Sub-ppt Detection of Geosmin and Other Odorants in Drinking Water with Ion Trap CI/MS/MS

The quality and safety of drinking water is a health and environmental concern of a global scale. Municipalities are monitoring many harmful organic, inorganic, and microbiological contaminants. Most of these contaminants are not detectable by human sensory function. However, a type of contaminants, called odorants, is

often detected, resulting in an alarming number of complaints to water agencies.

The high number of reports is due to the very low human olfactory threshold for these contaminants, in the low ppt (ng/L) range. The two most common odorants, causing musty, earthy fl avors, are geosmin and 2-methylisoborneol (MIB). They are ubiquitous in the environment, produced by a number of microorganisms,

and released when these microbes die. 2-isobutyl-3-methoxypyrazine (IBMP) and 2-isopropyl-3-methoxypyrazine (IPMP) also were reported as contributors to the unpleasant odor of water, with similar origins as geosmin and MIB. While trichloroanisol (TCA) is more commonly measured in alcoholic beverages, it also may be present in water; therefore, it was included in the measurements. Trichloroanisole-d5 was added as an internal standard.