Entech Sorbent Pens™ represent in advancement passive ’diffusive’ sampling, incorporating many subtle but critical engineering design elements that ensure quantitative recovery, reproducibility, and cost effective long term use. The result of decades of research into volatile chemical sampling and analysis has resulted in a sampler so accurate and reproducible that the data is almost unbelievable! Passive or diffusive sampling is defined as the unassisted molecular diffusion of gaseous analytes through a diffusive region and onto an adsorbent. The DSP (Diffusive Sorbent Pen) does not require a pump and contains no moving parts. After sampling, the adsorbed analytes are desorbed directly into the GC or GCMS of choice.