HPLC with electrochemical detector

[sofiane]

hello
I had a topic about electrochemical detection but anyanswers
now can you tell me about the mode used in EC detection: DC, PAD and SCAN modes
in whitch case we use each one
the difference between them

how to construct a voltammogram: steps and method
thank you

[Markus Laeubli, Metrohm]

Dear sofiane

DC = direct current is the basic version where a stable potention is applied to the electrodes. The measured current is proportional to the concentration of the analyte. Some reaction products my poison the electrode surface. In this case

PAD = Pulsed Amperometric Detection is applied. Here an oxidative and a reductive potential is applied after the analytical potention to renew the electrode surface.

Scan Mode: A potential scan is done to get the optimum working potential.

See also 871 Bioscan Manual.