Effect of pH on the analysis of 2-MIB and geosmin in water

Wen Hsing Hsieh, Wei Nung Hung, Gen Shuh Wang, Shu Ting Hsieh, Tsair Fuh Lin

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

2-Methylisoborneol (2-MIB) and trans-1,10-dimethyl-trans-9-decalol (geosmin) are two commonly observed taste and odor compounds present in drinking water sources. The effects of pH on the analysis of the two chemicals are investigated using a gas chromatograph and mass spectrometric detector (GC/MSD) coupled with three preconcentration methods, namely solid-phase microextraction (SPME), purge-and-trap concentration (PTC), and liquid-liquid extraction (LLE). At neutral and alkaline pH conditions, the concentrations detected for both compounds remain constant. However, a substantial reduction of concentration for both chemicals is observed when the water solution pH is less than 5. Under acidic conditions (pH≅2.5), the 2-MIB concentrations detected by GC/MSD coupled with SPME, PTC, and LLE are 87%, 16%, and 37% lower than those measured at pH 6-7, respectively. For geosmin, a decrease in concentration is only observed when using GC/MSD-SPME, presumably due to the higher extraction temperature compared to the other two techniques. The pH-dependent behavior was attributed to dehydration of the tertiary alcohols of 2-MIB and geosmin under acidic conditions. The dehydration for 2-MIB and geosmin is reversible, and the analysis can be mitigated by adjusting the water solution pH back to a neutral condition.

Original languageEnglish
Pages (from-to)715-721
Number of pages7
JournalWater, Air, and Soil Pollution
Volume223
Issue number2
DOIs
Publication statusPublished - 2012 Feb

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Environmental Chemistry
  • Ecological Modelling
  • Water Science and Technology
  • Pollution

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