Carbon quantum dot coated Fe 3 O 4 hybrid composites for sensitive electrochemical detection of uric acid

Malik Waseem Abbas, Razium Ali Soomro*, Nazar Hussain Kalwar, Mehvish Zahoor, Ahmet Avci, Erol Pehlivan, Keith Richard Hallam, Magnus Willander

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

41 Citations (Scopus)


The study explores carbon quantum dots (C-dots) as potential candidates for enhancing the signal sensitivity of an electrochemical sensor devised for biologically important molecule, such as uric acid (UA). The C-dots were evaluated for their electrochemical characteristics in combination with Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs), which were applied as the primary electro-catalytic promoter. The hybrid nanocomposite (C-dots/Fe 3 O 4 HCs) formation was achieved by facilitating the adsorption of C-dots over Fe 3 O 4 NPs using amine-carbonyl interactions. Unlike, one pot method, the proposed strategy enables aggregation-free coverage of Fe 3 O 4 NPs with highly conductive layer of C-dots that can act as conduction centres to support ultra-fast electron transfer kinetics to satisfy the need of high signal sensitivity. The hybrid composite demonstrated remarkable signal improvement when tested against the electrochemical oxidation of UA. The heighten current response and lower over-potential values enabled development of a DC-amperometric (DC-AMP) sensor for UA with a linear working range of 0.01 to 0.145 μM and signal sensitivity measurable up to 6.0 × 10 −9 M. The said improvement was manifested as a synergetic outcome of active redox couple (Fe (III/II)), larger surface area of Fe 3 O 4 NPs engulfed with a layer of highly conductive C-dots acting as efficient charge sensitisers.

Original languageEnglish
Pages (from-to)517-524
Number of pages8
JournalMicrochemical Journal
Early online date15 Jan 2019
Publication statusPublished - 1 May 2019


  • C-dots
  • Electrochemical sensors
  • Magnetite NPs
  • Uric acid


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