Amine-functionalized diatom frustules: a platform for specific and sensitive detection of nitroaromatic explosive derivative

• Published in: Environmental science and pollution research international 2018-07, Vol.25 (21), p.20540-20549
• Main Authors: Selvaraj, Viji, Thomas, Neethi, Anthuvan, Allen Joseph, Nagamony, Ponpandian, Chinnuswamy, Viswanathan
• Format: Article
• Language: English
• Subjects: Amines - chemistry; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Chromatography; Complex formation; Detection; Diatoms - chemistry; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Explosive Agents - chemistry; Explosives detection; Field emission microscopy; Fourier transforms; Infrared spectroscopy; Limit of Detection; Luminescence; Nanostructures - chemistry; Photochemical Processes; Photoluminescence; Photons; Plankton; Porous materials; Quantum dots; Quenching; Scanning electron microscopy; Sensitivity analysis; Sensors; Silica; Silicon dioxide; Silicon Dioxide - chemistry; Spectroscopy, Fourier Transform Infrared; Spectrum analysis; Voltammetry; Warfare; Waste Water Technology; Water Management; Water Pollution Control; Water: From Pollution to Purification
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-017-0916-z

In the present study, an attempt was made to develop a proof of concept for the detection of nitroaromatic explosive derivatives through the photoluminescence (PL) quenching process using functionalized diatom frustules as a sensing platform. The diatom frustules are composed of nanostructured, highly porous biogenic silica material and emit strong, visible blue PL upon UV excitation. PL-active biosilica was isolated from the marine diatom Nitzschia sp. and was amine-functionalized to develop a sensing platform. Functionalized diatom frustules were further characterized using field emission scanning electron microscope and a series of spectroscopic methods. When nitroaromatic compounds were bound to the functionalized diatom frustules biosilica, the PL intensity from the functionalized biosilica was partially quenched due to the electrophilic nature of the nitro (–NO) groups. The quenching process confirmed the Meisenheimer complex formation and was investigated by using Fourier transform infrared spectroscopy and time-resolved photoluminescence studies. The developed platform was further evaluated for its sensitivity and specificity, and the limit of detection (LOD) of the assay was determined as 1 μM for a series of nitroaromatic explosive compounds. In conclusion, the developed sensing platform will have great utility in the development of on-site detection platforms for sensitive detection of warfare explosive nitroaromatic compounds from the environment.