magnetic solid-phase microextraction of hazardous light green dye followed by fluorometric and colorimetric modes for detection using nife2o4 nanoparticles from an aqueous environment

This work suggests a new, easy, useful, and cost-effective magnetic solid phase microextraction (µ-mspe) method that is followed by dual-mode detection of dangerous light green (lg) dye in water. we utilized magnetic nickel ferrite nanoparticles (nife2o4nps) as an efficient lg adsorbent. we determined lg using dual-mode colorimetric and fluorometric detection. the colorimetric mode is based on measuring lg color at a maximum wavelength of 620 nm. in contrast, the fluorescence sensing mode depends on quenching the fluorescence emission of red-emissive cationic carbon dots (rc-cds) at λem= 680 nm after excitation at 340 nm via both electrostatic interaction and the inner-filter effect (ife). the as-synthesized rc-cds had a fluorescence quantum yield (φs) of 24.4%. scanning electron microscopy (sem), transmission electron microscopy (tem), energy dispersive x-ray (edx), fourier transform infrared spectroscopy (ft-ir), powder x-ray diffraction (pxrd), dynamic light scattering (dls), uv/vis spectroscopy, and fluorescence spectroscopy were used to confirm the identification of nife2o4 nps and rc-cds. all µ-mspe and determination-affecting factors were carefully optimized. the freundlich model best suited the adsorption isotherm, with an r՛² value of 0.9995 and a maximum adsorption capacity (qmax) of 35.1 mg/g. a pseudo-second-order (pso) model with a constant of 4.1 mg/min and r՛² of 0.9965 was used to explain the adsorption kinetics. from the results, the study revealed that absorption intensities increased linearly with lg concentration in the range of 10-300 µg/ml with a detection limit (s/n=3) of 2.9µg/ml. in contrast, fluorescence intensities exhibited a linear decrease with lg concentration in the 7-100 µg/ml range with a detection limit (s/n=3) of 2.1 µg/ml. the application of μ-mspe proved effective in determining lg in samples, with recoveries ranging from 93.7% to 101.5% and rsd % less than 3.9%, highlighting the reliability of the proposed methods.