Selective fluorescence response and magnetic separation probe for 2,4,6-trinitrotoluene based on iron oxide magnetic nanoparticles

Abstract

Despite the rapid development of nanomaterials and nanotechnology, it is still desirable to develop novel nanoparticle-based techniques which are cost-effective, timesaving, and environment-friendly, and with ease of operation and procedural simplicity, for assay of target analytes. In the work discussed in this paper, the dye fluorescein isothiocyanate (FITC) was conjugated to 1,6-hexanediamine (HDA)-capped iron oxide magnetic nanoparticles (FITC-HDA Fe3O4 MNPs), and the product was characterized. HDA ligands on the surface of Fe3O4 MNPs can bind 2,4,6-trinitrotoluene (TNT) to form TNT anions by acid-base pairing interaction. Formation of TNT anions, and captured TNT substantially affect the emission of FITC on the surface of the Fe3O4 MNPs, resulting in quenching of the fluorescence at 519 nm. A novel FITC-HDA Fe3O4 MNPs-based probe featuring chemosensing and magnetic separation has therefore been constructed. i.e. FITC-HDA Fe3O4 MNPs had a highly selective fluorescence response and enabled magnetic separation of TNT from other nitroaromatic compounds by quenching of the emission of FITC and capture of TNT in aqueous solution. Very good linearity was observed for TNT concentrations in the range 0.05-1.5 μmol L(-1), with a detection limit of 37.2 nmol L(-1) and RSD of 4.7 % (n = 7). Approximately 12 % of the total amount of TNT was captured. The proposed methods are well-suited to trace detection and capture of TNT in aqueous solution.

The mechanism of 2,4,6-trinitrotoluene detection with amino acid-capped quantum dots: a density functional theory study

“…3 displays the optical absorption spectra of S1, S2 and their combination at a 1 : 1 ratio. The superposition of the spectra of S1 and S2 comes to a curve, which is very close to the observed one 15,50,51,63 in band locations and shapes. The two bands at 447 nm and 506 nm are in accordance with the observed ones 15,50 at about 465 nm and 515 nm.…”

“…As IR and Raman spectra had been used to characterize the existence of either the Meisenheimer complex or TNT anion in a TNT-amino-QD solution, 26,43,51,63 we computed the vibrational spectra with IR and Raman intensities of S1 and S2 at the M06-2X/6-311++G(d,p) level and compared them with the measurements. Fig.…”

Fluorescence based explosive detection: from mechanisms to sensory materials

“…4.1.3 Other small organic fluorophores. Besides the above discussed small organic fluorophores, some other new small fluorophores have also been reported in explosive detection such as quinoline, 146,147 fluorescein, 148 rhodamine, 149 squaraine dye, 47 For example, Xu's group employed the ICT mechanism and found that DNSA-SQ could sense picric acid sensitively and selectively via a fluorescence turn-on signal in the near-infrared region (Fig. 11A).…”

A facile one-step photochemical strategy for preparation of polyacrylamide functionalized CdTe(S) quantum dots and their application in sensitive determination of 2,4,6-trinitrotoluene

“…Because of the three nitro groups in the TNT molecule, the aromatic ring of TNT is severely electron-deficient, it interacts readily with electron-rich molecules to form a complex. Other analogs of TNT with less nitro groups on the aromatic ring have much weaker interaction [45]. The proposed method exhibited good selectivity and reliability as supported by the standard addition in real samples, which is described in the following section.…”