Water Science and Technology Vol 40 No 6 pp 45–52 © IWA Publishing 1999

Flavor Profile Analysis and GC/MS Detection of Phenolic Iodinated Disenfection Byproducts in Drinking Water for the USA Space Program

Andrea M. Dietrich^*, Susan Mirlohi^**, Willian F. DaCosta^***, Jennifer Peters Dodd^****, Richard Sauer^*****, Mark Homan^****** and John Schultz^*******

^*Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA 24061-0246, USA
^**Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA 24061-0246, USA
^***Department of Chemistry, Universidade Estadual de Maringa, Maringa, PR, Brazil
^****Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA 24061-0246, USA
^*****Water and Food Analysis Laboratory, National Aeronautic and Space Administration, Johnson Space Center, Houston, TX 77058, USA
^******Water and Food Analysis Laboratory, National Aeronautic and Space Administration, Johnson Space Center, Houston, TX 77058, USA
^*******Water and Food Analysis Laboratory, National Aeronautic and Space Administration, Johnson Space Center, Houston, TX 77058, USA

Reactions of iodine and phenol were investigated to determine which iodophenols were produced and their odor properties. The research was performed in support of the USA space program that applies iodine to disinfect potable water for spacecraft use. Higher concentrations (50 mg/l) and higher iodine:phenol (e.g. 10:1) ratios resulted in the formation of greater iodophenol concentrations and higher substituted iodophenols. The reactions were fast and nearly complete within 1 hour. For pH 5.5 and 8 and all iodine:phenol ratios, formation of monosubstituted compounds indicated that 2-iodophenol was favored over 4-iodophenol. At the intermediate iodine:phenol ratios of 1:1 and 2:1, substantial amounts of the diiophenols formed and persisted for up to 32 days. The diiodophenols were not detected at iodine:phenol ratios of 0.2:1 and 10:1. The compound 2,4,6-triiodophenol was the major product formed at a 10:1 iodine:phenol ratio and the formation of this trisubstituted phenol appeared nearly complete. Odor evaluation indicated that the iodophenols have much lower odor threshold concentrations (OTC) than phenol. The 2- and 4- iodophenol had OTC values of 1 and 500 g/l, respectively, with odors described as "medicinal, phenol, chemical".

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