Nanotube-grafted polyacrylamide hydrogels for electrophoretic protein separation

Multiwalled carbon nanotube-modified polyacrylamide gels have been employed for the electrophoretic separation of proteins. Two approaches are compared in this investigation, one using nanotubes only as fillers inside the gel matrix and the other using nanotubes as catalyst for polymerization of acrylamide. In both the cases, polymerization of acryl-amide/bisacrylamide has been carried out in situ in the presence of nanotubes dispersed in the gel buffer containing monomer and cross-linker. In the former case, initiator and catalyst have been added after ultrasonication of nanotubes in the gel buffer mixture where the nanotubes play the role of filler. On the other hand, the second approach precludes use of catalyst and involves addition of initiator alone during ultrasonication of nanotubes in the gel buffer containing monomer and cross-linker, which leads to the formation of nanotube-grafted gel after 25 min. When nanotubes are used as a catalyst instead of N,N,N',N'-tetramethylethylenediamine, pore size distribution of the gel matrix and linearity of molecular weight calibration plots are found to be improved. In addition, other issues associated with the use of an external catalyst like handling the moisture-sensitive and corrosive reagent and associated irreproducibility are addressed in this approach.     

Synthesis of Co‐doped CeO2 nanorods modified glassy carbon electrode for electrochemical detection of nitrobenzene

CeO₂ nanoparticles (CNPs), Co‐doped CeO₂ nanoparticles (CCNPs) and Co‐doped CeO₂ nanorods (CCNRs) were synthesized by simple co‐precipitation method and explored their sensing behaviour towards nitrobenzene. XRD and TEM analysis confirmed the presence of cubic fluorite structure of the CNPs, CCNPs and CCNRs. EDX analysis confirmed the presence of Cobalt in CeO₂ nanorods. The electrochemical sensing of nitrobenzene was carried out using CCNRs‐modified glassy carbon (GC) electrodes by means of cyclic voltammetric (CV) technique. The peak current (I_p) was found to be linearly co‐related to nitrobenzene (NB) concentration (R² = 0.9665). A substantial enhancement in cathodic peak current (C1), and sensitivity (∼738.8 nA/μM) was observed for the CCNRs‐modified GC electrode than those of CNPs and CCNPs‐modified electrodes.