Cu@Pd core-shell nanostructures for highly sensitive and selective amperometric analysis of histamine.

We demonstrate a facile and rapid methodology for preparation of Cu@Pd core-shell nanostructures on a cost-effective pencil graphite substrate. Galvanic replacement reaction was carried out for palladium modification on template electrodeposited copper nanostructures on pencil graphite substrate. The nanostructures are shown to be very stable with excellent electrocatalytic activities. Under optimised conditions, they could be used for histamine sensing at a very low oxidation potential of +0.55V vs. Ag/AgCl. The low oxidation potential enabled sensitive and selective analysis of histamine using chronoamperometry without any interference from oxygen evolution reactions. We have demonstrated that the sensor shows excellent selectivity towards histamine even in the presence of many of the common interfering biogenic amines. The sensor exhibited a sensitivity of 0.082 μ A/μ M/cm 2 with a limit of detection as low as 3.2 ± 0.1nM. The oxidation potential and limit of detection obtained using this sensor are much superior to the results reported so far in the literature. Practical feasibility of the developed sensor was manifested by histamine analysis in canned tuna fish samples, where the chronoamperometric estimation was also validated by conventional HPLC analysis.