A synchronous-fluorescence analysis method combing with simple one-step extraction for determination of leonurine in traditional Chinese medicine

Abstract

Synchronous fluorescence spectroscopy (SFS) technology exhibits significant advantages in identifying target fluorescence signals within complex mixtures of multiple fluorescent compounds, owing to their closely overlapping spectra. In this study, a SFS method is reported for the first time for the direct analysis of leonurine in drugs containing concurrent natural products. By setting the wavelength interval (Δλ) to 30 nm, the characteristic emission peak of leonurine is observed at 307 nm, which increases proportionally with the concentration of leonurine without spectral overlap from other fluorescent species. The limit of detection (LOD) is estimated to be about 0.22 μM, and a low linear range of 0 to 20 μM is obtained. The common cations, anions and concomitant compounds display no interference with the SFS signal of leonurine, supporting the practical application of this method. Thus, we successfully applied this SFS method to detect leonurine in several real samples (leonurus granules, capsules, ointment and pills), in which the good relative standard deviation (RSD) values (0.04–4.24%) and recoveries (95.63–113%) were obtained. As a result, this work provides an efficient and convenient method to identify the target active compound from natural products without complex pre-treatment to diminish the fluorescent chaos that might be serving a potential role in the study of traditional Chinese medicine.