After hybridization with the target DNA (tDNA), a magnetic field is used to separate the sandwich complex consisting of MNP-2pDNA/tDNA/1pDNA-AuNP-bDNA-NT.
After the NTs (PbS and CdS) are dissolved in 1 M nitric acid, NT2+ ions (Pb2+ and Cd2+) are measured by square wave anodic stripping voltamme- try (SWASV) on a screen-printed carbon electrode (SPCE) chip and yield well-resolved highly sensitive stripping voltammetric signals for the corresponding targets.