A Rayleigh light scattering technique based on β- cyclodextrin modified gold nanoparticles for phenytoin determination in exhaled breath condensate.

In the current work, a RLS technique based on β-cyclodextrin modified gold nanoparticles was validated for phenytoin determination in the exhaled breath condensate. It relies on the complexation of β-cyclodextrins using -OH groups with amine groups of phenytoin which results in an aggregation-induced Rayleigh light scattering intensity enhancement proportional to phenytoin addition. The method shows a linear relationship with phenytoin concentration in the range of 0.005-0.6 µg.mL with a limit of detection of 0.003 µg.mL. The validated Rayleigh light scattering system is successfully used for phenytoin determination in the EBC of patients receiving phenytoin.