Determination of potassium by the use of new calibration approach in potentiometric measurements

摘要

The implementation of a new calibration approach, termed the Signal Increment Standard Addition Method (SI-SAM), to the potentiometric determination of potassium in the synthetic samples and certified reference materials, is investigated. SI-SAM is a modification of SAM that is based on the change in the way in which the extrapolation is carried out. The calibration graph is extrapolated to the intersection with the signal of the first standard solution, not to the abscissa. Potentiometry is the method of choice due to its simplicity, rapid measurements, wide linear range and fulfilment of green analytical principles. However, careful attention is required to the calibration procedure because various versions of the standard addition method, which are commonly used in potentiometry, may create some problems leading to serious systematic analytical errors. The present work proves that SI-SAM allows for the elimination of this drawback and, consequently, for the determination of the considered analyte with improved results, especially in terms of accuracy and precision.