Dual-excitation in-lab-made device based on a handy UV lamp and GQDs-modified PADs for simultaneous determination of acetaminophen and its endocrine disrupting impurity 4-nitrophenol

摘要

In this study, we first propose novel and intelligent strategies for simultaneous estimation of acetaminophen (AC) and its potential toxic impurity 4-nitrophenol (NP) using an in-lab-made device as well as a benchtop fluor-ometry technique. The developed approaches depend on the dual-excitation of fluorescent graphene quantum dots (GQDs) at 240 and 350 nm, and measurement of the characteristic emission at 440 nm. AC efficiently quenches the fluorescence of GQDs when excited at 240 nm, while NP quenches the fluorescence of GQDs when excited at 350 nm. The mechanism involved in the quenching has been established to be the inner filter effect via absorption of the incident excitation light by the quenchers. An in-lab-made device that integrates a dual-wavelength handy UV lamp and a GQDs modified paper-based analytical device (PAD) confined with a permanent ink marker has been developed. Imaging of the PAD was performed by a smartphone, and image processing permitted the selective estimation of AC and NP. This technique offers an affordable, easily fabricated, and widely accessible device for application in limited-resources laboratories. The benchtop approach permitted the determination of AC and NP over the range of 0.1-20 and 0.1-2.0 μg/mL, while the in-lab-made device approach allowed AC and NP determination within the ranges of 0.04-6.0 and 0.04-2.0 μg/detection zone, respectively. The two approaches have been successfully validated for the estimation of AC and NP in pharmaceutical preparations. The proposed strategies are the first to utilize a single nanomaterial for simultaneous analysis of two analytes adapting the dual excitation technique.