Selective fluorescence detection of acetylsalicylic acid, succinic acid and ascorbic acid based on a responsive lanthanide metal fluorescent coordination polymer†

Abstract

A fluorescent sensor for highly selective and ultrasensitive detection of acetylsalicylic acid (ASA), succinic acid (SA), and ascorbic acid (AA) was reported. The water-soluble fluorescent ligand salicylic acid (Sal) was generated through catalyzing ASA by the hydrolase activity of zeolitic-imidazolate framework-8 (ZIF-8) or natural esterase (Est). The Sal can coordinate with 2-methylimidazole (2-MIm) and Ln(III) to form a fluorescent lanthanide coordination polymer (LCP), which has a fluorescence emission peak with the maximum wavelength at 412 nm (the excitation wavelength at 300 nm). Therefore, the detection of ASA can be achieved through the fluorescence intensity changes of LCPs in the system, which has comparable sensitivity and good selectivity (linear range of 0.031–1.00 mM and LODs of 11.72 and 3.22 μM) as compared to a direct reaction between Est/ZIF-8 and ASA for detecting ASA (linear range of 0.05–1.20 mM and limits of detection (LODs) of 4.43 and 4.58 μM). Furthermore, upon the addition of SA and AA, the fluorescence intensity of the reaction system can be enhanced and weakened through changing the energy resonance transfer pathways and affecting the enzymatic reaction process, respectively, realizing their sensitive and selective fluorescence detection. The established fluorescent sensors can work well in a wide linear range of SA concentrations from 0 to 2.50 mM (Est-based reaction system) and 0 to 1.50 mM (ZIF-8-based reaction system) with the LODs of 0.032 and 0.028 mM, respectively. The linear ranges of AA concentrations are from 0.0078 to 0.25 mM (Est-based reaction system) and 0.0078 to 0.13 mM (ZIF-8-based reaction system) with the LODs of 2.54 and 3.80 μM, respectively. The established sensors were successfully used in the detection of SA in rabbit plasma, with a recovery of 84.0%–98.7%. Additionally, the contents of ASA in Aspirin Enteric-Coated tablets and AA in vitamin C tablets were also determined by the developed methods.