Improving selectivity in gas chromatography by using chemically modified multi-walled carbon nanotubes as stationary phase

2012 ◽  
Vol 403 (4) ◽  
pp. 1157-1165 ◽  
Author(s):  
Andrea Speltini ◽  
Daniele Merli ◽  
Daniele Dondi ◽  
Giorgio Paganini ◽  
Antonella Profumo
Keyword(s):  
Carbon Nanotubes ◽  
Gas Chromatography ◽  
Stationary Phase ◽  
Chemically Modified ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Electrochemical Determination of Rivastigmine Hydrogen Tartrate at β-Cyclodextrin/Multi-Walled Carbon Nanotubes Modified Electrode

2019 ◽  
Vol 15 (3) ◽  
pp. 211-216
Author(s):  
Bugçe Kılıçyaldır ◽  
Asiye Aslıhan Avan ◽  
Kubilay Güçlü ◽  
Mustafa Özyürek ◽  
Hayati Filik
Keyword(s):  
Carbon Nanotubes ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Pharmaceutical Formulations ◽  
Carbon Electrode ◽  
Good Sensitivity ◽  
Modified Glassy Carbon Electrode ◽  
Chemically Modified ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Background: Electrochemical techniques can easily be adopted to solve many problems of pharmaceutical interest. The implementation of electroanalytical methods in the assay of pharmaceutical formulations has increased greatly. Nowadays, owing to the critical importance of electron transfer and surface properties, chemically modified electrodes have been employed in electrochemical sensors. The chemically modified electrode is one of the most popular electroanalytical sensors and used in several applications. Methods: In this work, a β-cyclodextrine/multi-walled carbon nanotubes (β-CD/MWCNTs) composite modified glassy carbon electrode (GCE) was produced and applied to the detection of Rivastigmine hydrogen tartrate (RVT) in pharmaceutical formulations. The voltammetric feature of RVT at this β- CD/MWCNTs modified electrode was evaluated using cyclic voltammetry and square wave voltammetry. Results: The β-cyclodextrin and multi-walled carbon nanotubes modified glassy carbon electrode displayed good electrocatalytic activity in the oxidation of rivastigmine hydrogen tartrate with relatively high sensitivity, stability and lifetime. The calibration graph of the analyte was linear over the range 10- 1500 µM with two linear segments and the detection limit was obtained as 2.0 µM (S/N=3). The results showed that the electrochemical sensor has good sensitivity and selectivity. Conclusion: The β-CD/MWCNTs modified electrode displayed a high electrochemical activity and good sensitivity toward the oxidation of RVT. Compared with the bare MWCNTs coated sensor, the response of analyte increased soundly and the response potential of target analyte shifted negatively. The results indicated that the β-CD/MWCNTs film coated electrode had good catalysis to the voltammetric oxidation of RVT. The prepared sensor was applied to determine RVT in pharmaceutical samples with satisfactory yields. The outcomes indicate that β-CD/MWCNTs coated electrode is a safe choice for the detection of RVT.

Effects of Covalent Functionalization on the Biocompatibility Characteristics of Multi-Walled Carbon Nanotubes

2008 ◽  
Vol 8 (5) ◽  
pp. 2347-2356 ◽  
Author(s):  
Carolina Salvador-Morales ◽  
Elena V. Basiuk ◽  
Vladimir A. Basiuk ◽  
Malcolm L. H. Green ◽  
Robert B. Sim
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Modification ◽  
Human Plasma ◽  
Complement System ◽  
Complement Activation ◽  
Classical Pathway ◽  
Covalent Functionalization ◽  
Chemically Modified ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

We report the effect of chemical modification of multi-walled carbon nanotubes (MWNTs) on their activation of the human serum complement system, as well as the adsorption of human plasma proteins on MWNTs. Four different types of chemically-modified MWNTs were tested for complement activation via the classical and alternative pathways using haemolytic assays. Human plasma protein binding was also tested using an affinity chromatography technique based on carbon nanotube-Sepharose matrix. Covalent functionalization of MWNTs greatly altered the level of activation of the complement system via the classical pathway. For example, MWNTs functionalised with ε-caprolactam or L-alanine showed respectively >90% and >75% reduction in classical pathway activation compared with unmodified MWNTs. These results demonstrate for the first time that these types of chemical modification are able to alter considerably the levels of specific complement proteins bound by pristine MWNTs (used as a control experiment). The reduced levels of complement activation via the classical pathway, that are likely to increase biocompatibility, were directly correlated with the amount of C1q protein bound to chemically modified carbon nanotubes. An inverse correlation was also observed between the amount of complement factor H bound to chemically modified MWNTs and the level of complement consumption via the alternative pathway. Binding of human plasma and serum proteins to pristine and modified MWNTs was highly selective. The chemical modifications studied generally increased nanotube dispersibility in aqueous media, but diminished protein adsorption.

Electrocatalytic performances of multi-walled carbon nanotubes chemically modified by metal phthalocyanines in Li/SOCl2batteries

RSC Advances ◽  
2016 ◽  
Vol 6 (79) ◽  
pp. 75632-75639 ◽  
Author(s):  
Weixing Yang ◽  
Ronglan Zhang ◽  
Kai Luo ◽  
Weiping Zhang ◽  
Jianshe Zhao
Keyword(s):  
Carbon Nanotubes ◽  
Metal Phthalocyanines ◽  
Chemically Modified ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

​A series of metal 2,9,16,23-tetraaminophthalocyanines have been prepared and used to chemically modify fluorinated multi-walled carbon nanotubes (F-MWCNTs). The modified F-MWCNTs can dramatically improve the capacity of the Li/SOCl2battery.

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