title: Nanoporous anodic alumina rugate filters for sensing of ionic mercury: toward environmental point-of-analysis systems.
abstract: Herein, we present an ultrasensitive, cost-competitive, and portable optical sensing system for detecting ionic mercury in environmental water. This analytical system combines structurally engineered and chemically modified nanoporous anodic alumina rugate filters (NAA-RFs) with reflection spectroscopy (RfS). The sensing performance of the proposed system is assessed through several tests, establishing its sensing performance (i.e., linear working range from 1 to 100 μM of Hg(2+), low limit of detection 1 μM of Hg(2+) ions (i.e., 200 ppb), and sensitivity of 0.072 nm μM(-1)), chemical selectivity (i.e., exposure to different metal ions Co(2+), Mg(2+), Ni(2+), Cu(2+), Pb(2+), Fe(3+), Ca(2+), Cr(6+), and Ag(+)) and metal ions binding mechanism (i.e., fitting to Langmuir and Freundlich isotherm models). Furthermore, the detection of Hg(2+) ions in tap and environmental water (River Torrens) is successfully carried out, demonstrating the suitability of this system for developing environmental point-of-analysis systems.
authors.affiliation: School of Chemical Engineering, The University of Adelaide , Adelaide, SA 5005, Australia.
authors.forename: Tushar
authors.initials: T
authors.lastname: Kumeria
authors.forename: Mohammad Mahbubur
authors.initials: MM
authors.lastname: Rahman
authors.forename: Abel
authors.initials: A
authors.lastname: Santos
authors.forename: Josep
authors.initials: J
authors.lastname: Ferré-Borrull
authors.forename: Lluís F
authors.initials: LF
authors.lastname: Marsal
authors.forename: Dusan
authors.initials: D
authors.lastname: Losic