ZIF-8/h-BN coated solid-phase microextraction fiber via physical coating technology and sol-gel technology for the determination of nitro polycyclic aromatic hydrocarbons from water samples

Abstract

As an emerging pollutant, nitro polycyclic aromatic hydrocarbons (NPAHs) exist widely in the environment, and some of them are potential carcinogens and mutagens. Solid phase microextraction (SPME) is a valuable technique to determine trace level pollutants and the advancements in its fiber preparation are boosting its performance multifold. In our study, zeolite imidazolate framework-8/hexagonal boron nitride (ZIF-8/h-BN) coating material was synthesized successfully and used to prepare SPME fibers by physical coating technology (PCT) and sol–gel technology (SGT) for analyzing 15 NPAHs in environmental water samples. Box-Behnken design was employed to optimize the key factors of SPME condition, such as the time and temperature during extraction and desorption events. The optimized extraction temperature, desorption time and desorption temperature were 45 ℃, 4.5 min, and 265 ℃, respectively, for both coating techniques (PGT and SGT). The extraction time (37 min) of SGT was shorter than that of PCT (50 min) due to the thickness of coating fiber. Under the optimized SPME conditions, the method based on ZIF-8/h-BN-coated fiber and gas chromatography-mass spectrometry achieved a wide linearity (5–5000 ng L−1). The PCT fiber-based method showed lower detection limits (0.3–11.1 ng L−1), which is suitable for surface water, such as tap water and lake water. SGT fiber-based method showed better repeatability (<11.6%) and fiber-to-fiber precision (<13.2%), which is suitable for complex matrices like wastewater. The recoveries obtained by spiking 15 NPAHs at various concentrations for all three kinds of real water samples (70.3–107.0%) was found much suitable than any other methods for field application. Therefore, ZIF-8/h-BN coated fiber prepared by PCT and SGT exhibits a great potential for use in trace NPAHs analysis.