Chemiluminescence detection of lead (II) using ‘8–17’ DNAzyme and hemin/G-quadruplex with high sensitivity and selectivity

It is important to design new ways with high specificity and sensitivity to detect lead (II). Here, ‘8–17’ DNAzyme was used as a Pb 2+ -dependent probe with high sensibility and selectivity based on chemiluminescence (CL). When Pb 2+ was present, the substrate strand was cleaved and the active hemin/G-quadruplex DNAzyme structure was formed in the presence of another sequence which contained two parts, one could be complementary with part of the substrate strand and the other was a G rich subunit. The active hemin/G-quadruplex DNAzyme structure could catalyze luminol oxidation and quantitative analysis of Pb 2+ was carried out according to the CL of luminol. Results showed that CL intensity of luminol at 452   nm had a linear relation with the concentration of Pb 2+ in the range from 5   nM to 1   μM, and the limit of detection was 0.79   nM ( S / N   =   3). This method was also used to detect the contents of Pb 2+ in lake water and tobacco and the results (62.4   ±   4.0   nM and 15.2   ±   2.2   nM, respectively) were extremely closed to those of inductively coupled plasma-mass spectrometry (ICP-MS) (57.0   ±   1.4   nM and 14.5   ±   0.91   nM, respectively).