Hydrophobic melamine foam as the solvent holder for liquid-liquid microextraction

In this study, the hydrophobic melamine foam (HMF) was proposed as the solvent holder for liquid-liquid microextraction (LLME) purpose. The HMF contained 3D mesh structure with ultralight, compressible and hydrophobic properties. When it was used as the solvent holder, it had merits of convenient collection of the extractant phase by compressing the foam, enhanced extraction efficiency because of the large contact area between the extractant phase and sample solution, and reusability of the foam. The HMF-LLME combined with gas chromatography-mass spectrometry (GC-MS) was applied for the determination of polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. Under the optimized conditions, the proposed method showed linear ranges of 0.01-50.00 ng mL^-1 with good correlation coefficients (r > 0.99), low limits of detection (0.4-3.0 pg mL^-1), and good precision with intra-day and inter-day relative standard deviations in the range of 6.1-13.7% and 5.3-15.0%, respectively. The HMF retained good performance after 10 cycles' usages, demonstrating excellent reusability. The proposed HMF-LLME method provided comparable results with the traditional liquid-liquid extraction of PAHs based on United States Environmental Protection Agency Method 3510C on real water samples but with more operational convenience, less consumption of organic solvent and low cost. The HMF was suitable as the solvent holder for LLME purpose with accurate, convenient, rapid, eco-friendly and reusable properties.