Upper-Rim Nitro and Lower-Rim Methoxy Functionalized Calix[4]arene Based Colorimetric Sensor for Detection of 2,4,6-Trinitrophenol

Abstract

The development of effective sensors capable of detecting 2,4,6-trinitrophenol (TNP), or picric acid, at extremely low levels is a very interesting field of study for prevention of environmental contamination and terrorist threats. Therefore, in this study, a colorimetric sensor ( MNC4 ) based on calix[4]arene containing a chromophore group was prepared for the detection of TNP. The photophysical interaction of MNC4 with target nitroaromatic compounds (NACs) was evaluated using UV-Vis. spectroscopy. The initial MNC4 solution was colorless, but a distinct color change was observed in the case of TNP, indicating a stronger binding affinity with MNC4. Spectral investigations also confirmed the relatively strong complexation between MNC4 and TNP. The limit of detection (LOD) value for TNP was found to be 520 nM, indicating that MNC4 can detect TNP down to the nanomolar level, which is significantly lower than the permissible level (2.2 mu M). The stoichiometric ratio of the complex formed between MNC4 and TNP was determined to be 1:2. The developed sensor enables the colorimetric detection of TNP with the naked eye without the need for any instrumentation, highlighting its potential for real-world applications.