Fabrication of Titanium Dioxide Nanofiber Composite and Using in Modified Carbon Paste Electrode for Determination of Tryptophan in the Presence of Penicillamine and Folic acid

In this present work, we prepared a carbon paste modified electrode with 9,10-dihydroxy-7-methoxy-6H-benzofuro[3,2-c]chromen-6-one (DMC) and titanium dioxide nanofiber composite (DMC/NF/CP) as a electrochemical sensor for electrochemically sensitive and selective detection of tryptophan (Trp.) in the presence of penicillamine (PA) and folic acid (FA). The modified CPE was successfully used to determine the concentrations of Trp., PA and FA in real samples. The electron transfer rate constant, ks, and transfer coefficient, α, were calculated to be 1.88 s−1 and 0.6 respectively, by cyclic voltammetry measurements. The catalytic peak current obtained from differential pulse voltammetry (DPV was linearly towards the Trp. concentration in the range of 1.0-900.0 μM. The detection limit (3σ) for Trp. was 0.103 μM with a sensitivity of 0.128 μA μM-1.