Microchimica Acta

, Volume 184, Issue 7, pp 2063–2071 | Cite as

Chelation-enhanced fluorescence of phosphorus doped carbon nanodots for multi-ion detection

  • Khalid M. OmerEmail author
  • Aso Q. Hassan
Original Paper


The present paper reports on a chelation enhanced fluorescence (CHEF) effect that is observed on addition of certain metal ions to phosphorus doped carbon nanodots (P-CNDs). The effect is accompanied by a large shortwave shift of the emission peak. Highly passivated P-CNDs with sizes of around 3 nm were prepared from lactose and phosphoric acid, using a one-pot low temperature solvothermal method. The nanoparticles were purified according to polarity and size. The extent of blue shift and strength of enhancement depend on metal ions and actual pH value. For instance, the P-CND complex with Al(III) has a fluorescence that is shifted to shorter wavelengths, and the fluorescence quantum yield is enhanced from 12% (for the free P-CNDs) to almost 62% at 490 nm. The fluorescence is also enhanced and shifted by the ions Zn(II) and Cd(II). It is quenched by the ions Fe(II), Fe(III), Hg(II), Cu(II) and Sn(II), among others. The enhancement is attributed to the chelation of metal ions with the passivated surface functional groups of P-CNDs, mainly those of phosphorus. Phosphorous free CNDs (prepared via HCl instead of H3PO4) and low-passivated P-CNDs (prepared for longer period of time; typically 8 h) show no enhancement. The metal ion induced enhancement led to the design of a fluorometric assay for the detection of these ions. The detection limits are 4 nM for Al(III) and 100 nM for Zn(II). The two ions were quantified in spiked pharmaceutical formulations. Recoveries typically are 102% (for n = 7).

Graphical abstract

The fluorescence emission of phosphorous doped carbon nanodots is significantly enhanced and tuned after binding to Al3+, Zn2+ and Cd2+. The enhancement mechanism is attributed to chelation enhanced fluorescence (CHEF).


Carbon nanodots Enhancement CHEF Fluorescence enhancement Phosphorus doped carbon dots Quantum yield 



The authors would like to thank Genom Research Center at the University of Koya, Kurdistan. Thanks for Sheffield Surface Analysis Centre for XPS measurements.

Compliance with ethical standards

The author(s) declare that they have no competing interests.

Supplementary material

604_2017_2196_MOESM1_ESM.docx (7 mb)
ESM 1 (DOCX 6.97 mb)


  1. 1.
    Xu X, Ray R, Gu Y, Ploehn HJ, Gearheart L, Raker K, Scrivens WA (2004) Electrophoretic analysis and purification of fluorescent single-walled carbon nanotube fragments. J Am Chem Soc 126(40):12736–12737CrossRefGoogle Scholar
  2. 2.
    Zuo P, Lu X, Sun Z, Guo Y, He H (2016) A review on syntheses, properties, characterization and bioanalytical applications of fluorescent carbon dots. Microchim Acta 183(2):519–542CrossRefGoogle Scholar
  3. 3.
    Ding C, Zhu A, Tian Y (2013) Functional surface engineering of C-dots for fluorescent biosensing and in vivo bioimaging. Acc Chem Res 47(1):20–30CrossRefGoogle Scholar
  4. 4.
    Arcudi F, Đorđević L, Prato M (2016) Synthesis, separation, and characterization of small and highly fluorescent nitrogen-doped carbon NanoDots. Angew Chem 128(6):2147–2152CrossRefGoogle Scholar
  5. 5.
    Valeur B, Berberan-Santos MN (2012) Molecular fluorescence: principles and applications. John Wiley & Sons, HobokenCrossRefGoogle Scholar
  6. 6.
    Huston ME, Haider KW, Czarnik AW (1988) Chelation enhanced fluorescence in 9, 10-bis [[(2-(dimethylamino) ethyl) methylamino] methyl] anthracene. J Am Chem Soc 110(13):4460–4462CrossRefGoogle Scholar
  7. 7.
    Akkaya EU, Huston ME, Czarnik AW (1990) Chelation-enhanced fluorescence of anthrylazamacrocycle conjugate probes in aqueous solution. J Am Chem Soc 112(9):3590–3593CrossRefGoogle Scholar
  8. 8.
    Burdette SC, Walkup GK, Spingler B, Tsien RY, Lippard SJ (2001) Fluorescent sensors for Zn2+ based on a fluorescein platform: synthesis, properties and intracellular distribution. J Am Chem Soc 123(32):7831–7841CrossRefGoogle Scholar
  9. 9.
    Burdette SC, Frederickson CJ, Bu W, Lippard SJ (2003) ZP4, an improved neuronal Zn2+ sensor of the Zinpyr family. J Am Chem Soc 125(7):1778–1787CrossRefGoogle Scholar
  10. 10.
    Mukhopadhyay C, KumaráMondal T (2015) A new visible-light-excitable ICT-CHEF-mediated fluorescence turn-on probe for the selective detection of cd 2+ in a mixed aqueous system with live-cell imaging. Dalton Trans 44(12):5763–5770CrossRefGoogle Scholar
  11. 11.
    Liu Z, He W, Guo Z (2013) Metal coordination in photoluminescent sensing. Chem Soc Rev 42(4):1568–1600CrossRefGoogle Scholar
  12. 12.
    Kim HN, Ren WX, Kim JS, Yoon J (2012) Fluorescent and colorimetric sensors for detection of lead, cadmium, and mercury ions. Chem Soc Rev 41(8):3210–3244CrossRefGoogle Scholar
  13. 13.
    Chandra S, Pathan SH, Mitra S, Modha BH, Goswami A, Pramanik P (2012) Tuning of photoluminescence on different surface functionalized carbon quantum dots. RSC Adv 2(9):3602–3606CrossRefGoogle Scholar
  14. 14.
    Zhang Z, Shi Y, Pan Y, Cheng X, Zhang L, Chen J, Li M-J, Yi C (2014) Quinoline derivative-functionalized carbon dots as a fluorescent nanosensor for sensing and intracellular imaging of Zn 2+. J Mater Chem B 2(31):5020–5027CrossRefGoogle Scholar
  15. 15.
    Williams ATR, Winfield SA, Miller JN (1983) Relative fluorescence quantum yields using a computer-controlled luminescence spectrometer. Analyst 108(1290):1067–1071CrossRefGoogle Scholar
  16. 16.
    Umberger JQ, LaMer VK (1945) The kinetics of diffusion controlled molecular and ionic reactions in solution as determined by measurements of the quenching of fluorescence1, 2. J Am Chem Soc 67(7):1099–1109CrossRefGoogle Scholar
  17. 17.
    Kubin RF, Fletcher AN (1983) Fluorescence quantum yields of some rhodamine dyes. J Lumin 27(4):455–462CrossRefGoogle Scholar
  18. 18.
    Li X, Zhang S, Kulinich SA, Liu Y, Zeng H (2014) Engineering surface states of carbon dots to achieve controllable luminescence for solid-luminescent composites and sensitive Be2+ detection. Sci Report 4:4976–4983CrossRefGoogle Scholar
  19. 19.
    Qu S, Wang X, Lu Q, Liu X, Wang L (2012) A biocompatible fluorescent ink based on water-soluble luminescent carbon Nanodots. Angew Chem 124(49):12381–12384CrossRefGoogle Scholar
  20. 20.
    Gao X, Lu Y, Zhang R, He S, Ju J, Liu M, Li L, Chen W (2015) One-pot synthesis of carbon nanodots for fluorescence turn-on detection of Ag+ based on the Ag+−induced enhancement of fluorescence. J Mater Chem C 3(10):2302–2309CrossRefGoogle Scholar
  21. 21.
    Chen X, Jin Q, Wu L, Tung C, Tang X (2014) Synthesis and unique photoluminescence properties of nitrogen-rich quantum dots and their applications. Angew Chem Int Ed 53(46):12542–12547Google Scholar
  22. 22.
    Lu Y-C, Chen J, Wang A-J, Bao N, Feng J-J, Wang W, Shao L (2015) Facile synthesis of oxygen and sulfur co-doped graphitic carbon nitride fluorescent quantum dots and their application for mercury (II) detection and bioimaging. J Mater Chem C 3(1):73–78CrossRefGoogle Scholar
  23. 23.
    Wang C, Xu Z, Cheng H, Lin H, Humphrey MG, Zhang C (2015) A hydrothermal route to water-stable luminescent carbon dots as nanosensors for pH and temperature. Carbon 82:87–95CrossRefGoogle Scholar
  24. 24.
    Qu D, Zheng M, Zhang L, Zhao H, Xie Z, Jing X, Haddad RE, Fan H, Sun Z (2014) Formation mechanism and optimization of highly luminescent N-doped graphene quantum dots. Sci Report 4:5294CrossRefGoogle Scholar
  25. 25.
    Xu Z-Q, Yang L-Y, Fan X-Y, Jin J-C, Mei J, Peng W, Jiang F-L, Xiao Q, Liu Y (2014) Low temperature synthesis of highly stable phosphate functionalized two color carbon nanodots and their application in cell imaging. Carbon 66:351–360CrossRefGoogle Scholar
  26. 26.
    Gong X, Lu W, Liu Y, Li Z, Shuang S, Dong C, Choi MM (2015) Low temperature synthesis of phosphorous and nitrogen co-doped yellow fluorescent carbon dots for sensing and bioimaging. J Mater Chem B 3(33):6813–6819CrossRefGoogle Scholar
  27. 27.
    Pan D, Zhang J, Li Z, Wu C, Yan X, Wu M (2010) Observation of pH-, solvent-, spin-, and excitation-dependent blue photoluminescence from carbon nanoparticles. Chem Commun 46(21):3681–3683CrossRefGoogle Scholar
  28. 28.
    Cayuela A, Soriano M, Carrillo-Carrión C, Valcárcel M (2016) Semiconductor and carbon-based fluorescent nanodots: the need for consistency. Chem Commun 52(7):1311–1326CrossRefGoogle Scholar
  29. 29.
    Song Y, Zhu S, Xiang S, Zhao X, Zhang J, Zhang H, Fu Y, Yang B (2014) Investigation into the fluorescence quenching behaviors and applications of carbon dots. Nano 6(9):4676–4682Google Scholar
  30. 30.
    Geddes CD, Lakowicz JR (2002) Editorial: metal-enhanced fluorescence. J Fluoresc 12(2):121–129CrossRefGoogle Scholar
  31. 31.
    Aslan K, Geddes CD (2010) Metal-enhanced fluorescence: progress towards a unified plasmon-fluorophore description. In: Geddes CD (ed) Metal-Enhanced Fluorescence. John Wiley & Sons, Inc., HobokenGoogle Scholar
  32. 32.
    Drexhage K (1970) Influence of a dielectric interface on fluorescence decay time. J Lumin 1:693–701CrossRefGoogle Scholar
  33. 33.
    Liu M, Chen W (2013) Green synthesis of silver nanoclusters supported on carbon nanodots: enhanced photoluminescence and high catalytic activity for oxygen reduction reaction. Nano 5(24):12558–12564Google Scholar
  34. 34.
    Kavarnos GJ (1993) Fundamentals of photoinduced electron transfer. Vch Pub, New YorkGoogle Scholar
  35. 35.
    Rurack K, Kollmannsberger M, Resch-Genger U, Daub J (2000) A selective and sensitive fluoroionophore for HgII, AgI, and CuII with virtually decoupled fluorophore and receptor units. J Am Chem Soc 122(5):968–969CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Wien 2017

Authors and Affiliations

  1. 1.Department of Chemistry, College of ScienceUniversity of SulaimaniSulaymaniaIraq
  2. 2.Komar Research CenterKomar University of Science and TechnologySulaymania CityIraq

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