Determination of prostate cancer marker Zn2+ with a highly selective surface-enhanced Raman scattering probe on liquid–liquid self-assembled Au nanoarrays

As the concentration of Zn 2+ in patients with prostate cancer is much less than that in healthy persons, Zn 2+ concentration can be used as a marker to expediently screen prostate cancer. In this study, a sensitive and highly selective surface-enhanced Raman scattering (SERS) method to detect Zn 2+ concentration in human prostatic fluids by utilizing water-insoluble 2-carboxyl-2′-hydroxyl-5′-sulfoformazylbenze (Zincon) as a SERS probe based on self-assembled Au nanoarrays at a liquid–liquid interface between n-hexane and Au colloids was proposed. Zincon showed remarkably different SERS bands before and after coordinating Zn 2+ in the controlled conditions (70 μL of ethanol, 500 μL of n-hexane, pH value of 7.1 and 10 s of vortex mixing time), which can be used in quantifying Zn 2+ with characteristic peaks. The proposed SERS method presented a good linear relationship ranging from 0.5 to 10 μmol/L and a satisfactory detection limit of 0.1 μmol/L as well as low interference with other metal ions . Moreover, the detection results are close to those of the conventional standard atomic absorption spectroscopy (AAS) method.