Lanthanide Molecular Species Generated Fe₃O₄@SiO₂-TbDPA Nanosphere for the Efficient Determination of Nitrite

The presence of nitrite (NO₂^-) in water and food leads to serious problems in public health and the environment. Therefore, it is important to develop a rapid and efficient method for the selective detection of NO₂^-. In this work, the synthesis and characterization of magnetic Fe₃O₄@SiO₂-TbDPA nanoprobe have been carried out. The Fe₃O₄@SiO₂-TbDPA aqueous solution exhibits a strong green emission. Due to the addition of various concentrations of NO₂^- (0-100 μM), the fluorescence intensity has been suppressed. The nanoprobe Fe₃O₄@SiO₂-TbDPA exhibits excellent selectivity and sensitivity toward NO₂^- ions. Excellent linearity is obtained in the range of 5-80 μM with a detection limit of 1.03 μM. Furthermore, the presence of magnetic Fe₃O₄ nanoparticles in Fe₃O₄@SiO₂-TbDPA nanospheres will also facilitate the effective separation of Fe₃O₄@SiO₂-TbDPA from the aqueous solution. Our proposed strategy is expected to fabricate an organic-inorganic hybrid magnetic nanomaterial and can be used as an efficient sensor. It has been shown that this new strategy has numerous advantages, such as high stability, selectivity, and simplicity of operation. It demonstrates great potential for simple and convenient NO₂^- detection. It may expand to a variety of ranges in environmental monitoring and biomedical fields.