Novel non-target analysis of fluorine compounds using ICPMS/MS and HPLC-ICPMS/MS

Abstract

Measuring sub-ppm levels of fluorine (F) directly with a commercial ICPMS is not possible due to the high ionisation potential of F. Mixing of barium and fluorine solutions enabled a new approach in fluorine analysis through the formation of the polyatomic ion BaF⁺ using ICPMS/MS. Different parameters such as reaction gas flow rate, sampling position, nebuliser and makeup gas flow rate, waiting and acquisition time as well as RF power were optimized in order to obtain the highest possible sensitivities for ¹³⁸Ba¹⁹F⁺, as these parameters were important for polyatomic ion formation, avoiding barium oxide and barium hydroxide ion interference and sensitive detection in MS/MS. A limit of detection (LOD) of 0.043 mg L⁻¹ was achieved with a good recovery of fluoride spiked in deionised water. For fluorine speciation analysis, coupling of anion exchange chromatography online with ICPMS/MS allowed separation and fluorine specific detection of fluoride and fluoroacetate. The response was compound independent as expected for ICPMS. The LODs of fluoride and fluoroacetate were 0.022 mg L⁻¹ and 0.11 mg L⁻¹, respectively. Both compounds were baseline separated and detected quantitatively, making this newly developed method a promising candidate for non-target fluorine speciation analysis in environmental samples.