Can you use a peristaltic pump for low-flow sampling techniques and to collect a representative VOCs sample?

Yes, peristaltic pumps can be used for low-flow sampling with groundwater levels within 23-25 feet of the ground surface as long as the water level will remain constant as you pump the well. Note: there are some states that prohibit peristaltic pumps for VOC sampling using the low-flow approach. Their concern is that at higher lifts you can de-gas the sample to the point that VOC concentrations are affected. Those states either require a different form of sampling, or that you withdraw the peristaltic pump tubing from the well with a valve at the bottom and a pinch at the top basically decanting the water from the tubing, and that will be the VOC sample. Ultimately though, VOCs are not your only concern with peristaltics, if you significantly de-gas the sample because of high suction you can see a loss of CO2 and then an upward shift in pH which can affect metals concentrations.