Department of Chemistry, Fudan University, Shanghai, China.
J Sep Sci. 2012 Jul;35(13):1667-74. doi: 10.1002/jssc.201200062.
In this work, magnetic multiwalled carbon nanotubes were synthesized through a facile hydrothermal process, and then successfully used as magnetic solid-phase extraction sorbents for the determination of p-hydroxybenzoates in beverage. The prepared magnetic multiwalled carbon nanotubes presented both satisfactory superparamagnetism and strong capacity of absorption, with magnetic Fe(3)O(4) beads of 200 nm average diameters decorated at either ends of the tubes. The hybrid nanocomposites showed a high efficiency in the extraction and enrichment of p-hydroxybenzoates via π-π stacking of targeted molecules onto the polyaromatic composed surface of multiwalled carbon nanotubes, which entitled them promising magnetic solid-phase extraction sorbents for p-hydroxybenzoates at trace level from complex drink samples. By using an external magnetic field, p-hydroxybenzoates adsorbed on magnetic multiwalled carbon nanotubes could be rapidly isolated in only 30 s, and subsequently analyzed by liquid chromatography-diode array detector after elution with organic solvents. Extraction conditions such as eluting solvent, the amounts of magnetic sorbents added, pH values, adsorption and desorption time were investigated and optimized to achieve the best effect. Method validations including linearity, detection limit, and precision were also studied. The linearities were in the wide range of 0.05-500 μg/mL with correlation coefficients higher than 0.9983 for all p-hydroxybenzoates. The limits of detection were less than 20 ng/mL. Acceptable RSDs were achieved within 5-8% for all analytes. The results indicated that the proposed method based on magnetic multiwalled carbon nanotubes as magnetic solid-phase extraction absorbents was rapid, efficient, and convenient for the analysis of the targeted compounds of p-hydroxybenzoates in beverage sample.
在这项工作中，通过简单的水热法合成了磁性多壁碳纳米管，然后成功地将其用作磁性固相萃取吸附剂，用于测定饮料中的对羟基苯甲酸酯。所制备的磁性多壁碳纳米管具有令人满意的超顺磁性和强大的吸附能力，两端都装饰有平均直径为 200nm 的磁性 Fe(3)O(4)珠。通过目标分子π-π堆积在多壁碳纳米管的多环芳烃组成表面上，杂化纳米复合材料在提取和富集对羟基苯甲酸酯方面表现出高效率，这使它们成为从复杂饮料样品中痕量水平测定对羟基苯甲酸酯的有前途的磁性固相萃取吸附剂。通过使用外部磁场，仅需 30 秒即可将吸附在磁性多壁碳纳米管上的对羟基苯甲酸酯快速分离，然后用有机溶剂洗脱后通过液相色谱-二极管阵列检测器进行分析。研究并优化了提取条件，如洗脱溶剂、添加的磁性吸附剂的量、pH 值、吸附和解吸时间，以达到最佳效果。还研究了方法验证，包括线性、检测限和精密度。所有对羟基苯甲酸酯的线性范围均为 0.05-500μg/mL，相关系数均高于 0.9983。检测限均小于 20ng/mL。所有分析物的 RSD 均在 5-8%之间。结果表明，基于磁性多壁碳纳米管作为磁性固相萃取吸附剂的方法快速、高效、方便，适用于饮料样品中目标化合物对羟基苯甲酸酯的分析。
