As Passive Sampling grows in acceptance and popularity we wanted to reiterate that there are different sampling techniques available and that not all passive samplers are the same.
Groundwater passive sampling claims to be able to deliver cost savings of up to 70% together with more consistent, accurate results acquired safely, quickly and cost effectively. As a result different types of passive sampling principles have been developed to capture samples either by: diffusion, adsorption or by ‘grabbing’ a sample. Each has its merits and limitations.
When deciding which method to adopt we recommend that you consider several factors including costs, repeatability, sample volumes and the type of compounds you are sampling.
For an equilibrated, instantaneous, snap shot of a groundwater sample the grab method works well and we supply the Snap Sampler for this method of passive sampling. It is easily deployed in a well and left until the groundwater conditions have re-equilibrated; when that happens a sample is captured, sealed and is then ready to send off to a laboratory for analysis.
We have produced an Information Sheet to help you decide which technique is most appropriate for a specific project, click here for details. In addition we have a considerable amount of research to support the grab method available on http://www.vanwalt.com/samplers-passive-snap.htm.