Effect of surface modification of indium tin oxide by nanoparticles on the electrochemical determination of tryptophan

Rajendra N. Goyal; Sunita Bishnoi; Himanshu Chasta; Md Abdul Aziz; Munetaka Oyama

doi:10.1016/j.talanta.2011.08.031

Effect of surface modification of indium tin oxide by nanoparticles on the electrochemical determination of tryptophan

Rajendra N. Goyal^*
, Sunita Bishnoi
, Himanshu Chasta
, Md Abdul Aziz
, Munetaka Oyama

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

57 Scopus citations

Abstract

The effect of surface modification of indium tin oxide (ITO) by multi wall carbon nanotube (MWNT) and gold nanoparticles attached multi wall carbon nanotube (AuNP-MWNT) has been studied to determine tryptophan, an important and essential amino acid for humans and herbivores. A detailed comparison has been made among the voltammetric response of bare ITO, MWNT/ITO and AuNP-MWNT/ITO in respects of several essential analytical parameters viz. sensitivity, detection limit, peak current and peak potential of tryptophan. The AuNP-MWNT/ITO exhibited a well defined anodic peak at pH 7.2 at a potential of ∼669 mV for the oxidation of tryptophan as compared to 760 mV at MWNT/ITO electrode. Under optimum conditions linear calibration curve was obtained over tryptophan concentration range 0.5-90.0 μM in phosphate buffer solution of pH 7.2 with detection limit and sensitivity of 0.025 μM and 0.12 μA μM ^-1, respectively. The oxidation of tryptophan occurred in a pH dependent, 2e^- and 2H⁺ process and the electrode reaction followed adsorption controlled pathway. The method has been found selective and successfully implemented for the determination of tryptophan in human urine and plasma samples using standard addition method. The electrode exhibited an efficient catalytic response with good reproducibility and stability.

Original language	English
Pages (from-to)	2626-2631
Number of pages	6
Journal	Talanta
Volume	85
Issue number	5
DOIs	https://doi.org/10.1016/j.talanta.2011.08.031
State	Published - 15 Oct 2011
Externally published	Yes

Keywords

Carbon nanotubes
Human plasma
Human urine
Indium tin oxide
Nanogold
Tryptophan

ASJC Scopus subject areas

Analytical Chemistry

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10.1016/j.talanta.2011.08.031

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title = "Effect of surface modification of indium tin oxide by nanoparticles on the electrochemical determination of tryptophan",

abstract = "The effect of surface modification of indium tin oxide (ITO) by multi wall carbon nanotube (MWNT) and gold nanoparticles attached multi wall carbon nanotube (AuNP-MWNT) has been studied to determine tryptophan, an important and essential amino acid for humans and herbivores. A detailed comparison has been made among the voltammetric response of bare ITO, MWNT/ITO and AuNP-MWNT/ITO in respects of several essential analytical parameters viz. sensitivity, detection limit, peak current and peak potential of tryptophan. The AuNP-MWNT/ITO exhibited a well defined anodic peak at pH 7.2 at a potential of ∼669 mV for the oxidation of tryptophan as compared to 760 mV at MWNT/ITO electrode. Under optimum conditions linear calibration curve was obtained over tryptophan concentration range 0.5-90.0 μM in phosphate buffer solution of pH 7.2 with detection limit and sensitivity of 0.025 μM and 0.12 μA μM -1, respectively. The oxidation of tryptophan occurred in a pH dependent, 2e- and 2H+ process and the electrode reaction followed adsorption controlled pathway. The method has been found selective and successfully implemented for the determination of tryptophan in human urine and plasma samples using standard addition method. The electrode exhibited an efficient catalytic response with good reproducibility and stability.",

keywords = "Carbon nanotubes, Human plasma, Human urine, Indium tin oxide, Nanogold, Tryptophan",

author = "Goyal, \{Rajendra N.\} and Sunita Bishnoi and Himanshu Chasta and Aziz, \{Md Abdul\} and Munetaka Oyama",

year = "2011",

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doi = "10.1016/j.talanta.2011.08.031",

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T1 - Effect of surface modification of indium tin oxide by nanoparticles on the electrochemical determination of tryptophan

AU - Goyal, Rajendra N.

AU - Bishnoi, Sunita

AU - Chasta, Himanshu

AU - Aziz, Md Abdul

AU - Oyama, Munetaka

PY - 2011/10/15

Y1 - 2011/10/15

N2 - The effect of surface modification of indium tin oxide (ITO) by multi wall carbon nanotube (MWNT) and gold nanoparticles attached multi wall carbon nanotube (AuNP-MWNT) has been studied to determine tryptophan, an important and essential amino acid for humans and herbivores. A detailed comparison has been made among the voltammetric response of bare ITO, MWNT/ITO and AuNP-MWNT/ITO in respects of several essential analytical parameters viz. sensitivity, detection limit, peak current and peak potential of tryptophan. The AuNP-MWNT/ITO exhibited a well defined anodic peak at pH 7.2 at a potential of ∼669 mV for the oxidation of tryptophan as compared to 760 mV at MWNT/ITO electrode. Under optimum conditions linear calibration curve was obtained over tryptophan concentration range 0.5-90.0 μM in phosphate buffer solution of pH 7.2 with detection limit and sensitivity of 0.025 μM and 0.12 μA μM -1, respectively. The oxidation of tryptophan occurred in a pH dependent, 2e- and 2H+ process and the electrode reaction followed adsorption controlled pathway. The method has been found selective and successfully implemented for the determination of tryptophan in human urine and plasma samples using standard addition method. The electrode exhibited an efficient catalytic response with good reproducibility and stability.

AB - The effect of surface modification of indium tin oxide (ITO) by multi wall carbon nanotube (MWNT) and gold nanoparticles attached multi wall carbon nanotube (AuNP-MWNT) has been studied to determine tryptophan, an important and essential amino acid for humans and herbivores. A detailed comparison has been made among the voltammetric response of bare ITO, MWNT/ITO and AuNP-MWNT/ITO in respects of several essential analytical parameters viz. sensitivity, detection limit, peak current and peak potential of tryptophan. The AuNP-MWNT/ITO exhibited a well defined anodic peak at pH 7.2 at a potential of ∼669 mV for the oxidation of tryptophan as compared to 760 mV at MWNT/ITO electrode. Under optimum conditions linear calibration curve was obtained over tryptophan concentration range 0.5-90.0 μM in phosphate buffer solution of pH 7.2 with detection limit and sensitivity of 0.025 μM and 0.12 μA μM -1, respectively. The oxidation of tryptophan occurred in a pH dependent, 2e- and 2H+ process and the electrode reaction followed adsorption controlled pathway. The method has been found selective and successfully implemented for the determination of tryptophan in human urine and plasma samples using standard addition method. The electrode exhibited an efficient catalytic response with good reproducibility and stability.

KW - Carbon nanotubes

KW - Human plasma

KW - Human urine

KW - Indium tin oxide

KW - Nanogold

KW - Tryptophan

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DO - 10.1016/j.talanta.2011.08.031

M3 - Article

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SN - 0039-9140

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EP - 2631

JO - Talanta

JF - Talanta

IS - 5

ER -

Effect of surface modification of indium tin oxide by nanoparticles on the electrochemical determination of tryptophan

Abstract

Keywords

ASJC Scopus subject areas

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