Fiber optic surface plasmon resonance based hexachlorobenzene sensor exploiting layer-by-layer coatings of GNP/SnO₂ dendrites nanocomposite

An efficient fiber optic surface plasmon resonance based hexachlorobenzene (HCB) sensor is designed using layer by layer coating method. SnO₂ nanoparticle [(SnO₂)_N] and SnO₂ dendrites [(SnO₂)_D] are used to synthesize graphene nanoplatelets (GNP) based nanocomposites (labelled as GS_N and GS_D, respectively) to fabricate potential sensing layer. The combination of GNP and SnO₂ nanostructures shows synergistic effects and provides high sensitivity and selectivity to the sensor. Post-immobilization method is used to prepare nanocomposites. Owing to difference in structures, GS_N and GS_D possess unique properties such as large surface area, catalytic nature, tunable porosity and non-toxicity and hence provide potential pathway for efficient sensing performance for HCB. Scanning electron microscopy (SEM) is used to confirm the preparation of [(SnO₂)_N], [(SnO₂)_D] and GS_D. The GS_D based probe fabricated with optimized parameters operates in the concentration range 0 g l⁻¹ to 10⁻² g l⁻¹ with low detection limit 1.085  ×  10⁻¹⁵ g l⁻¹. The selectivity of the sensor is confirmed by carrying out the experiments using various possible interferands. The sensor can be used for online monitoring and remote sensing. (paper)