Determination of phenols in soils by in situ acetylation headspace solid-phase microextraction

A headspace solid-phase microextraction (HSSPME) method for the determination of phenols in soils has been developed. The samples were suspended in water and phenols were derivatized in situ by adding potassium bicarbonate and acetic anhydride. Afterward, the sample was stirred and HSSPME was performed exposing the PDMS fiber with a 100 mu m thickness to the headspace over the sample. Finally, the fiber was inserted in the GC injector port and GC-MSD analysis was carried out. Parameters affecting the extension of the adsorption process were studied (addition of water to the soil sample, sample size, salting out effect, volume of headspace). Also the extraction kinetics at 25 and 100 degrees C were studied and compared. The proposed HSSPME method exhibits good performance in terms of precision, sensitivity, and linearity. Detection limits were in the sub-ng/g. This method has been applied to a real contaminated soil and the concentrations of phenols found with the proposed method were in good agreement with the certified phenol values. (C) 2000 John Wiley & Sons, Inc.