Diamond nanoparticles coating for in-tube solid-phase microextraction to detect polycyclic aromatic hydrocarbons

Diamond nanoparticles were coated onto stainless steel wires as a extraction material, then it was filled into a poly(ether ether ketone) tube for in-tube solid-phase microextraction. Coupled with high-performance liquid chromatography, the extraction tube was evaluated with different types of analytes including polycyclic aromatic hydrocarbons, estrogens and plasticizers. As the coating, diamond nanoparticles exhibited greater extraction capacity for hydrophobic analytes. Several polycyclic aromatic hydrocarbons were used as model analytes, four main extraction and desorption factors were optimized, including sampling volume, sampling rate, methanol content in sample and desorption time. A sensitive analysis method was established with wide linear range (0.016-20 μg/L), good correlation coefficients (0.9991-0.9997), low limits of detection (0.005-0.020 μg/L), low limits of quantitation (0.016-0.070 μg/L) and high enrichment factors (305-2396). Relative standard deviations for intra- and interday were less than 2.4% (n = 3) and 8.4% (n = 3), respectively. Durability and chemical stability were satisfactory with relative standard deviations less than 7.9% (n = 3). Finally, the method has been successfully applied to the detection of polycyclic aromatic hydrocarbons in real samples.