Synthesis of nitrogen-doped carbon quantum dots@Fe2O3/multiwall carbon nanotubes ternary nanocomposite for the simultaneous electrochemical detection of 5-fluorouracil, uric acid, and xanthine

Simultaneous quantification of anticancer drug and inflammatory agents in the biological fluids with a fast and responsive approach is essential for successful treatment and tracking. Here we report the simultaneous electrochemical determination structurally similar analytes of anticancer drug 5-fluorouracil (5-FU) and inflammatory agents uric acid (UA) and xanthine (XA) for the first time. Initially, nitrogen-doped carbon quantum dots (N-CQD) decorated iron oxide (N-CQD@Fe2O3) were synthesized using the hydrothermal method. Then this material and multiwall carbon nanotube (MWCNT) were dispersed with an ultrasonicator, and a ternary nanocomposite was prepared. N-CQDs play a key role in ternary nanocomposite formation and electrochemical efficiency. Interestingly, the ternary nanocomposite exhibited surprisingly low charge transfer resistance (R-ct) due to N-CQDs' inclusion in the Fe2O3 matrix and its hybridization with MWCNT, indicating rapid electron transport on its surface. Thus, the modified electrode, N-CQD@Fe2O3/MWCNT/GCE, showed excellent sensitivity for the detection of UA, XA, and 5-FU with the detection limit of 0.106, 0.092, and 0.019 mu M (S/N = 3), respectively. Also, the established sensor has excellent stability, repeatability, and reproducibility. Further, the sensor was testified with a human urine sample, and the observed remarkable recovery results replicate its practical applicability. (C) 2021 Elsevier B.V. All rights reserved.