Solinst - Model 425 - Discrete Interval Samplers
From Groundwater Samplers
The Model 425 Discrete Interval Sampler is a stainless steel groundwater sampler, with LDPE tubing mounted on a convenient reel. Discrete interval sampling is ideal for obtaining truly representative groundwater samples from below floating product layers, or for obtaining samples of the product itself. The Discrete Interval Sampler can also be used to profile open bodies of water, boreholes, and to collect samples from distinct levels or points of inflow. The Discrete Interval Sampler is a passive sampler that is pressurized when lowered and upon retrieval, to prevent water mixing at different levels. Designed to give zero purge samples.
The Solinst Model 425 Discrete Interval Sampler (DIS) is a stainless steel sampler, with LDPE tubing mounted on the convenient Solinst reel. The reel has a pressure attachment for a high pressure hand pump, and a pressure/vent switch which is used to apply and release the pressure on the sampler. A sample release device is included with each Discrete Interval Sampler.
The sampler is pressurized before being lowered into the well to prevent water flowing into the sampler. Once the desired depth is reached, the pressure is released and hydrostatic pressure fills the sampler with water directly from the sampling zone. A floating checkball inside the 1.66'ø (42 mm) and 1'ø (25 mm)samplers prevents water from entering the tubing, thus avoiding the need to decontaminate the tubing.
When the sampler is filled, it can be repressurized and raised to the surface. The sample is decanted using the sample release device, which regulates flow and minimizes degassing of the sample. The sampler is easily disassembled for decontamination.
Discrete Interval No-Purge Sampling:
Discrete interval sampling is ideal for obtaining truly representative water samples and for obtaining samples of product (LNAPL and DNAPL). The DIS 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.
Discrete Interval Sampling is also used to profile open bodies of water, open boreholes and screened wells, and to collect samples from distinct levels or points of inflow. Mixing of water from different levels in the well is minimized.
The Model 425 Discrete Interval sampler is also recognized as a no-purge sampler. No-purge, also known as zero-purge or passive sampling methods, have gained acceptance by many regulatory agencies worldwide for obtaining high quality groundwater samples.
These sampling methods are based on the principle that groundwater which flows into a well, maintains equilibrium with the adjacent water bearing unit. Sampling at the discrete interval should result in representative samples, without the need for purging.
It is also used to profile open bodies of water, open boreholes and screened wells, and to collect samples from distinct levels or points of inflow.
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 water which is most representative of the groundwater outside of the well at that depth.
For the most accurate VOC 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.
- Obtaining a representative groundwater sample from below oil/product layers
- Discrete interval sampling in lakes, rivers and wells
- Chemical profiling of wells
- Sampling at points of inflow to well
- LNAPL and DNAPL sampling
- High quality samples
- Sample has not been pumped through tubing
- No mixing of water from different levels
- Minimal disturbance of the water
- Easy disassembly for decontamination
- Avoids purging and disposal of purge water
- Less cost and time to retrieve samples
- Easy operation and transportation