Analysis Of Geosmin And 2-Methylisoborneol Utilizing The Stratum PTC And Aquatek 70

By Teledyne Tekmar

Geosmin and 2-Methylisoborneol are organic compounds that have a distinct scent. These compounds also have an extremely low odor detection threshold and because of this, many drinking water laboratories require detection levels of below 10ppt. This application note investigates the detection of Geosmin and 2-Methylisoborneol at a one part per trillion (ppt) level utilizing Purge and Trap (P&T) coupled with a Gas Chromatograph and Mass Spectrometer (GC/MS).

Geosmin and 2-Methylisoborneol have very poor purge efficiencies. In order to detect these compounds down to the 1ppt level it was necessary to optimize the P&T and GC/MS techniques.

In this study, the GC/MS was run in Selective Ion Monitoring (SIM) mode while the P&T conditions were modified in order to achieve a 1ppt level of detection. A 10% (w/v) salt solution was utilized along with a 25mL purge volume in order to aid in compound detection. The Stratum PTC was configured with a #1 trap and three different injection techniques were examined in order to determine the optimum method for injection.