With an electrochemical detector like the AZURA ECD 2.1, several different modes can be run.
PAD means "Pulsed Amperometric Detection" and describes the detetion mode that is used in electrochemical detection of carbohydrates for example.
It is characterized by a Multi-Step potential waveform and is used to detect hard to oxidize compounds. As a working electrode, catalytic materials like gold or platinum have to be used.
Process of PAD:
Reactant is absorbed onto oxide-free Au surface
Followed by either oxidation
Or reactant remains on surface (fouling)
Any surface oxide inhibits detection
-> Pulsed potential required to continuously clean and regenerate an oxide-free Au surface
For an overview of different pulsed potential waveform program, please read the following FAQ.