A Simple and Rapid Analytical Method for the Determination of Nutrient and Toxic Elements in Nut-Based Milk Alternative Beverages by ICP-OES

Abstract

Plant-based drinks are non-dairy milk alternative beverages that are nowadays widely consumed across the world. Among them, nut-based milk alternative beverages such as almond drink, walnut drink, and peanut drink are gaining more and more popularity. This study presents the development and validation of an inductively coupled plasma–optical emission spectrometry (ICP-OES) method for the determination of nutrient and toxic metals elements in nut-based drinks. The determined metals were Ag, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, In, Mg, Mn, Ni, Pb, and Zn. The mineralization process of drink samples was optimized in order to achieve complete dissolution. Under optimized conditions, mineralization of 2 g of the nut-based drinks was achieved by the addition of 3 mL of nitric acid and heating at 120°C for 60 min into Teflon autoclaves. The proposed method was validated in terms of linearity, accuracy, precision, limits of detection (LODs), and limits of quantification (LOQs). The relative standard deviations (RSD%) for all elements were 0.4–10.8%, and the relative recovery values (RR%) were 90.0–109.7%, demonstrating that the method offered good precision and accuracy. The LODs for the determined elements were found to be 0.03–1.08 mg kg−1, while the LOQs were found to be 0.10–3.23 mg kg−1. The developed method was successfully employed for the analysis of different commercial nut-based drinks (e.g., almond-based drinks, walnut-based drinks, peanut-based drinks etc.) obtained from the local market.