The determination of six taste and odour compounds in water using Ambersorb 572 and high resolution mass spectrometry

Abstract

A method for the analysis of six taste and odour causing compounds in aqueous samples using the granular adsorbent, Ambersorb 572, and gas chromatography-high resolution mass spectrometry (GC-HRMS) has been developed. This method for the determination of geosmin, 2-methylisoborneol (2-MIB), 2-isopropyl-3-methoxypyrazine (IPMP), 2-isobutyl-3-methoxypyrazine (IBMP), 2,3,6-trichloroanisole (236-TCA) and 2,4,6-trichloroanisole (246-TCA) is highly productive [up to 40 samples per day + 23 quality control (QC) samples] and provides rapid (24–48 h) turnaround times. The analytes are extracted from water by the addition of Ambersorb 572 to the sample bottle and rolling for 1 h. The adsorbent is isolated by filtration and allowed to air dry for 1 h. The Ambersorb 572 is transferred to an autosampler vial and the analytes are desorbed into dichloromethane. The extract is analysed by GC-HRMS at 7000 resolving power (RP). Quantification is performed by isotope dilution and internal standard techniques utilizing d₃-geosmin, d₃-2-MIB, d₅-246-TCA and 2-sec-butyl-3-methoxypyrazine (s-BMP). Method precisions of 3.5–5.8% and accuracies of ±5.7–8.9% were obtained. Reporting detection limits (RDLs) of 1.0 ng L⁻¹ were obtained for 2-MIB, geosmin, IPMP and IBMP, while RDLs of 2.0 ng L⁻¹ were obtained for 236-TCA and 246-TCA.