In this work, fluorescent carbon quantum dots (CQDs) was prepared using natural on ions as carbon source with hydrothermal method and it was modified with polyethyleneimine (PEI). The properties of PEI modified CQDs (PEI-CQDs) were characterized by fluorescence, infrared spectroscopy
and ultraviolet method, the morphology characteristics of PEI-CQDs was observed by transmission electron microscope. The results shown that the fluorescence excitation and emission wavelength were at 340 nm/462 nm, respectively. The fluorescence quantum yield was 8.68%, the average diameter
of the PEI-CQDs was 2.82 nm. The infrared showed that the PEI-CQDs contained hydroxyl and amino groups on its surface. The Co2+ has selective quenching effects on fluorescence of PEICQDs, PEI-CQDs can be used for detection and analysis of Co2+ in samples. The limit of
detection and linear range of Co2+ using the PEI-CQDs as fluorescence probe are 0.048 μM and 0.05–11 μM, respectively. The recovery was in the range of 97.00–100.64%. Moreover, the PEI-CQDs are also successfully utilized for monitoring the Co2+
content of tap water.
N-doped carbon dots (N-CDs) were synthesized from L-glutamine and triethanolamine using a one-step hydrothermal method. The N-CDs emitting blue fluorescence had selective responses to tetracyclines (TCs) and could be used as a fluorescent probe to realize the quantitative detection and qualitative analysis of TCs. A method for the determination of TCs using the N-CDs in actual samples was successfully established. The recovery rate was maintained at 97.50-105.60%, and the relative standard deviation (RSD) was less than 3%. In addition, TCs can be visually distinguished using filter paper by the different fluorescence colours (light green, dark blue, and yellow-green) of the N-CDs/TCs system under ultraviolet light. This study provides a relatively simple method to detect and identify TCs.fluorescent probe, N-doped carbon dots, tetracyclines
| INTRODUCTIONTetracyclines (TCs), mainly including tetracycline (TC), chlortetracycline (CTC), and oxytetracycline (OTC), are commonly used as a disease-preventive medicine and feed additive in animal husbandry and aquaculture. [1,2] However, the long-term abuse of TCs has caused extensive drug residues in the environment that may endanger human health. Many studies have shown that the excessive intake of TCs can
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