In situ detection of organic molecules: Optrodes for TCE (trichloroethylene) and CHCl sub 3

Technical Report · Tue May 01 00:00:00 EDT 1990

DOI:https://doi.org/10.2172/7045952· OSTI ID:7045952

Angel, S. M.; Langry, K. C.; Ridley, M. N.

We have developed new absorption-based chemical indicators for detecting chloroform (CHCl{sub 3}) and trichloroethylene (TCE). These indicators were used to make very sensitive optical chemical sensors (optrodes) for each of these two contaminants. Concentrations below 10 ppb can be accurately measured using these sensors. Furthermore, they are selective and do not response to similar contaminants commonly found with TCE and CHCl{sub 3} in contaminated groundwater. In addition, the sensor response is linearly proportional to the chemical concentration. In this report, we describe the details of this optrode and the putative reaction sequences of the indicator chemistries with CHCl{sub 3} and TCE and present an analysis of the spectral data obtained from the reaction products. A key part of the development of this optrode was designing a simple readout device. The readout is a dual-channel fiber-optic fluorimeter modified to measure transmission or absorption of light. The system is controlled by a lap-top microcomputer and is fully field portable. In addition to describing the final absorption optrode, details of the chemical indicator reactions are presented for both absorption- (colorimetric) and fluorescence-based optrodes. Finally, we report on the syntheses of several compounds used to evaluate the indicator chemical reactions that led to the development of the absorption optrode. 23 refs., 26 figs., 1 tab.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: DOE/DP
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7045952
• Report Number(s): UCRL-21213; ON: DE90012893
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
47 OTHER INSTRUMENTATION
CHLOROFORM
DETECTION
GROUND WATER
MONITORING
MEASURING INSTRUMENTS
DESIGN
ORGANIC CHLORINE COMPOUNDS
ABSORPTION SPECTRA
ABSORPTION SPECTROSCOPY
EMISSION SPECTRA
FIBER OPTICS
FLUORESCENCE
FLUORIMETERS
POLLUTANTS
SPECIFICITY
CHLORINATED ALIPHATIC HYDROCARBONS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROGEN COMPOUNDS
LUMINESCENCE
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXYGEN COMPOUNDS
SPECTRA
SPECTROSCOPY
WATER
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)
440600 - Optical Instrumentation- (1990-)