A novel visual detection method was developed for the determination of zinc (Zn) in whole blood and cells using gold nanoclusters (AuNCs) immobilized paper. The detection of Zn was based on a headspace-solid phase extraction (HS-SPE), visible fluorescence from the AuNCs coated paper was quenched by ZnH 2 generated from hydride generation (HG). The potential mechanism was investigated by using X-ray photoelectron spectroscopy (XPS) and Density Functional Theory (DFT). The selectivity was significantly increased because the zinc hydride was effectively separated from sample matrices by hydride generation. A limit of detection (LOD) of 3 μg L −1 Zn 2+ and a relative standard deviation (RSD, n = 7) of 2% at a concentration of 50 μg L −1 of Zn 2+ were obtained when using a commercial fluorescence spectrophotometer as the detector. In visual detection, as low as 20 μg L −1 of Zn 2+ in biological samples can be easily discriminated from the blank with the naked eye. The proposed method retains several unique advantages, including straightforward, rapid, affordable and equipment-free for visual detection.
The on-site detection of mancozeb in food samples holds immense value for food safety. A red-fluorescent europium complex ( Eu-PYDC-Phen ) has been prepared and employed as a fluorescence probe for mancozeb detection. The optimized probe suspension exhibits excellent detection performances, including a wide linear range (0–0.24 mM), low detection limit (65 nM), rapid response (2 mins) and high selectivity . Moreover, a portable detection platform was carefully designed, integrating the Eu-PYDC-Phen -based fluorescent test strips with smartphone color recognition software. This innovative platform enables visual and on-site detection of mancozeb in tomato, apple, and lettuce, achieving satisfactory recovery rates (90.34 to 106.50%). Furthermore, the integration of machine learning techniques based on hierarchical clustering algorithm has the potential to further improve the prediction and decision-making efficiency in mancozeb detection. This work provides an economical, convenient, and reliable strategy for on-site detection of pesticide in agricultural products, thereby making a meaningful contribution to food safety.
危险品化学品经营许可证（带存储）