Cetyltrimethylammonium Bromide Capped 9-Anthraldehyde Nanoparticles for Selective Recognition of Phosphate Anion in Aqueous Solution Based on Fluorescence Quenching and Application for Analysis of Chloroquine

Abstract

Cetyltrimethylammonium bromide (CTAB) capped 9-Anthraldehyde nanoparticles (9-AANPs) in aqueous suspension prepared by reprecipitation method are seen brick shaped in Scanning Electron Microscope image. The Dynamic Light Scattering histogram of nanoparticle suspension reveals narrow particle size distribution and average particle size is 89 nm. The positive zeta potential 20.8 mV measured on zeta sizer indicates high level stability of nanoparticle suspension. The blue shift of 65359.47 cm(-1) observed in the UV-Visible absorption spectrum of CTAB capped 9-AANPs from the absorption maximum of dilute solution of 9-Anthraldehyde (9-AA) in acetone is an indication of formation of H-bonded aggregates by π stacking effect. The strong Aggregation Induced Enhanced Emission (AIEE) of CTAB capped 9-AANPs at 537 nm is selectively quenched with addition of phosphate anion solution. The fluorescence quenching results of the nanoparticle in aqueous solution fit into conventional Stern-Volmer relation in the range of phosphate ion concentration of 0-40 μM. The possible mechanism of fluorescence quenching of nanoparticle is explained by considering adsorption of phosphate anion electrostatistically on positively charged surface of nanoparticle generated by CTAB cap. The Langmuir adsorption plot constructed for PO(4)(3-) adsorption on the basis of fluorescence quenching results of CTAB capped 9-AANPs is linear. The estimated value of Langmuir constant (K) and Stern - Volmer constant (K(sv)) are in close agreement within experimental limits. The sensing method of phosphate ion based on fluorescence quenching of 9-AANPs is applied successfully for quantification of phosphate from pharmaceutical tablet chloroquine phosphate and hence to determine the amount of chloroquine.

N-methyl isatin nanoparticles as a novel probe for selective detection of Cd2+ ion in aqueous medium based on chelation enhanced fluorescence and application to environmental sample

“…The low emission intensity in solution of isolated molecule is due to dissipation of energy to molecular rotations. The aggregation induced enhanced emission is usually correlated to the restricted intramolecular rotations resulting in decreased non-radiative pathways and enhanced emission [28,33,34]. The formation of nanostructure is further supported by the fluorescence lifetime measured at its emission wavelength 417 nm.…”

“…The structured, broad absorption band of methyl isatin seen in the region 370-450 nm is reduced appreciably due to aggregation of molecules and a new blue shifted sharp band appeared with maximum at 272 nm is assigned to the nanostructure. The large blue shift in the absorption spectrum of N-MINPs with respect to N-MI in acetone indicate formation of H-type aggregates due to strong lateral -stacking interactions and functional polar C O groups point outward towards aqueous phase [28,32]. The fluorescence spectrum of N-MINPs in aqueous suspension shown in Fig.…”

“…N-MINPs were prepared by a reprecipitation method [12,28,29] in aqueous medium. A 2 mL, 1 × 10 −5 M solution of N-MI in acetone was injected directly into 50 mL water and stirred for 60 min, followed by ultrasonication for 10 min.…”

“…Above pH 6, ring-opened monomer structure predominates and destabilize the N-MINPs [36,37]. At low and high pH, the nanoparticle suspension stability is affected by disruption of the structural cavity resulting in lowering the fluorescence intensity due to disaggregation of nanoparticles [28,29,38]. …”

Polyvinyl pyrrolidone capped fluorescent anthracene nanoparticles for sensing fluorescein sodium in aqueous solution and analytical application for ophthalmic samples

“…The particle size estimated from the SEM image was 200 nm and relatively greater than the average diameter obtained from DLS histogram. This was due to the agglomeration of the nanoparticles during preparation of thin film on glass substrate for SEM images The reports available in literature on IR‐studies have shown that –C=O in the pyrrolidone ring is very sensitive to hydrogen bond formation with water molecule and hence the polymeric form of vinyl pyrrolidone provided a flexible charged membrane around anthracene colloids .…”