Visual colorimetric sensor for nitroguanidine detection based on hydrogen bonding−induced aggregation of uric acid−functionalized gold nanoparticles

• Published in: Talanta (Oxford) 2023-08, Vol.260, p.124585-124585, Article 124585
• Main Authors: Can, Kader, Can, Ziya, Üzer, Ayşem, Apak, Reşat
• Format: Article
• Language: English
• Subjects: Gold nanoparticles aggregation; Hydrogen bonding; Nitroguanidine detection; Uric acid
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2023.124585

A colorimetric assay is proposed for the quantification of nitroguanidine (NQ), based on triggering the aggregation of uric acid−modified gold nanoparticles (AuNPs@UA) by intermolecular hydrogen bonding interaction between uric acid (UA) and NQ. The red-to-purplish blue (lavender) color change of AuNPs@UA with increasing NQ concentrations could be perceived with the naked eye or detected by UV–vis spectrophotometry. The absorbance versus concentration correlation gave a linear calibration curve in the range of 0.6–3.2 mg L−1 NQ, with a correlation coefficient of 0.9995. The detection limit of the developed method was 0.063 mg L−1, lower than those of noble metal aggregation methods in the literature. The synthesized and modified AuNPs were characterized using UV–vis spectrophotometry, scanning transmission electron microscopy (STEM), dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FTIR). Some critical parameters such as modification conditions of AuNPs, UA concentration, solvent environment, pH, and reaction time were optimized for the proposed method. The non-interference of common explosives (i.e., nitroaromatic, nitramine, nitrate ester, insensitive and inorganic explosives), common soil and groundwater ions (Na+, K+, Ca2+, Mg2+, Cu2+, Fe2+, Fe3+, Cl−, NO3−, SO42−, CO32−, PO43−) and possible interfering compounds (used as camouflage agents for explosives; D-(+)-glucose, sweeteners, acetylsalicylic acid (aspirin), household powder detergents, and paracetamol) on the proposed method was demonstrated, proving that the procedure was fairly selective for NQ, due to special hydrogen bonding interactions between UA−functionalized AuNPs and NQ. Finally, the proposed spectrophotometric method was applied to NQ−contaminated soil, and the obtained results were statistically compared with those of the liquid chromatography-tandem mass spectrometric (LC-MS/MS) method in the literature. [Display omitted] •A nanosensor based on uric acid (UA)−modified AuNPs was designed to determine NQ.•Selective intermolecular hydrogen bonding between NP−UA and NQ induced aggregation.•Nitroguanidine (NQ) sensor had lowest LOD among colorimetric methods as 0.063 mg L−1.•The AuNPs@UA were characterized using UV–vis and FTIR spectroscopy, STEM, and DLS.•Method not affected from common soil/water ions, other explosives, camouflage materials.