Molecular architecture of novel potentially bioactive (co)oligoesters containing pesticide moieties established by electrospray ionization multistage mass spectrometry.

RATIONALE

Pesticides are commonly used in agriculture to ensure high crop yield; however, because of their low resistance to environmental conditions, a large amount of pesticides does not reach target pests and becomes an environmental pollutant. One of the ways to reduce these drawbacks is synthesis of polymeric systems, which allows for controlled release of pesticides for a prolonged period of time. Herein we report the synthesis and characterization of novel potentially bioactive (co)oligoesters with bioactive moieties (selected from pesticides) which are covalently linked along an oligoester backbone.

METHODS

The delivery systems of pesticides were prepared via anionic ring-opening polymerization of β-substituted β-lactones containing bioactive moieties as a pendant group selected from pesticides and their copolymerization with β-butyrolactone in the presence of carboxylates as initiators. Electrospray ionization multistage mass spectrometry (ESI-MS(n)) supported by (1)H NMR were applied in order to establish the structure, at a molecular level, of the new biodegradable oligomeric release system of selected pesticides.

RESULTS

Based on ESI-MS(n) analyses, the structures of the resulting (co)oligoesters were established at the molecular level. The ESI-MS/MS allowed to confirm the structures of end groups and to determine the composition of individual (co)oligoester molecules which contained one, two or three bioactive molecules per (co)oligomer. Additionally, it was shown that fragmentation of selected ions of potentially bioactive (co)oligoesters proceeded via random breakage of ester bonds along the oligomer chain and ester bonds of the bioactive pendant group.

CONCLUSIONS

An analytical method for detailed structural characterization at the molecular level of potentially bioactive (co)oligoesters has been developed. These results are important in the analysis of designed biodegradable polymeric controlled-release systems of pesticides with potential agricultural applications.