Electrochemical determination of tyrosine in the presence of uric acid at a carbon paste electrode modified with multi-walled carbon nanotubes enhanced by sodium dodecyl sulfate

چکیده مقاله

Tyrosine (Tyr) was quantitated with high sensitivity and selectivity in the presence of uric acid (UA) using a carbon paste electrode modified with multi-walled carbon nanotubes. Tyr and UA were catalytically oxidized with diffusion-controlled characteristics. They were determined simultaneously by differential pulse voltammetry with a potential difference of 350 mV. The electrocatalytic currents increase linearly with Tyr and UA concentrations 4×10 -7 -1×10 -4 M and 3×10-7 -2×10 -4 M. Their detection limits were 1×10-7 and 5.1×10 -8 M respectively. In the presence of sodium dodecyl sulfate the Tyr detection limit improved from 1×10-7 to 6.9×10 -8 M. The electrode was successfully used to quantitate Tyr and UA in serum.