| abstract |
The invention discloses an electrochemical sensor and its preparation method. The electrochemical sensor comprises an electrode, which includes a conductive substrate and a composite film adhered to the surface of the conductive substrate. Specifically, the composite film comprises at least one nano-particle layer and at least one polyelectrolyte layer that are alternately stacked, and the nano-particle layer and the polyelectrolyte layer have opposite charges, the first layer of the composite film in direct contact with the conductive substrate and the conductive substrate have opposite charges. The nano-particle can be one or more of transition metal oxides, heteropoly acids and isoplyacids. The electrochemical sensor provided by the invention can show selective response to low concentration dopamine in the presence of high concentration ascorbic acid, and has the advantages of high sensitivity and fast response, thus being applicable to real-time monitoring of dopamine. |