Application of Fe₃O₄-Functionalized Manganese-Metal-Organic Framework in Dispersive Solid-Phase Microextraction with Slotted Quartz Tube-Flame Atomic Absorption Spectrometry for Sensitive Determination of Cadmium in Apple Tea Samples

Abstract A straightforward methodology was presented for the preconcentration of cadmium from apple tea samples using Fe3O4-functionalized metal-organic framework (Fe3O4@Mn-MOF). The magnetic composite was produced via solvothermal method and characterized by different methods. Fe3O4@Mn-MOF nanocomposites were then employed as an adsorbent in the dispersive solid phase microextraction (DSPME) prior to the slotted quartz tube (SQT)-FAAS for trace level cadmium quantification. The variables of DSPE method were univariately optimized to enhance the quantification capability of FAAS system. Using the optimized parameters, linear working range extended from 0.10 μg L-1 to 5.0 μg L–1 with a satisfactory linearity (R2=0.9998). The detection limit was calculated as 0.07 μg L-1. The proposed Fe3O4@Mn-MOF-DSPME-FAAS method provided 147.3-fold enhancement factor based on limit of detection (EFLOD). The method was successfully applied to the determination of trace cadmium in the spiked apple tea samples with recoveries ranging from 78.1-126.6%. These findings demonstrate that the developed analytical methodology can be reliably implemened for the quantification of cadmium in the apple tea samples.