The invention relates to a method for measuring
metallic lead ion based on a nano-gold probe and markless color comparison of
nuclease. 17E type
nuclease forms a
double chain structure with the substrate through hybridization. If the specimen to be tested contains lead
ion, the lead
ion can greatly increase the speed of catalyzing and transecting the substrate by the 17E type
nuclease, after the transaction of the substrate, the
double chain structure is dissociated to generate free single-chain
DNA which can be adsorbed on the surface of the nano-gold probe, in order to protect the nano-gold probe from being inducted by salt and aggregated, therefore, the nano-gold probe solution is in claret red color; if the specimen to be tested does not contain lead ion, the
double chain structure of the 17E type nuclease and the substrate thereof can not be damaged, reaction can not happen between the double
chain structure and the nano-gold probe, therefore, the nano-gold probe can be inducted by salt and aggregated and in bluish
violet color. Through the color change of the nano-gold probe, the detection of the lead ion can be realized. The
detection limit to the lead ion is 500 nanomole per
liter. By using the method to detect the lead ion, the selectivity is high, the sensitivity is high, the operation is simple, and complex instruments are not needed.