Detection Method Of Lead Base On Nucleic Acid Fluorsence Probe

With the increasing use of metal products, lead to a broad variety of ways to enter into people's living environment, and the trend was increasing, not only affects crop growth and development, yield, quality and so on, but also on human health through the food chain, causing serious hazards, lead pollution has caused widespread concern. Traditional heavy metal detection technology has been difficult to meet the environment and food safety monitoring requirments, the establishment of convenient, fast heavy metal detection technology is necessary.This study based on the new development of the specificity bettween DNAzyme and metal ion in recent years, using FRET as a monitor tool, designed an nucleic acid fluorescent probe which can detect heavy metals. The method would be nucleic acid analysis method combined with light-emitting method for detection of heavy metal lead that to enhance our environment and food safety control and supervision of the provision of technical support.In the test, at first ,we desinged three kinds of probe. structure of the 8-17 DNAzyme was modified with two pairs of"G-C"to enhance its secondary structure'thermal stability and a double quenching fluorescent probe P1 was designed by employing one fluorophore"FAM"and two quenchers"Dabcyl"based on the fluorescence resonance energy transfer (FRET) principle. Structure of the 8-17 DNAzyme was modified with two pairs of"G-C"to enhance its secondary structure'thermal stability and a single quenching fluorescent probe P2 was designed by employing one fluorophore"FAM"and two quenchers"Dabcyl"based on the fluorescence resonance energy transfer (FRET) principle. And another single quenching fluorescent probe P3 was designed by employing one fluorophore"FAM"and two quenchers"Dabcyl"based on the fluorescence resonance energy transfer (FRET) principle. Compared the thermal stability of the three kinds of nucleic acid fluorsence probe by temperature gradient method, and choose the most stable P1 for in-depth study.At second, the qualitative assays was studied by monitoring the change of the probe fluorescent intensity after adding Cd²⁺, Zn²⁺, Mg²⁺, Cu²⁺, Mn²⁺, Pb²⁺, individually. Among these metal ions, Pb²⁺ showed a strong specificity to the probe. In addition, when the probe concentration was 2.5×10^-7mol/L, a good linear relationship was found between the probe fluorescent intensities and Pb²⁺ concentration in the range of 8.5×10^-8mol/L～7.5×10^-6mol/L with a detection limit 8.5×10^-8mol/L. The consisten rate of tap water recovery rate bettween probe P1 and FAAS is 99.25%. The results showed that the probe could be used for both qualitative and quantitative detection of Pb²⁺ at room temperature.