Modified carbon nanotubes in online speciation of chromium in real water samples using hyphenated FI-FAAS

2017 ◽  
Vol 41 (12) ◽  
pp. 5034-5039 ◽  
Author(s):  
Shelja Tiwari ◽  
Niharika Sharma ◽  
Reena Saxena

Fast preconcentrative speciation of chromium in polluted water samples using l-arginine functionalized multi-walled carbon nanotubes.

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5729
Author(s):  
Jiping Ma ◽  
Liwei Hou ◽  
Gege Wu ◽  
Liyan Wang ◽  
Xiaoyan Wang ◽  
...  

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.


2012 ◽  
Vol 622-623 ◽  
pp. 781-786
Author(s):  
Sarojini Swain ◽  
Subhendu Bhattacharya ◽  
Ram Avatar Sharma ◽  
Lokesh Chaudhari

Hydroxyl modified multi-walled carbon nanotubes (OH-MWCNT)/ polyurethane (PU) and graphene nanosheets (GNS)/PU composites were prepared by dispersing the OH-MWCNT and GNS at different wt % in to the PU matrix. It was found that the electrical percolation threshold of the GNS/PU composite is much higher compared to that of OH-MWCNT/PU and also the electrical conductivity of the OH-MWCNT/PU composite is higher than the GNS/PU composite in the same level of filler content. This may be due to the two composites having different electrical conduction mechanisms: The OH-MWCNT/PU composite represents a three dimensional conduction system while, the GNS/PU composite represents a two dimensional conduction system. The improvement in the electrical conductivity with the incorporation of GNS as a filler in the composite is far lower than what theoretically expected. It is also observed that the tensile strength of the OH-MWCNT/PU composite is higher compared to the GNS/PU in the same level filler content.


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