Pb2+-ISEs were used to demonstrate a new multicalibrational approach which gives comprehensive information about the response of a potentiomeric sensor. The method was used to study and optimize the non-equilibrium response of sensors, such as obtained with solid-contact ISEs used in time dependent conditioning procedure with recovery of the low detection limit at lowest analyte concentrations. The developed method allows better handling of non-equilibrium conditions in quantitative determinations of analytes. The multicalibrational approach with time optimization showed to be superior when compared to fixed measurement time approach using Pb2+-ISEs at non-equilibrium in the determination of lead(II) in environmental sample. (C) 2014 Elsevier Ltd. All rights reserved.