A sensitive bromide determination has been developed that consists of the following steps: isolation (purification) of bromide; oxidation of bromide to bromine with potassium permanganate and subsequent reaction with acetone, to give the volatile bromoacetone; quantification of bromoacetone by capillary gas chromatography. The method can also be used with small sample volumes appropriate for paediatric applications. Thermodynamic arguments are used to calculate the equilibria involved. The accuracy and reproducibility of the method have been determined. Finally, the bromide space of six volunteers was determined and the clearance of the bromide by the kidneys was investigated.