Fig. 5.

Noise monitoring. A microelectrode loaded with K⁺ selective ionophore was submerged in a solution containing 500 μM K⁺ and, after a stable signal was achieved, it was left to measure during 120 min at a frequency of 300 samples s⁻¹ and an averaging of 200 samples, Tre results showed an average voltage of −160.09 ± 0.04 mV and a drift of 20 μV h⁻¹ (see Table 3).