Quantifying trace odorants in water by GC–MS with trap-based preconcentration: Assessing SPME and high‑capacity sorptive extraction
This study describes the use of the new Centri sample automation and concentration platform to extract and quantify trace-level odorants in water, using two headspace sampling methods – multi-phase SPME fibers or HiSorb high-capacity sorptive extraction probes – in conjunction with trap-based preconcentration and GC–MS. Performance for the target analytes IPMP, IBMP, 2-MIB, 2,4,6-TCA and geosmin was within the requirements of ISO 17943 and GB 5749, with linearities >0.996 and mean MDLs of the order of 1 ppt. We also describe the key attributes of each sampling method, and discuss the options offered by Centri that allow the optimum choice to be made based on specific application requirements.
contributed by Markes International Ltd |
Introduction
The presence of volatile organic compounds (VOCs) in drinking water can have a significant effect on consumer experience. The naturally occurring compounds geosmin, 2-methyl isoborneol (2-MIB) and 2,4,6-trichloroanisole (2,4,6-TCA) have particularly strong odours, and are often the source of complaints to water companies, while the emerging odorants 2-isopropyl-3-methoxypyrazine (IPMP) and 2-isobutyl- 3‑methoxypyrazine (IBMP) are also of concern. Reliable detection of these compounds is therefore important, but this is challenged by their low odour thresholds, which are typically at the low-ppt level.
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