Voltammetric determination of tryptophan at a single-wall carbon nanotubes modified electrode.
A single-wall carbon nanotubes (SWNT)-film coated glassy carbon electrode (GCE) was described for the determination of tryptophan. In pH 2.5 Na2HPO4-citric acid buffer, tryptophan yields a well-defined and very sensitive oxidation peak at about 1.08 V at the SWNT-film coated GCE. The oxidation peak current increases greatly and the peak potential shifts toward more negative direction at the SWNT-modified GCE in contrast to that at the bare GCE. Under optimized conditions, the oxidation peak current is proportional to the concentration of tryptophan over the range from 4 x 10(-8) to 1 x 10(-5) mol/L. The detection limit is 1 x 10(-8) mol/L at 3 min of accumulation. Using the proposed method, tryptophan in the human's blood serum samples was determined.
Huang
Wensheng
W
Department of Chemistry, Hubei Institute for Nationalities, Enshi 445000, Hubei, China.
Mai
Guo
G
Liu
Yingxuan
Y
Yang
Chunhai
C
Qu
Wanyun
W
D002138:Calibration; D002244:Carbon / Q000737:chemistry; D019343:Citric Acid / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods*; D004566:Electrodes; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry* / Q000378:metabolism; D013499:Surface Properties; D013997:Time Factors; D014364:Tryptophan / Q000097:blood / Q000737:chemistry*
D037742:Nanotubes, Carbon; D019343:Citric Acid; D002244:Carbon; D014364:Tryptophan; D010100:Oxygen