AWWA QTC97008

Geosmin and MIB (2-methylisoborneol) are complex organic compounds responsible for earthy or musty odors in drinking water. They are produced by actinomycete bacteria, commonly found in water and sediments of rivers and lakes, that live within or on algae and other aquatic plants. Odor outbreaks are common during large algal blooms and present costly and challenging problems for public water supplies. Concentrations of geosmin and MIB as low as 9 ng/L and 4 ng/L respectively, can be detected by the human nose. A very sensitive analytical technique is therefore required to detect and quantitate these compounds in water. Since an outbreak can cause considerable public concern, water suppliers need to monitor source water with a reliable analytical technique that will provide fast, accurate results. Standard Method 6040B is currently used to detect geosmin and MIB. This method calls for CLSA (closed-loop stripping analysis) followed by gas chromatography/mass spectrometry (GC/MS). However, this method requires a complex apparatus, is labor intensive and uses toxic elution solvents. The purpose of this paper is to present a new cost effective purge-and-trap technique in which geosmin and MIB are efficiently removed from a water sample by purging with helium gas at a specified flow rate, sample temperature, and length of time. The analytes are trapped on a sorbent material and subsequently desorbed directly into a GC/MS system. Method validation data are presented including initial calibration (linear range study), demonstration of capability and method detection limits.

Product Details

Published:

01/01/1997

ISBN(s):

0898679583

Number of Pages:

11

File Size:

1 file , 180 KB