We have extended our previous direct measurement of the electrochemical potential of the two-dimensional electron gas (2DEG) in GaAs/GaAlAs heterostructures relative to a reference material as a function of magnetic field using a “floating gate” technique. the analysis of the jumps in the electrochemical potential of the 2DEG indicates that there is a strongly temperature depenpendent non-zero density of states between the Landau levels. We have also observed the effect of eddy currents, induced in the 2DEG by changing magnetic field which form persistent currents in the quantum Hall regime.