Different techniques are used to clean SPE, depending on SPE surface type and level of contamination. The cleaning may be further divided into three types:

  1. Chemical cleaning methods (using solvents).
    • Piranha solution (owing to strong aggression, not preferred).
    • Aqua regia
  2. Thermal cleaning method:
    • UV ozone cleaning
  3. Electrochemical cleaning methods (using cyclic voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) technique)
    • KOH sweep method.
    • Potential cycling using H2SO4 or HCl.
    • CV sweeping using potassium ferricyanide.
    • Taking negative sweeping potential (using CV technique).

[Reference: 10.3390/pr10040723]