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Heavy metal contamination is a great harm, it can not be degraded in vivo long-term accumulation, minimal content to show great toxicity. Therefore, detection of heavy metals in medicine, food and the environment is very important. The presence of existing detection techniques rely on large-scale heavy equipment, consuming consuming, require specialized technical personnel to operate, is not sensitive to certain heavy metals, and even unable to detect such problems, it is difficult to adapt to the needs of the current testing work, to find a simple , rapid and sensitive detection of heavy metal ions qualitative and quantitative significance. This is the first gold will QCM sensor technology and quality combined amplification effect, a kind of signal enhancement based on gold QCM quantitative detection of heavy metal ions. By heavy metal ions and nanoparticles self-assembled QCM electrode causing the electrode to detect changes in the surface quality of heavy metal ions. First in the QCM gold electrode surface modification of metal ion binding agent for the adsorption of heavy metal ions. Metal ions adsorbed on the QCM electrode binder added after completion of the modified gold nanoparticles, and make the QCM surface adsorption of heavy metal ions. Metal ion, binding agent and binding agent-modified gold surface modified gold particles by three metal ions and the interaction between the binding agent is formed on the surface layer of the sandwich structure QCM nanocomposite, causing QCM resonant frequency is significantly decreased, in order to achieve QCM for detection of heavy ions. This specific research work is divided into the following parts: ① reduction with sodium citrate solution of gold chloride acid prepared gold nanoparticles by transmission electron microscopy shows that the obtained gold nanoparticles of uniform size, particle size of 10 ± 0.8nm, its shape is spherical, well dispersed. using UV-visible spectra measured at 517.5nm characteristic absorption peak appeared at and narrow peak shape. Were studied through experiments of pH and salinity on naked gold nanoparticles, MBA modified gold nanoparticles and short chain oligonucleotide-modified (SH-T5) stability of gold nanoparticles, and from the acid distribution coefficient and electrical double layer theory , affecting the stability mechanism was discussed, to prepare for the subsequent experiments. ② with MBA modified QCM electrode and gold nanoparticles, is designed based on signal enhancement MBA modified gold QCM heavy metal ion detection methods. Metal ions and gold nanoparticles through MBA and heavy ion complexation between the ligand acts on the QCM electrode surface self-assembly, causing the electrode surface quality changes, enabling detection of heavy metal ions. On the solution of cadmium (Ⅱ), Cu (Ⅱ), Pb (Ⅱ), Cobalt (Ⅱ), mercury (Ⅱ) six kinds of heavy metal ions were detected, and the effects of interfering ions and pH influence on the test results. Experimental results show that the method detection limit and sensitivity than existing QCM detection methods have greatly improved, especially for Cd 2 , Cu 2 , Pb 2 , the detection sensitivity is high. ③ with with mercury (Ⅱ) ion-specific binding is rich in thymine (T) oligonucleotides (SH-T5) modified QCM electrode and the gold nanoparticles, the design of a gold-based amplification QCM Hg 2 Selective detection methods. By thymine with Hg 2 strong role of the specific binding of Hg 2 and SH-T5-modified gold nanoparticles in self-assembled QCM electrode surface, causing frequency changes , enabling Hg 2 selective detection. Experiment with different concentrations of Hg 2 solution were determined, and the effects of Hg 2 detection selectivity. This method Hg 2 high detection sensitivity, good reproducibility, anti-interference ability.
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