SERS spectrum of imazalil. Experimental and quantum-chemical vibrational analysis

DÍAZ-MIRÓN, GONZALO; SÁNCHEZ, MARÍA A.; CHEMES, DOLY M.; ÁLVAREZ, ROSA M.S.

JOURNAL OF RAMAN SPECTROSCOPY

JOHN WILEY & SONS LTD

Año: 2018 vol. 49 p. 638 - 650

0377-0486

Imazalil [1‐[2‐(2,4‐dichlorophenyl)‐2‐(2‐propenyloxyl‐ethyl]‐1 H imidazole] isa systemic fungicide that is toxic to a number of plant pathogens, particularlyspecies of Penicillum. Its activity is based on the inhibition of moldsporulation on fruit skin, which makes it one of the most commonly usedfungicide in post‐harvest citrus treatments for fruit preservation duringstorage, shipping, and marketing. Due to its wide application, the presenceof imazalil needs to be monitored to avoid the excessive and/or improperuse. This work reports a complete analysis of the Fourier‐transform infraredspectroscopy and Raman spectra of imazalil as a pure compound aswell as in the commercial product for agricultural use; the band assignmentrelays in the vibrational predictions acquired by quantum‐chemicalcalculations (B3LYP/6?311 + g(2df, p)) for the imazalil molecule. An analyticalapplication of surface‐enhanced Raman spectroscopy (SERS) is alsopresented here. It is done so by using a novel, low‐cost, and sensitiveSERS‐active substrate built with silver nanoparticles supported on a Si/ZnO nanowires platform to detect traces of imazalil in aqueous solutions.Comparison between the Raman and SERS spectra allowed the characterizationof the interaction between the pesticide and the silver nanoparticlesurface.