I have a method of analysis which is used for analysis of sodium ions using flame photometry in a pesticide active ingredient. the sample preparation procedure includes addition of small volume (5 mL) of about 2% potassium chloride solution to the test item.
but it is unclear what is the potassium chloride used for in the solution.
is it used to enhance extraction of sodium ions to the aqueous phase?
(doe not make sense since ionic strength is increased and common ion effect will reduce solubility)
other reasons?
thanks in advance!