A novel yet simple, rapid and robust thermometric endpoint titration (TET)
method for the determination of sodium in various foodstuffs is described. Sodium
reacts exothermically with aluminium in the presence of an excess of potassium and fluoride ions to form NaK2AlF6 (“elpasolite”).
This reaction forms the basis of a ro- bust, reliable analytical procedure
suitable for routine process control. The reaction of calcium under similar conditions
(to form KCaAlF6) suggests that potentially, calcium may interfere
in the determination of sodium in some foodstuffs. Results of an investigation
suggest that at molar ratios [Ca]/[Na] < 0.85, an error of <1% of the
measured value of sodium is incurred.