Tripodal pyridyl-imine capped gold nano-aggregates for selective detection of picric acid in aqueous media

Highlights: • Pyridyl-imine capped gold nano-aggregates (AuONPs) have been developed. • The developed AuONPs were successfully used for quantifying Picric Acid in aqueous medium. • Exhibits remarkable low detection limit within nano-molar concentration (15 nM) based on 3σ/K. • The developed fluorescence sensor can be regarded as a fast-response and stable system for PA analysis. • AuONPs are potentially applicable in the determining trace PA explosive in real water samples also. In the present investigation, we have design and develop pyridyl-imine capped gold nanoaggregates; fully characterized via various spectroscopic techniques. The photophysical and electrochemical studies revealed that the developed pyridyl-imine capped gold nanoaggregates are proven to be selective sensor for picric acid with remarkable low detection limit within nano-molar concentration (15.0 nM) based on 3σ/K; a common constituent of many powerful explosives. The quenching of fluorescence intensity at λ 357 nm occurs which may ascribe to the electron transfer phenomenon exhibited by the electron rich receptor and emergence of red shift in fluorescence spectroscopy (λ_em 464 nm) after gradual addition of picric acid; a selective phenomenon towards the most electron deficient nitroaromatic (picric acid) sensing. Additionally, the results obtained for the analysis of spiked samples in real water samples such as river and tap water, show that the developed PA sensor is potentially applicable in the determination of trace PA explosive without any interference.