Determination of limonin D-ring lactone hydrolase activity by solid phase extraction with indirect fluorescence detection.

A method for the evaluation of limonin D-ring lactone hydrolase activity is described. The method utilizes solid phase extraction (SPE) for the isolation of limonin A-ring limonoate (LARL), which is subsequently converted to limonin and quantitated by fluorescence. The fluorescence method is capable of quantifying the formation of LARL in concentrations as low as 75 ng and is applicable to both purified and crude enzyme preparations. The coupling of SPE with fluorescence detection allows for the simple and rapid analysis of samples.