ERACHECK and ASTM D7678-11 - A Perfect Combination
Recently, ASTM International has published method D7678-11. It is the first infrared standard method, which does not rely on CFC or carcinogenic solvents for precise quantification of hydrocarbons in water. Instead, an environment-friendly cycloalkane (cyclohexane or cyclopentane) is used for extraction. Here, laser-based infrared absorption spectroscopy is the key to measure sub-ppm hydrocarbon concentrations in a hydrocarbon extraction solvent.
The ERACHECK by QuantaRed Technologies fully complies with method ASTM D7678-11. It is the only oil-in-water analyzer in the world that fulfils the requirements of this method. Based on quantum cascade laser technology, it is a portable and rugged oil-in-water analyzer which brings back the benefits of the infrared. The ERACHECK provides fast and reliable results on-site in the range from 0.5 to 2000 mg/L.
Depending on the method applied, clean-up procedures have to be performed after extraction to get rid of polar substances (often referred to as "grease") before the measurement. This sample preparation step is time consuming, involves preparation and cleaning of equipment (e.g. columns, separating funnels, etc.) and might lack of reproducibility. To circumvent these difficulties a simple, automated clean-up procedure has been
developed by QuantaRed Technologies for use with the ERACHECK:
Ready-made solid-phase extraction (SPE) cartridges are directly plugged to the instrument’s sample inlet port and connected with the inlet tubing. With an embedded pump, the ERACHECK automatically primes the cartridge, performs the solid phase extraction, rinses the measurement cell and starts the measurement. Afterwards the cardridge is unplugged and disposed. Clear instructions are given on the large color touch-screen when to plug and unplug the cartridge.
The use of cartridges with the ERACHECK is optional. The cartridges simplify and speed-up the clean-up procedure while maximizing reproducibility and applicability of oil-in-water analysis. The use of TPH cartridges is in full compliance with standard ASTM D7678-11.
Comparison to alternative methods
In comparison to alternative methods for oil-in-water detection, ASTM D7678 offers significant benefits. The most relevant methods used world-wide are included in the following table:
Further methods for oil-in-water analysis rely on attenuated total reflection (ATR), flourescense and solid phase extraction by means of a membrane. None of these techniques are able to provide accurate and reproducible results for total petroleum hydrocarbons (TPH) concentrations in the low ppm range. The values are jeopardized by slight changes in sample preparation or sample composition. This is crucial whenever oils from several wells with varying oil compositions have to be monitored.
QuantaRed Service for oil-in-water analysis
Our service of QuantaRed chemical analysis for water samples supports clients with oil-in-water measurements using the CFC-free and reliable method ASTM D7678. Further we offer comparison studies to alternative methods for oil-in-water detection.