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

Abstract A single-step process has been demonstrated for the synthesis of poly(m-aminophenol) (PmAP) nano-fiber and fabrication of thin film on a plate of thin layer chromatography (TLC) through crosslinking by ammonium persulfate in dimethyl sulfoxide and it was doped with the sodium ion following solvent running method. The average diameter of PmAP nano-fiber was confirmed as 250 nm which was noted as 200 nm after sodium ion doping. The thin film of PmAP nano-fiber on TLC plate was successfully employed as chemiresistive sensor for arsenic ion, i.e., arsenic(III) or arsenic(V) or their mixture in water. Upon running the aqueous solution of arsenic ion, the resistance of PmAP nano-fiber was decreased showing 80–90 % response without theoretical detection limit irrespective of the pH of the medium. However, a logarithmic relationship was found for the resistance change of PmAP nano-fiber with increasing concentration of arsenic ion in water. Moreover, the PmAP nano-fiber sensor has shown about ∼80 % selective response for arsenic ion in water in presence of other cations or anions. The results have been correlated with the proposed sensing mechanism by considering the unique strong associations of arsenic ions and PmAP nano-fiber through ionic as well as hydrogen bonding interactions.