Abstract: Considering the complex matrix of egg samples and the limited research on PCP detection, the method mentioned by the title was proposed based on the characteristic that PCP and its sodium salt could transform into each other under certain acidity conditions. The 5.00 g of egg sample was taken, and 30 μL of 10.0 mg·L⁻¹ 2,4,6-tribromophenol internal standard solution, 10 mL of n-hexane-ethyl acetate mixed solution at a volume ratio of 9∶1, and 2.5 mL of 5% (volume fraction) trifluoroacetic acid solution were added. After shaking by vortex for 5 min, extracting by ultrasound for 10 min, and centrifuging for 5 min at 0 ℃, the upper organic phase was extracted and blown to 3 mL by nitrogen at 60 ℃. The 3 mL of 0.1 mol·L⁻¹ sodium hydroxide solution was added, the mixture was shaken by vortex for 3 min, and centrifuged for 2 min at 0 ℃. The upper organic phase was discarded, and 0.5 mL of 6 mol·L⁻¹ hydrochloric acid solution and 5 mL of n-hexane were added to the aqueous phase. After shaking by vortex for 2 min and centrifuging for 2 min at 0 ℃, the upper organic phase was sucked out, and blown to dryness by nitrogen at 60 ℃. The 1.5 mL of acetonitrile was added, and the mixed solution was sonicated for 2 min, and centrifuged for 2 min. The upper acetonitrile phase was extracted, and passed through the activated SLC solid phase extraction column. After eluting the column with 4 mL of acetonitrile, the eluate was collected and blown to 0.5 mL by nitrogen at 60 ℃. The 0.2 mL of acetic anhydride-pyridine mixed solution at a volume ratio of 1∶1 was added, and the mixed solution was sealed and reacted for 15 min at 60 ℃. The 1 mL of n-hexane and 2.0 mL of 0.2 mol·L⁻¹ potassium carbonate solution were added, and the mixture was shaken by vortex for 2 min and centrifuged for 2 min. The organic phase was sucked out, and injected into the gas chromatograph-mass spectrometer, and PCP in the solution was separated on the Rtx-5ms chromatographic column with the heating program, ionized by EI ion source, detected by SIM mode, and quantified by internal standard method. It was shown that linear ranges of standard curves were found in the range of 10-200 ng, with detection limit (3S/N) of 0.11 μg·kg⁻¹. Test for recovery was made according to the standard addition method, giving recoveries in the range of 83.0%-104%, and RSDs (n=6) of the determined values ranged from 4.2% to 9.4%. The proposed method was used for the analysis of 18 commercially available egg samples, and PCP was detected in one egg sample, with the detection amount of 5.07 μg·kg⁻¹.