Resonance light scattering sensor of the metal complex nanoparticles using diethyl dithiocarbamate doped graphene quantum dots for highly Pb(II)-sensitive detection in water sample.

This study was aimed to detect Pb using diethyl dithiocarbamate-doped graphene quantum dots (DDTC-GQDs) based pyrolysis of citric acid. The excitation maximum wavelength (λ ex = 337 nm) of the DDTC-GQDs solution was blue shift from bare GQDs (λ ex = 365 nm), with the same emission maximum wavelength (λ em = 459 nm) indicating differences in the desired N, S matrices decorating in the nanoparticles. Their resonance light scattering intensities were peaked at the same λ, ex/em = 551/553 nm without any background effect of both ionic strength and masking agent. Under optimal conditions, the linear range was 1.0-10.0 μg L (R = 0.9899), limit of detection was 0.8 μg L and limit of quantification was 1.5 μg L. The precision, expressed as the relative standard deviations, for intra-day and inter-day analyses was 0.87% and 4.47%, respectively. The recovery study of Pb for real water samples was ranged between 80.8% and 109.5%. The proposed method was also proved with certified water sample containing 60 μg L Pb giving an excellent accuracy and was then implied satisfactorily for ultra-trace determination of Pb in drinking water and tap water samples.