Surface modifications of functional electrodes of a light addressable potentiometric sensor (LAPS)

Non-dependency of pH sensitivity on the surface functional group

Yasuo Yoshimi, Takehisa Matsuda, Yoshitaka Itoh, Fukashi Ogata, Teruaki Katsube

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

To achieve a functional surface design on the electrode of a light addressable potentiometric sensor (LAPS), two different surface modification techniques were adopted to determine the effect of surface functional groups on the sensitivity and reliability of the LAPS. One was chemisorption of alkanethiols (HS-(CH2)n-X, n is 2 or 11, X is CH3, COOH or NH2) on a gold-deposited electrode, and the other was photochemical immobilization of copolymers containing benzophenone and functional groups of CON(CH3)2, COOH and N(CH3)2 in their side chains on a propyltrimethoxysilane-treated electrode. Linearity was observed between the potentials of inflection points on photocurrent-potential curves (Vpip) and the pH of the contacting solution: Vpip = a - b · pH. Gold deposition on the electrode reduced both the pH sensitivity of the Vpip and the degree of linearity of relationship between Vpip and pH. The alkanethiol chemisorption on the gold surface hardly changed the Vpip-pH relationship irrespective of the terminal functional groups of the alkanethiols, Neither the propyltrimethoxysilane treatment nor the photogel immobilizations changed the pH sensitivities of the Vpip or the linearities between Vpip and at pH 3-8. In conclusion, gold deposition is not suitable for modification of the LAPS electrode, while surface modification with photogel immobilization of a propyltrimethoxysilane-treated electrode can be used without reducing the pH sensitivity or reliability.

Original languageEnglish
Pages (from-to)131-139
Number of pages9
JournalMaterials Science and Engineering C
Volume5
Issue number2 C
Publication statusPublished - 1997 Dec
Externally publishedYes

Fingerprint

Potentiometric sensors
Functional groups
Surface treatment
Gold
Electrodes
electrodes
sensitivity
sensors
immobilization
gold
Chemisorption
linearity
chemisorption
Photocurrents
inflection points
Copolymers
photocurrents
copolymers
propyltrimethoxysilane

Keywords

  • Alkanethiol
  • Benzophenone
  • Light addressable potentiometric sensor (LAPS)
  • pH
  • Photoreactive copolymer
  • Self-assembled monolayer

ASJC Scopus subject areas

  • Biomaterials

Cite this

Surface modifications of functional electrodes of a light addressable potentiometric sensor (LAPS) : Non-dependency of pH sensitivity on the surface functional group. / Yoshimi, Yasuo; Matsuda, Takehisa; Itoh, Yoshitaka; Ogata, Fukashi; Katsube, Teruaki.

In: Materials Science and Engineering C, Vol. 5, No. 2 C, 12.1997, p. 131-139.

Research output: Contribution to journalArticle

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