Development of deep eutectic solvent extraction method for extraction of Zn2+ from powdered milk and baby formula samples and its determination by ICP-OES

In the present study, the deep eutectic solvent-based extraction method has been developed for separation of Zn prior to ICP-OES analysis. Five different choline chloride-based deep eutectic solvents were prepared. The Zn extraction ability of DESs from milk powder and baby formulation samples which contain a high amount of milk protein was investigated. The parameters affecting the extraction efficiency such as the amount and type of solvent, extraction time and ambient temperature were optimized. Oxalic acid-based DES gave the highest yield and reproducible results and appropriate preparation criteria. It is concluded from the results that DES-oxalic can quantitatively extract Zn from milky samples. The analytical parameters such as linear calibration range, limit of detection (4.2 mu g L-1) and quantification (14.1 mu g L-1) were also calculated. The added-found method is successfully applied to ERM BD 150 standard reference material, and the recovery values and standard deviation values were found between the ranges of 79.4-97.21 mu g L-1 and 4.1-6.31 mu g L-1, respectively. The method was also applied to real samples, and the recovery values were found between 73 and 106% in the spiked samples.