scholarly journals Solid phase extraction of polyhalogenated pollutants from freshwater using chemically modified multi-walled carbon nanotubes and their determination by gas chromatography

2009 ◽  
Vol 32 (10) ◽  
pp. 1769-1769 ◽  
Author(s):  
Mohamed Abdel Salam ◽  
Robert Burk
Keyword(s):  
Carbon Nanotubes ◽  
Gas Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Phase Extraction ◽  
Chemically Modified ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

scholarly journals Solid-phase extraction cartridges with multi-walled carbon nanotubes and effect of the oxygen functionalities on the recovery efficiency of organic micropollutants

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Marta O. Barbosa ◽  
Rui S. Ribeiro ◽  
Ana R. L. Ribeiro ◽  
M. Fernando R. Pereira ◽  
Adrián M. T. Silva
Keyword(s):  
Carbon Nanotubes ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Surface Groups ◽  
Phase Extraction ◽  
Organic Micropollutants ◽  
Oxidation Method ◽  
Hydrothermal Oxidation ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

AbstractPristine and functionalized multi-walled carbon nanotubes (MWCNTs) were investigated as adsorbent materials inside solid-phase extraction (SPE) cartridges for extraction and preconcentration of 8 EU-relevant organic micropollutants (with different pKa and polarity) before chromatographic analysis of surface water. The recoveries obtained were > 60% for 5/8 target pollutants (acetamiprid, atrazine, carbamazepine, diclofenac, and isoproturon) using a low amount of this reusable adsorbent (50 mg) and an eco-friendly solvent (ethanol) for both conditioning and elution steps. The introduction of oxygenated surface groups in the carbon nanotubes by using a controlled HNO3 hydrothermal oxidation method, considerably improved the recoveries obtained for PFOS (perfluorooctanesulfonic acid) and methiocarb, which was ascribed to the hydrogen bond adsorption mechanism, but decreased those observed for the pesticide acetamiprid and for two pharmaceuticals (carbamazepine and diclofenac), suggesting π–π dispersive interactions. Moreover, a good correlation was found between the recovery obtained for methiocarb and the amount of oxygenated surface groups on functionalized MWCNTs, which was mainly attributed to the increase of phenols and carbonyl and quinone groups. Thus, the HNO3 hydrothermal oxidation method can be used to finely tune the surface chemistry (and texture) of MWCNTs according to the specific micropollutants to be extracted and quantified in real water samples.

scholarly journals Multi-Walled Carbon Nanotubes for Magnetic Solid-Phase Extraction of Six Heterocyclic Pesticides in Environmental Water Samples Followed by HPLC-DAD Determination

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5729
Author(s):  
Jiping Ma ◽  
Liwei Hou ◽  
Gege Wu ◽  
Liyan Wang ◽  
Xiaoyan Wang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Solid Phase Extraction ◽  
Water Samples ◽  
Solid Phase ◽  
Magnetic Solid Phase Extraction ◽  
Environmental Water ◽  
Phase Extraction ◽  
Multi Walled Carbon Nanotubes ◽  
Magnetic Solid ◽  
Walled Carbon Nanotubes

Magnetic multi-walled carbon nanotubes were prepared as magnetic solid-phase extraction (MSPE) adsorbent for the enrichment of six heterocyclic pesticides in environmental water samples, including imidacloprid, triadimefon, fipronil, flusilazole, chlorfenapyr and fenpyroximate. Then six heterocyclic pesticides were separated and determined by high-performance liquid chromatography-diode-array detector (HPLC-DAD). Major factors influencing MSPE efficiency, including the dose of mag-multi-walled carbon nanotubes (mag-MWCNTs), extraction time, solution pH, salt concentration, type and volume of eluent and desorption time were investigated. Under the optimized conditions, the enrichment factor of the method reached to 250. The linearity was achieved within 0.05–10.0 μg/L for imidacloprid and chlorfenapyr, 0.10–10.0 μg/L for fipronil, flusilazole, triadimefon and fenpyroximate. Limits of detection were in the range of 0.01–0.03 μg/L. Good precision at three spiked levels were 1.1–11.2% (intra-day) and 1.7–11.0% (inter-day) with relative standard deviation of peak area, respectively. The developed method was utilized to analyze tap water, river water and reservoir water samples and recoveries at three spiked concentration levels ranged from 72.2% to 107.5%. The method was proved to be a convenient, rapid and practical method for sensitive determination of heterocyclic pesticides.

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