Activated Nickel Platform for Electrochemical Sensing of Phosphate

摘要

We report here a highly selective enzymeless approachnfor the determination of phosphate (PO4n3-) by flowninjection analysis (FIA). In this system, the activationnof barrel plated nickel electrode (Ni-BPE) in alkalinenmedia to form a Ni(OH)2/NiO(OH) film was found tontrigger the adsorption of phosphate at the electrodensurface. Based on the suppressed current of thenelectrocatalytic oxidation of glucose at the activated Ni-nBPE in 0.1 M NaOH solution caused by adsorption ofnphosphate, we develop an FIA detection scheme fornthe determination of phosphate. Under the optimizednconditions of flow rate )300 μL/min and detectionnpotential )0.55 V vs Ag/AgCl with 25 μM glucose inn0.1 M NaOH as carrier solution, the calibration curvenshowed a linear range up to 1 mM. Possible interferencesnfrom the coexisting ions were also investigated.nThe results demonstrated that sensor could be usednfor the determination of phosphate in the presence ofnnitrate, chloride, sulfate, acetate, oxalate, carbonate,nand some anionic species of toxicological and environmentalninterest, such as chlorate, chromate, and arsenatenions. The electrode can be effectively regeneratednwithout extra treatment under the hydrodynamicncondition. For eight continuous injections of 40 μMnPO4n3-, a relative standard deviation of 0.28% wasnobtained, indicating good reproducibility of the proposednmethod. The detection limit (S/N ) 3) wasncalculated as 0.3 μM.