SmartData Solutions® LIF - Laser-Induced Fluorescence, Direct Sensing Technology

COLUMBIA Technologies now offers laser-induced fluorescence (LIF) mapping in combination with our other industry-leading direct sensing and SmartData Solutions® mapping services.

Our (LIF) mapping technology profiles underground petroleum, oil, and lubricant contamination using the latest state-of-the-art UltraViolet Optical Screening Tool, (UVOST™).

With laser-induced fluorescence (LIF) technology and SmartData Solutions® data processing services, detailed site conceptual models provide you accurate, high definition 3-D maps of your site using thousands of data points, delivered immediately, at prices competitive with older sampling technology. Data reports include color-coded logs that convey qualitative at-a-glance information.



Like other direct sensing tools, LIF is used with all types of direct push machines, such as Geoprobe® or cone penetrometer (CPT). Using real- time computer displays, our systems rapidly screen potentially contaminated sites - typically 10-20 boring locations per day – while you watch.

Principles of Operation

The fiber optic-based laser-induced fluorescence (LIF) sensor system is deployed with standard direct push equipment (DPT) or cone penetrometer (CPT) equipment. Light at a specific wavelength generated from a laser is passed down a fiber optic cable to a sapphire window in the tip of the rod string as it is advanced into the subsurface. The laser light excites two or three ring aromatic compounds or polycyclic aromatic hydrocarbons (PAH), in the soil adjacent to the sapphire window, causing them to fluoresce. The relative response of the sensor depends on the specific analyte being measured because of the varying ratios of PAHs in each hydrocarbon mixture. The induced fluorescence from the PAHs is returned over a second fiber to the surface where it is quantified using a detector system. The peak wavelength and intensity provide information about the type of petroleum product or potential interferences as described below. In the UVOST™ LIF system four unique wavelengths bands of light are monitored in real-time to provide a signal which is an indicator of the relative contaminant concentration.

Interferences

The in situfluorescence response of the LIF sensor to hydrocarbon compounds is sensitive to a number of interferences, but variations in the soil matrix are the most pronounced. LIF sensitivity to petroleum hydrocarbons in soil has been shown to be inversely proportional to the available surface area of the soils. Sandy soils tend to have a much lower total available surface area than clay soils, so hydrocarbon compounds in sandy soils generally yield a higher fluorescence response than they do in clay-rich soils.

Although intended to specifically target petroleum hydrocarbons, the excitation energy produced by the laser-induced fluorescence (LIF) system's laser may cause other substances to fluoresce as well, which may cause interference problems. Many common fluorescent minerals such as calcite can produce a measurable LIF signal.  Other man-made non-hydrocarbon fluorescent material may be found in the subsurface environment: deicing agents, antifreeze additives, and many detergent products are all known to fluoresce very strongly, for example. Naturally occurring organic matter, which include PAHs, also can fluoresce.  In many cases it is possible for an experienced operator to differentiate between the fluorescent signatures of hydrocarbons and other interfering compounds.

Detection Limits

Laser-induced fluorescence (LIF) data quality is highly effective for qualitative site screening.  Site-specific detection limits vary from levels of 50 to 1,000 mg/kg, but exact detection limits are difficult to determine and will vary between sites and petroleum products. The UVOST™ LIF system can reliably detect the following compounds:

• Gasoline (highly weathered and aviation yield is very low)
• Diesel
• Jet (Kerosene)
• Motor Oil
• Cutting Fluids
• Hydraulic Fluid
• Crude oil
• Fuel oils

LIF systems do not detect aliphatic chlorinated compounds, polychlorinated bi-phenyls (PCBs), or dissolved phase petroleum hydrocarbons.

Call toll free at 1-888-344-2704 for immediate availability.

Ref: http://clu-in.org/char/technologies/lif.cfm
UVOST™ is a trademark of Dakota Technologies, Inc.