PRECONCENTRATION AND VOLTAMMETRIC DETERMINATION OF TRACE MYOGLOBIN ATA 6-MERCAPTOPURINE MODIFIED SILVER ELECTRODE

6-Mercaptopurine(G-MP) is covalently modified onto a silver electrode to construct a chemically modified electrode (CME). It exhibits the ca pability of selectively complexing myoglobin and can be applied as a s elective biosensor for this compound. Myoglobin is accumulated onto th e CME at 0.32 V (vs, SCE); after exchanging the medium it is determine d by differential pulse stripping voltammetry. A cathodic stripping pe ak is obtained at 0.15 V (vs. SCE) by scanning the potential from 0.35 to -0.1 V.The peak currents are Linearly proportional to the concentr ation of myoglobin in the range of 0.2 similar to 4 mu g/mL with a rel ative standard deviation of 7.8%. The detection limit is about 0.1 mu g/mL. The mechanism of the complexation is also discussed.