Sampled DC Stripping Voltammetry

Introduction

This is an extension of the Sampled DC Voltammetry technique. It works identically to Sampled DC Voltammetry except it includes an “accumulation” step.

In the accumulation step, analytes are plated or otherwise accumulated on the electrode. Typically the accumulation is done for tens or hundreds of seconds. The accumulated material is then removed (stripped) from the electrode quickly. Accumulating analyte on the electrode increases the mass of material available for the electrochemical reaction. Currents are higher, so the level of detection falls dramatically. In some systems, Sampled DC Stripping Voltammetry can achieve sensitivity in the parts-per-trillion range.

Setup

The setup for Sampled DC Stripping Voltammetry adds one input parameter to the setup for Sampled DC Voltammetry. The new parameter is Accumulation Time. Enter a value in seconds. The working-electrode potential is held at the Initial E for the time specified.

NOTE: The accumulation phase of the test is done at the Initial Voltage. In a typical stripping voltammetry test this is a voltage where analytes plate onto the electrode surface. You therefore must choose an Initial E where this will occur.

NOTE: The accumulation phase must have reproducible transport of the analyte to the electrode surface. We strongly recommend stirring whenever the accumulation time is greater than 3 s. If you do not stir, random vibration in the lab environment will lead to very poor run-to-run reproducibility. Most electrochemical cells can be used with a magnetic stirrer and a stir bar in the electrolyte.

You can plot and analyze the data files from this test with Gamry’s Echem Analyst™.