EPA Approved Water Testing Method

The CLAM uses the same solid phase extraction media disks that are used by water testing labs to extract water by EPA method 3550. This allows for easy incorporation into in-house quality control acceptance criteria. The media disks can be easily spiked before deployment with surrogates or target analytes, or spiked prior to elution to validate efficacy of the field extraction and the laboratory elution.

Utilizing this water testing method resolves holding time issues because of the unique SPE cartridges designed for shipping and storage of SPE media disks. This makes the SPE media disk simple to submit for elusion and water sample analysis, rather than having to ship an entire liter of water.

Additionally, the SPE cartridge containing the media disk may be frozen for several months up to a year depending on the analyte, prior to analyte elution and analysis. This allows the laboratory to keep a flexible schedule while evading fines due to missed holding times, thus saving thousands of dollars on resampling costs.

The CLAM extracts many liters of the actual environment into the media disk housed in the SPE cartridge. The water testing lab will not have to extract the water of the submitted SPE cartridge, thus reducing costs associated with labor, equipment time, solvent use and disposal. This water testing method only requires simple solvent elution of the SPE media disk/cartridge to obtain the extract for analysis.

Subsets of the solvent extract can be used for many different water testing methods, since each subset still represents many liters of water. The standard practice of collecting sample subsets from a large field container leaves a high percentage of non-polar analytes adhering to the container walls that cannot be solvent rinsed into the extract elutant volume, resulting in data biased low. This problem is addressed through use of the field extracted SPE disk, which is solvent eluted. The elutant is then aliquoted into sample subsets for many analytical methods without analyte retention loss on container walls.

Supporting Documents