Niu Hongyun, Cai Yaqi, Shi Yali, Wei Fusheng, Liu Jiemin, Mou Shifen, Jiang Guibin
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China.
Anal Chim Acta. 2007 Jun 26;594(1):81-92. doi: 10.1016/j.aca.2007.05.017. Epub 2007 May 21.
The adsorptive potential of carbon nanotubes (single-walled carbon nanotubes and multi-walled carbon nanotubes) for solid-phase extraction of three groups of highly polar compounds (namely cephalosporins antibiotics, sulfonamides and phenolic compounds) was tested in this article. The analytes were strongly retained by the carbon nanotubes. And acceptable recoveries were obtained with the addition of ammonium acetate into eluents. The effects of solution pH on the recoveries of the antibiotics and phenolic compounds were examined. To check the retention abilities of three groups of compounds on carbon nanotubes, fixed amount of each analyte was added to different volumes (up to 500 mL) of aqueous solution, and then extracted by the sorbents. Comparative studies showed that the carbon nanotubes were much superior to C18 for the extraction of the highly polar analytes. For the cephalosporins antibiotics and sulfonamides, the carbon nanotubes showed stronger retention capability than graphitized carbon blacks, but for some of the phenolic compounds graphitized carbon blacks seemed to be more suitable, indicating different retention mechanisms of these analytes. To further assess the enrichment ability of carbon nanotubes for highly polar compounds, the solid-phase extraction method of multi-walled carbon nanotubes packed cartridge was well developed, and the sulfonamides were used as model compounds. Under the optimal procedures, the detection limits of sulfonamides were in the range of 27-38 ng L(-1). The spiked recoveries from several real water samples obtained for sulfathiazole and sulfadiazine ranged from 55% to 79% and 72% to 92%, respectively, while the recoveries of sulfapyridine and sulfamethazine were in the range of 85-102%.
本文测试了碳纳米管（单壁碳纳米管和多壁碳纳米管）对三类高极性化合物（即头孢菌素类抗生素、磺胺类药物和酚类化合物）进行固相萃取的吸附潜力。分析物被碳纳米管强烈保留。通过在洗脱液中添加醋酸铵获得了可接受的回收率。研究了溶液pH对抗生素和酚类化合物回收率的影响。为了检验三类化合物在碳纳米管上的保留能力，将固定量的每种分析物添加到不同体积（高达500 mL）的水溶液中，然后用吸附剂进行萃取。对比研究表明，对于高极性分析物的萃取，碳纳米管比C18优越得多。对于头孢菌素类抗生素和磺胺类药物，碳纳米管显示出比石墨化炭黑更强的保留能力，但对于某些酚类化合物，石墨化炭黑似乎更合适，这表明这些分析物的保留机制不同。为了进一步评估碳纳米管对高极性化合物的富集能力，完善了多壁碳纳米管填充柱的固相萃取方法，并将磺胺类药物用作模型化合物。在最佳条件下，磺胺类药物的检测限在27 - 38 ng L(-1)范围内。从几个实际水样中加标回收得到的磺胺噻唑和磺胺嘧啶的回收率分别为55%至79%和72%至92%，而磺胺吡啶和磺胺二甲嘧啶的回收率在85 - 102%范围内。
