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

A headspace solid-phase microextraction (HSSPME) method for the determinati on of phenols in soils has been developed. The samples were suspended in wa ter and phenols were derivatized in situ by adding potassium bicarbonate an d acetic anhydride. Afterward, the sample was stirred and HSSPME was perfor med 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 ad sorption process were studied (addition of water to the soil sample, sample size, salting out effect, volume of headspace). Also the extraction kineti cs at 25 and 100 degrees C were studied and compared. The proposed HSSPME m ethod exhibits good performance in terms of precision, sensitivity, and lin earity. 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 t he proposed method were in good agreement with the certified phenol values. (C) 2000 John Wiley & Sons, Inc.