Green methodology for quality control of elemental content of infant milk powder

Abstract A green methodology for the direct determination of elemental content in infant milk powder samples from 0 to 3 years was developed. A portable energy dispersive X-ray fluorescence (ED-XRF) tool has been used as a direct method for the quantification of five essential elements (Ca, K, Fe, Cu and Zn). For analysis pellets from 0.8 g of each sample weight were made and analyzed. Due to the high dependence of the ED-XRF signal with the sample matrix, external calibrations using cocoa powder diluted with glucose were performed. Infant milk samples were diluted with lactose and the signals were interpolated in the external calibrations. Concentrations obtained by ED-XRF were compared with the concentration found by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) determination and those indicated in the package label of the corresponding milk samples. Direct determination by ED-XRF provides accurate results, and shows a good correlation with ICP-OES with r 2 values ranging between 0.80 till 0.95. Limits of detection (LOD) were 114, 178, 14, 0.9 and 1.7 μg/g for Ca, K, Fe, Cu and Zn, respectively, being relative standard deviation (RSD) for real milk powder sample analysis lower than 10% for most of the elements.