Total reflection x-ray fluorescence spectroscopy as a tool for evaluation of iron concentration in ferrofluids and yeast samples

• Ferrofluids and yeasts samples were analysed by TXRF spectroscopy.
• Simple protocol for iron quantification by means of TXRF was proposed.
• Results were combined with magnetic, structural, and morphological characterization.
• Preliminary conclusion on nanoparticles uptake mechanism was made.

In this study, total reflection x-ray fluorescent (TXRF) spectrometry was applied for the evaluation of iron concentration in ferrofluids and biological samples containing iron oxide magnetic nanoparticles obtained by the laser target evaporation technique. Suspensions of maghemite nanoparticles of different concentrations were used to estimate the limitation of the method for the evaluation of nanoparticle concentration in the range of 1–5000 ppm in absence of organic matrix. Samples of single-cell yeasts grown in the nutrient media containing maghemite nanoparticles were used to study the nanoparticle absorption mechanism. The obtained results were analyzed in terms of applicability of TXRF for quantitative analysis in a wide range of iron oxide nanoparticle concentrations for biological samples and ferrofluids with a simple established protocol of specimen preparation.