Without the addition of ISA, an Ion Selective Electrode would measure ion activity; addition of ISA stabilises the ionic strength and allows measurements as ion concentration. With some ISEs, the ISA solution is also used to adjust the solution’s pH or to remove any potential interference from competing ions present.
TISAB III is a concentrated ISA solution formulated for water sample analysis to provide samples and standards alike with a constant ionic strength. The solution also adjusts the pH background of the solution and complexes with various metal ions, such as aluminium and iron, which form compounds with fluoride. The ability of TISAB III ensures a total fluoride measurement can be achieved.
