Abstract:

In the process of “Peking Roast Duck” with a novel heating technique, namely air jet impingement, polycyclic aromatic hydrocarbons (PAHs) may be formed. A method of HPLC coupled with fluorescence detector was developed for the determination of PAHs in fat- and protein-rich foods, such as “Peking Roast Duck”. Homogenized duck skin samples were pretreated by using methanol containing 2 mol/L KOH-water (8:2, V/V) for saponification, issoctane for extraction, methanolwater (1:1, V/V) for washing, DMF-water-issoctane (1:1:1, V/V) for liquid-liquid partition, and Florisil solid-phase column for cleaning up. Results showed that the recoveries of benzo[a]pyrene (B[a]P), dibenzo[a,h]anthracene (DB[a.h]A) and 7,12- dimethylbenzene[a] anthracene (7,12-DMB[a]A) in blank sample at the spiked amounts of 2 × 10-8 and 1 × 10-7 g were between 83.59% and 92.97%, and their recoveries at the spiked amount of 1, 2 and 2 μg/kg respectively, were 73.85% to 80.31%, and the RSDs were less than 10%. Their contents in roasted duck ranged from 0.56 to 3.19 μg/kg, but no these three compounds were found in raw duck. Our results suggested the high clean-up efficiency and recovery of this method and the sensitivity and accuracy of detection could meet the requirements for analysis of trace compounds in complex matrices. The B[a]P content of 0.56 μg/kg is far less than the maximum limit value of 5 μg/kg in the smoked and roasted foods in term of the national standards.

Key words: “Peking Roast duck”, air-jet impingement, polycyclic aromatic hydrocarbons (PAHs), high performance chromatography-fluorescence detection (HPLC-FD)