INVESTIGADORES
RIVAS Gustavo Adolfo
artículos
Título:
Dispersion of multi-wall carbon nanotubes in polyhistidine: characterization and analytical applications
Autor/es:
DALMASSO PABLO; M. L. PEDANO; G. A. RIVAS
Revista:
ANALYTICA CHIMICA ACTA
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2012 vol. 710 p. 58 - 64
ISSN:
0003-2670
Resumen:
We report for the first time the use of polyhistidine (Polyhis) to efficiently disperse multiwall carbon
nanotubes (MWCNTs). The optimum dispersion MWCNT?Polyhis was obtained by sonicating for 30 min
1.0 mg mL−1 MWCNTs in 0.25 mg mL−1 Polyhis solution prepared in 75:25 (v/v) ethanol/0.200 M acetate
buffer solution pH 5.00. The dispersion was characterized by scanning electron microscopy, and by cyclic
voltammetry and amperometry using ascorbic acid as redox marker. The modification of glassy carbon
electrodes with MWCNT?Polyhis produces a drastic decrease in the overvoltage for the oxidation of
ascorbic acid (580 mV) at variance with the response observed at glassy carbon electrodes modified just
with Polyhis, where the charge transfer is more difficult due to the blocking effect of the polymer. The
reproducibility for the sensitivities obtained after 10 successive calibration plots using the same surface
was 6.3%. The MWCNT-modified glassy carbon electrode demonstrated to be highly stable since after 45
days storage at room temperature the response was 94.0% of the original. The glassy carbon electrode
modified with MWCNT?Polyhis dispersion was successfully used to quantify dopamine or uric acid at
nanomolar levels, even in the presence of large excess of ascorbic acid. Determinations of uric acid in
human blood serum samples demonstrated a very good correlation with the value reported by Wienner
laboratory.
buffer solution pH 5.00. The dispersion was characterized by scanning electron microscopy, and by cyclic
voltammetry and amperometry using ascorbic acid as redox marker. The modification of glassy carbon
electrodes with MWCNT?Polyhis produces a drastic decrease in the overvoltage for the oxidation of
ascorbic acid (580 mV) at variance with the response observed at glassy carbon electrodes modified just
with Polyhis, where the charge transfer is more difficult due to the blocking effect of the polymer. The
reproducibility for the sensitivities obtained after 10 successive calibration plots using the same surface
was 6.3%. The MWCNT-modified glassy carbon electrode demonstrated to be highly stable since after 45
days storage at room temperature the response was 94.0% of the original. The glassy carbon electrode
modified with MWCNT?Polyhis dispersion was successfully used to quantify dopamine or uric acid at
nanomolar levels, even in the presence of large excess of ascorbic acid. Determinations of uric acid in
human blood serum samples demonstrated a very good correlation with the value reported by Wienner
laboratory.
−1 MWCNTs in 0.25 mg mL−1 Polyhis solution prepared in 75:25 (v/v) ethanol/0.200 M acetate
buffer solution pH 5.00. The dispersion was characterized by scanning electron microscopy, and by cyclic
voltammetry and amperometry using ascorbic acid as redox marker. The modification of glassy carbon
electrodes with MWCNT?Polyhis produces a drastic decrease in the overvoltage for the oxidation of
ascorbic acid (580 mV) at variance with the response observed at glassy carbon electrodes modified just
with Polyhis, where the charge transfer is more difficult due to the blocking effect of the polymer. The
reproducibility for the sensitivities obtained after 10 successive calibration plots using the same surface
was 6.3%. The MWCNT-modified glassy carbon electrode demonstrated to be highly stable since after 45
days storage at room temperature the response was 94.0% of the original. The glassy carbon electrode
modified with MWCNT?Polyhis dispersion was successfully used to quantify dopamine or uric acid at
nanomolar levels, even in the presence of large excess of ascorbic acid. Determinations of uric acid in
human blood serum samples demonstrated a very good correlation with the value reported by Wienner
laboratory.