OPAA/fluoride biosensor chip towards field detection of G-type nerve agents

•Development of a solid-contact fluoride ion-selective electrode by comparing different fluoride ionophores.•Solid-contact fluoride electrode displayed near-Nernstian behavior at neutral pH, high selectivity and reproducibility.•Field detection of G-type nerve agent simulant via combining OPAA reaction with recognition of the liberated fluoride ion.•Fast, sensitive and selective DFP detection over a wide dynamic range of 250–3000 μM.•Selective OPAA-based biocatalytic hydrolysis of G-type nerve agents to discriminate against common OP pesticides.