Chemiluminescence determination of dopamine using N, P-graphene quantum dots after preconcentration on magnetic oxidized nanocellulose modified with graphene quantum dots

A novel sorbent consisting of magnetic oxidized nanocelluloses modified with graphene quantum dots was prepared and used for the separation and preconcentration of dopamine. The eluted dopamine from the sorbent was determined by a designed chemiluminescence system containing luminol, H2O2, Fe3+, and graphene quantum dots doped with nitrogen and phosphorus. Graphene quantum dots cause an increase in the intensity of the chemiluminescence system of luminol-H2O2, but the presence of Fe3+ ions in this system decreases its intensity because of the sorption of the Fe3+ ions on the surface of P, N-graphene quantum dots. However, the addition of dopamine resulted in the retrieval of P, N-graphene quantum dots, as well as the chemiluminescence intensity, due to the formation of its complex with Fe3+. The sorbent made of magnetic oxidized nanocelluloses modified with graphene quantum dots was characterized by various analytical techniques, and the effective parameters on the extraction of dopamine were investigated and optimized. Under the optimized conditions, the method displayed good linearity in the concentration range 0.25-17.5 mu g L-1 for dopamine (R-2 = 0.9918) with a limit of detection of 0.054 mu g L-1. The intra- and inter-day relative standard deviations at a 10.0 mu g L-1 concentration level of dopamine (n = 6) were 2.6 and 4.1%, respectively. This method was successfully applied to the extraction and determination of dopamine in human serum and urine samples.

Automated summary

A novel sorbent consisting of magnetic oxidized nanocelluloses modified with graphene quantum dots was developed for the separation and preconcentration of dopamine. A chemiluminescence system was used to determine the eluted dopamine, and the presence of graphene quantum dots and Fe3+ ions affected the intensity of the system. The method showed good linearity, low limit of detection, and small relative standard deviations.