A water stable europium coordination polymer based on mixed organic ligands as a luminescence sensor for the detection of an anthrax biomarker

The development of luminescence sensors capable of detecting anthrax biomarkers is crucial for preventing anthrax. In this study, a two-dimensional europium coordination polymer [Eu(dlba)(phen)·2(H2O)]n (CP-1) was prepared based on a rigid 1,10-phenanthroline (phen) and a flexible 2-(3,5-dicarboxybenzyloxy) benzoic acid (H3dlba) under the hydrothermal conditions. The CP-1 was characterized by powder X-ray diffraction, elemental analysis, thermogravimetric analysis, infrared spectroscopy, and single crystal X-ray diffraction. The CP-1 exhibits excellent water stability and thermal stability. Luminescence experiments demonstrated a high luminescence quenching efficiency (98.1 %) upon addition of the anthrax biomarker dipicolinic acid (DPA). Additionally, the sensor shows good sensitivity and a rapid response time of 30 s. The detection limit is as low as 0.12 µM, which is much lower than the infection dose of spores (60 µM). The sensor has a recovery rate of 95–105 % when tested on actual samples, indicating its potential for practical applications. The luminescence quenching effect may be due to the competitive absorption of DPA, which affects the efficiency of energy transfer from the ligands to the europium ions.