Application of microbial alkaloid prodigiosin as a potent matrix for the MALDI mass spectrometry analysis of low-molecular-weight plant antioxidants

Abstract

Microbial alkaloid prodigiosin is proposed as a new effective matrix for the analysis of low-molecular- weight plant antioxidants by MALDI mass spectrometry in the negative ion detection mode. It is demonstrated that the physicochemical characteristics of prodigiosin, such as ability to activate ionization/ desorption of analyte, high absorption coefficient at the working wavelengths of lasers, good solubility in solvents used for analytes, uniformity of crystallization on the target, stability under working conditions, and the absence of interfering peaks of fragment and cluster ions, are consistent with the recommendations for effective matrices. Prodigiosin as a matrix ensures the high-resolution detection of various plant antioxidants in complex mixtures. The obtained mass spectra of flavonoid aglycones were characterized by high quality (signal-to-noise ratio higher than 10³) and reproducibility. The use of prodigiosin for analyzing a complex preparation of plant antioxidants ensures the simultaneous recording and interpretation of more than two dozens of ions corresponding to various antioxidants with the molecular weights of 100–500 Da.