Solinst Discrete Interval Sampler Model 425
Discrete interval sampling can be used to profile an open borehole or screened well, to collect samples from distinct levels or points of inflow, to obtain representative water samples from below floating product layers (LNAPL), and to obtain samples of sinking product layers (DNAPL). There is negligible disturbance, as can be caused by pumping and purging. Mixing of water from different levels in the well is minimized.

Purging and disposal of purged water can be avoided. Sampling directly from a specific depth results in the collection of the most recent water that has flowed into the well at that depth.

The Model 425-T Discrete Interval Sampler offers a zero-headspace sampler that can be transported directly to the laboratory in down-hole condition.

Solinst also has a stainless steel Point-Source Bailer with a second check valve at the top of the bailer, to prevent water entering the sampler on the way out of the well

The Solinst Model 425 is a stainless steel sampler, with LDPE tubing mounted on the convenient Solinst reel. The reel has a pressure attachment for the high pressure hand pump, and a pressure/vent switch to apply and release the pressure on the sampler. A sample release device is also included.

The sampler is pressurized using a high pressure hand pump before being lowered into the well. This prevents water flowing through the sampler on the way down the well. Once the desired depth is reached, the pressure is released and hydrostatic pressure allows the sampler and tubing to fill with water directly from the sampling zone.

When the sampler is filled, it is repressurized and raised to the surface and the sample is decanted using the sample release device provided, to avoid degassing of the sample.

The sampler is ideal for groundwater sampling from below an oil/product layer on the surface of the water, as it allows a sample to be obtained which is untouched by the oil.

The sampler is easily disassembled for decontamination, without the need for tools.

Obtaining a representative groundwater sampler from below oil/product layers
Discrete interval sampling
Chemical profiling of wells
Sampling at points of inflow to well
DNAPL sampling
Discrete interval samplers are excellent for VOC sampling. There is no mixing with water from different levels in the well. The sample does not travel through a long length of tubing, risking loss of volatile organics. The sample has minimal contact with air.

For the most accurate VOA results the Model 425T Transportable DIS can be used. It retains the volatiles at down-hole conditions with zero headspace during retrieval and transport to the laboratory.

Sample not pumped through tubing
No mixing of water from different levels
Avoids purging and disposal of purged water
No-tools disassembly for decontamination
The Discrete Interval Sampler is connected to the tubing. The high pressure hand pump, or a compressed air source, is attached to the reel.

The operating pressure required is determined using the chart at right. For other depths the formulas may be used. Pressure is applied, which closes the check valve in the bottom of the sampler, preventing any water from entering the sampler.

The sampler is then lowered to the chosen sampling depth while pressurized. At the chosen depth the pressure is released. Hydrostatic pressure fills the sampler and tubing, as the water rises to hydrostatic level.

The sampler is again pressurized to close the lower check valve, and is raised to the surface. It is removed from the borehole and the sample is transferred to a sample bottle using the sample release device for controlled flow.

The samplers are constructed entirely of stainless steel with Viton o-rings.

The tubing most commonly used is low density polyethylene (LDPE), however, Teflon or Teflon-lined polyethylene tubing is also available.


Ekman Grab Sampler
This is the grab to choose for soft, finely divided littoral bottoms that are free from vegetation, such as sticks and decayed leaves (or with short, erect vegetation only) as well as intermixtures of sand, stones, and other coarse debris. Its specialized function is the taking of quantitative and qualitative samples of macroscopic bottom fauna to determine the productivity of soft bottoms, particularly those composed of finely divided muck, mud, ooze, submerged marl and fine peaty materials. Versatile and durable, it is suited for preliminary as well as more precise observation. It is not recommended for rocky or sandy bottoms or moderate macrophyte growth because small pebbles or macrophyte stems prevent proper jaw close.

Two thin, hinged overlapping lids on top open during descent to let water pass through. They close during retrieval and are held shut by water pressure to reduce washout. The closing springs easily unhook from their loaded position for safe handling during transportation and storage.

An important and distinguishing feature of the Wildco design is the messenger-operated Twin-pin scoop release mechanism. This release is very reliable, has few working parts and is the best of its type in the field.

To operate, attach to a line and pass through the trip mechanism. Set the springs over the knobs and pull the jaws completely apart. Lower the dredge till it rests on the bottom and send a messenger down the line, allowing the springs to close the scoops.

Scoops overlap to reduce sample loss
Dependable release closing
316 or 18-8 stainless steel construction
Lightweight yet stable due to wide base
Extra weights available
Center pivot for low bottom disturbance


Ponar Grab Sampler
Widely used in fresh and salt water for taking samples of hard bottoms such as sand, gravel, consolidated marl or clay, this is a deliberately heavy device for biting deep into the bottom and has proven success at animal recovery. The simple design means it is simple to use. Heavy duty hinges and hinge pin can absorb thousands of bottom impacts. Self-closing scoops have center pivot closing action. When the scoop strikes the bottom, their tapered cutting edges penetrate well with very little sample disturbance. An attached underlip wipes the scoop clean of pebbles and cobble that would interfere with closing. By the same token, removable side plates prevent the lateral loss of sample as scoops close.

This well-regarded self-closing sampler uses a patented spring-load pinch pin that releases when cable or line slackens. A safety pin replaces the pinch-pin when not in use to prevent injury. Removable screens on top of each scoop allow water to flow through as it descends. This lessens the frontal shock wave and reduces surface disturbance. Both screens are covered with neoprene rubber flaps that close during retrieval.

Center pivot for low bottom disturbance
Tapered scoop edges for a clean cut
Heavy duty hinges for high impact work
Hefty scoop volume: 8200 mL
316 SS scoops and underlip or all 316 SS
Removable stainless steel top screens
Self-releasing pinch pin
Extra weights available





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