Pre-column Derivatization-GC Determination of Trace Amounts of Phenol in Water After Separation by Micro-wave Heated Extraction

Water sample containing phenol was extracted with mixed solvent of acetone and cyclohexane(1+1),heated at 60 ℃ in a microwave oven for 30 s.An aliquot of the extract was reacted with the derivatizing reagent,acetic anhydride for 15 min at pH 8~9.The derivatized product of phenol was then extracted with petroleum ether.An aliquot of the organic phase,after dehydration,was used for GC determination.DB-17 capillary chromatographic column (30 m×0.53 mm,1.0 μm) and hydogen flame ionization detector were used in the gas chromatography.Detection limit (3S/N) found under the optimum condition was 0.01 mg·L-1.Precision and recovery were tested by analyzing 8 simulated water samples with addition of standard phenol,giving values of RSD′s and average recovery of 4.2% and 94.0% respectively.