Investigating the robustness and extraction performance of a matrix-compatible solid-phase microextraction coating in human urine and its application to assess 2-6-ring polycyclic aromatic hydrocarbons using GC-MS/MS

In this work, a polydimethylsiloxane/divinylbenzene fiber overcoated with a layer of polydimethylsiloxane was evaluated as analytical sampling tool for the first time in human urine. Urinary polycyclic aromatic hydrocarbons with 2-6 aromatic rings were considered as target compounds. The analyte uptake in kinetic and thermodynamic regime was evaluated and compared to the performances of polydimethylsiloxane/divinylbenzene and polydimethylsiloxane fibers. The assessment of the robustness and endurance of the overcoated fiber was carried out by direct immersion solid-phase microextraction in undiluted urine performing up to 120 consecutive extractions. The overcoated fiber was then used to develop a fast and easy direct immersion solid-phase microextraction with gas chromatography and triple quadrupole mass spectrometry protocol for the quantification of the target polycyclic aromatic hydrocarbons. The attained values of accuracy and precision were 75-114% and 2-19%, respectively, while the limits of quantification ranged between 0.05 and 1 ng/L. The proposed protocol was applied to the screening of urine samples collected from smoking and nonsmoking volunteers. The successful results obtained by using the overcoated fiber create not only new alternatives for polycyclic aromatic hydrocarbon exposure assessment but also new perspectives for the application of direct immersion solid-phase microextraction to the analysis of bioclinical matrixes.