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Surfactant-capped nanoparticles of 9, 10-diphenyl anthracene prepared by reprecipitation method found highly fluorescent due to aggregation-induced enhanced emission (AIEE). Cetyltrimethyl ammonium bromide (CTAB) surfactant not only generated positive zeta potential on the surface of nanoparticles to attract anions of interest but also stabilized nanoparticles into brickshape morphology. The fluorescence of nanoparticles is quenched by Cr 2 O 7 2ion very significantly in comparison with other diverse ions, namely, MnO 4 -, S 2 O 8 2-, HCO 3 -, and Cr 2 O 4 2-. Though S 2and IO 3 showed increase in the fluorescence of nanoparticles, the interference found is negligible in the Cr (VI) analysis. The selectivity and sensitivity of nanoparticles for recognition of Cr 2 O 7 2− were explored by systematic fluorescence titration. The fluorescence quenching data fits into the usual Stern-Volmer equation. A calibration curve constructed by plotting quenching of fluorescence (ΔF) against concentration of Cr (VI) exhibiting a linear fit in the equation, ΔF = 3070x, is used for the estimation of chromium concentration (x). The correlation coefficient value R 2 = 0.998 obtained from curve is nearly equal to 1 indicates linear fit between quenching data and concentration of Cr (VI). The estimated values of limit of detection (LOD) in the method 0.01392 μg.mL −1 is far below the permissible value of Cr (VI) 0.05 μg.mL −1 in drinking water approved by world health organization (WHO) and United State Environmental Protection Agency (USEPA). The proposed method of Cr (VI) detection is applied for real sample collected from hard chrome deposition industry from nearby region. The amount of Cr (VI) estimated by present method is comparable with AAS determination for the same samples.

The sodium dodecyl sulfate capped 9,10 Diphenylanthracene nanoparticles is prepared by using reprecipitation method. The average particle size of NPs obtained from DLS examination is 67 nm. The aqueous suspension of NPs exhibits red shifted aggregation induces enhanced emission. The zeta potential value—42.9 mV indicates stability of NPs and generation of expected negative surface charge over the NPs to attract and adsorb cations from the solution on the surface. The cation recognition test based on fluorescence shows that the presence of Al3+ ion significantly enhances the fluorescence of NPs. Furthermore, the proposed system is successfully applied for the detection of Al3+ ion from environmental water samples and Digene table available in the market. The advantage of developed analytical method is lower value of LOD and even in presence of interfering ion Mg2+ the Al3+ is estimated with no need of their separation prior to analysis.

In present study, magnetically separable cobalt ferrite nanoparticles (CoFe2O4·NPs) have been prepared by low cost chemical precipitation method and reported as reusable, proficient heterogeneous catalyst for the synthesis of 1-oxo-hexahydroxanthenes among other ferrites. The structural and morphological studies by X-ray diffraction and scanning electron microscopy confirmed the formation of CoFe2O4 nanoparticles. The current protocol evaluated a proficient catalyst for reaction between various salicylaldehydes and 1,3-diketones. The ambient reaction conditions, shorter reaction time, good to excellent yields of the products, ease of purification of the products and reusa-bility of catalyst up to five catalytic cycles without significant loss of catalytic activity making the current protocol promising for its practical application.