a nanoprobe for furazolidone determination based on the n, p graphene quantum dots and copper ions

Abstract: furazolidone (fzd) is one of the nitrofuran antibiotics that was widely used as a growth stimulant in the livestock and poultry industry. it was also used for the prevention and treatment of gastrointestinal infections caused by escherichia coli and salmonella in birds, especially chickens and roosters. despite the strong antibacterial properties of furazolidone, its residues are recognized to be mutagenic and carcinogenic. so, since 1991, the food and drug administration has refused the prescription of furazolidone and nitrofurans, and in 1995 the european union banned the use of furazolidone in food-producing animals. however, because of its low price, availability, and strong effectiveness, it is still illegally used in many livestock, poultry, and aquaculture farms. thus, the development of sensitive and selective methods for monitoring furazolidone residues in biological tissues and food products is a necessary task [1]. graphene quantum dots are a new type of nanomaterials belonging to the graphene family which gained noticeable interest in the design of sensors for the determination of drugs [2, 3]. in this study, a sensitive and selective fluorimetric method is designed for the direct determination of furazolidone based on the nitrogen and phosphorus graphene quantum dots (p, n-gqds) and copper ions. thus, the addition of copper ions to the p, n-gqds, resulted in a decrease in its fluorescence intensity at 447 nm due to the electrostatic interaction between copper ions and the charged surface of quantum dots. however, in the presence of furazolidone, the fluorescence emission of p, n-gqds is retrieved as the result of the formation of the complex between the drug and copper ions and the release of the p, n-gqds surface. under optimal conditions, the calibration graph was linear in the concentration range of 0.05-20.0 μm with a limit of detection of 0.009 μm. the intra- and inter-day relative standard deviations at the 2.0 μm level of furazolidone (n = 5) were 1.8 and 3.7%, respectively. the method was successfully employed for the determination of furazolidone in urine and serum samples.