Passive sampling comes of age

June 13, 2012

The definition of a “passive” sampler is a device that is able to acquire a sample from a discrete location without the need for pumping or purge techniques.  A sampling device is exposed to a medium in an ambient equilibrium, for example, in a well where the water is expected to be in a natural exchange with the formation water.

The benefits of passive sampling techniques range from an ability to deploy passive samplers in almost all aqueous environmental conditions, regardless of water quality to substantial labour savings because most passive samplers are easy to deploy and deliver consistent results. Savings of up to 30% are regularly banded about when compared to traditional intensive sampling techniques.

Also passive sampling techniques allow for the concentration of trace, yet toxicologically relevant, contaminant mixtures over extended periods of time to be recorded and much lower detection levels of chemicals can be established which fits well with the higher monitoring demands of the Water Framework Directive.

The other major benefit of passive samplers is they can provide time-weighted average concentrations of chemicals so give realistic chemical loading levels, often from various sources and they can detect episodic changes in environmental contaminant concentrations.

Most passive samplers can test for two major types of contaminants at the same time, those that readily dissolve in water such as herbicides and those that are only slightly soluble such as polychlorinated biphenyls (PCBs).

With the Snap Sampler there are no limitations to what analytes can be tested but some analytes require large sample volumes to achieve appropriate detection limits. Sample volume can be a constraint on these analytes or on an extensive analyte list.

For more information on the Snap Sampler click here.