Biomolecule-Free, Selective Detection of o-Diphenol and Its Derivatives with a Screen-Printed Electrochemical Sensor

摘要

We report here biomolecule-free, selective detection of o -diphenol and its derivatives with a screen-printed electrochemical sensor. It is based on the preparation of a highly stable slurry made of 2,2-diphenyl-1-picrylhydrazyl (DPPH) dissolved in 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF~(6)) room temperature ionic liquid for use as screen-printed ink in fabricating the proposed sensor. A detailed investigation by scanning electron microscope (SEM) along with UV-visible and FT-IR spectroscopic studies indicates that DPPH is well dispersed and stabilized by BMIMPF~(6)ionic liquid. Enhanced current response is observed using the as-printed electrode (designated as SP-DPILE) in electrochemical measurements of o -diphenols with good sensitivity and selectivity. Its selectivity is proved through the discrimination of catechol signal from resorcinol and hydroquinone in the absence of biomolecule auxiliary. This is valuable in real sample analysis, and the feasibility of the SP-DPILE is demonstrated for the detection of gallic acid in green tea by flow injection analysis. A highly stable slurry made of 2,2-diphenyl-1-picrylhydrazyl (DPPH) distributed within room temperature ionic liquid ([BMIM] [PF~(6)]) was developed for use as screen-printing ink in fabricating disposable sensors. Graphical Abstract.