2D Ti3C2Tx flakes prepared by in-situ HF etchant for simultaneous screening of carbamate pesticides

Abstract

Present work reports preparation of colloidal single/few layer Ti3C2Tx MXene flakes using minimally intensive layer delamination (MILD) method for rapid electroanalytical screening of carbamate pesticides. Lithium fluoride salt and hydrochloric acid (7.5 M LiF/9M HCl) was used to produce in-situ generated HF as etchant to remove Al successfully from Ti3AlC2 MAX phase. Unlike the clay method (5 M LiF/6M HCl), this methodology simplified Ti3C2Tx synthesis protocol resulting in Li+ ions intercalated Ti3C2Tx which was delaminated without further sonication. The delaminated Ti3C2Tx flakes were found to be single/few layered sheets with mostly –OH and –O terminated surface groups. The characteristic 002 peak observed in X-ray diffraction (XRD) at 2θ = 6.4° with interplaner distance of 1.1137 nm suggested broadening of the peak attributed to the presence of Li+ ions between Ti3C2Tx flakes. Delaminated Ti3C2Tx flakes were utilized as working electrode which demonstrated simultaneous and selective detection of carbamate pesticides methiocarb and diethofencarb by voltammetry. The oxidation peaks of the two pesticides were well separated by a potential difference of 0.35 V in 0.5 M H2SO4 and DPV detection limits were calculated as 0.19 μg mL−1 and 0.46 μg mL−1 for methiocarb and diethofencarb respectively. Ti3C2Tx flakes as electrochemical sensor exhibited long term stability and acceptable recoveries in real sample for environmental applications.