A green analytical method for the determination of Cu, Fe, Mn, and Zn in wheat flour using total reflection X-ray fluorescence

Abstract

A simple, fast, and environmentally friendly method for sample preparation and subsequent determination of Cu, Fe, Mn, and Zn in wheat flour using total reflection X-ray fluorescence (TXRF) was developed and validated. Furthermore, TXRF and two other analytical techniques currently used for elemental analysis in foodstuffs, namely flame atomic absorption spectrometry (FAAS) and electrothermal atomic absorption spectrometry (ETAAS), were compared to confirm the suitability of TXRF for routine and screening analyses of metallic elements in wheat flour. The TXRF sample preparation procedure takes around 6 min and does not require a mineralization step. Although the detection limits of the TXRF technique were higher than those of FAAS and ETAAS, they were suitable for the proposed purpose. The advantages of the proposed method are also discussed. The TXRF method was applied to the analysis of five commercial wheat flour samples representing all brands available in Montevideo, Uruguay. TXRF proved to be suitable for the determination of Cu, Fe, Mn, and Zn in wheat flour, and is a promising technique for routine and screening analyses of bakery foodstuffs.