Functionalized Fluorescent Nanodots for Discrimination of Nitroaromatic Compounds

Abstract

Multiplexing the sensor array can save the time and sensor elements in detection of various unknowns. However, sometimes, that method compromises the sensitivity of a sensor system. Alternatively, a sequential on−off strategy can be applied in a sensor array to enhance the sensitivity. In this strategy, instead of separating individual sensor elements, sequential addition of quenching and masking agents to the pre-established sensor array can enhance the signal output information, sensitivity, and classification accuracy. Herein, three different quantum dots, that is, gold nanoclusters (AuNCs), MoS 2 quantum dots (MQD) and WS 2 quantum dots (WQD) were used as fluorescent receptors for the sensing of nitroaromatic compounds. These electron-rich quantum dots with versatile surface property provide an array based on the quenching efficiency of nitroaromatic compounds. By using standard array-based sensing, we were not able to classify a large number of nitroaromatic compounds, whereas 100% classification was achieved by employing the suitable surface functionality and sequential on−off strategy. Furthermore, we have studied the mechanism of sequential sensing. According to the optical study, the primary inner-filter effect plays an important role in the quenching of fluorescence intensity of quantum dots. Fluorescence lifetime measurement suggests that AuNCs exhibit the dynamic mode of quenching and transition-metal dichalcogenide quantum dots (MQD and WQD) exhibit the static mode of quenching. This developed methodology can be extended to sensing of other analytes.

Advances in Optical Sensors for Persistent Organic Pollutant Environmental Monitoring

“…Concerning the possibility to QDs as sensing elements in multisensorial platforms, De et al [ 109 ] recently investigated the potentialities of functionalized QDs to detect, recognize, and quantify nitroaromatic compounds in aqueous media by fluorescence quenching/recovery protocol. In the paper, the authors did not produce a real sensor array but rather investigated the three fluorophores separately, and in a second stage, they combined the responses to perform multivariate data analysis such as LDA.…”

“…The histograms report both Jackknifed classification accuracy and unknown detection accuracy. Image is rearranged from Figures 1, 5 and 6 of [ 109 ].…”

Cell-Based Chemical Safety Assessment and Therapeutic Discovery Using Array-Based Sensors

“…Array-based sensing systems can be created by using a wide range of synthetic elements [ 28 , 29 , 30 , 31 ]. Nanoparticles are one of the most commonly used sources for sensor array fabrication due to their ease of functionalization and large surface areas, providing surfaces for biomolecular recognition [ 32 , 33 , 34 ]. In addition, metallic nanoparticles are excellent fluorescent quenchers, providing distinguishable fluorescent signatures with a higher sensitivity that facilitates transduction [ 35 ].…”

A March to Shape Optical Artificial Olfactory System toward Ultrasensitive Detection of Improvised Explosives

“…Reproduced with permission. [ 142 ] Copyright 2020, American Chemical Society. f) HCA dendrogram of TATP and HMTD tested at the bulk sample size of 10 mg and a control out of 65 trials.…”