Cotton swabs decorated with Ag@BPQD for the fluorescence determination of 3-aminosalicylic and 5-aminosalicylic acid

Novel and portable cotton swab-based fluorometry was constructed for the first time for 3-aminosalicylic acid (3-ASA) and 5-aminosalicylic acid (5-ASA) detection. It was carried out by fluorescence enhancement on silver (Ag)-doped black phosphorus quantum dots (Ag@BPQD). Ag@BPQD were prepared from AgNO3 and bulk black phosphorus in N, N-dimethylformamide (DMF) solution by solvothermal decomposition after mechanical exfoliation. Ag@BPQD show blue fluorescence with a quantum yield (QY) of 2.43%. In the presence of Ag@BPQD, 3-ASA exhibited bright blue fluorescence (lambda(ex) = 328 nm, lambda(em) = 448 nm). The fluorescence of 5-ASA was also enhanced significantly and exhibited bright green emission (lambda(ex) = 328 nm, lambda(em) = 484 nm). The linear range of 3-ASA is 0-90 mu M with a detection limit (LOD) of 0.10 mu M, relative standard deviation (RSD) <= 2.04%, and a recovery range of 98.0-104.3%. The linear range of 5-ASA is 0-120 mu M with a LOD of 0.12 mu M, RSD <= 1.34%, and a recovery range of 98.0-101.3%. When 3-ASA and 5-ASA were mixed in different ratios, the fluorescence showed different colors. The possible mechanism of the interaction between 3-ASA (or 5-ASA) and Ag@BPQD may be ascribed to the generation of excited-state intramolecular proton transfer. To realize convenient detection of 3-ASA and 5-ASA, a Ag@BPQD portable sensing method using cotton swabs were built. The proposed approach provides the detection of 3-ASA and 5-ASA in environmental and biological samples with high efficiency, accuracy and portability.

Automated summary

A novel and portable cotton swab-based fluorometry was developed for the detection of 3-aminosalicylic acid (3-ASA) and 5-aminosalicylic acid (5-ASA). This method utilized silver (Ag)-doped black phosphorus quantum dots (Ag@BPQD) to enhance fluorescence. The linear range, detection limit, and recovery range for 3-ASA were 0-90 μM, 0.10 μM, and 98.0-104.3% respectively, while for 5-ASA they were 0-120 μM, 0.12 μM, and 98.0-101.3% respectively. By mixing different ratios of 3-ASA and 5-ASA, the fluorescence exhibited different colors. The proposed portable sensing method using Ag@BPQD and cotton swabs allows for convenient and efficient detection of 3-ASA and 5-ASA in environmental and biological samples, with high accuracy and portability requirements.