Is a peristaltic pump suitable for low-flow sampling?

If the liquid level is less than 7-8 meters below ground surface, a peristaltic pump will work effectively for purging purposes. For sampling purposes, it depends on your parameters of interest. There are at least a couple of states, New Jersey and Florida, that restrict the use of peristaltic pumps, and now USPCA Region 1 has also put out a guidance document in January of last year, that warns against using peristaltic pumps for certain parameters, predominantly VOCs. However, it's really going to depend on a couple of things.  If the water level below ground is fairly shallow, then you have very limited suction on the sample, and you will not see very much change to the water chemistry because of the pump. If your lift is very close to the limit of what the peristaltic pump can achieve, 7-8 meters at the maximum, then you are going to have the greatest effect on the sample. There are some published papers on different sampling devices that you can use to decide whether or not a peristaltic pump is applicable for your type of sampling. But in terms of using it for low-flow purging, as long as it can be adjusted for the flow rate needed for your requirements it should work.