Technical Abstract: The impact of sample preparation on the extraction of phenolic compounds from a phenolic enriched substrate, parsley (Petroselinum crispum) flakes, was investigated. Five different extraction procedures (shaking, vortexing, sonication, stirring and pressurized liquid extraction or PLE), and three different solvents (methanol, ethanol, and acetone), with five different proportions of solvent to water ratios per solvent were used for extraction. Extracts were analyzed for phenolic content by HPLC analysis and Folin-Ciocalteu assay. The yields of phenolic compound extracted with PLE were better than or comparable to the other four classical extraction procedures. Optimum extraction efficiency with PLE was obtained when extractions were performed with four extraction cycles using ethanol:water (50:50, % v/v). The amount of apiin (4,5,7-trihydroxyflavone-7-apiosylglucoside) and malonyl-apiin (apigenin-malonyl-apiosylglucoside) isolated from parsley varied with the composition of extraction solvent. Apiin extractability was found to be maximum with a ratio of 30% solvent (ethanol, methanol or acetone) to 70% water, whereas, higher amounts of malonyl-apiin were isolated with 70% solvent. Malonyl-apiin was not detected when parsley samples were extracted with 10% and 30% solvent.