In this paper an electrochemical DNA-based biosensor incorporating a signal enhancement for the determination of mercury (II) ions (Hg2+) in aqueous solution was designed by using a thymine (T)-rich, mercury-specific oligonucleotide (MSO) probe and gold nanoparticles (GNPs) modification. The electrochemical DNA-based biosensors were fabricated by immobilizing the MSO probe onto the surface of GNPs modified gold electrode via thiol-Au interactions. In the presence of Hg2+, the thiolated MSO probe could form stable DNA duplexes by the specific binding interactions between Hg2+ and thymine (T-Hg2+-T). The MSO-bound Hg2+ can be electrochemically reduced to Hg+, which provides a readout signal for quantitative detection of Hg2+. The reduction peak current is linearly related to the concentration of Hg2+ from 1.0×10-9 M to 1.0×10-6 M with a detection limit of 5×10-10 M. This work demonstrates that GNPs-modified gold electrode provides a promising platform for immobilizing the MSO probe and enhancing the sensitivity.
the Specialised Research Fund for the Doctoral Programme of Higher Education of China（No. 20096101120011）
The National Natural Science Funds of China （ 20126101120023）
Northwest University, Xi’an 710069,Northwest University, Xi’an, Shaanxi 710069, China,Northwest University, Xi’an, Shaanxi 710069, China,Northwest University, Xi’an, Shaanxi 710069, China
For gas reservoir driving, the main gas driving force , the dynamic changes of gas reservoir and the interreaction between gas reservoir and its surrounding water area in each development phase should be considered. The dynamic change of gas reservoir means the changes of gas reservoir pressure and PORV of gas storage; By introducing the least-square method to the material balance equation of gas reservoir and considering the liquid expansion and decreased pore volume caused by the decreased pressure and combining the liquid state equation and the elastic medium state equation , a new method to analyze the gas reservoir driving has been established, and relative new calculating formula of degree of reserve recovery, effective compressibility, relative pressure coefficient, cumulative gas production and geologic reserve of gas reservoir have been produced; This new method lays a theoretical foundation for the traditional formation pressure method, the law of water cutting volume factor and the Havlena-Odeh method, and it can be applied to the driving analysis of normal gas reservoir, abnormally pressured gas reservoir and condensate gas reservoir; By putting this new method into the Anderson 'L' gas reservoir: An abnormally pressured gas reservoir in south Texas of America, we get good analyzing results.
Funded by the national natural science funds of China （No:50874094）
the Higher school specialized research fund for the doctoral program（NO.20095121110003）
Major cultivation project of department of education of Sichuan province（No.09zz035）
Petroleum engineering of Southwest petroleum university