Simultaneous voltammetric measurement of nitrite ion, dopamine, serotonin with ascorbic acid on the GRC electrode

A novel voltammetric method using a new carbon electrode has been developed for simultaneous measurement of any combination of nitrite ion (NO2-), dop amine (DA) and serotonin (5-HT) with ascorbic acid (AA). Both cyclic voltam metry (CV) and differential pulse voltammetry (DPV) were used for measureme nts of the neurotransmitters by means of a GRC (graphite reinforced by carb on) electrode in phosphate buffered saline (PBS) solution (pH 7.3). Anodic peaks of DA, 5-HT and NO2- with AA were observed at 0.17, 0.35 and 0.85 V v s Ag/AgCl on the DP voltammogram, respectively. A linear relationship was f ound between the DA concentration and the peak height on the voltammogram i n the range of 1-20 micro mol dm(-3) (mu M) DA, even in the presence of 10 mu M 5-HT, 50 mu M NO2- and 0.2 mM AA. A linear relationship was similarly found for 5-HT in the range of 1-20 mu M with 50 mu M NO2- and 0.2 mM AA, a nd it was also found for NO2- in the range of 5-200 mu M with 10 mu M DA an d 0.2 mM AA. These results showed that the method was quite effective not o nly to detect DA, 5-HT and NO2- even in the presence of AA, but also to det ermine simultaneously the concentration of each content. (C) 1999 Elsevier Science Ltd. All rights reserved.