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In this paper, we prepared a fluorescent sensor based on carbon quantum dots (CDs) and molecularly imprinted technology (MIT) that was successfully synthesized and applied to the detection of aspirin (Asp) residues in biological and pharmaceutical samples. The molecularly imprinted fluorescence sensor had the high sensitivity of quantum dots and the high selectivity of molecularly imprinted polymers (MIPs). Nitrogen-doped carbon quantum dots (N-CDs) with high fluorescence intensity were prepared and then was coated with silicon by the reverse microemulsion method. Finally, 3-aminopropyltriethoxysilane (APTES) was used as the functional monomer and Asp as the template molecule, molecularly imprinted layers were formed around the N-CDs. Under the best experimental conditions, the detection limit of the sensor was 0.198 mg L − 1 . Between 0.9–9.0 mg L − 1 , this fluorescence sensor had a good linear relationship with the concentration of Asp. To test the practicability of the sensor, we used this fluorescent sensor to detect Asp in human urine and saliva. Satisfied recovery rate between 101.1–105.1% and 102.1–106.0% were obtained, respectively. In this paper, a molecularly imprinted fluorescence sensor was prepared by the inverse microemulsion method. Fluorescence quenching method based on molecularly imprinted fluorescence sensor was used to determine the content of Asp. When Asp combined with N-CDs@SiO2@MIPs, the fluorescence of N-CDs was quenched. The experimental results showed that the molecularly imprinted fluorescent sensor could quickly and accurately detect Asp residues in human urine and saliva. [ABSTRACT FROM AUTHOR]

In this paper, a novel fluorescent nanoswitch based on carbon dots (CDs) was developed for the sensitive and selective determination of Hg and I. The CDs were obtained by simple hydrothermal process and had a strong fluorescence emission at 440nm. The fluorescence of the CDs can be selectively quenched by Hg ion, and then the I was added into the system, which can interact with Hg and recover fluorescence of the CDs. Under optimal conditions, the quenching fluorescence intensity on addition of Hg has obtained a satisfactory linear relationship covering the linear range of 0-50M with the linear relationship (), and the limit of detection is 0.047M. The additions of I could lead to the fluorescence intensity of the solution of CDs and Hg (50M) recover rapidly, which is linearly related () to the concentration of I in the range from 0 to 70M, the detection limit for I was calculated to be 0.084M. Moreover, the developed method to detect Hg and I was evaluated in real examples, and the fluorescence switching can sensitively and selectively detect Hg and I over some potentially interfering ions, the recoveries were up to 97.8-107.0% and 96.7-106.6%, respectively. A water-soluble fluorescent nanoswitch of carbon dots (CDs) has been designed for detecting Hg and I, which was fabricated by hydrothermal process. Hg ions can be recognized by the amino groups of the CDs to form charge-transfer state and result in quenching fluorescence of the CDs. After adding I ions to the system of CDs/ Hg, the Hg ions were extracted from the CDs due to the stronger binding between Hg and I, leading to the released CDs having restrained the photo-induced electron transfer and recovered the fluorescence. [ABSTRACT FROM AUTHOR]