In situ ultraviolet fluorescence probe for detection of volatile organic hydrocarbons in groundwater

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:230990

Morlock, C R ^[1]

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1. Morlock Environmental, Inc., Lebanon, NH (United States)

The authors have developed a miniature ultraviolet (UV) fluorescence device for measuring volatile organic compound (VOC) concentrations in ground water. The device consists of a mercury vapor lamp, excitation filter, sample chamber, emission filter and a miniature photomultiplier tube. Filters are chosen for optimal fluorescence signals from BTEX compounds. The prototype device is a benchtop model where a water sample is introduced into a sample chamber. Fluorescence is measured for the water/contaminant mix. This is followed by an air purge of the water to eliminate all volatile compounds. A second fluorescence measurement is taken after the purge. Any detected fluorescent after the purge results from system noise or fluorescence of substances other than VOCs. By rationing the two fluorescence measurements the authors arrive at a number which is proportional to VOC concentration. The results indicated that the authors can detect BTEX compounds in the sub-ppm range. The authors are currently designing an instrument to be lowered into a bore hole for continuous depth profiling and in situ measurement. They believe that it will be possible to build a device suitable for installation within a cone penetrometer or other sounding device. The intended use of the instrument is for rapid in situ assessment of VOCs and for permanent installation in a well for long term monitoring. The cost of all components that are part of this device is less than $2000.

• OSTI ID: 230990
• Report Number(s): CONF-950209--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ALKYLATED AROMATICS
BENZENE
DATA
DESIGN
GROUND WATER
MONITORING
MONITORS
TOLUENE
ULTRAVIOLET RADIATION
WATER POLLUTION
XYLENES