration in the range 1 to 100 mu mol L-1, with a correlation of 0.9986. Our preliminary work showed that the proposed method had fairly good selectivity and sensitivity. Only small amounts of plant sample are needed to complete the analysis. This described method enables the analysis of JA in crude extracts without extra purification and enrichment procedures.