Ti3C2@Pd nanocatalytic amplification-polypeptide SERS/RRS/Abs trimode biosensoring platformfor ultratrace trinitrotoluene

A new MXene supported Pd nanoparticles (Ti3C2@Pd) nanosol with good stability and strong catalysis was prepared by the two-step procedure. Experiment was found that Ti3C2@Pd could strongly catalyze the reduction of HAuCl4 by H2O2 to produce gold nanoparticles (AuNPs), with strong surface enhanced Raman scattering (SERS), resonance Rayleigh scattering (RRS) and surface plasmon resonance absorption (Abs). Coupled this new SERS/RRS/Abs trimode nanocatalytic indicator reaction with specific TNT polypeptide (PTTNT), a facile and selective trimode polypeptide biosensoring platform was established for the detection of ultratrace TNT, with a linear range of 1.1–66, 1.1–66 and 4.4–66 pmol/L TNT, and detection limit (DL) of 0.69, 0.97 and 3.36 pmol/L by SERS, RRS and Abs assay respectively. It has been used to detect TNT in wastewater and soil samples, with recovery of 98.7–106% and RSD of 6.22–8.77%. In addition, this biosensoring platform can be also used to assay glyphosate and estradiol, respectively.