Qualitative\nand Quantitative Luminescence Detection\nof 2,6-Dipicolinic Acid and Levofloxacin Based on a High-Nuclearity\nEu(III) Nanomolecular Sensor

Rapid and accurate testing of 2,6-dipicolinic acid (DPA)\nand levofloxacin\n(LFX) has been attracting much attention due to the fact that the\nformer is an important biomarker of anthrax spores and the latter\nis a third-generation fluoroquinolone drug and has been recognized\nas an important environmental pollutant. Herein, we report the preparation\nof a 13-metal Eu(III) nanomolecular sensor (molecular sizes: 2.0 ×\n2.4 × 3.2 nm) bearing a new flexible Schiff base ligand for luminescence\ntesting of DPA and LFX with high selectivity and sensitivity. The\nrapid enhancement of the Eu(III) luminescence of <b>1</b> caused\nby DPA and LFX is expressed by fitting equation <i>I</i><sub>615nm</sub> = <i>k</i> × [C] + <i>a</i>, which can be used to quantitatively detect DPA and LFX concentrations\nin CH<sub>3</sub>CN, fetal calf serum (FCS), and a real drug. The\nresponse times of <b>1</b> to DPA and LFX are less than ten\nseconds, with detection limits as low as 3.78 × 10<sup>–2</sup> to 2.71 nM. The test strips containing <b>1</b>, as well as <b>1</b>@SA films, can be used to qualitatively detect DPA and LFX\nby the color changes under the irradiation of UV light.