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    The EQUILIBRATOR® Passive Diffusion Sampler (PDS or PDB) is the world-wide number one passive groundwater sampler.

    Diffusion samplers obtain representative, discrete interval samples of Volatile Organic Compounds in groundwater without purging or pumping. Effective for any site where VOCs are the main contaminant of concern.

    How Easy Is It? Attach the PDB filled with DI water to a weighted suspension tether using zip-ties, and lower into the saturated zone in the well screen. Attach the tether to the well cap and secure the well as usual. Recover the Equilibrator at the next sampling event (minimum 2 weeks residence), decant the sampler contents into lab bottles and send to the lab for analysis. For an added cost benefit- before leaving the well, install another DI water filled DMPDB™ for the next sampling round and eliminate a separate installation trip to the well. There is virtually no maximum time between installation and recovery.

    How Does It Work? While installed, VOC molecules from the groundwater flowing through the well diffuse through the semi-permeable sampler membrane into the sampler until the VOC concentrations in the PDB are in equilibrium with the surrounding groundwater. The sampler contents maintain dynamic equilibration with the surrounding groundwater even when the groundwater concentrations change.

    Why Use the Equilibrator?

    • Sample for VOCs
    • Reduce sampling cost 50%-70% by eliminating field time spend purging and the cost of purge-water disposal.
    • Easy and quick installation and recovery helps in high-traffic areas and for allows for Social Distancing.
    • No expensive, complicated, or bulky equipment to purchase. maintain or mobilize
    • Obtain depth-specific concentration profiles.
    • Reduce sampling error and improve repeatability.
    • A Greener sampling method; less disposable material, no batteries, gasoline or waste.

        Ordering Hints

        Prefilled Equilibrator PDBs: For the easiest and most convenient installation, order prefilled samplers so they arrive on-site filled with certified de-ionized (DI) water, ready to install. Certificate of Analysis (COA) available for each DI water lot. 

        De-ionized Water Travel Blanks: EON provides a separate and inexpensive water "Travel Blank" of the exact same DI water and membrane used in the prefilled sampler so you can validate the pre-installation contents without sacrificing a sampler. 

        Option: Fill Your Own Equilibrator PDBs: Order the unfilled Equilibrator PDBs and fill them with de-ionized water, on site, in your office or any other convenient place, using water from your lab or get bottled de-ionized water from EON. 

        Reusable Suspension Tether: PDBs are installed on a reusable, weighted suspension tether connected to the underside of the well cap. EON’s Tether Service provides a custom tether for each well; cut to length, with attached weight, locking well cap, stamped well ID Tag, and connection rings located in the precise depth location you specify. The tether is reused in the same well to ensure samplers are placed in the exact same location time after time.

        Equilibrator Design Features

        • Built-in Protective Mesh protects the sampler membrane and adds strength.
        • Connection loops to facilitate easy attachment to the suspension tether using zip-ties
        • Semi-permeable LDPE membrane holds deionized water and allows transmission of VOCs into sampler.
        • Easy to empty. Just puncture with our VOC “Juice-Box Straw” and empty directly into lab bottle.
        • Filling port for field, lab, or factory filling.

        Required Components

        • Equilibrator samplers, one per sample interval
        • Deionized water to fill samplers (or purchase Prefilled samplers)
        • Fill kit (1 per deployment team, reusable)
        • Tether/suspension cord (1 per well, reusable)
        • Stainless steel weight (1 set per well, reusable. Comes with suspension Tether)
        • Well cap with attachment ring from which to suspend the Tether (1 set per well, reusable. Comes with suspension Tether)
        • Cable ties to attach PDBs to Tether

        Optional Items

        • Tether preparation service
        • VOC resistant shipping and storage pouch

        EON's Equilibrator Passive Diffusion Sampler can be used for surface water, too!

          Item # Description/Size Availability Qty Break Price Quantity
          GSD200-PF1
          Equilibrator Passive Diffusion Sampler (PDB), Prefilled with ASTM Type 1 Deionized Water; 18in x 1.75in 350 ml. Discharge Straws (GSD290) are included but packaged separately.
          In Stock 1 $25.70
          GSD210-PF1
          Equilibrator Passive Diffusion Sampler (PDB); 24in x 1.75in, Prefilled with ASTM Type 1 Deionized Water; 500 ml Discharge Straws (GSD290) are included but packaged separately
          In Stock 1 $29.70
          GSD220_PF1
          Equilibrator Passive Diffusion Sampler (PDB); 36in x 1.75in, Prefilled with ASTM Type 1 Deionized Water; 750 ml Discharge Straws (GSD290) are included but packaged separately
          In Stock 1 $50.25
          GSS10-100
          Service: PDB Blank, prefilled w/ 100 ml of ASTM I deionized water
          In Stock 1 $4.00
          GSD325
          PDB Storage Pouch. Resists diffusion of VOCs from the air into the pouch. Used to help prevent VOCs in surrounding air from entering the PDBs in the pouch during transit and storage.
          In Stock 1 $5.35
          GSD200
          Equilibrator Passive Diffusion Sampler (PDB); 18in x 1.75in 350 ml Discharge Straws (GSD290) are included but packaged separately
          In Stock 1 $17.80
          GSD190
          Equilibrator Passive Diffusion Sampler (PDB); 12in x 1.75in 150 ml Discharge Straws (GSD290) are included but packaged separately
          In Stock 1 $17.80
          GSD210
          Equilibrator Passive Diffusion Sampler (PDB); 24in x 1.75in 500 ml Discharge Straws (GSD290) are included but packaged separately
          In Stock 1 $19.50
          GSD220_
          Equilibrator Passive Diffusion Sampler (PDB); 36in x 1.75in 750 ml Discharge Straws (GSD290) are included but packaged separately
          In Stock 1 $37.80
          GSD307
          PDB Fill Kit for Equilibrator 1.75in Diffusion Sampler
          In Stock 1 $3.70