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6 SAMPLE ANALYSIS TOOLS for VOCs, SVOCS, and PESTICIDES

6.2 EX-SITU ANALYSIS

6.2.12 Ultraviolet (UV) Fluorescence

Use: Ultraviolet (UV) fluorescence has been used in a number of applications for field screening including: (1) semi-quantitative analysis of solvent extracted PAHs, (2) in conjunction with fiber optic sensors (see 6.1.1), and (3) as a surface contamination detector, in which a non-fluorescing substance sprayed on the ground surface reacts chemically with the contaminant of interest to form a substance that fluoresces with UV excitation.

Description:

Light emission from atoms or molecules can be used to quantify the amount of the emitting substance in a sample. Fluorometry is a spectroscopic technique in which the electronic state of a molecule is elevated by absorption of electromagnetic radiation. When the molecule returns to its ground state, radiation is emitted to produce a distinctive excitation and emission spectrum. Instruments used for fluorometric analysis contain four basic components:

  1. Source of excitation energy (such as UV, laser (see 6.1.2), x-ray (see 7.1.3)).
  2. Sample cuvette.
  3. Detector to measure photoluminescence
  4. Pair of filters or monochromators for selecting the excitation and emission wavelengths.

Analytes:

1. Non-Halogenated VOCs 3. Halogenated VOCs 5. PAHs

Media:

Soil/Sediment Water Gas/Air
ADEQUATE BETTER ADEQUATE
Selectivity: Technique measures a part of the compound.
Susceptibility to Interference: Medium.
Detection Limits : 100-100 ppb (soil); 1-50 ppb (water).
Turnaround Time per Sample: Hours.
Applicable To:
Screen/Identify Characterize Concentration/Extent Cleanup Performance Long-Term Monitoring
BETTER ADEQUATE BETTER BETTER
Quantitative Data Capability: Data become quantitative with additional effort.
Technology Status: Commercially available technology with moderate field experience..
Certification/Verification: Technology has not participated in CalEPA certification and/or CSCT verification program.
Relative Cost per Analysis: Mid-range expense.

Limitations:

ASTM Standards/EPA Methods:

No applicable ASTM standards or EPA methods are cited for this technology.

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