“…However, these methods usually require expensive and sophisticated instrumentation, time consumption and complex sample pretreatment procedures. In recent years, a variety of novel sensors have been exploited for the determination of Pb 2+ based on imprinted polymer nanoparticles [13], thermosensitive tri-block copolymers [14], functionalized multiwalled carbon nanotubes [15] and magnetic mesoporous silica [16], 4 DNAzyme [17][18][19], nobel metal-based nanoparticles such as Au [20,21] and Ag [22,23], and semiconductor quantum dots (QDs) [24,25]. However, these sensors needed multiple pretreatment steps, rigorous synthetic conditions and some raw materials were very expensive.…”