Dr Sagarika MISHRA (School of Physics & Astronomy University of St Andrews)

Abstract:

Overuse of herbicides and pesticides has led to persistent agrochemical residues that threaten environmental health, creating a pressing need for efficient detection strategies in aqueous media. Here, we report luminescent carbazole-based molecules designed to sense a group of pesticides and herbicides, including trifluralin and DNOC. The sensor molecules readily form highly luminescent nanoaggregates in near aqueous environments. Aggregation behaviour was examined through emission measurements and fluorescence lifetime measurements across varying DMSO/water fractions from 0 % to 99 % water in DMSO. Particle sizes determined by SEM and DLS confirmed nanoscale aggregates of 20 nm to 950 nm diameter. These nanoaggregates display strong sensitivity as fluorescence-quenching sensors toward multiple common pesticides, achieving detection limits in the nanomolar to micromolar range, highlighting their potential as efficient luminescent probes for monitoring environmental pollutants.