Electroanalytical sensing of trace amounts of As(III) in water resources by Gold–Rare Earth alloys

Abstract

Gold–Rare Earth (Au-RE, RE = Sm, Dy, Ho, Y) alloys were prepared by co-melting stoichiometric amounts of metals. XRPD and SEM/EDX analysis revealed the formation of equiatomic compounds. These alloys were used for the preparation of electrodes for As(III) sensing in aqueous samples. All four electrodes gave a clear response in the presence of As(III) in weakly alkaline media (NaHCO3 + Na2CO3 buffer). Following optimisation of operating parameters (deposition potential of −0.9 V vs SCE and deposition time of 180 s), limits of detection of As(III) at four electrodes were determined to be in 0.8–2.3 ppb region. Au-RE electrodes gave a clear response in the presence of Cu(II) as model interferent and, finally, showed the ability for As(III) sensing in a real sample.