Green synthesis of carbon dots and then functionalization with silver nanoparticles as a turn-off probe for highly selective and sensitive detection of chlorpromazine and histidine

Fluorescent carbon dots (CDs) are a type of novel nanomaterial that possess good photostability and low Toxicity [1]. the preparation of fluorescent carbon dots and their applications have expanded rapidly, with new types are constantly emerging[2] Chlorpromazine (CPZ) is one of phenothiazines with high biological importance which sensitive and accurate methods are needed to monitor it in pharmaceuticals and biological fluids [3]. In this work we are develop a simple, rapid, selective and sensitive method for determination of Chlorpromazine. In this study, we developed a simple, green and one-step method to generate C-dots from inexpensive broad beans through a one-step heating reaction. The as-prepared CDs exhibit good water-solubility. Carbon dot nanoparticles were characterized by transmission electron microscopy (TEM), UV-vis spectroscopy and photoluminescence (PL) emission spectroscopy. The generated C-dots can be used as sensing probes for chlorpromazine determination. Under the optimum conditions, The fluorescent CDs probe demonstrated a wide linear range between 50 nM and 118 nM and the detection limit was 31 nM. Furthermore, chlorpromazine was determined by this method in human urine samples with satisfactory results. furthermore, the strongly fluorescent carbon dots were modified with Ag nanoparticles (CD-AgNPs). The results showed that the fluorescence of the CD-AgNPs could be quenched effectively by histidine. This was exploited to design a simple and selective method for the determination of histidine in the concentration range from 60 to 300 nM, with a detection limit of 40 nM. The method presented here is simple, rapid, inexpensive, sensitive and suitable for practical application.