Development and validation of an SPE-GC-MS/MS taste and odour method for analysis in surface water

The goal of this research was to develop a robust method for taste and odour compounds that can be implemented by laboratories with mass spectrometers lacking chemical ionisation capabilities or specialised sample introduction hardware that are commonly used for taste and odour methods. Development, optimisation, and validation of a solid-phase extraction method using liquid injection and gas chromatography - tandem mass spectrometry detection with electron impact ionisation are described. Camphor was used as an internal standard, and through method development and robustness testing it was shown to extract similarly to other taste and odour compounds, making it a cost-effective alternative to deuterated analogs. The instrumental parameters and extraction procedure were fully optimised prior to assessing the method's linearity, precision, and accuracy. Using a 2000-fold enrichment factor, method recoveries for priority compounds geosmin (GSM) and 2-methylisoborneol (2-MIB) were >90%. Excellent linearity was obtained from the reportable detection limits up to 200ng L-1 and precision %relative standard deviations were 8.5% and 10.9% for GSM and 2-MIB, respectively. Detection limits of 0.9 and 5.5ng L-1 for GSM and 2-MIB respectively were deemed fit-for-purpose in comparison to their odour thresholds. Validation data were also obtained for other commonly analysed taste and odour compounds, including 2,4,6-trichloroanisole, 2-isopropyl-3-methoxypyrazine, and 2-isobutyl-3-methoxypyrazine. The validated method was used to screen surface waters in Nova Scotia, Canada for presence of taste and odour compounds, highlighting the presence of GSM on the east coast of Canada.