Understanding of the mechanism of potential development on each of the interfaces allows to adjust the design and measurement protocol and push the limits of analytical parameters of the sensors. Properly selected composition of the liquid internal solution allows lowering the detection limit from micro-to sub-nanomolar range , and provides more precise means of estimation of selectivity coefficients . The internal solution can be optimized by adding chelators such as EDTA or NTA , an ion-exchanging resin , complexing agents , or lipophilic interfering ion with a salt of the analyte, which all influence the magnitude of transmembrane ion flux.