A preconcentrator-separator two-in-one online system for polycyclic aromatic hydrocarbons analysis

Abstract

A novel preconcentrator-separator two-in-one online system has been developed for the online analysis of trace amounts of four polycyclic aromatic hydrocarbons (PAHs) in tea samples. A micro-preconcentrator unit of zeolite imidazolate framework-8-poly(vinyl alcohol) cryogel (ZIF-8-PVA cryogel) and a micro-separation unit of multiwalled carbon nanotubes-poly(vinyl alcohol) cryogel (MWCNTs-PVA cryogel) were fabricated onto an acrylic plate. The eluent from this two-in-one system flowed directly to an on-column UV–visible detector. Under optimum conditions, the system provided a wide linear range from 0.10µgL−1 to 2.00mgL−1 for benzo(a)anthracene (BaA) and chrysene (Chry), 0.15µgL−1 to 3.00mgL−1 for benzo(a)pyrene (BaP) and 0.20µgL−1 to 5.00mgL−1 for benzo(b)fluoranthene (BbF). The limits of detection were 0.05µgL−1 of both BaA and Chry, 0.10µgL−1 of BaP and 0.20µgL−1 of BbF. This two-in-one system was cost-effective, easy to prepare, had excellent stability for up to 417 consecutive injection cycles and provided a good system-to-system reproducibility (n=6) with a relative standard deviation of less than 4%. The system was successfully applied to detect PAHs in tea samples. The concentrations of BaA, Chry, BaP and BbF in seven tea samples were found in the range of non-detectable 2.73±0.07mgL−1 with good recoveries of 83±6 to 108±4%. In addition, it can be easily applied for the detection of other aromatic compounds in contaminated water samples.