425 Discrete Interval Sampler

425 Discrete Interval Sampler

The Model 425 is a discrete interval sampler that allows groundwater samples below the hydrocarbon layers (floating or heavy) to be obtained at desired depths without cross contamination of the upper layers.

Available for rental



Ideal for chemical profiles in wells. The sampler is made of stainless steel and can be supplied with tubing mounted on a reel. It comes with a device to release the sample. It is easy to clean.

 Discreet Sampling without Purge

Discrete sampling is ideal for taking representative samples of groundwater and samples from Floating Layers (light non-aqueous phase floating liquids LNAPL) and Heavy Naps (dense non-aqueous phase liquids DNAPL). The Discrete Sampler is ideal for sampling groundwater below oil / hydrocarbon layers and allows the sample to be taken from water that has not been touched by the oil.

It is also used to profile bodies of water, open holes and wells with slotted areas, and to collect samples at different levels and points of entry of water. The possibility of mixing water from different levels within the same well is minimized.

Model 425 is also recognized as a non-purge sampler. The passive sampling method, or also known as the zero-purge method, has gained wide acceptance worldwide by regulatory agencies, making it an instrument for obtaining high-quality groundwater samples.

These sampling methods are based on the principle that the water flowing in the well maintains equilibrium with the adjacent water in the aquifer. Sampling at discrete intervals results in representative samples, without the need to purge.


The sampler is pressurized at the surface using the manual pressure pump before being inserted into the well to prevent water from entering as it moves down the water column. Once the desired depth is reached, the pressure is released, and the water enters the sampler by the hydrostatic pressure filling it with water directly from the sampling location. A valve located inside the 1.66 “(42mm) and 1” (25mm) diameter samplers prevents water from entering the hose, and also avoids having to clean the hose.

When the sampler is full, pressure is applied again and rises to the surface. The sample is decanted using the device to release the sample, with which the outflow can be regulated and thus minimize the degassing of the sample. The sampler can be easily disassembled for cleaning.


  • High quality samples.
  • The sample has not been pumped through a hose.
  • There is no mixing of the water at different levels.
  • Minimal water alteration.
  • Easy to assemble and disassemble to decontaminate.
  • Avoid having to purge water and dispose of it.
  • Less time and cost to collect samples.
  • Easy to operate and transport.


  • Obtaining representative samples of groundwater below hydrocarbon layers.
  • Discrete interval sampling in lakes, rivers and wells.
  • Profiling for chemical analysis of water in wells.
  • Sampling at water entry points to the well.
  • Sampling of LNAPL and DNAPL layers.


Modo de utilización del 425

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