Fast Sequential Determination of Zn, Fe, Mg, Ca, Na, and K in Infant Formulas by High-Resolution Continuum Source Flame Atomic Absorption Spectrometry Using Ultrasound-Assisted Extraction

In this work, an analytical procedure based on ultrasound-assisted extraction (UAE) was developed for the fast sequential determination of six elements (Zn, Fe, Mg, Ca, Na, and K) in infant formulas using high-resolution continuum source flame atomic absorption spectrometry (HR-CS F AAS). The analytes extraction was performed using HNO3 2.1 mol L−1 and 10 min of sonication time at 80 °C. The limits of detection obtained were 12, 13, 0.48, 96, 137, and 14 mg kg−1 for Zn, Fe, Mg, Ca, Na, and K, respectively. The analysis of a certified reference material of non-fat milk powder (SRM 1549) and infant formula samples after microwave digestion confirmed the trueness of the developed method. Thus, the UAE procedure was employed in order to determine these six elements and their concentration in six infant formulas and their content (in mg kg−1) ranged between 64 and 431 for Zn, 64–370 for Fe, 420–2421 for Mg, 1145–8547 for Na, 750–14,491 for K, and 2827–11,340 for Ca.