Objective To develop the method of simultaneous determination of four odorants in drinking water (2-methylisoborneol, geosmin, dimethyl disulfide, and dimethyl trisulfide) using purge and trap-gas chromatography-mass spectrometry (P&T-GC-MS) versus solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS).

Methods In P&T-GC-MS, the analytes in water sample were purged with nitrogen in a purge tube and captured by a trap, and the trap was quickly heated to desorb the analytes. In SPME-GC-MS, the analytes in water sample were enriched by a solid-phase microextraction fiber and then desorbed in the GC injection port. The desorbed analytes were separated on a HP-5 MS column and detected by GC-MS. A qualitative analysis was performed based on retention time and characteristic ions, and a quantitative analysis was conducted using the internal standard method.

Results For the P&T-GC-MS method, the sample volume was 25 mL, the linear range for all four odorants was 10-100 ng/L, the limits of detection were 1.8-3.5 ng/L, the recovery rates were 84.4%-108.3%, and the relative standard deviations were 2.0%-9.8%. For the SPME-GC-MS method, the sample volume was 10 mL, the linear range of dimethyl disulfide and dimethyl trisulfide was 10-100 ng/L, the range of 2-methylisoborneol and geosmin was 5.0-100 ng/L, the limits of detection were 1.8-6.0 ng/L, the recovery rates were 81.7%-114.0%, and the relative standard deviations were 3.7%-13.4%.

Conclusion Both method achieved detection limits at the ng/L level, the recovery rates and precision met the detection requirements, and these method were suitable for simultaneous determination of the four odorants in drinking water.