Sensitive optical NO sensor based on bis [(2,9-dimethyl-1,10-phenanthroline)] copper(II) complex

The reaction of Cu(dmp)22+ with NO has been investigated for potential development into an optical fibre chemical sensor. In aqueous solutions, a linear calibration (r = 0.9950) was obtained between 0 and 2.5 μM NO with a detection limit of 0.32 μM (∼0.0096 ppm) (s/n = 3). The complex electrostatically immobilised in nafion produced a highly linear calibration (r = 0.999) between 0 and 3 ppm in NO gas phase with a detection limit of 0.072 ppm (∼2.38 μM in solution). The response was shown to be fully reversible by immersing the films in hydroxylamine hydrochloride solutions and a steady state response was achieved within 100 s exposure time. The nafion films were also shown to be more selective to NO over O2 (183:1), NO2 (16:1) and CO (795:1). In solution nitrite, H2O2 and peroxynitrite anion did not interfere.