A novel nickel oxide nanoparticle-deposited silica (SiO2@NiO) composite was prepared via liquid-phase deposition (LPD) and then employed as a solid-phase extraction (SPE) sorbent. When the SPE was coupled with liquid chromatography–electrospray ionization mass spectrometry (LC–ESI/MS) analysis, an analytical platform for the sensitive determination of benzimidazole residues in egg and milk was established. The limits of detection of nine benzimidazoles were in the range of 0.8–2.2 ng/mL in milk and 0.3–2.1 ng/g in eggs, respectively, which was 5–10 times superior to the methods with other adsorbents for SPE. The recoveries of nine benzimidazoles spiked in milk and egg ranged from 70.8 to 118.7%, with relative standard deviations (RSDs) being less than 18.9%. This work presented the excellent extraction performance of NiO on benzimidazoles for the first time, and the applicability of the LPD technique used as sorbents for trace analysis in complex matrices was also demonstrated.

Polypyrrole (PPy)-functionalized Fe3O4 magnetic nanoparticles (Fe3O4–PPy) were prepared and applied as magnetic solid-phase extraction (MSPE) sorbents for the extraction of polycyclic aromatic hydrocarbons (PAHs) from environmental water samples. To achieve the optimal extraction performance, several parameters were investigated, including the amounts of sorbent, volume of desorption solvent, extraction and desorption time, inorganic salt and organic solvent content of the sample matrix. Coupled with gas chromatography/mass spectrometry (GC/MS) analysis, a rapid, sensitive and cost-effective method for the analysis of PAHs in aqueous samples was established. The low detection limits (LODs) for the target PAHs in the proposed method were in the range of 0.38 to 5.01 ng L−1, which are much lower than those LODs reported in previous methods. Good linearity of the detection method was obtained with correlation coefficients (R) between 0.9904 and 0.9992. Satisfactory reproducibility was also achieved with relative standard deviations (RSDs) less than 13.3% by an intra- and inter-day precision evaluation. The recoveries of the 10 PAHs in several environmental water samples ranged from 72.4% to 115.7% with the RSDs being less than 9.7%.

Polypyrrole (PPy)-functionalized Fe3O4 magnetic nanoparticles (Fe3O4–PPy) were prepared and applied as magnetic solid-phase extraction (MSPE) sorbents for the extraction of polycyclic aromatic hydrocarbons (PAHs) from environmental water samples. To achieve the optimal extraction performance, several parameters were investigated, including the amounts of sorbent, volume of desorption solvent, extraction and desorption time, inorganic salt and organic solvent content of the sample matrix. Coupled with gas chromatography/mass spectrometry (GC/MS) analysis, a rapid, sensitive and cost-effective method for the analysis of PAHs in aqueous samples was established. The low detection limits (LODs) for the target PAHs in the proposed method were in the range of 0.38 to 5.01 ng L−1, which are much lower than those LODs reported in previous methods. Good linearity of the detection method was obtained with correlation coefficients (R) between 0.9904 and 0.9992. Satisfactory reproducibility was also achieved with relative standard deviations (RSDs) less than 13.3% by an intra- and inter-day precision evaluation. The recoveries of the 10 PAHs in several environmental water samples ranged from 72.4% to 115.7% with the RSDs being less than 9.7%.