Why would I want to measure Refined Oils (Fuels)? 
Refined fuels such as benzene, toluene, ethylbenzene, and xylenes (BTEX) are volatile organic compounds (VOC’s) found in petroleum derivatives. These compounds are harmful to humans and animals if absorbed through the skin, ingested, or inhaled. There are many pathways that lead to environmental contamination by refined oils or fuels, primarily through leakage from broken or degraded storage tanks, pipelines, or containers. These compounds can adsorb onto soils or particles, evaporate, and/or biologically degrade at a very slow rate. The slow degradation rate allows for accumulation causing high concentrations which may result in a health risk to communities, both animal and human. Quantification of Refined Oils (Fuels) in water is typically done using Gas or Liquid Chromatography and the instrumentation required, reagents, and methods can be expensive. Eureka’s Refined Oil sensor from Turner Designs provides data for rapid in situ detection of these compounds. The MantaPlus or Trimeter sonde is ideal for researchers who are interested in detecting the presence or absence of VOC’s, and measuring relative fluorescence changes that can be used as an indication of increasing or decreasing concentrations.
 
There are many harmful effects that result from exposure to oil and fuel compounds, ranging from mild effects such as dizziness, nausea, headaches, and drowsiness or life threatening effects such as anesthesia, convulsions, delirium, or coma. Knowing the threshold effects for exposure to various concentrations of refined oils and fuels is important in maintaining a safe and healthy lifestyle, business, or research.
 
How is refined oil measured?
Eureka’s refined oil sensor is a fluorometric sensor.  Fluorescence occurs when a molecule absorbs light energy at one wavelength and then emits that energy at a different wavelength.  Fluorometric sensors emit light at a certain wavelength, and look for a very specific, different wavelength in return.  
 
Eureka’s Refined Oils (Fuels) fluorometer from Turner Designs uses deep UV wavelengths for excitation (<300nm).  A broadband emission filter is used for detection between 300 and 400nm. It outputs an analog signal based on the relative fluorescence intensity of Refined Oils (Fuels) in water.   This signal is converted to a digital output in the Eureka multiprobe and reports the Refined Oil value in ppm. 
 
What should I know about Refined Oil measurement in the field?
Fouling is the biggest field problem for fluorescence sensors.  Any foreign material that accumulates on the active surface of the sensor will either reduce the amount of emitted light or received light, or both.  And sometimes the foreign material might provide a false signal by fluorescing at the same wavelengths as the refined oil.  Normally, fouling should be a problem only in long-term deployments, not in daily surveys. 
 
Features of Eureka’s Refined Oil Sensor.
Eureka uses refined oil sensors manufactured by Turner Designs, recognized as the world’s expert for in-situ fluorescence sensors. Refined Oil sensors may be installed in MantaPlus multiprobes, along with other sensors such as dissolved oxygen, pH and conductivity, and additional fluorometers.  This cost-effective approach eliminates the need to buy dedicated fluorometers.  Operation is made easy, as the refined oil sensor is controlled by the Manta software, like other installed sensors.  If only refined oil is needed, the sensor may be installed on a smaller probe such as the Trimeter. 
 
Manta Plus and Trimeter multiprobes may be configured as loggers with battery backs for autonomous self-powered deployment, used with field displays for site-to-site spot checking, or connected to data telemetry stations for real-time remote monitoring. For continuous deployment, anti-fouling accessories may be added, such as Eureka’s universal wiper system, and copper mesh sensor guard. Eureka multiprobes are portable, durable, and cost-effective.