Regulating peroxidase-like activity of Pd nanocubes through surface inactivation and its application for sulfide detection.

A new analytical method is described for the colorimetric detection of sulfide. This approach involves the use of Pd nanocubes (PdNCs) as artificial peroxidases that can effectively generate a colored signal by catalyzing the oxidation of peroxidase substrates. In the presence of sulfide, the colored signal is greatly diminished because of the specific and efficient inhibition of the peroxidase-like activity of the PdNCs through their surface inactivation by the formation of PdS. Based on this finding, sulfide assay can be achieved in the 0.125–2.75 μM concentration range with a detection limit of 80 nM. This method shows high selectivity to sulfide besides other ions, and has been applied for the determination of sulfide in spiked real samples. It also features simplicity and rapidness since the assay can be conducted at room temperature, in aqueous solution, and requires only ∼5 min. [ABSTRACT FROM AUTHOR]