Yes, chronoamperometry can be used as a pre-concentration step for the detection of heavy metal ions.

• Key parameters to set are the applied potential, deposition time, stirring rate, pH, and electrode material. Choose a potential that will reduce and deposit the target metals on the electrode surface. Allow enough time for the metals to concentrate on the surface. Faster stirring speeds help transport metals to the surface faster. Optimize the pH to get the metals into an ionic state that will deposit on the electrode. Consider electrode materials like gold, platinum, or mercury that readily pre-concentrate metals.
• For the potential step, consider values from -0.1 to -1.5 V vs Ag/AgCl reference electrode, depending on the target metal and electrode material. Deposition times can range from 30 seconds to 10 minutes. Stirring speeds of a few hundred rpm or more help the pre-concentration.
• After pre-concentration, you can transfer the electrode to a clean solution and use stripping voltammetry techniques like anodic stripping voltammetry to detect the concentrated metals. The peak currents correlate with concentrations.
• Be sure to condition the electrode surface well between measurements. Acid cleaning solutions or polishing can help remove residual metals.