Visual distance-based paper analytical device for on-site detection of Pb(II)

Abstract

A simple, inexpensive, fast, and visual distance-based paper analytical device has been developed for on-site detection of Pb(II). Pb(II) can inhibit the catalytic activity of G-quadruplex/hemin (G4/hemin) DNAzyme induced by K+, which catalyzes 3,3,5,5-tetramethyl benzidine (TMB) immobilized on paper to produce a visible blue band. The factors affecting Pb(II) detection have been optimized with PS concentration of 3 μM, K+ concentration of 10 mM, and hemin concentration of 10 μM, as well as the straight channel width of 2.0 mm. It can be well found that the formed length correlates with the concentration of Pb(II) with a linear detection range of 0.02 μM − 50 μM. A fitting linear equation of Y = 20.793–5.391LogC (R2 = 0.9788) can be obtained with a lowest detection limit of 1 nM. Additionally, the method is capable of selectively detecting Pb(II) and works well for Pb(II) detection in real samples. Overall, the visual distance-based paper analytical device offers an ideal platform for on-site detection of heavy metal ions, especially in resource-limited areas.