Non-Targeted Chemical Fingerprinting of Phytotoxins in Environmental Matrices

Researchers from the University of Copenhagen (Denmark) have developed a novel, sensitive, and reliable analytical method to analyze phytotoxins in environmental matrices using reversed‐phase liquid chromatography with electrospray ionization high‐resolution mass spectrometry (RPLC–ESI‐HRMS).

Phytotoxins have been classified as chemicals of emerging concern (CECs) (1). This class of secondary plant metabolites has gained attention because of their impact on the environment and potential adverse affects on human health. The development of new analytical methods to analyze these compounds is therefore highly desirable, and new methods for the targeted and non‐targeted screening analysis of phytotoxins in environmental samples are in demand. The researchers from Copenhagen developed a non‐targeted RPLC–ESI‐HRMS method to identify five major groups of phytotoxins—steroids, alkaloids, flavonoids, terpenoids, and aromatic polyketides—in environmental matrices.

A novel, sensitive method for the targeted and non‐targeted screening of phytotoxins was developed. This new non‐targeted screening method was 40 times more sensitive than previous methods, according to the researchers, and allowed more than 30 phytotoxins to be identified from soil and water samples. The researchers suggested that for a balance between sensitivity, number of compounds detected, high‐throughput, and peak capacity, a mobile phase consisting of 5 mM furmic acid at pH 3.0 with a gradient of 0.95% acetonitrile over 30 min should be used for both ESI + and ESI − with a column temperature of 25 °C.

In this study, the researchers also established that the negative ionization of phenols was assisted by the number of hydroxyl groups present on the ring rather than on their substitution position. This new RPLC–ESI‐HRMS method will help to understand the fate of phytotoxins in the environment and assist in developing guidelines to monitor phytotoxins for public health, according to the researchers.

Reference

1. X. Liang, J.H. Christensen, and N.J. Nielsen, J. Chrom A. 1642, 462027 (2021).