A Pyrido[1,2-a]pyrazinium bromide derivative as a fluorescent indicator for visual and rapid detection of carbamate pesticides in water

[Display omitted] •A new fluorescent pH indicator, pyrido[1,2-a]pyrazinium bromide with a ester group is developed.•The integration of pyrido[1,2-a]pyrazinium bromide and AChE-ATCh hydrolysis system enables visual and selective fluorometric detection of carbamates in lake water.•Highly sensitive detection of carbaryl residues in lake water with a detection limit as low as 0.008 mg/L.•This practical fluorometric method is applicable to outdoor detection using a very simple and portable 365 nm UV instrument. Visual and rapid detection of carbamate pesticides in lake water has not been developed. In this work, a new fluorescent pH indicator pyrido[1,2-a]pyrazinium bromide derivative was designed and synthesized. The integration of this fluorescent pH indicator and AChE-ATCh hydrolysis system allows visual and selective fluorometric detection of carbamates in lake water. Such AChE inhibition-based fluorometric reagents are well tolerated in complex aquatic environments. The detection limit for carbaryl residues in lake water reaches 0.008 mg/L. This practical fluorometric method is applicable to outdoor detection using a very simple and portable 365 nm UV instrument.