Electrochemical Impedance Spectroscopy (EIS)
Electrochemical impedance spectroscopy (EIS) is a method for the non-destructive characterisiation of thin layers, membranes, surfaces and films. Typically a small amplitude AC voltage (or current) signal is applied to a sample while the amplitude and phase relationship of the corresponding current (or voltage) signal is monitored.
For an impedance spectrum, measurements are made over several decades of AC frequency with up to about 10 measurements per decade.
The results can be mathematically modelled, typically by treating the sample as a number of sublayers each with its own electrical resistance and capacitance. In particular, the capacitance and dielectric constant of each sublayer enables the thickness of that layer to be determined.
In other experiments sample impedance can be used for quantitative readings from biosensors.
eDAQ offers Four EIS systems:
- ERZ100. This impedance system offers versatile performance at economical pricing and is suitable for many biosensor applications. (±100 mA to ±20 nA)
- Zive Potentiostat. High quality potentiostat/galvanostat/impedance system especially for electrochemistry studies of batteries, fuels cells, corrosion, and solar cells. (±1 A to ±100 nA)
- SDx-R1 tethaPod system for the determination of membrane resistance and capacitance in tethered phospholipid bilayers.