ZnO/Ag nanorods as a prominent SERS substrate contributed by synergistic charge transfer effect for simultaneous detection of oral antidiabetic drugs pioglitazone and phenformin

It is popular and promising to explore a prominent surface-enhanced Raman scattering (SERS) substrate for simultaneous determination of multiple analytes in drug safety and quality monitoring. To achieve the goal, in this work, we constructed a plasmonic metal/semiconductor oxide heterostructure by depositing Ag nanoparticles (NPs) on ZnO nanorods. The ZnO/Ag substrate exhibited prominent SERS performance by using rhodamine 6 G as the probe molecule, including transferable nature onto various available substrate, high enhancement factor, stability and uniformity. The synergistic charge transfer effect was systematically studied, including the effects of the Ag loading amount and laser wavelength, photoluminescence, UV-vis spectra and XPS analysis. The ZnO/Ag substrate was developed as a SERS probe for separate and simultaneous detection of two oral antidiabetic drugs (OADs), pioglitazone (PIO) and phenformin (PHE) in human urine. The detection limits were as low as 1 and 5 nM for PIO and PHE (respectively) with good selectivity and satisfactory recoveries. This type of SERS substrate will be suitable for rapid and noninvasive determination of OADs in clinic applications.