On‐line HfF5−/WF5− separation in an O2‐filled radiofrequency quadrupole gas cell

RATIONALE An experimental Isobar Separator for Accelerator Mass Spectrometry (ISAMS) instrument has been used to demonstrate an on-line separation of HfF5− from its isobar WF5−. This is necessary, in addition to sample preparation chemistry, for measuring 182Hf at natural levels by Accelerator Mass Spectrometry (AMS). METHODS The device utilizes a radiofrequency quadrupole (RFQ) controlled gas cell, wherein anion-gas reactions at eV energies attenuate the interfering isobars of the analyte molecular anions, leaving HfF5− for AMS analysis. The RFQ also helps to control the multiple scattering resulting from the ion-gas collisions. RESULTS O2 gas was used in the HfF5−/WF5− separation and WF5− was attenuated by nearly 3 orders of magnitude while maintaining ~75% transmission of HfF5−. It is expected that the transmission and attenuation can be increased by further research. CONCLUSIONS This result advances the possibility of detecting natural 182Hf when AMS is supplemented with an isobar separator in the injection system. Copyright © 2013 John Wiley & Sons, Ltd.