چكيده به لاتين
Bacillus anthracis is an extremely dangerous bacterium that is associated with high morbidity and mortality. 2,6-Pyridine dicarboxylic acid (DPA) is a major biomarker of Bacillus anthracis, its diagnosis with a rapid, significance and sensitive method can reduce the potential threats of this disease. Herein, in the present research, three new fluorescence sensors based on the integration of red, green and yellow quantum carbon nanostructures derived from ortho phenylenediamine, 4-aminophenol and amaranth plant leaves with different metal-organic frameworks ZIF-67, Zn-BTC and Er-BTC was developed. Optical, structural and chemical properties of metal-organic frameworks, carbon quantum nanostructures and their hybrids fully investigated using UV-Vis, fluorescence, CIE, XRD, FTIR, FESEM, EDS, TEM, DLS and zeta potential methods. The results confirmed the special morphology and remarkable optical properties of these compounds. As-prepared sensors with different mechanisms of fluorescence quenching, fluorescence intensification, and fluorescence ratiometry were used for DPA measurement, and the effect of operational factors of temperature, pH, and interaction time were optimized in order to achieve the best results. The ZIF-67/r-CQNSs-EY, Zn-BTC/g-CQNSs and Er-BTC/r-CQNSs/MIP sensing platforms revealed satisfactory linear relationship from 10 to 280, 5 to 140 and 0.5 to 125 μM with a detection limit of 3.23 μM, 1.65 μM and 1.65 μM. The designed sensors showed revealed satisfactory selectivity in the presence of terephthalic acid, trimesic acid, 2,5-pyridinedicarboxylic acid, picolinic acid and some other important biological species. However, in one case, a DPA molecular template polymer (MIP) were used to improve the sensor selectivity. As designed sensors was applied for DPA monitoring in human urine and well water real samples and finding revealed the satisfactory recoveries in the range of 94.80 to 106.60 with relative standard deviation 3.20 to 5.97 More Importantly, on-site signal recording with a smartphone was successfully combined to perform noticeable fluorescence visual color change and holding a great promise in practical applications. Also, a fluorescence sensor was designed to detect the picolinic acid isomer as an essential component in organic chemistry and food additives, and the results were compared with DPA.
