DETERMINATION OF IODIDE IN SERUM AND URINE BY ION-PAIR REVERSED-PHASEHIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH COULOMETRIC DETECTION

An HPLC method is described for the determination of iodide in serum a nd urine using ion-pair chromatography with coulometric detection, Aft er adding hexadecyltrimethylammonium chloride, the ions pairs formed w ith the iodide in the sample are extracted using an organic solvent. T he solvent is then evaporated and the dry residue obtained is mixed wi th an appropriate volume of mobile phase so as to concentrate the samp le prior to injection into the chromatograph. For a sample of 0.5 mi o f serum, the method features a limit of detection (signal-to-noise rat io of 3) of 0.2 mu gl(-1), sufficient to be applied in paediatric assa ys for the diagnosis of both iodide deficiency and excess.