Determination of polynuclear aromatic hydrocarbons in human blood serum by proteolytic digestion — direct immersion SPME

A proteolytic digestion — direct immersion solid phase microextraction (SPME) method has been developed for the determination of polynuclear aromatic hydrocarbons in human blood serum. Non-specific serine protease, Proteinase K , was employed to remove the fouling of the SPME stationary phase by the lipoprotein in blood serum during extraction. Optimization of protease concentration and duration of the proteolytic digestion as well as SPME sampling have been performed. Proteinase K concentration of 190 μg protease/ml of serum and digestion time of 60 min at 25°C were found to be the optimum conditions for the determination. PAH recoveries of the direct immersion SPME method ranged from 81.1 to 98.5%. The relative repeatability of the method was found to be 5.6% ( n = 10). Detection limits for the 16 prioritized PAHs ranged from 2.7 to 30.4 ppb.