Polychlorinated biphenyls (PCBs) have been known pollutants, which are ubiquitous in various matrix, even in some food products and beverages like fruit juices. It is of great importance to develop efficient and simple method to detect them in such matrix. In this work, an effective magnetic composite integrating the advantages of the magnism of CoFe 2 O 4 , hydrophilicity and multisites of Ti 3 C 2 and high adsorption properties of polyaniline (CoFe 2 O 4 @Ti 3 C 2 @PANI) was designed and synthesized. CoFe 2 O 4 @Ti 3 C 2 @PANI-based magnetic solid-phase extraction coupled with gas chromatography-tandem mass spectrometry was established for determination of nine PCBs in fruit juices. The developed method achieved low detection limits of 0.4–0.8 ng L −1 . The established method was validated with three beverages and achieved good spiked recoveries ranging from 77.2 % to 104.7 %. These findings exhibited that the established method was very simple, efficient, and credible for the analysis of PCBs in food, environmental, and other fields.
Rapid and accurate discrimination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an available approach to implement a rapid diagnosis of the coronavirus disease 2019 (COVID-19). Here we fully exploited the cleavage properties of exonuclease III (Exo III) and hairpin DNA-assisted target cycling technology to generate bulk single-stranded DNA (ssDNA) that was employed to facilitate the constitution of a three-way junction structure on polymetallic particle (Ag-Au NPs) and Ti 3 C 2 (Ti 3 C 2 @Ag-Au) complexes. Ag-Au NPs presented favorable stability without adding extra stabilizers, demonstrating the potential value of Ag-Au NPs as an alternative to Au NPs in the field of bioanalysis. Uppon the three-way junction structure, the dumbbell hybridization chain amplification (DHCA) was occurred which generated DNA nanostructure with tight conformation. Target cycling and DHCA reactions improved the electrochemiluminescence (ECL) signal, which dramatically advanced the assay sensitivity of SARS-CoV-2 (0.59 fM). Moreover, our strategy remained to demonstrate favorable specificity and repeatability in environmental conditions and real human serum samples.
危险品化学品经营许可证（带存储）