Direct amperometric detection of glucose on a multiple-branching carbon nanotube forest.
We show here that a re-structured carbon nanotube (CNT) forest can be used 'as-received' for high selectivity, non-enzymatic glucose detection without the need to incorporate catalytic metal nanoparticles or an exclusion polymeric membrane. Direct amperometric sensing of glucose has been achieved by using multiply-branched CNTs prepared by growing secondary or tertiary 'offshoot' CNTs on top of the existing CNT layer. The increased roughness factor on these re-structured CNTs enhances the amperometric detection sensitivity for glucose by a factor of 20x over that of interfering species like ascorbic acid or uric acid. A sensitivity of 60 microA mM(-1) cm(-2) and a detection limit of 1 microM, with a linear detection range of 1-11 mM (R(2) = 0.999), could be attained on the re-grown CNTs. When the re-grown CNTs were subjected to further anodization in acid to introduce a highly-charged interface, the sensitivity to glucose was enhanced to 157 microA mM(-1) cm(-2).
Tan
Chow Khim
CK
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore.
Loh
Kian Ping
KP
John
Thong T L
TT
D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D005947:Glucose / Q000032:analysis*; D008855:Microscopy, Electron, Scanning; D036103:Nanotechnology; D037742:Nanotubes, Carbon / Q000648:ultrastructure; D012680:Sensitivity and Specificity
D037742:Nanotubes, Carbon; D005947:Glucose