3.5. Analysis of coffee and tea samples
The proposed method was further applied to the analysis of PAHs in coffee and tea samples to confirm its applicability. The method was validated using real samples spiked with PAH standards at three known concentrations. All of the samples were analyzed in three replicates, and the detailed results are presented in Table 3. For all of the real samples, no analytes were initially detected in coffee, while BaA and BaP were found in tea samples. After determination and calculation, the concentrations for BaA and BaP were 14.6 mg/kg and 18.2 mg/kg , respectively. The spiked recoveries of the target PAHs in coffee and tea samples ranged from 87.5% to 104.5%, with RSDs under 3.6%, and 88.8% to 103.2%, with RSDs of less than 3.7%, respectively.
The recovery values were in conformity with the required range stipulated by Association of Official. Analytical chemists (AOAC), and this indicated that the proposed method could be considered a useful tool for the quantification of PAHs in coffee and tea samples. HPLC chromatograms of a standard solution and tea samples are presented in Fig.3 .