Peanut shell-derived biochar materials for effective solid-phase microextraction of polycyclic aromatic hydrocarbons in environmental waters

In this contribution, low-cost and robust biochar material fabricated from waste peanut shells manifest highly-efficient adsorption capability and was prepared into a solid-phase microextraction fiber coating on the external surface of a stainless-steel wire. It was observed from scanning electron microscopy that, a homogeneity of cavities makes up the external surface of the coating, and Raman signals revealed that it contained graphite structures. Coupled with gas chromatography-mass spectrometry (GC-MS), headspace SPME (HS-SPME) based on the novel fiber was applied for the analysis of six polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. Under the selected optimum conditions in both extraction and desorption processes, satisfactory analytical performances were achieved, which included good intra-fiber repeatability (relative standard deviations, RSDs in the range from 6.93% to 10.86%, n = 6) and inter-fiber reproducibility (RSDs from 5.61% to 13.59%, n = 4), together with low limits of detection (LODs, 1.09–2.46 ng L−1) and limits of quantification (LOQs, 3.62–8.20 ng L−1), as well as a satisfactory linear range for the analysis of the target PAHs (10–2000 ng L−1). This established method also showed good reliability in the analysis of target PAHs in river water as well as pond water in the downtown area of Guangzhou, China, as the spiked recoveries were in the range from 81% to 116%.