Identification and simultaneous analysis of Polycyclic Aromatic Hydrocarbons (PAHs) in Barbary bread samples using Gas Chromatography-Mass Spectrometry (GC-MS)

In this research a validated and effective method for simultaneous analysis of 24 poly aromatic hydrocarbons (PAHs) using gas chromatography-mass spectrometric detector was developed in traditional and semi industrial bread samples. Sample preparation was done based on QuEChERS method and developed method was validated and applied for analysis of bread samples. Matrix effect was evaluated by comparing the slopes of solvent-based calibration curve and spiked calibration curve in blank sample. Among the 24 analyzed compounds, 22 (91%) and 2 (8%) compounds presented the ion enhancement and ion suppression respectively. Therefore’ spiked calibration curve was used for overcoming matrix effect. In the concentration range of 10-500 ng/g, the calibration curves for each analyte was linear with a determination coefficient (R2) of 0.990 to 0.999. The limits of detection (LODs) and quantitation (LOQs) for different PAHs were between 0.14-1.49 and 0.46-4.91 ng/g, respectively. The mean recoveries obtained for three fortification levels (25, 50 and 200 ng/g, three replicates in each day) in three consecutive days were 86-111% (n=27), and also the average of relative standard deviations (RSDs) of PAHs were in the range of 2.85-11.57%  with a satisfactory precision (RSD<20%). Analysis of bread samples using the validated method showed that Naphthalene was found in 9 traditional Barbary bread samples (45%) in the range of 46.34±1.89 ng/g and any compounds was detected in semi- industrial samples. All of the obtained positive results were higher than the legal permissible limits (1.0 ng/g) proposed by the European ::union:: for processed cereal-based foods. The final findings showed that direct flame exposure in gas oven during baking of Barbary bread could produce PAH compounds.