López-Feria Silvia, Lucena Rafael, Cárdenas Soledad, Valcárcel Miguel
CIFA Venta del Llano, IFAPA, Ctra. Bailén-Motril km 18.5 Mengíbar, 23620 Jaén, Spain.
Anal Bioanal Chem. 2009 Oct;395(3):737-46. doi: 10.1007/s00216-009-3066-4.
This article presents a novel application of the surfactant-coated carbon nanotubes for the joint extraction of phthalates, xylene isomers and styrene from virgin olive oils. For this purpose, two carbon nanotubes, multi-walled and single-walled carbon nanotubes, were evaluated, the former providing the better results. The target migrants were liquid-liquid extracted from the virgin olive oil samples by means of the carbon nanotube pseudophase, and the aqueous extracts were analysed by headspace-gas chromatography-mass spectrometry. Sodium chloride was added to favour the release of the analytes to the gaseous phase of the vial. The comparison of the chromatograms obtained with the direct analysis reveals a sensitivity enhancement with the use of the surfactant-coated carbon nanotubes, especially for the phthalates, which can be ascribed to the pi-pi interaction between the aromatic ring and the nanotube surface. Limits of detection were between 6 and 30 microg L(-1) for 1 mL of sample. The precision of the method was better than 7.6% and the recoveries higher than 92%. Finally, the influence of the package material and the storage conditions on the concentration of the analytes was accomplished, and it was found that the concentration of phthalates increases with time in all the packages studied, while the more volatile compounds were found to decrease under the same conditions.
本文介绍了表面活性剂包覆的碳纳米管在从初榨橄榄油中联合萃取邻苯二甲酸酯、二甲苯异构体和苯乙烯方面的新应用。为此，对两种碳纳米管，即多壁碳纳米管和单壁碳纳米管进行了评估，结果表明前者效果更佳。通过碳纳米管假相从初榨橄榄油样品中液 - 液萃取目标迁移物，水相萃取物采用顶空气相色谱 - 质谱联用仪进行分析。添加氯化钠有利于分析物释放到小瓶的气相中。与直接分析获得的色谱图比较表明，使用表面活性剂包覆的碳纳米管可提高灵敏度，尤其是对于邻苯二甲酸酯，这可归因于芳环与纳米管表面之间的π - π相互作用。对于1 mL样品，检测限在6至30 μg L⁻¹之间。该方法的精密度优于7.6%，回收率高于92%。最后，研究了包装材料和储存条件对分析物浓度的影响，结果发现，在所研究的所有包装中，邻苯二甲酸酯的浓度随时间增加，而在相同条件下，挥发性较强的化合物浓度则降低。
