16 phenolic compounds along with typical drinking water off-flavor compounds like geosmin, 2-methylisoborneol (MIB), and 2,4,6-trichloroanisole (TCA) were determined using two different approaches:
- In-situ derivatization with acetic anhydride followed by SBSE using the PDMS Twister and Thermal Desorption (TD)-GCMS;
- Direct SBSE without derivatization using the EG-Silicone Twister and subsequent TD-GCMS. In the case of the EG-Silicone twister, derivatization is not required due to its higher affinity for polar compounds.
Both methods were evaluated for the extraction of 0.01 to 1 μg/L of phenols from water samples. Good linearity (> 0.996 for EG-Silicone Twister and > 0.993 for PDMS Twister with derivatization) and repeatability (0.7-11.8 % RSD for EG-Silicone Twisters and 1.0-13.6 % RSD for PDMS Twisters) were achieved for both methods. Limits of detection (LODs) were in the range 0.007-0.036 μg/L for the EG-Silicone Twister and 0.011-0.053 μg/L for the PDMS Twister respectively. The recoveries obtained with EG-Silicone Twisters were between 17 % (2-methylphenol) and 127 % (2,3,5-trichlorophenol). Both Twister types were successfully applied for the analysis of phenolic compounds in tap water samples.