Ultrasensitive fluorometric determination of daclatasvir in exhaled breath condensate samples after magnetic solid-phase extraction by carbon-coated Fe3O4 magnetic nanoparticles: method optimization via central composite design combined with desirability function

In this study, due to the low concentration of daclatasvir in exhaled breath condensate (EBC), for the first time, a simple, fast, sensitive, and accurate method based on magnetic nanoparticles for preconcentration of daclatasvir in EBC samples before analysis by spectrofluorometer was suggested. Magnetic nanoparticles were synthesized by the chemical co-precipitation method, and the surface of the nanoparticles was then modified by carbon through a simple hydrothermal reaction using glucose as a carbon resource. Carbon-coated Fe3O4 magnetic nanoparticles were used as adsorbents in the magnetic solid-phase extraction method. The parameters affecting the extraction efficiency, including the kind of desorption solvent, the effect of desorption time, and the volume of desorption solvent, were optimized by the univariate method. The rest of the parameters, including salt concentration, pH, adsorbent amount, and equilibrium time, were studied and optimized by a central composite design. Under the optimal conditions, a wide linear range (0.5–15 ng/mL), low detection limit (0.12 ng/mL), and excellent extraction recovery (94.80%) were obtained.