Development, characterization, and applications of optical pH sensors supported at cellulosic film

Technical Report · Thu Aug 09 00:00:00 EDT 1990

DOI:https://doi.org/10.2172/6655170· OSTI ID:6655170

Jones, T P

Sensors for the determination of pH have been developed which are based on the immobilization of direct dyes at hydrolyzed cellulosic films. The performance and structural characteristics of the sensors were investigated by a variety of spectroscopic methods, and applications for remote sensing were developed. Films of cellulose acetate were base hydrolyzed in 0.07 M KOH to yield a porous support structure. The structural changes resulting from the hydrolysis on cellulose acetate were probed with infrared internal reflectance spectroscopy. The progress of the hydrolysis reaction was monitored by the changes in vibrational modes of the acetyl group, and other spectral changes indicated changes in film thickness as a result of solvent incorporation. Direct dyes, including Congo Red and C. I. Direct Blue 8, were then immobilized at these porous cellulosic films. The optical response characteristics of the Congo Red pH sensor were characterized, including the UV-visible absorption spectra as a function of pH, the response time as a function of ionic strength and ionic size of electrolyte, the long-term stability of the sensor, the effects of metal-ion interference, and the concentration of Congo Red in the polymer film. The structural characteristics of the sensor were investigated by internal reflectance spectroscopy and resonance-enhanced Raman spectroscopy, and the protonation sites were identified as the two azo groups of Congo Red. Infrared internal reflection spectra of immobilized Congo Red led to the development of a sensor for pH based on infrared spectroscopy. Finally, a two-wavelength fiber-optic photometer, which is based on solid-state sources and detectors, and a fiber-optic photometer, which is based on solid-state sources and detectors, and a fiber-optic probe were developed for pH determinations using Congo Red and C. I. Direct Blue 8 pH sensors.

• Research Organization: Ames Lab., Ames, IA (United States)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6655170
• Report Number(s): IS-T-1484; ON: DE90016416
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ACETATES
HYDROLYSIS
CELLULOSE
MEASURING INSTRUMENTS
PERFORMANCE
PH VALUE
MEASURING METHODS
CHEMICAL REACTION KINETICS
CONGO RED
INFRARED SPECTRA
OPTICAL PROPERTIES
POLYMERS
RAMAN SPECTROSCOPY
THIN FILMS
AMINES
AZO COMPOUNDS
AZO DYES
CARBOHYDRATES
CARBOXYLIC ACID SALTS
CHEMICAL REACTIONS
DECOMPOSITION
DYES
FILMS
INDICATORS
KINETICS
LASER SPECTROSCOPY
LYSIS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PHYSICAL PROPERTIES
POLYSACCHARIDES
REACTION KINETICS
SACCHARIDES
SOLVOLYSIS
SPECTRA
SPECTROSCOPY
SULFONIC ACIDS
400102* - Chemical & Spectral Procedures
400201 - Chemical & Physicochemical Properties