Chemiresistive sensing of arsenic ion in water by thin film of poly(m-aminophenol) nano-fiber

•Single-step thin film fabrication of poly(m-aminophenol) nano-fiber on a TLC plate.•Novel doping and sensing method by running the mobile solution phase over the TLC.•80–90 % response without theoretical detection limit irrespective of the pH•∼80 % selective response for arsenic ion in presence of other anions or cations.•Sensing mechanism has been proposed supported by spectroscopic characterization.