Determination of Polycyclic Aromatic Hydrocarbons (PAHS) in Ancient and Commercial Tea Using Ultra-High-Performance Liquid Chromatography with Diode Array Detection (UHPLC-DAD)

Ku, Pei Yin (2026) Determination of Polycyclic Aromatic Hydrocarbons (PAHS) in Ancient and Commercial Tea Using Ultra-High-Performance Liquid Chromatography with Diode Array Detection (UHPLC-DAD). Final Year Project (Bachelor), Tunku Abdul Rahman of Management and Technology.

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Abstract

Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants that are carcinogenic, mutagenic, and hepatotoxic. They can be accumulated by the tea plants through dry and wet deposition. This study aimed to determine the PAH concentration levels in ancient and commercial tea using Ultra-High-Performance Liquid Chromatography with Diode Array Detection (UHPLC-DAD). There is 11 PAHs targeted in this study, from low molecular weight PAHs to high molecular weight PAHs. Hexane extraction followed by solid phase extraction (SPE) was employed to extract the PAHs from the tea samples, while the PAHs were detected using UHPLC-DAD. This analytical method was validated. The optimized procedure achieved recoveries from 53.42 to 100.85% in commercial tea, and from 71.85 to 112.55% in ancient tea. Furthermore, in terms of linearity, the R2 values were greater than 0.9900. For sensitivity, the LODs ranged from 0.1440 to 1.6670 μg/L, while the LOQs ranged from 0.4363 to 5.0515 μg/L. The %RSD values were below 5.5% for repeatability and intermediate precision. 7 of the targets 11 PAHs were detected in the tea samples. The results from sample analysis showed that the average PAH concentration levels in commercial teas were greater than ancient teas, with 163.55 μg/L and 82.44 μg/L detected respectively. The cultivation environment of the tea plants was identified as a possible factor which influenced the accumulation of PAHs in the teas.