Conjugated Polymer Nanoparticles for the Amplified Detection of Nitro-explosive Picric Acid on Multiple Platforms

Abstract

Spontaneously formed conjugated polymer nanoparticles (CPNs) or polymer dots displayed remarkable fluorescence response toward nitroexplosive-picric acid (PA) in multiple environments including 100% aqueous media, solid support using portable paper strips and vapor phase detection via two terminal device. This new cationic conjugated polyelectrolyte (CPE) poly(3,3'-((2-phenyl-9H-fluorene-9,9-diyl)bis(hexane-6,1-diyl))bis(1-methyl-1H-imidazol-3-ium)bromide) (PFMI) was synthesized by Suzuki coupling polymerization followed by post functionalization method without employing any hectic purification technique. Highest quenching constant value (K(sv)) of 1.12 × 10(8) M(-1) and a very low detection limit of 30.9 pM/7.07 ppt were obtained exclusively for PA in 100% aqueous environment which is rare and unique for any CPE/CPNs. Contact mode detection of PA was also performed using simple, cost-effective and portable fluorescent paper strips for achieving on-site detection. Furthermore, the two terminal sensor device fabricated with nanoparticles of PFMI (PFMI-NPs) provides an exceptional and unprecedented platform for the vapor mode detection of PA under ambient conditions. The mechanism for the ultrasensitivity of PFMI-NPs probe to detect PA is attributed to the "molecular-wire effect", electrostatic interaction, photoinduced electron transfer (PET), and possible resonance energy transfer (RET).

Phenylene(vinylene) based fluorescent polymer for selective and sensitive detection of nitro‐explosive picric acid

“…Which shows a significant spectral change on the absorbance and fluorescence intensity of the PVP (Fig. ) …”

“…), There is a possibility of excited state electron transfer from LUMO (−2.35 eV) of PVP to LUMO of PA (−3.89 eV) (Fig. ) …”

Fluorescent zinc oxide nanoparticles of Boswellia ovalifoliolata for selective detection of picric acid

“…The bands of aromatic compounds around 757, 902 and 1063 cm -1 corresponds to stretching of aromatic C-H and stretching of alcoholic C-O. Figure S2 shows a new peak at 1715 cm -1 of C=O stretching in ZnO-picric acid 25,35 . The peaks intensity of ZnO-Picric acid was relatively reduced than ZnO NPs which may be due to the quenching effect of picric acid by removal of the organic compound from ZnO NPs 25 .…”

Amine decorated polystyrene nanobeads incorporating π-conjugated OPV chromophore for picric acid sensing in water

“…2 This makes it easier to enter the environment and pollute soil and natural water resources, causing several concerns. [3][4][5] Multiple uorescence based sensors like quantum dots (QD), 6 polymers, 7 upconverting nanoparticles (UCNP), 8 metal-organic frameworks (MOF), 9 small molecules 10 etc. are available for detection of PA. One such example of a MOF based sensor has been reported by Shi et al 11 for detection of PA in dimethyl acetamide.…”