Acid diffusion in the presence of hexamethyldisiloxane (HMDS) enables complete recovery of ionic ﬂuoride fromstandards containing varying concentrations of aluminium as one of the main interfering ions. Acid diffusion withoutHMDS shows a decrease in ﬂuoride recovery as aluminium ion concentration increases. The ﬂuoride concentrationin the trapping solution is determined directly on the diffusion cover with a combination ﬂuoride electrode afterneutralising and buffering. The same procedure was used for the analysis of ﬂuoride in soil and plant materialscontaining high concentrations of aluminium ions. For the same samples, the concentrations of aluminium, iron andsilicon were determined using atomic absorption spectrophotometer (AAS). © 1997 Elsevier Science B.V.
Keywords: HMDS microdiffusion; Interfering ions; GLC