Highly sensitive detection of trinitrotoluene in water by chemiresistive sensor based on noncovalently amino functionalized single-walled carbon nanotube

We developed a chemiresistive sensor based on 1-pyrenemethylamine (PMA) functionalized single-walled carbon nanotube (SWCNT) networks for highly sensitive and rapid detection of 2,4,6-trinitrotoluene in water. In this sensor, the SWCNT network was deposited between interdigitated electrodes, and the functional PMA molecule was noncovalently attached to the sidewall of the SWCNTs via π–π interaction. The amino substituent of PMA could selectively interact with 2,4,6-trinitrotoluene to form negative charged complexes on the SWCNT surface. These charged complexes can act as effective molecular gate and strongly change the electrical conductance of the SWCNTs, enabling the sensors easily to detect 2,4,6-trinitrotoluene at 10 parts-per-trillion (ppt) concentration in aqueous solutions, with the response time of less than 1 min, without the need of pre-concentration of the analytes. The functionalized sensors also show excellent selectivity toward 2,4,6-trinitrotoluene over those interfering organic molecules.