Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz, Iran.
Engineering Faculty, Near East University, 99138 Nicosia, North Cyprus, Mersin 10, Turkey.
Anal Methods. 2022 Jun 23;14(24):2376-2388. doi: 10.1039/d2ay00404f.
In the present work, a new and efficient sorbent has been prepared using the co-precipitation method for magnetic dispersive solid phase extraction followed by dispersive liquid-liquid microextraction. This method was used for the extraction and preconcentration of some widely-used pesticides (chlorpyrifos, haloxyfop--methyl, oxadiazon, diniconazole, clodinafop-propargyl, fenpropathrin, and fenoxaprop--ethyl) from fruit juices prior to their determination by gas chromatography-flame ionization detection. The sorbent was prepared by octadecylamine co-precipitation with FeO. In the first step, mg amount of the magnetic sorbent was spread into an aqueous sample solution including the selected analytes and vortexed. Then the analytes were eluted with acetonitrile from the surface of the nanoparticles separated with an external magnetic field from the aqueous solution. In the second step, the obtained eluent was mixed with an extraction solvent (chloroform) at the μL-level and rapidly injected into deionized water. After centrifugation, an aliquot of the sedimented phase was injected into the separation system. Experimental parameters which control the performance of both steps were investigated and optimized. Using optimum extraction conditions, the proposed method provided low limits of detection (0.23-0.41 μg L) and quantification (0.81-1.3 μg L), high enrichment factors (353-443), acceptable extraction recoveries (70-88%), and satisfactory relative standard deviations (≤6%) for intra- ( = 6) and inter-day ( = 4) precisions at a concentration of 30 μg L of each pesticide.
在本工作中，采用共沉淀法制备了一种新的高效吸附剂，用于随后的磁性分散固相萃取和分散液液微萃取。该方法用于从果汁中提取和预浓缩一些广泛使用的农药（毒死蜱、精噁唑禾草灵、恶草酮、烯唑醇、氯禾灵、甲氰菊酯和苯醚甲环唑），然后用气相色谱-火焰离子化检测法进行测定。吸附剂是用十八胺共沉淀 FeO 制备的。在第一步中，将 mg 量的磁性吸附剂铺展到包含所选分析物的水溶液中，并进行涡旋。然后用乙腈从纳米粒子表面洗脱分析物，纳米粒子在外磁场的作用下从水溶液中分离出来。在第二步中，将得到的洗脱液与萃取溶剂（氯仿）以 μL 级混合，并迅速注入去离子水。离心后，将沉淀相的一部分注入分离系统。考察并优化了控制两步性能的实验参数。在最佳萃取条件下，该方法提供了低检测限（0.23-0.41 μg L）和定量限（0.81-1.3 μg L）、高富集因子（353-443）、可接受的萃取回收率（70-88%）和令人满意的相对标准偏差（≤6%），在 30 μg L 每种农药的浓度下，日内（ = 6）和日间（ = 4）精密度良好。
