Hybrid materials based on lichen-polysiloxane matrices: application as electrochemical sensors

Chemically modified electrodes based on the incorporation of lichens in a rigid matrix obtained by sol-gel process show higher ruggedness and stability than conventional carbon paste electrodes. The lichen ion-exchange properties in the uptake of metal ions are combined with the improved physical characteristics of the synthesized materials. SEM, EIS and AS-LSV techniques have been applied to characterize the sol-gel/lichen materials and to evaluate their ability in the construction of electrochemical devices. The coating of solid graphite electrodes with the lichen-polysiloxane materials by means of a spin-coating process allows the development of robust electrochemical sensors. Such devices exhibit a long-time stability and a suitable electroanalytical performance in the amperometric determination of heavy metal ions in water samples. The impedancimetric response of the sensor towards sodium ions has been also demonstrated.