Zn/Al-layered double hydroxide-graphene oxide nanocomposite use in the solid-phase extraction-preconcentration and HPLC determination of diclofenac

A rapid and inexpensive hydrothermal process was employed for the synthesis of a nanocomposite composed of zinc/aluminum-layered double hydroxide with carbonate interlayer anions and graphene oxide (Zn/Al LDH-GO). Fourier-transform infrared spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller area analysis, and X-ray diffraction technique were employed for the characterization of the prepared nanocomposite. Considering the possible cooperative adsorption effect of LDH and GO moieties, a column packed with this adsorbent has been used, for the first time, in the solid-phase extraction (SPE) of diclofenac. The analysis of DCF was carried out by employing high-performance liquid chromatography (HPLC). The parameters influencing the SPE and elution processes were optimized by the univariate sequential optimization procedure. Under optimized experimental conditions, the linear calibration plots for the determination of DCF in hospital wastewater and human serum samples were obtained in the ranges of 1-730 mu g L-1(R-2 = 0.999) and 4-625 mu g L-1(R-2 = 0.998), respectively. The limits of detections were correspondingly 0.12 and 0.5 mu g L-1, with the preconcentration factors of 68 and 59. The column stability was excellent, and its efficiency was almost constant, even after 192 adsorption/desorption cycles. The results confirmed the abilities of the developed method for the efficient preconcentration and thus precise trace analysis of DCF in real samples.