title: Determination of nicotinyl pesticide residues in vegetables by micellar electrokinetic capillary chromatography with quantum dot indirect laser-induced fluorescence.
abstract: 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.
authors: College of Food and Bioengineering, Jiangsu University, Zhenjiang, China. chengh@ujs.edu.cn
authors: Guan-Hua
authors: GH
authors: Chen
authors: Juan
authors: J
authors: Sun
authors: Yong-Jia
authors: YJ
authors: Dai
authors: Min
authors: M
authors: Dong
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000295:instrumentation / Q000379:methods*; D005453:Fluorescence; D007093:Imidazoles / Q000032:analysis*; D007834:Lasers; D057230:Limit of Detection; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000032:analysis*; D010078:Oxazines / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*; D011725:Pyridines / Q000032:analysis*; D045663:Quantum Dots; D013691:Tellurium / Q000737:chemistry; D000077922:Thiamethoxam; D013844:Thiazoles / Q000032:analysis*; D014675:Vegetables / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D007093:Imidazoles; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010078:Oxazines; D010573:Pesticide Residues; D011725:Pyridines; D013844:Thiazoles; C082359:imidacloprid; C464485:acetamiprid; D000077922:Thiamethoxam; D013691:Tellurium; C028337:cadmium telluride