Selectivity Quantification with the Fluorescent Quantitative Model-Assisted Semi-Selective Probe (Carbon Dots): Accurate Determination of Chlortetracycline in Aqueous Environments with Interference

Abstract

Probes such as carbon dots (C-dots) have extensive and important applications in the quantitative analysis of complex biological and environmental systems. However, the development of probes is often hindered by incomplete selectivity, i.e., a probe that responds to one substance is also prone to respond to coexisting structurally similar substances. Therefore, the above dilemma often leads to be developed as semi-selective probes, so that the development of probes is abandoned halfway. This work shows how a semi-selective probe can enhance selectivity by combining a proper multivariate calibration model. Primarily, we developed a semi-selective fluorescent probe that responded to tetracyclines (TCs) with discarded tobacco leaves. Then, we introduced the multivariate quantitative fluorescence model (QFM) to enhance its selectivity and solve the problem of fluorescence spectral shift. For the determination of chlortetracycline (CTC) with this semi-selective C-dots probe in mineral and lake water samples and compared to the traditional quantitative model, the introduced QFM resulted in an average relative predictive error (ARPE) in mineral water spiked samples decreased from 57.1 to 5.6%, which reduced the ARPE in the lake water spiked samples from 18.1 to 4.7%. The above results show that the QFM-assisted semi-selective probe C-dots strategy (QFMC−dots) can enhance selectivity, and QFMC−dots achieved high-selective and accurate determination of CTC in interfering mineral and lake water samples, with the limit of detection and limit of quantitation of 0.55 and 1.66 μM, respectively. The proposed strategy of enhancing selectivity by introducing a proper multivariate calibration model can reduce the difficulty and increase success rate of developing probes, which can be expected to provide an interesting alternative for the development of probes, especially when encountering semi-selective problems.

Development of a Lateral-Flow Immunochromatographic Strip for the Detection of Oxytetracycline Residues in Biological Fluids

“…For OTC, the European Union (EU) set the MRL value at 0.1 mg/L (100 μg/L) . In the recent era, many screening and confirmatory assays like microbiological assays, enzyme-linked immunosorbent assays (ELISA), different chromatographic assays coupled with mass spectrometry, and fluorescent detection methods based on copper nanoclusters, poly­(adenine) (poly A) DNA-templated Au nanoclusters, and carbon dots have been developed for the detection and quantification of OTC in milk. – Although these methods are highly specific and sensitive and have high throughput, they require expensive chemicals and instruments and highly skilled personnel for the operation and maintenance of instruments. Moreover, these methods also require sample pretreatment and a long time for the analysis of a single sample.…”