Tantalum-modified graphite furnace as a novel approach for total fluorine determination and indirect PFAS analysis by HR-CS-MAS

Abstract

Fluorine is vital to the environment and biological systems. However, given the limited analytical capabilities of the instrumental techniques currently available, there is a need for the development of novel methodological approaches for its determination. It has recently been demonstrated that there is significant potential in applying high resolution continuum source molecular absorption spectrometry (HR-CS-MAS). In this approach, optimal analytical parameters for fluorine determination can be achieved by monitoring molecular absorption of monofluorides formed in the presence of a mixture of modifiers, in which monofluoride forming elements and stabilizing substances are essential. One potential alternative to the “modifier cocktail” is the use of tantalum foil inserted into the atomizer to cover the graphite surface. However, given the limited thermomechanical strength of the tantalum foil, this study examined the possibility of applying tantalum(V) ethoxide solution to direct the modification of the graphite surface. The objective of this study was to develop a simplified protocol with enhanced analytical parameters for fluorine determination. The morphology and chemical composition of the graphite surface were investigated using surface techniques (TOF-SIMS and LA-ICP-MS). The analytical performance of the proposed approach for fluorine determination was evaluated and compared with previously reported methods. The optimized time-temperature programme was used to determine the fluorine content in groundwater, and the protocol, which had been elaborated, was applied to analyze fluorine in PFAS.