Study on the Performance of the Ionic Liquids [Emim]CH3SO3 and [Emim]PF6 to Prepare the Biosensor of the Detection of Heavy Metals in Seawater

Electrochemical sensors can detect the heavy metal ions in seawater quickly, conveniently and accurately with the advantages such as the fast detection speed, the simple operability and the low cost. The ionic liquid [Emim]CH3SO3 showed excellent electrochemical performance and could meet the initial application requirements as electrochemical sensors. The characters of the ionic liquids [Emim]CH3SO3 and [Emim]PF6 which include IR, LC-MS, conductivity, electrochemical window and viscosity were detected. The influence of trace impurity on the conductivity of the ionic liquids was investigated. Results suggested that the conductivity of the ionic liquids increased with the concentration of the added organic solvents. In addition, though the conductivity of the ionic liquids increased with temperature, there is no significant difference in the influence of the same impurity at varying temperatures. Muti Walls Carbon Nanotubes (MWCNTs) are appropriate materials which are commonly used materials for electrochemical sensor applications. The effect of the Imidazolium-based ionic liquids on the performance of the conductivity of the MWCNTs was studied. It was found that Ionic liquid is an excellent extraction agent for metal ions and its presence in the sensor system improves significantly the detection of heavy metal ions.