The importance of Si determination has risen with the increased production of silanes, siloxanes, and silicones, alongside stricter requirements from environmental and health agencies. Consequently, the need to monitor Si in ultra-trace amounts has also grown. Si determination plays a crucial role in identifying the presence of such compounds in solutions and providing quantitative data.

However, analyzing Si is not a trivial task. Si is one of the most ubiquitous elements on Earth and is a common contaminant introduced by most glassware. For ICP-based methods that utilize conventional quartz torches, Si background levels hinder achieving low detection limits. As a result, many methods have detection limits in the mg$\cdot$L$^{−1}$ to μg$\cdot$L$^{−1}$ range.

In this study, to comply with the maximum permitted levels for Si absorption through food and dietary supplements, it was necessary to determine Si in the very low μg$\cdot$L$^{−1}$ to high ng$\cdot$L$^{−1}$ range. In lieu of specialized, Si-free instrumentation, we developed a graphite furnace-atomic absorption spectroscopy method for determining ultra-trace amounts of Si in food simulants, ethanol, and acetic acid.

Upon establishment, the method was validated according to FDA guidelines. The validation acceptance criteria were met, achieving Si quantification limits of 0.2 μg$\cdot$L$^{−1}$ for ethanol and 0.4 μg$\cdot$L$^{−1}$ for acetic acid. The newly developed method has since been used to determine ultra-trace levels of Si in food contact simulants and polymer gels.