Soil gas sampling
Quantitative purge-and-trap with GC(–MS) is a common approach for the analysis of VOCs and SVOCs in soil, but it involves labour-intensive sample preparation and pre-screening analysis. Soil probes are a complementary approach to purge-and-trap for analysis of VOCs in soil vapour that overcomes many of these issues. Their use supports compliance with ASTM D7758.
Stainless-steel assemblies are inserted into the ground, allowing soil gas to be sampled in-situ onto a sorbent tube, either pumped or passively.
Established VOC air monitoring technology has also been applied to the monitoring of contaminated land, but the frequently-used approach of canister sampling excludes many heavier organic pollutants. Sampling onto sorbent tubes, followed by thermal desorption analysis, allows a much wider volatility range to be addressed. Soil probe technology therefore has the potential to significantly speed up and reduce the cost of surveys of contaminated land.