Tris (2,2 '-bipyridil) copper (II) chloride complex: a biomimetic tyrosinase catalyst in the amperometric sensor construction

The use of tris (2,2'-bipyridil) copper (II) chloride complex, [Cu(biPY)(3)]Cl(2)(.)6H(2)O, as a biornimetic catalyst, is reported in the construction of an amperometric sensor for dopamine. The sensor was prepared modifying a glassy carbon electrode with a Nafion(R) membrane doped with the complex. The optimized conditions for the sensor response were obtained in 0.25 mol dm(-3) Pipes buffer (pH 7.0) containing 150 mumol dm(-3) H2O2, with an applied potential of -50 mV versus saturated calomel electrode (SCE). In these conditions, a linear response range between 9 and 230 mumol dm(-3), with a sensitivity of 1.43 +/- 0.01 nA dm(3) mumol(-1) cm(-2) and a detection limit of 4.8 mumol dm(-3) were observed for dopamine. The response time for this sensor was about Is, presenting the same response for at least 150 successive measurements, with a good repeatability (4.8%) expressed as relative standard deviation for n = 13. After its construction, this sensor can be used after 180 days without loss of sensitivity, kept at room temperature. The difference of the sensor response between four preparations was 4.2%. A detailed investigation about the sensor response for other eighteen phenolic compounds and five interfering species was performed. The sensor was applied for dopamine determination in pharmaceutical preparation with success. (C) 2002 Elsevier Science Ltd. All rights reserved.48785586