The 2013 NEPM amendment included a change in terminology from Total Petroleum Hydrocarbons (TPH) to Total Recoverable Hydrocarbons (TRH). This was an important terminology correction as the chlorinated solvents that laboratories traditionally used to extract hydrocarbons from soil and water matrices (commonly dichloromethane - DCM) extract both biogenic (biological) and petrogenic (petroleum) hydrocarbons.
In the Environmental Industry, one of the major uses of the TRH analysis is to assess petroleum source contamination. Where significant levels of non-petroleum hydrocarbons are suspected, NEPM recommends a silica gel clean-up be performed (referred to as TRH silica), the purpose of which is to remove non-petroleum hydrocarbon interferences and provide a “TPH’ estimate.
Unfortunately silica gel clean-up is not precisely selective in removing non-petroleum hydrocarbons. CCME methods comment that the use of silica gel to remove polar compounds must be performed carefully with well-defined procedures otherwise hydrocarbons will be lost and by the same token some non-hydrocarbons can pass through silica gel in some samples.
So the question becomes ‘is there an alternative way to accurately measure Petroleum Hydrocarbons in environmental matrices?’
A possible solution is to use extracting solvents that are more selective for petroleum hydrocarbons, thus eliminating or reducing the need to perform silica gel clean-up. This method is commonly referred to as Extractable Petroleum Hydrocarbons (EPH).
What is inside this EnviroMail?
- Extractable Petroleum Hydrocarbons (EPH) - Solvent Selection
- ALS EPH Method
- Benefits of ALS EPH Methodology