COMPREHENSIVE MULTIDIMENSIONALLIQUID CHROMATOGRAPHIC METHOD (CHIRAL×ACHIRAL) FOR THE SIMULTANEOUS RESOLUTION OF CHIRAL AND ACHIRAL PESTICIDES

DÍAZ MERINO, MATÍAS E.; ACQUAVIVA, AGUSTÍN; PADRO JUAN MANUEL; CASTELLS, CECILIA B.

Virtual

Workshop; 13th. Multidimensional Chromatography Virtual Workshop; 2022

Ministry of Environment and Climate Change (MOECC)

Pesticides are intensively used in modern agriculture. Approximately 30% of the registered pesticides are chiral compounds, and most of them are marketed as racemic mixtures1. However, only about 7% of chiral pesticides are sold as pure enantiomers or as mixtures enriched with one of their enantiomers 1.The main objective of this work was to demonstrate the potential of 2D-LC to increase the resolution capacity of multiple chiral pesticides (with one or more chiral centers), of samples that even contain achiral agrochemical compounds in a single analysis run.In most of the 2D-LC published works involving chiral separations of different types of compounds2, the chiral stationaty phase (CSP) is used in the second dimension (2D) and they are mainly developed in the heart-cutting mode (LC-LC). Moreover, the available examples reported in the literature for the enantiomeric determination of pesticides by 2D-LC are very scarce2. We have recently demonstrated the potentiality of 1D enantioseparation and an achiral separation in reverse mode (RP) in the second dimension using the comprehensive operating modality (LCxLC) for the qualitative analysis of DL-amino acids in honey samples 3.In this work, a robust, reproducible and reliable analytical technique was developed for the analysis of 24 pesticides of diverse chemical nature (17 chiral and 7 achiral compounds). For this, various experimental tests were carried out individually (additives and organic modifier, with different elution gradients were studied) analyzing 4 CSPs based on derivatized polysaccharides, with the aim of reach the largest number of enantioresolved chiral pesticides.