Figure 4
From: Paper strip-embedded graphene quantum dots: a screening device with a smartphone readout
Performance of the LED-based device compared to the UV light readouts. Fluorescence quenching of GQDs with increasing concentrations of quercetin observed under the UV light (A); and with the LED device (B), respectively. Concentrations are 0 (0.01 M PBS Buffer), 1.66 × 10−5, 4.98 × 10−5, 8.30 × 10−5, 1.33 × 10−4, 1.99 × 10−4, 2.51 × 10−4, 5.01 × 10−4, 7.52 × 10−4, 1.25 × 10−3, 1.50 × 10−3 M, from 1 to 10, respectively. Three replicates of the same concentrations are denoted by the blue arrow. Graphics of estimated fluorescence of the spots with increasing concentration of quercetin observed under the UV lamp (black dots); and with the LED device (red dots) (C). Inset is the correlation of the two methods. Decreasing concentrations of 4-nitrophenol (4-NP) (D) and paraoxon (E) ranging from 0 to 5 × 10−4 M are denoted by the purple arrow. The corresponding Stern–Volmer relationship for paraoxon (F) and 4-NP (inset).
