Amidosulfonic acid-capped silver nanoparticles for the spectrophotometric determination of lamotrigine in exhaled breath condensate

Amidosulfonic acid-capped silver nanoparticles (ASA-AgNPs) were synthesized and characterized by UV-Vis, FTIR and TEM methods. It was found that in the presence of lamotrigine (LTG) in aqueous solution, the ASA-AgNPs undergo a visual color change from yellow to red to violet. This corresponds to absorption peaks at 390, 450 and 620 nm depending on the concentration of LTG. TEM images confirmed that the observed changes are as a result of the LTG-induced aggregation of nanoparticles. A linear relationship exists between LTG concentration and the absorbance ratios at 390 and 450 nm. The limit of detection is 5 ng.mL(-1). The method was applied successfully to the determination of LTG in exhaled breath condensate of epileptic patients' receiving LTG.