A disposable electrochemical sensor for simultaneous determination of norepinephrine and serotonin in rat cerebrospinal fluid based on MWNTs-ZnO/chitosan composites modified screen-printed electrode

A new electrochemical sensor for simultaneous determination of norepinephrine (NE) and serotonin (5-HT) was fabricated. The electrochemical behavior of NE and 5-HT were investigated using CV and SWV at the MWNTs-ZnO/chitosan composites modified screen-printed electrode (MWNTs-ZnO/chitosan SPE). The results showed that the current responses of NE and 5-HT greatly enhanced due to the high catalytic activity of composites. The peak potentials of NE and 5-HT were separated at about 90 mV and 280 mV, respectively. The peak currents of NE and 5-HT were linearly dependent on their concentrations in the range of 0.5-30 mu M and 0.05-1 mu M, with the limit of detection of 0.2 mu M and 0.01 mu M, respectively. The modified electrode can be stored stably for at least 3 month at 4 degrees C in a refrigerator. Furthermore, the modified electrode was successfully applied to detect the level of NE and 5-HT in rat cerebrospinal fluid (CSF) with excellent selectivity and sensitivity. (C) 2014 Elsevier B.V. All rights reserved.