The State Key Laboratory of Environmental Chemistry and Ecotoxicology of the Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Anal Chem. 2010 Mar 15;82(6):2363-71. doi: 10.1021/ac902589t.
In the present study, chitosan-coated octadecyl-functionalized magnetite nanoparticles (Fe(3)O(4)-C(18)-chitosan MNPs) are synthesized and used as an adsorbent to extract trace analytes from environmental water samples. The magnetic nanoparticles, 20 nm in diameter, are of uniform size and have a high magnetic saturation value of 52 emu g(-1), which endue the adsorbent with a large surface area and convenience of isolation. The anionic pollutants, perfluorinated compounds (PFCs), are trapped by the octadecyl group of the interior hydrophobic layer. The positively charged chitosan polymer coating also contributes to PFC enrichment. At the same time, the coating improves the dispersibility of MNPs in aqueous solution and enhances the anti-interference ability of the adsorbent to natural organic macromolecules in complex samples by size exclusion or electrostatic repulsion. A liquid chromatography-tandem mass spectrometry system is employed in the determination of PFCs after preconcentration with the MNP adsorbent. The predominant factors affecting preconcentration are investigated and optimized. Under the selected conditions, concentration factors of 1000 are achieved by extracting the analytes from 500 mL of several environmental water samples and concentrating the eluants to 0.5 mL with a nitrogen flow. The method detection limits obtained for perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorononanoic acid (PFNA), perluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), and perfluorotetradecanoic acid (PFTA) in Gaobeidian wastewater are 0.24, 0.093, 0.24, 0.14, 0.075, 0.24, and 0.17 ng L(-1), respectively. Recoveries of PFOA, PFOS, PFNA, PFDA, PFUnDA, PFDoDA, and PFTA are in the ranges of 88-108%, 63-112%, 79-109%, 56-107%, 66-106%, 56-106%, and 66-103% for four spiked water samples with low relative standard deviation (2-8%), which indicates good method precision. The advantages of this novel adsorbent are high extraction efficiency, anti-interference, and convenient operation.
在本研究中，合成了壳聚糖包覆的十八烷基功能化磁铁矿纳米粒子（Fe(3)O(4)-C(18)-壳聚糖 MNPs），并将其用作吸附剂从环境水样中提取痕量分析物。这种直径为 20nm 的磁性纳米粒子具有均匀的尺寸和 52 emu g(-1)的高饱和磁化强度，使吸附剂具有较大的表面积和方便的分离性。带负电荷的全氟化合物（PFCs）被内部疏水性层的十八烷基捕获。带正电荷的壳聚糖聚合物涂层也有助于 PFC 富集。同时，该涂层通过尺寸排阻或静电排斥提高了 MNPs 在水溶液中的分散性，并增强了吸附剂对复杂样品中天然有机大分子的抗干扰能力。在预浓缩后，采用液相色谱-串联质谱系统测定 PFCs。考察并优化了影响预浓缩的主要因素。在所选择的条件下，从 500ml 几种环境水样中提取分析物，并通过氮气流将洗脱液浓缩至 0.5ml，可获得 1000 倍的浓缩因子。在高碑店废水中，对全氟辛酸（PFOA）、全氟辛烷磺酸（PFOS）、全氟壬酸（PFNA）、全氟癸酸（PFDA）、全氟十一烷酸（PFUnDA）、全氟十二烷酸（PFDoDA）和全氟十四烷酸（PFTA）的方法检出限分别为 0.24、0.093、0.24、0.14、0.075、0.24 和 0.17ng L(-1)。四种低相对标准偏差（2-8%）加标水样中 PFOA、PFOS、PFNA、PFDA、PFUnDA、PFDoDA 和 PFTA 的回收率在 88-108%、63-112%、79-109%、56-107%、66-106%、56-106%和 66-103%之间，表明方法精密度良好。这种新型吸附剂的优点是萃取效率高、抗干扰能力强、操作方便。
