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Title: Optical pH sensor based on the chemical modification of a porous polymer film

Abstract

A new approach to the design and construction of an optical pH sensor has been developed by immobilizing a direct azo dye at a porous cellulosic polymer film. This sensor was fabricated by binding Congo Red to a cellulose acetate film that had previously been subjected to an exhaustive base hydrolysis. Advantageous features of the design include (1) a rapid equilibration time (< 1.3 s), (2) a large dynamic range (> 4 pH units), and (3) ease of fabrication. The rapid response results from the porous structure of the polymeric support, which minimizes barriers to mass transport. The large dynamic range results from both the polyprotic acid-base reactivity of Congo Red and the large optical absorptivities of its various ionic forms. Furthermore, these results indicate that a variety of optical sensors which exhibit a rapid and sensitive response for the analysis of pH can be easily fabricated by immobilizing carefully selected direct dyes at porous polymeric substrates such as hydrolyzed cellulose acetate.

Authors:
;
Publication Date:
Research Org.:
Iowa State Univ., Ames (USA)
OSTI Identifier:
7247968
DOE Contract Number:  
W-7405-ENG-82
Resource Type:
Journal Article
Journal Name:
Anal. Chem.; (United States)
Additional Journal Information:
Journal Volume: 60:5
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; OPTICAL SPECTROMETERS; DESIGN; FABRICATION; PH VALUE; MEASURING METHODS; ABSORPTION SPECTROSCOPY; ACETATES; AZO DYES; CELLULOSE; EXPERIMENTAL DATA; ORGANIC POLYMERS; THIN FILMS; AZO COMPOUNDS; CARBOHYDRATES; CARBOXYLIC ACID SALTS; DATA; DYES; FILMS; INFORMATION; MEASURING INSTRUMENTS; NUMERICAL DATA; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; POLYMERS; POLYSACCHARIDES; SACCHARIDES; SPECTROMETERS; SPECTROSCOPY; 400102* - Chemical & Spectral Procedures

Citation Formats

Jones, T P, and Porter, M D. Optical pH sensor based on the chemical modification of a porous polymer film. United States: N. p., 1988. Web. doi:10.1021/ac00156a006.
Jones, T P, & Porter, M D. Optical pH sensor based on the chemical modification of a porous polymer film. United States. https://doi.org/10.1021/ac00156a006
Jones, T P, and Porter, M D. 1988. "Optical pH sensor based on the chemical modification of a porous polymer film". United States. https://doi.org/10.1021/ac00156a006.
@article{osti_7247968,
title = {Optical pH sensor based on the chemical modification of a porous polymer film},
author = {Jones, T P and Porter, M D},
abstractNote = {A new approach to the design and construction of an optical pH sensor has been developed by immobilizing a direct azo dye at a porous cellulosic polymer film. This sensor was fabricated by binding Congo Red to a cellulose acetate film that had previously been subjected to an exhaustive base hydrolysis. Advantageous features of the design include (1) a rapid equilibration time (< 1.3 s), (2) a large dynamic range (> 4 pH units), and (3) ease of fabrication. The rapid response results from the porous structure of the polymeric support, which minimizes barriers to mass transport. The large dynamic range results from both the polyprotic acid-base reactivity of Congo Red and the large optical absorptivities of its various ionic forms. Furthermore, these results indicate that a variety of optical sensors which exhibit a rapid and sensitive response for the analysis of pH can be easily fabricated by immobilizing carefully selected direct dyes at porous polymeric substrates such as hydrolyzed cellulose acetate.},
doi = {10.1021/ac00156a006},
url = {https://www.osti.gov/biblio/7247968}, journal = {Anal. Chem.; (United States)},
number = ,
volume = 60:5,
place = {United States},
year = {Tue Mar 01 00:00:00 EST 1988},
month = {Tue Mar 01 00:00:00 EST 1988}
}