基于柑橘皮渣纳米多孔碳分散固相萃取-气相色谱法 测定果蔬中14种有机磷农药残留

以废弃柑橘皮渣为碳源,通过ZnCl2活化后高温煅烧制备了纳米多孔碳材料(NPC),将其作为吸附剂,建立了分散固相萃取净化、气相色谱法测定果蔬中有机磷农药残留的方法.扫描电子显微镜(SEM)、X射线衍射(XRD)、傅立叶红外光谱(FT-IR)、拉曼光谱及氮气吸附分析(BET)等表征显示,NPC是无定形的多孔碳材料,孔径大小为0~15 nm,比表面积和孔体积分别为1243 m2/g和1.28 cm3/g.以果蔬中14种有机磷类农药为分析对象,考察了吸附剂的用量和净化时间,并将NPC与商业化材料N-丙基乙二胺(PSA)、十八烷基硅胶键合相(C18)和石墨化碳黑(GCB)进行了对比.结果表明,NPC最佳使用量为0.01 g,净化时间只需2 min.NPC成本远低于C18、PSA和GCB,因具有丰富的孔道结构,NPC净化效果显著优于3种商业化材料.在最优条件下,14种有机磷农药在0.02~1.0 mg/L范围内的线性关系良好(R2>0.99),检出限(S/N=3)为0.63~5.30μg/kg.3个添加水平下的平均回收率为71.3%~114.7%,相对标准偏差(RSD)为0.9%~12.9%.本方法操作简便、快速、成本低,在果蔬样品前处理中具有广阔的应用前景.

Determination of Organophosphorus Pesticide Residues in Fruits and Vegetables Using Porous Carbon Nanoparticles Based on Citrus Compose

Porous carbon nanoparticles ( NPC) were prepared by ZnCl2 activation and carbonization using citrus waste as carbon source. A sample pretreatment method with NPC as dispersive solid phase extraction (d-SPE ) absorbent was established for the determination of organophosphorus pesticides in fruits and vegetables by gas chromatography. The NPC was characterized by scanning electron microscopy (SEM), X-ray diffraction ( XRD), FT-IR spectra, Raman spectroscopy, Brunauer, Emmett and Teller surface area(BET). Those results showed that the NPC was an amorphous porous carbon material with pore size in the range of 0-15 nm. Its specific surface area and pore volume were 1243 m2 / g and 1. 28 cm3 / g, respectively. The analysis conditions, including the amount and clean up time of adsorbent, were optimized by analysis of 14 kinds of oranophosphorus pesticides in fruits and vegetables with gas chromatography-flame photometric determination(GC-FPD). Moreover, the comparison for NPC with commercial materials of PSA, C18 and GCB was investigated in this study. The results indicated that the purification time was only 2 min using 0. 01 g NPC. The cost of NPC was about 25% of C18 , 21% of PSA and 16% of GCB. Because of the porous structure of NPC, the purification efficiency was significantly higher than the three commercial materials mentioned above. Under the optimum conditions, the calibration curves of the 14 organophosphorus pesticides were linear in the range of 0. 02-1. 00 mg / L with good correlation coefficients (R2>0. 99) and detection limits (S / N=3) of 0. 63-5. 30 μg / kg. The recoveries of the pesticides at three spiked levels ranged from 71. 3% to 114. 7%with the relative standard deviations (RSDs) of 0. 9% -12. 9% . The method is simple, rapid, sensitive, and low cost, and can satisfy the requirements of detection of organophosphorus pesticide residues in fruits and vegetables, displaying a good application prospect.