Comparison of two selective methods for determination of geosmin (1,2,7,7-tetramethyl-2-norborneol) and 2-MIB (2-methylisoborneol) in drinking and raw water samples by capillary gas chromatography - mass spectrometry

Abstract

Two sample preparation methods were introduced and compared in this study to establish a simple, rapid, sensitive and selective method of analysis for geosmin and 2-MIB in raw and drinking water samples. Geosmin and 2-MIB are major organic pollutants responsible for undesirable taste and odour in aqueous matrices. Thus, there is a need to continue monitoring these compounds since they occur at very low levels (ng/L) in our water systems. Purge and trap (P/T) and solid phase extraction(SPE) methods were evaluated and optimised for separation of these compounds. Mean percentage recoveries obtained in spiked distilled Milli-Q water (18.2 Ω) for 2-MIB and geosmin ranged from 90.1 ± 2.32 (geosmin) to 97.3 ± 3.34 (2-MIB) and from 78.5 ± 4.82 (geosmin) to 87.1 ± 1.02 (2-MIB) for SPE and P/T respectively. Concentration levels obtained in drinking water were between not detected (ND)-6.05 ng/L whereas in raw water samples concentration levels ranged from less than 1 to 371 ng/L. Gas chromatography-mass spectrometry (GC-MS) was used for identification and quantification of target compounds in this study.