Linear Sweep Potentiometry (LSP)
Linear Sweep Potentiometry (LSP) is an electrochemical technique that can be applied with the following instruments from PalmSens:
Linear Sweep Potentiometry is very similar to Linear Sweep Voltammetry, but in this case, the current is controlled, instead of the potential. It is also known as Galvanodynamic Step. A current scan is performed from the begin current, ‘i begin’, to the end current, ‘i end’. The scan is not really linear, but small current steps (‘i step’) are made. The potential is measured (sampled) during the last 25% interval period of each step. So, the number of points in the curve of the current versus potential is (i end – i begin) / E step + 1.
The scan rate is specified in current per time (i.e. µA/s), which determines the time between two steps and thus the sampling time. The interval time is ‘i step’ / ‘Scan rate’. I.e.: when ‘i step’ is 0.005 mA and the scan rate 0.1 mA/s the interval time is 0.05 s.
Measuring
As other Galvanostatic tecnhiques, The LSP is particularly useful in systems where a Reference Electrode is not possible, but the Electrochemical Surface Area is well known. As a controlled current is applied to the electrode, this ensures a stable and consistent rate of reaction, which is advantageous when dealing with complex or multi-step electrochemical reactions. Galvanodynamic experiments also allow for the determination of rate constants and reaction mechanisms directly from the current-time data, facilitating quantitative analysis. Moreover, they are less susceptible to artifacts caused by double-layer charging effects and potential drift, often encountered in potentiodynamic experiments.
In some applications, it is important that the potential does not get too high. This might ruin the working electrode. If the current at which this will occur is not known, it is possible to specify a maximum potential value at which the scan stops. In this case, the end current specified by the user may not be reached.
