The electrode array detector also gives improved apparent chromatographic resolution in a similar way to that of the diode array detector. Two peaks that have not been chromatographically resolved and are eluted together can still be shown as two peaks that are resolved electrochemically and can be  quantitatively estimated. Another advantage is that high oxidation potentials can be used without the high background currents and noise that usually accompany such operating conditions. The electrodes that are operating at high voltages are "buffered" by the previous electrodes operating at lower voltages which results in reduced background currents and noise.

Another example of the application of the detector to the separation of a number of neuroactive substances (54)is shown in figure 63. It is seen that for certain applications the electrochemical array detector can be extremely useful.

Mobile Phase 1% Methanol to 40% Methanol in a Phosphate (0.1 mol l-1 buffer with ion pairing (pH 3.4)


1.   Dihydroxyphenylacetic acid 16. Metenephrine
2.   Dihydroxyphenylethylene glycol 17. Methoxyhydroxyphenyl glycol
3.   L-Dopa 18. Methoxytyramine
4.   Dopamine 19. N-methylserotonin
5.   Epinephrine 20. Norepinephrim
6.   Guanine 21. Normetenephrine
7.   Guanosine 22. Salsolinol
8.   Homovanallic acid 23. Octopamine
9.   Hydroxybenzoic acid 24. Seratomin
10. Hydroxyindoleacetic acid 25. Tryptophan
11. Hydroxyphenylacetic acid 26. Tyrosine
12. Hydroxyphenyllactic acid 27. Uric Acid
13. Hydroxytryptophan 28. Vanillic acid
14. Kynurenine 29. Vanylmandelic acid
15. Melatonin 30. Xanthine


Courtesy of the Analyst.


Figure 11 The Separation of 30 Neuroactive Substances Monitored by an Electrochemical Array

 Nevertheless, in order to use the detector, the solutes must be amenable to electrochemical reaction and capable of being separated using a mobile phase that will conduct an ion current