Quantification of amino-PAHs in human urine using UHPLC- hybrid quadrupole orbitrap high resolution MS (Q-orbitrap-HRMS): Assessing potential carcinogenic risks of Nitro-PAHs

Considering only parent polycyclic aromatic hydrocarbons (PAHs), such as benzo(a)pyrene as a representative compound, may underestimate the carcinogenic risk of polycyclic aromatic compounds (PACs). Nitrated polycyclic aromatic hydrocarbons (nitro-PAHs), known for their higher toxicity relative to parent PAHs, are widely present in the environment. In this study, a novel, highly sensitive, and accurate method utilizing ultra-performance liquid chromatography coupled with hybrid quadrupole Orbitrap high resolution MS (Q-Orbitrap-HRMS) was developed to quantify 15 amino-PAHs, which are metabolites of nitro-PAHs, in human urine samples. Our analysis revealed the presence of 10 out of the 15 targeted amino-PAHs in urine samples obtained from adults residing in Nanjing, China. The cumulative concentrations of the 10 amino-PAHs (∑ 10 amino-PAHs) in each urine sample ranged from not detected (ND) to 19.12 ng/mL, with mean and median concentrations of 2.85 and 2.09 ng/mL, respectively. Risk assessment using the potency equivalency factor (PEF) indicated that the mean estimated cancer risks for 1,6-dinitropyrene and 1,8-dinitropyrene, two dinitro-PAHs classified by the International Agency for Research on Cancer (IARC) as possibly carcinogenic to humans (Group 2B), were 2.96 × 10 −4 and 4.93 × 10 −5 , respectively, exceeding the commonly accepted risk threshold of 1 × 10 −6 , and indicating a potential public health concern. Overall, this study established a robust method for the identification and quantification of amino-PAHs in urine samples, highlighting the presence of nitro-PAHs, particularly dinitro-PAHs, in the human body and their significant yet often overlooked carcinogenic potential, necessitating further investigation and attention.