Decaying algae blooms that occur in drinking water
sources sometimes release “earthy” and “musty” odor
compounds (2-methylisoborneol, or MIB, and geosmin –
shown in Figure 1). This aroma is a major source of public
complaints about unpleasant tasting drinking water.
Although odor is only regulated by a secondary maximum
contaminant level (a non-mandatory water quality standard),
it is critical for utilities and environmental laboratories to
accurately identify and quantify specific compounds
potentially involved in Taste and Odor (T&O) events.
Therefore, a highly sensitive, robust, accurate, and high-throughput
technique is required for the analysis of MIB and
geosmin at concentrations down to their odor threshold
levels (low ng/L).
Standard Method 6040 details several sample
introduction methods that can be used for trace-level
analysis of MIB and geosmin in drinking water samples.
Included are closed-loop stripping analysis, purge and trap,
and solid phase microextraction (SPME). SPME is the most
rapid method that is capable of achieving comparable
sensitivity, when coupled with GCMS. The use of SPME
Arrow, however, which is more sensitive and robust than
conventional SPME fibers, has not been evaluated for use
with this method.
In this work, we implemented Standard Method 6040D
with SPME Arrow, rather than SPME fiber, for the analysis of
MIB and geosmin at levels that would occur in T&O events.
This workflow will help utilities and environmental labs in
managing T&O events quickly and accurately.