TiO₂ nanotube arrays prepared by anodization as an adsorbent in micro-solid-phase extraction to preconcentrate and determine nitrogen-containing polycyclic aromatic hydrocarbons in water samples.

In this study, a simultaneous determination method for nitrogen-containing polycyclic aromatic hydrocarbons including 7-methylquinoline, acridine, 5,6-benzoquinoline, carbazole, and 9-methylcarbazole was developed. This method is based on a micro-solid phase extraction using TiO2 nanotube arrays as an adsorbent in combination with HPLC. Some factors that had an effect on the enrichment were optimized, such as sample pH, surfactant concentration, ion strength, type of eluent, equilibrium time, and desorption time. Under the optimized conditions, the linear ranges and LODs were in the range of 0.01-100 and 0.0035-0.81 μg/L, respectively. The precisions of the proposed method were <9.51% (RSD, n = 6). The developed method was validated with four real samples, and the spiked recoveries were in the range of 77-109.6%. All these results demonstrated that this novel micro-solid-phase extraction technique was a reliable alternative to conventional preconcentration method for the extraction and analysis of such nitrogen-containing polycyclic aromatic hydrocarbons in complex samples.