Agricultural Research Center, Central Laboratory of Residue Analysis of Pesticides and Heavy Metals in Foods (QCAP), Ministry of Agriculture and Land Reclamation, Giza 12311, Egypt.
Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Cairo 11884, Egypt.
Food Chem. 2024 Apr 16;438:137869. doi: 10.1016/j.foodchem.2023.137869. Epub 2023 Oct 29.
This study aimed to develop simple, fast, and sensitive methods for the determination of diquat (DQ) in various matrices such as water and beverages. For water, direct injection was tested first, however, the sensitivity of the incurred samples were too low and couldn't possibly achieve the targeted limit of quantification. Hence, dilution with "weaker" injection solvents were tested, and the final conditions involved the dilution of water with acetonitrile (0.4 % ammonium hydroxide) which increased the sensitivity by more than ten times. Nevertheless, the beverages samples needed further treatment to achieve acceptable spiked recovery. The final conditions involved extraction using the aforementioned solvent, followed by heating and partitioning. Both of the methods satisfied the validation requirements, with an average recovery ranging from 85.9 to115 % and associated relative standard deviation (RSD %) within the range 3-8. Further applications on real samples were done to test the levels of contamination.
本研究旨在开发简单、快速和灵敏的方法，用于测定各种基质（如水和饮料）中的敌草快（DQ）。对于水，首先测试了直接进样，但受干扰样品的灵敏度太低，不可能达到目标定量限。因此，测试了用“较弱”进样溶剂稀释的方法，最终条件涉及用乙腈（0.4%氨水溶液）稀释水，这将灵敏度提高了十倍以上。然而，饮料样品需要进一步处理才能达到可接受的加标回收率。最终条件涉及使用上述溶剂进行提取，然后进行加热和分配。这两种方法都满足验证要求，平均回收率在 85.9%至 115%之间，相对标准偏差（RSD%）在 3-8%范围内。进一步对实际样品进行了应用，以检测污染水平。
