Qualitative and Quantitative Luminescence Detection of 2,6-Dipicolinic Acid and Levofloxacin Based on a High-Nuclearity Eu(III) Nanomolecular Sensor.

Rapid and accurate testing of 2,6-dipicolinic acid (DPA) and levofloxacin (LFX) has been attracting much attention due to the fact that the former is an important biomarker of anthrax spores and the latter is a third-generation fluoroquinolone drug and has been recognized as an important environmental pollutant. Herein, we report the preparation of a 13-metal Eu(III) nanomolecular sensor (molecular sizes: 2.0 × 2.4 × 3.2 nm) bearing a new flexible Schiff base ligand for luminescence testing of DPA and LFX with high selectivity and sensitivity. The rapid enhancement of the Eu(III) luminescence of 1 caused by DPA and LFX is expressed by fitting equation I615nm = k × [C] + a, which can be used to quantitatively detect DPA and LFX concentrations in CH3CN, fetal calf serum (FCS), and a real drug. The response times of 1 to DPA and LFX are less than ten seconds, with detection limits as low as 3.78 × 10-2 to 2.71 nM. The test strips containing 1, as well as 1@SA films, can be used to qualitatively detect DPA and LFX by the color changes under the irradiation of UV light.