Determination of isatin and monoamine neurotransmitters in rat brain with liquid chromatography using palladium hexacyanoferrate modified electrode

The fabrication and application of a novel electrochemical detector (ED) with palladium hexacyanoferrate (PdHCF) chemically modified electrode (CME) for liquid chromatography (LC) were described. The electrochemical behaviors of isatin, monoamine neurotransmitters and their metabolites at this CME were investigated by cyclic voltammetry. It was found that the CME exhibited efficiently electrocatalytic of isatin and showed high sensitivity and stability for determination of monoamine neurotransmitters. The linear ranges were over three orders of magnitude and the detection limits were 2.5 × 10−8 mol L−1 for isatin, 2.5 × 10−10 mol L−1 for norepinephrine (NE), 2.5 × 10−10 mol L−1 for 5-hydroxyindoleacetic acid (5-HIAA), 5.0 × 10−10 mol L−1 for dopamine (DA), 1.0 × 10−9 mol L−1 for 3,4-dihydroxyphenylacetic acid (DOPAC), 1.2 × 10−10 mol L−1 for 5-hydroxytryptamine (5-HT) and 2.5 × 10−9 mol L−1 for homovanillic acid (HVA). Combined with microdialysis, the method was successfully applied to study the effect of isatin on the levels of monoamine neurotransmitters in experimental Parkinsonian rats. The results showed that isatin could significantly increase striatal monoamine neurotransmitters release to the basal level.