Bifunctional Amine- and Thiol-Modified Ti 3 C 2 T x MXene for Trace Detection of Heavy Metals.

Surface functionalization of two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides, also known as MXenes, is a powerful approach for modification of their physical and chemical properties for new applications. In this study, we demonstrate the synthesis of a bifunctional Ti 3 C 2 T x MXene modified with amine and thiol groups through a facile condensation reaction. We successfully employed the resulting NH 2 /SH-Ti 3 C 2 T x MXene as a solid phase in the ultrasonic-assisted dispersive micro solid-phase extraction (d-μ-SPE) method for the analytical determination of heavy metals at trace levels in food and soil samples. The prepared NH 2 /SH-Ti 3 C 2 T x MXene showed remarkable performance in the ultrasonic-assisted d-μ-SPE method with limits of detection of 0.12 and 2.30 ng mL -1 , with linear dynamic ranges of 0.50-90 μg L -1 and 10-120 μg L -1 for cadmium (Cd 2+ ) and lead (Pb 2+ ) ions, respectively. Furthermore, the extraction efficiencies were greater than 97%, with a relative standard deviation of less than 3% for five separate batch experiments in the determination of 5.0 μg L -1 of Cd 2+ and Pb 2+ . This study shows that NH 2 /SH-Ti 3 C 2 T x can be used as a simple, rapid, reliable, selective, and sensitive material in the d-μ-SPE method for the trace determination of Cd 2+ and Pb 2+ in soil and agricultural products. This study demonstrates the utility of MXenes for analytical chemistry and suggests that further advances in methods for the functionalization of MXenes can open new applications for these already exciting materials.