Determination of Cl, Br, and I in Geological Materials by Sector Field Inductively Coupled Plasma Mass Spectrometry

In this study, a simple and effective method for the simultaneous analysis of Cl, Br, and I in geological materials based on NH4HF2 digestion in open vessels (Savillex Teflon vials) is proposed. It is very interesting to note that Cl, Br, and I are not lost during NH4HF2 digestion at temperatures of 200–240 °C for 0.5–12 h in open vessels. This should be related to the alkaline atmosphere environment caused by the NH3 produced during NH4HF2 digestion, which suppresses the volatilization loss of Cl, Br, and I. A 100 mg sample of geological materials can be completely digested by using 400 mg of NH4HF2 at 220 °C for 2 h in Savillex Teflon vials. The use of new Savillex Teflon vials significantly reduced the procedural blanks of halogens compared with the old Savillex Teflon vials. The developed method was successfully applied to the simultaneous determination of Cl, Br, and I in a series of international geological reference materials. Most of the results were found to be in reasonable agreement with values reported in the literature. This simple, rapid, effective, and economical analytical method will significantly promote the development of halogen geochemistry.