Chemical adsorption of phenothiazine dyes onto carbon nanotubes: Toward the low potential detection of NADH

The cyclic voltammetric responses for phenothiazine dyes, adsorbed onto CNT have been assessed as a means of promoting the low potential, sensitive and stable determination of NADH. The analytical signal of the toluidine blue modified carbon nanotubes (TB-CNT) has been evaluated and compared with those of the bare carbon nanotubes and toluidine blue coated basal plane graphite electrodes; significant improvements in both the sensitivity and stability are demonstrated when using amperometic detection. The bulk modification of the CNT has allowed for the development of an inexpensive and facile electrode design, in which the CNT are packed into a small cavity. The electrode was found to be stable and gave greatly improved signals over its toluidine blue coated graphite powder counterpart.