Preparation of carbonaceous materials and investigation of their nanobiosensor properties

The novel carbonized electrode materials were prepared from pyrolysis of cane tassel (Phragmites communis, CT) and coal tar pitch (CTP) composite (m% for CT: 1%, 3%, 5% and 10%). The carbonized materials were denoted as CTP-CT1, CTP-CT2, CTP-CT3 and CTP-CT4. The materials were characterized with spectroscopic, electrochemical, microscopic and optical techniques. The carbonaceous materials were covered on pencil electrode (PE) surface. The sensitive PE/CTP-CT2 electrode was used in the determination of dopamine (DA), uric acid (UA) and Folic acid (FA) by differential pulse voltammetry (DPV). The linear equations for DA, UA, and FA were Ip(DA)= 1.8595[DA]+ 3.6875 (R2:0.9913), Ip(UA)= 1.1149 [UA]+ 0.9032 (R2:0.9867), and Ip(FA)= 1.6625 [UA]+ 2.4318 (R2:0.9915), respectively, with the linear range of 1 M to 20 M for DA, 2 M to 20 M for UA and 1 M to 18 M for FA. The detection limits (S/N=3) for DA, UA and FA are 0.01 M, 0.04 M and 0.02 M, respectively. Precision and accuracy results of the method were studied. The method was applied to urine sample. Analytical recovery of DA, UA and FA added to urine samples was calculated as ≤ 104.5%. The influences of some ions and important biological molecules on the peak currents of 1 μM UA, DA and FA, in 0.1 M PBS (pH 7.0) were studied. The values of signal change are approximately 4.06% and -3.37%. In conclusion, it is not an important factor of interference effect of these molecules and ions in the selected concentrations