An aptasensor for arsenic on a carbon‑gold bi-nanoparticle platform

We report an electrochemical aptasensor for the detection of As (III) in water based on carbon nanoparticle (CNPs) and gold nanoparticles (AuNPs) immobilisation platform. The carbon and gold nano-platform was prepared by drop coating CNPs on a glassy carbon electrode (GCE) followed by electrodeposition of AuNPs on the CNPs modified electrode by cyclic voltammetry from −300 mV to 1200 mV at 50 mVs−1 scan rate. The aptamer biosensor was prepared by the immobilisation of a 100-base thiolated Ars-3 aptamer on the nano-platform (CNPs/AuNPs) modified GCE by chemisorption. A detection limit of 0.092 ppb was obtained and the biosensor was not susceptible to interferences from Cd, Cu and Hg. This work thus presents an alternative approach to mitigating interferences in the electrochemical sensing of arsenic. Keywords: Arsenic aptamer, Aptamer biosensor, Arsenic, Carbon nanoparticles, Gold nanoparticle