Quantification of Lipopeptides Using High-performance Liquid Chromatography with Fluorescence Detection after Derivatization.

A highly sensitive and selective high-performance liquid chromatographic (HPLC) method has been developed for the determination of microbial lipopeptides of fluorescent derivatization with 1-bromoacetylpyrene to overcome the limitations of trace detection of lipopeptides in aqueous solutions. The derivatization of lipopeptides with 1-bromoacetylpyrene was conducted at 60°C for 20 min under catalysis of triethylamine. The resulting derivative products were separated by HPLC and determined by a fluorescence detector. Each homolog of lipopeptides in samples was identified by HPLC-MS and the detection limit after derivatization in an aqueous solution was 2.5 μg/mL (S/N = 3). The calibration curve for lipopeptides was linear in the concentration range of 0.250 - 4.00 mg/mL. This method has adequate sensitivity and selectivity for microdetection of lipopeptides in aqueous solutions in mild reaction conditions, which allows this method to be used in the determination of trace lipopeptides in environmental samples and complex samples.