Synthesis and characterization of ZnS quantum dots and application for development of arginine biosensor

Arginine deiminase co-immobilized with ZnS QDs coupled micro-disk was applied for the sensing of arginine in real and spiked fruit samples. Intracellular arginine deiminase from Lactococcus lactis MTCC 460 was partially purified by ammonium sulphate precipitation and co-immobilized on hydrosol gel disk with ZnS quantum dots. Surface study and topology of immobilized ZnS QDs were characterized by SEM. The size of MPA capped ZnS quantum dots was achieved up to 200 nm. Excitation and emission wavelength of synthesized ZnS QDs was observed to be 259 and 580 nm respectively. Linear range of detection of arginine was found to be 1.0 to 10− 4 M and developed biosensor was used to monitor arginine in water melon and pomegranate fruit juices. Main advantage of the developed system is there is no need of pretreatment of sample for the estimation of arginine content.