Comparison of gas chromatography–mass spectrometry and capillary electrophoresis in analysis of phenolic compounds extracted from solid matrices with pressurized hot water

Self-constructed pressurized hot water extraction (PHWE) equipment was used in dynamic mode to extract spiked phenolic compounds (phenol, 3-methylphenol, 4-chloro-3-methylphenol and 3,4-dichlorophenol) from sea sand and soil. Phenols were analyzed by both gas chromatography–mass spectrometry (GC–MS) and capillary zone electrophoresis (CZE) to compare the techniques and to find out if CZE is a suitable tool for analysis of phenols extracted from environmental matrix. Good recoveries of phenols spiked in sea sand were achieved at all PHWE temperatures (50, 100, 200, 300 °C). GC–MS studies showed that phenols were selectively extracted from soil at 50 °C but various other compounds (e.g. polyaromatic hydrocarbons) were extracted along with the phenols at 300 °C. In the case of CZE, phenols extracted from the soil, at 300 °C were separated with good resolution at pH 9.7, and co-extracted compounds did not interfere with the analysis. The analytical values obtained by GC–MS and CZE were generally of similar magnitude.