Dispersive liquid-liquid microextraction coupled with ultra performance liquid chromatography-fluorescence detection for the determination of polycyclic aromatic hydrocarbons in tea: Method development, validation, greenness assessment, and dietary exposure risk assessment.

This study presents an improved dispersive liquid-liquid microextraction with ultra performance liquid chromatography-fluorescence detection (DLLME-UPLC-FLD) method for determination of eight European Food Safety Authority-recommended polycyclic aromatic hydrocarbons (PAHs) in teas marketed in Malaysia. DLLME used dichloromethane as extraction solvent and methanol as dispersive solvent. Separation was effected using C18 column with FLD detection at 270 nm excitation and four emission wavelengths. The method demonstrated good linearity, detection limits (3.87-32.5 ng L-1), precision (≤9.91% RSD), recoveries (85.13-101.71%), enrichment factors (35-48), and greenness scores of 0.53 (AGREE). The analysis of 43 commercial tea infusions and tisanes showed chrysene was the most prevalent PAHs. The mean total concentration of ∑PAH8 followed the trend: post-fermented tea >non-fermented tea (31.61 ng kg-1) > fully fermented tea (17.10 ng kg-1) > semi-fermented tea (8.35 ng kg-1) > tisanes (4.28 ng kg-1). Margin of exposure values were above the critical safety threshold (10,000) for all categories.