College of Food and Bioengineering, Jiangsu University, Zhenjiang, China.
Electrophoresis. 2012 Jul;33(14):2192-6. doi: 10.1002/elps.201200043.
A new assay was developed by use of micellar electrokinetic capillary chromatography with indirect LIF fluorescence for the determination of thiamethoxam, acetamiprid, and imidacloprid residues in vegetables, in which the cadmium telluride quantum dots (QDs) synthesized in aqueous phase were used as fluorescent background substance and their excitation and emission wavelengths matched with LIF detector by engineering their size. The factors that affected the peak height and the resolution were optimized. The running buffer was composed of 4.4 μM cadmium telluride QDs as fluorescent background substance, 40 mM borate and 60 mM SDS, and its pH was adjusted to 8.0. The separation voltage was 25 kV. Under the optimum conditions, the detection limits were 0.05, 0.01, and 0.009 mg/kg; the linear dynamic ranges were 0.5-30, 0.1-30, and 0.1-30 mg/L; and the average recoveries of spiked samples were 72.0-101.2, 74.0-106.7, and 77.8-105.1% for thiamethoxam, acetamiprid, and imidacloprid, respectively. The assay can meet the requirement of maximum residue limits to these three pesticides in the regulations of European Union and Japan, and has been applied for determining their residues in vegetables.
建立了一种利用胶束电动毛细管色谱间接激光诱导荧光检测技术测定蔬菜中噻虫嗪、乙酰甲胺磷和吡虫啉残留量的新方法。该方法以水相合成的碲化镉量子点（QDs）为荧光背景物质，通过控制其粒径使其激发和发射波长与激光诱导荧光检测器相匹配。优化了影响峰高和分辨率的因素。运行缓冲液由 4.4 μM 碲化镉 QDs 作为荧光背景物质、40 mM 硼酸盐和 60 mM SDS 组成，pH 值调至 8.0。分离电压为 25 kV。在最佳条件下，检测限分别为 0.05、0.01 和 0.009 mg/kg；线性动态范围分别为 0.5-30、0.1-30 和 0.1-30 mg/L；噻虫嗪、乙酰甲胺磷和吡虫啉的加标回收率分别为 72.0%-101.2%、74.0%-106.7%和 77.8%-105.1%。该方法的检测限满足了欧盟和日本法规对这三种农药的最大残留限量要求，并已应用于蔬菜中这些农药残留量的测定。
