Development of a novel electrochemical sensor based on cobalt(II) complex useful in the detection of dopamine in presence of ascorbic acid and uric acid

- Dopamine could be determined in human urine sample.
- Cobalt complex improved sensitivity.
- The modified electrode showed good reproducibility.
- Ascorbic acid and uric acid not produce significant interference.
- The samples needed no pre-treatment.

[(Co(bdmpzm)2(NCS)2] (bdmpzm = bis(3,5-dimethylpyrazol-1-yl)methane) was synthesized and combined with single walled carbon nanotubes (SWCNT) and nafion on a screen printed carbon electrode (SPCE). The electrocatalytic activity of modified electrode (Nafion-SWCNT-[Co(bdmpzm)2(NCS)2]/SPCE) was evaluated for dopamine (DA) oxidation. Anodic and cathodic peak were seen to 0.42 V.and0.29 V respectively, showed a much more quasi-reversible process, (∆ V 0.128) compared with the electrode without cobalt complex. The detection limit (3σ/b) for dopamine was 0.095 μmol L− 1. The studies of reproducibility determined as relative standard deviation (RSD) was 2.5%.(n = 5) with four different electrodes. The repeatability were 1.5% (n = 5) The new sensor was used in the quantify DA in human urine with an average recovery between 83.0 and 93.0%.