Air-assisted dispersive micro-solid phase extraction of polycyclic aromatic hydrocarbons using a magnetic graphitic carbon nitride nanocomposite

An air-assisted dispersive micro solid phase extraction method (AA-d mu-SPE) is described that is based on the use of a magnetic graphitic carbon nitride (g-C3N4/Fe3O4) nanocomposite. In AA-d mu-SPE, magnetic nanocomposite was dispersed into the aqueous sample solution by air bubbles, which promoted the analytes adsorption. The magnetic adsorbents were then separated from sample solution using a magnetic field. The method was shown to be efficient, rapid and reliable to extract the polycyclic aromatic hydrocarbons (PAHs) from biological samples prior to their determination by GC with FID detection. The nanocomposite was characterized by X-ray diffraction, FT-IR spectroscopy, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer and thermogravimetric techniques. A main reason of selection of the g-C3N4/Fe3O4 nanocomposites as adsorbent is their high affinities to PAHs and ease of collection from the solution. Several parameters affecting adsorption and desorption phenomena were studied. Under optimum conditions, the limits of detection, linear ranges and relative standard deviations (RSDs, for n = 6) were ranged from 0.3 to 0.6 (ng mL(-1)), 1 to 100 ng mL(-1), and 3.49 to 5.94 %. The adsorbents can be reused up to 7 times. The method was applied for the determination of naphthalene, fluorene, phenanthrene, anthracene and pyrene in (spiked) saliva and blood samples, and satisfactory results were achieved.