Surface plasmon resonance optical sensing of hydrocarbon vapours using a Schiff base-piperazine chemoreceptor

Abstract

Herein, a Schiff base sensor candidate derived from piperazine heterocycle and substituted aromatic group, namely 4-methyl-N-(3-nitrobenzylidene)piperazin-1-amine (NBPA) was synthesized and thin films of this de rivative were examined through surface plasmon resonance technique for its chemoreceptor feature against some organic vapours of distinct character such as benzene, ethanol and acetone. The ranges of some sensor parameter values, including sensitivity (0.0763–0.2675 × 10− 3 response/ppm), LOD (43.25–12.33 ppm), and LOQ (131.06–37.38 ppm), are presented for the NBPA-based thin film exposed to these organic vapours. Furthermore, the adsorption kinetics of the NBPA thin film when exposed to these vapours at different concentrations were investigated by analysing the experimental SPR data using the Elovich model. For acetone, ethanol, and benzene vapours, the Elovich constant a ranged from 524.19 to 5493.24, 458.47–3734.67, and 598.03–2900.75 ppm/ mm2, respectively, while the corresponding b values were between 0.17 and 0.01, 0.22–0.02, and 0.42–0.02 mm2 s/ppm. These results indicated that heterocyclic and aromatic moiety aided Schiff base material could be triggered for superior intermolecular interactions, and thus the potential of Schiff bases to reveal sensitive chemoreceptors that will broaden new horizons has been confirmed once again.