Determination of essential elements in beverages, herbal infusions and dietary supplements using a new straightforward sequential approach based on flame atomic absorption spectrometry

- We developed a simple FAAS method to determine essential elements in food products.
- Multi-element determination was performed using a unique sample solution.
- Less than 3.5 mL of sample were necessary to determine in triplicate five elements.
- An accurate and precise determination of Si was performed using this FAAS methodology.
- Commercial beverages, infusions and dietary supplements were successfully analyzed.

A simple method based on FAAS was developed for the sequential multi-element determination of Cu, Zn, Mn, Mg and Si in beverages and food supplements with successful results. The main absorption lines for Cu, Zn and Si and secondary lines for Mn and Mg were selected to carry out the measurements. The sample introduction was performed using a flow injection system. Using the choice of the absorption line wings, the upper limit of the linear range increased up to 110 mg L−1 for Mg, 200 mg L−1 for Si and 13 mg L−1 for Zn. The determination of the five elements was carried out, in triplicate, without the need of additional sample dilutions and/or re-measurements, using less than 3.5 mL of sample to perform the complete analysis. The LODs were 0.008 mg L−1 for Cu, 0.017 mg L−1 for Zn, 0.011 mg L−1 for Mn, 0.16 mg L−1 for Si and 0.11 mg L−1 for Mg.