Dopamine sensing and selectivity of Nafion-coated plant tissue powder sensors.

Dopamine tissue sensors were prepared using biofilms containing pretreated tissue powder of potato, banana, mushroom and apple. These sensors showed good stability, reproducibility and service life span of more than 200 days involving 300 to 500 measurements. Overlaying the sensors with a Nafion coating considerably improved the sensor selectivity for dopamine by effectively precluding neutral and anionic solutes from entering the biofilm thus removing the interference of most of the 23 solutes examined in this study. The response of the Nafion-coated apple powder sensor in a mixture containing dopamine and the three strong interferents (arterenol, histidine and tyrosine), at concentrations within their respective linear calibration range, was linear with respect to the concentration of each of the solutes. The sensitivity of each of the components in the mixture was higher than the corresponding single component linear range sensitivity.