Search

By integration of benzene-constructed porous organic polymer (KBF) and multiwalled carbon nanotube (MWCNT), a MWCNT-KBF hybrid material was constructed through in situ knitting benzene with formaldehyde dimethyl acetal in the presence of MWCNTs to form a network. MWCNT-KBF was then adopted as a novel solid-phase microextraction (SPME) fiber coating. Coupled to gas chromatography-flame ionization detection, the MWCNT-KBF–assisted SPME method showed large enhancement factors (483–2066), low limits of detection (0.04–0.12 μg L−1), good linearity (0.13–50 μg L−1), and acceptable reproducibility (4.2–10.2%) for the determination of polycyclic aromatic hydrocarbons (PAHs). The method recoveries of seven PAHs were in the range 80.1–116.3%, with relative standard deviations (RSDs) ranging from 3.5 to 11.9%. The SPME method was successfully applied to the determination of PAHs in river, pond, rain, and waste water, providing a good alternative for monitoring trace level of PAHs in environmental water.

A fibrous magnetic boron nitride nanocomposite was synthesized and is shown to be a viable adsorbent for the magnetic solid phase extraction of pesticides prior to their quantitation by gas chromatography with electron capture detection. The optimum conditions were obtained by both single factor optimization and response surface analysis (Box-Behnken design). Under the optimized conditions, the response to the ten pesticides (dicofol, α-endosulfan, p,p’-DDE, nitrofen, β-endosulfan, p,p’-DDD, p,p’-DDT, bifenthrin, permethrin and fenvalerate) is linear in the 0.03–40 ng·mL−1 concentration range with the coefficients of determination ranging from 0.9970 to 0.9992. The relative standard deviations at concentration levels of 0.5 ng·mL−1, 20 ng·mL−1 and 40 ng·mL−1 were below 8.7%. The recoveries of the analytes from spiked tea water and tea beverage samples varied between 84.5% and 122%, with relative standard deviations ranging from 4.8 to 12%. The limits of detection are between 0.01 and 0.05 ng·mL−1. The adsorbent can be reused over 50 times without significant loss of extraction efficiency.