Modified analytical method for polycyclic aromatic hydrocarbons, using SEC for sample preparation and RP-HPLC with fluorescence detection.: Application to different food samples

An HPLC method with fluorescence detection has been developed for determination of eight polycyclic aromatic hydrocarbons (PAH) with four to six condensed aromatic carbon rings in edible oils and smoked products. The method employs preparative size-exclusion chromatography for efficient one-step lipid removal without saponification; benzo[b]chrysene is used as internal standard for quantification. Two other methods (liquid-liquid extraction and solid-phase extraction) were tested for one-step clean-up and sample enrichment but it was found that one-step procedures did not remove lipids completely. Linearity of calibration plots was good for all PAH in the concentration range from the detection limit (approx. 0.1 ppb) to 100 ppb. The repeatability (RSD, n = 6) for different PAH ranged from 0.5 to 5%. Analysis of standard reference materials from the National Institute of Standards and Technology (mussel tissue, SRM 2978), the Community Bureau of Reference (coconut oil, CRM 458), and the Central Science Laboratory (olive oils, FAPAS 0615, 0618, and 0621) resulted in a good agreement between measured and certified concentrations. The method described has been used for determination of the PAH content of twelve samples of edible oil, rape seed, milk powder, hens' egg white and yolk, smoked sausage, white cottage cheese, and sprats. The PAH were identified from their fluorescence spectra.