# Solid-Phase Extraction Based on Captiva EMR-Lipid for Determination of 19 Aromatic Amine Antioxidants and Two p-Phenylenediamine Quinones in Human Plasma

## TL;DR

A new method was developed to detect antioxidants and quinones in human plasma, offering improved accuracy and sensitivity for biomonitoring.

## Contribution

A novel solid-phase extraction method using Captiva EMR-Lipid was developed for simultaneous detection of 19 antioxidants and two quinones in plasma.

## Key findings

- The method achieved high recovery (73.0–96.8%) and sensitivity (detection limits 0.81–21 pg/mL).
- Eleven aromatic amines were detected in plasma samples from 20 adults at concentrations of 240–710 pg/mL.
- Diphenylamine derivatives like DBDPA and DPA were the most prevalent compounds detected.

## Abstract

A robust analytical method based on Captiva EMR-Lipid solid-phase extraction and HPLC-MS/MS was developed and validated for the simultaneous determination of 19 aromatic amine antioxidants (AAs) and two p-phenylenediamine-derived quinones (PPD-Qs) in human plasma. The optimized protocol effectively removed phospholipid interferences from complex blood matrix, significantly mitigating ion suppression and improving the recovery of hydrophobic AAs compared to conventional liquid–liquid extraction. Method validation demonstrated good accuracy (spike recoveries: 73.0–96.8%), precision (RSD < 11%), and sensitivity with method detection limits ranging from 0.81 to 21 pg/mL. The method was successfully applied to plasma samples from 20 adults, in which 11 AAs were detected at total concentrations of 240–710 pg/mL. Diphenylamine derivatives, particularly bis(4-tert-butylphenyl)amine (DBDPA) and diphenylamine (DPA), were identified as the predominant compounds, contributing over 69% of the total AA burden. No PPDs or PPD-Qs were detected, which may be attributed to their biotransformation and urinary excretion, as well as the limited sample size. This study provides a comprehensive biomonitoring tool for assessing combined human exposure to multiple AAs and establishes a foundation for further investigation into their health implications.