Accurate iron quantification in colloids and nanocomposites by a simple UV-Vis protocol


The selection and comparative study is reported of calibration curves to quantify iron by a simple UV-Vis protocol based on the formation of iron (III) chloride complexes. The reliability of each calibration curve was evaluated using statistical and analytical parameters. The robustness of each calibration curve using superparamagnetic iron oxide nanoparticles (SPIONs) of different sizes and surface functionalization is demonstrated . We have also evaluated the effect of the particle coating and estimated the minimum time to ensure the full oxidation of iron (II) to (III) in sample solutions. Results from UV-Vis are comparable with those obtained from ICP-OES and from other spectroscopic techniques to quantify the iron. We advocate the proposed protocol as a simple and non-expensive route to determine accurately the iron content in colloidal and nanocomposite iron-based materials.

Graphical abstract

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6


  1. 1.

    Kandasamy G, Maity D (2015) Recent advances in superparamagnetic iron oxide nanoparticles (SPIONs) for in vitro and in vivo cancer nanotheranostics. Int J Pharm 496:191–218.

    CAS  Article  PubMed  Google Scholar 

  2. 2.

    Roca AG, Costo R, Rebolledo AF, Veintemillas-Verdaguer S, Tartaj P, Gonzalez-Carreño T, Morales MP, Serna CJ (2009) Progress in the preparation of magnetic nanoparticles for applications in biomedicine. J Phys D Appl Phys 42(13):224002.

    CAS  Article  Google Scholar 

  3. 3.

    Pankhurst QA, Thanh NKT, Jones SK, Dobson J (2003) Progress in applications of magnetic nanoparticles in biomedicine. J Phys D Appl Phys 42:R167–R181.

    CAS  Article  Google Scholar 

  4. 4.

    Safarik I, Safarikova M (2004) Magnetic techniques for the isolation and purification of proteins and peptides. Biomagn Res Technol 2:1–17.

    Article  Google Scholar 

  5. 5.

    Laurent S, Saei AA, Behzadi S, Panahifar A, Mahmoudi M (2014) Superparamagnetic iron oxide nanoparticles for delivery of therapeutic agents: opportunities and challenges. Expert Opin Drug Deliv 11:1449–1470.

    CAS  Article  PubMed  Google Scholar 

  6. 6.

    Kallumadil M, Tada M, Nakagawa T, Abe M, Southern P, Pankhurst QA (2009) Structural properties of magnetic nanoparticles determine their heating behavior - an estimation of the in vivo heating potential. JMMM 321:1509–1519.

    CAS  Article  Google Scholar 

  7. 7.

    Coral DF, Andrea Soto P, Blank V, Veiga SAE, Gonzalez A, Saracco GP, Bab MA, Muraca D, Setton-Avruj PC, Roig A, Roguin L, Fernández van Raap MB (2018) Nanoclusters of crystallographically aligned nanoparticles for magnetic thermotherapy: aqueous ferrofluid, agarose phantoms and ex vivo melanoma tumour assessment. Nanoscale 10:21262–21274.

    CAS  Article  PubMed  Google Scholar 

  8. 8.

    Stephen ZR, Kievit FM, Zhang M (2011) Magnetite nanoparticles for medical MR imaging. Mater Today 14:330–338.

    CAS  Article  Google Scholar 

  9. 9.

    Barrow M, Taylor A, Fuentes-Caparrós AM, Sharkey J, Daniels LM, Mandal P, Park K, Murray P, Rosseinsky MJ (2018) In vivo fate of free and encapsulated iron oxide nanoparticles after injection of labelled stem cells. Biomater Sci 6:101–112.

    CAS  Article  Google Scholar 

  10. 10.

    Costo R, Heinke D, Grüttner C, Westphal F, Morales MP, Veintemillas-Verdaguer S, Gehrke N (2018) Improving the reliability of the iron concentration quantification for iron oxide nanoparticle suspensions: a two-institutions study. Anal Bioanal Chem 411:1895–1904.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  11. 11.

    Maurizi L, Sakulkhu U, Gramoun A, Vallee J-P, Hofmann H (2014) A fast and reproducible method to quantify magnetic nanoparticle biodistribution. Analyst 139:1184–1191.

    CAS  Article  PubMed  Google Scholar 

  12. 12.

    Boutry S, Forge D, Burtea C, Mahieu I, Murariua O, Laurent S, Vander Elsta L, Muller RN (2009) How to quantify iron in an aqueous or biological matrix: a technical note. Contrast Media Mol Imaging 4:299–304.

    CAS  Article  PubMed  Google Scholar 

  13. 13.

    Totan M, Antonescu E, Gligor FG (2018) Quantitative spectrophotometric determinations of Fe3+ in Iron Polymaltose solution. Indian J Pharm Sci 80:268–273.

    CAS  Article  Google Scholar 

  14. 14.

    Støving C, Jensen H, Gammelgaard B, Stürup S (2013) Development and validation of an ICP-OES method for quantitation of elemental impurities in tablets according to coming US pharmacopeia chapters. J Pharm Biomed Anal 84:209–214.

    CAS  Article  PubMed  Google Scholar 

  15. 15.

    Senila M, Drolc A, Pintar A, Senila L, Levei E (2014) Validation and measurement uncertainty evaluation of the ICP-OES method for the multi-elemental determination of essential and nonessential elements from medicinal plants and their aqueous extracts. J Anal Sci Technol 5:37–45.

    Article  Google Scholar 

  16. 16.

    Lee MS (2004) Chemical equilibria in ferrous chloride acid solution. Met Mater Int 10:387–392.

    CAS  Article  Google Scholar 

  17. 17.

    Persson I (2018) Ferric chloride complexes in aqueous solution: an EXAFS study. J Solut Chem 47:797–804.

    CAS  Article  Google Scholar 

  18. 18.

    Liu W, Etschmann B, Brugger J, Spiccia L, Foran G, McInnes B (2006) UV–Vis spectrophotometric and XAFS studies of ferric chloride complexes in hyper-saline LiCl solutions at 25–90 °C. Chem Geol 231:326–334.

    CAS  Article  Google Scholar 

  19. 19.

    Stefansson A, Lemke K, Seward TM (2008) Iron (III) complexation in hydrothermal solutions. An experimental and theoretical study. 15th international conference on the properties of water and steam 15:1-7

  20. 20.

    Yu SM, Laromaine A, Roig A (2014) Enhanced stability of superparamagnetic iron oxide nanoparticles in biological media using a pH adjusted-BSA adsorption protocol. J Nanopart Res 16:2484–2499.

    CAS  Article  Google Scholar 

  21. 21.

    Moya C, Escudero R, Malaspina DC, de la Mata M, Hernández-Saz J, Faraudo J, Roig A (2019) Insights into preformed HSA corona on iron oxide nanoparticles: structure, effect of particle size, impact on MRI efficiency and metabolization. ACS Appl Bio Mater 2:3084–3094.

    CAS  Article  Google Scholar 

  22. 22.

    Zhang Y, García-Gabilondo M, Grayston A, Feiner IVJ, Anton-Sales I, Llop J, Ramos-Cabrer P, Barba I, Loiola RA, Garcia-Dorado D, Gosselet F, Rosell A, Roig A (2020) In vivo studies of PLGA nanocapsules as a drug delivery platform with made-to-order multimodal imaging modalities. Nanoscale 12:4988–5003.

    CAS  Article  PubMed  Google Scholar 

  23. 23.

    Roig-Sanchez S, Jungstedt E, Anton-Sales I, Malaspina DC, Faraudo J, Berglund LA, Laromaine A, Roig A (2019) Nanocellulose films with multiple functional nanoparticles in confined spatial distribution. Nanoscale Horizons 4:634–641.

    CAS  Article  Google Scholar 

  24. 24.

    Meier PC, Zünd RE (2000) Statistical methods in analytical chemistry, 2nd edn.

    Google Scholar 

  25. 25.

    McNaught AD (1997) Wilkinson a (1997) IUPAC compendium of chemical terminology, 2nd edition (the "gold book"), vol 39. Scientific Publications, Oxford, p 150.

    Google Scholar 

  26. 26.

    Serra-Mora P, Moliner-Martínez Y, Herráez-Hernández R, Verdú-Andrés J, Campíns-Falcó P (2016) Simplifying Iron determination with o-Phenanthroline in food ashes using 2-Nitrophenol as an Acid-Base indicator. Food Anal Methods 9:1150–1154.

    Article  Google Scholar 

  27. 27.

    Dadashzadeha ER, Hobsona M, Bryant LH Jr, Deana DD, Frank JA (2013) Rapid spectrophotometric technique for quantifying iron in cells labeled with superparamagnetic iron oxide nanoparticles: potential translation to the clinic. Contrast Media Mol Imaging 8:50–56.

    CAS  Article  Google Scholar 

  28. 28.

    Posner AM (1953) The kinetics of autoxidation of ferrous ions in concentrated HCl solutions. Trans Faraday Soc 49:382–388.

    CAS  Article  Google Scholar 

  29. 29.

    Porsch K, Kappler A (2011) FeII oxidation by molecular O2 during HCl extraction. Environ Chem 8:190–197.

    CAS  Article  Google Scholar 

Download references


The authors thank the Ph.D. students Soledad Roig and Yajie Zhang for helping in the sample fabrication and characterization. The authors would also like to thank Dr Judith Oró from the TEM service at ICMAB.


This research received funding from the Spanish Ministry of Science, Innovation, and Universities through the PCIN-2017-090 and RTI2018-096273-B-I00, projects and financial support through the Severo Ochoa Programme for Centers of Excelence in R&D (SEV-2015-0496). The Spanish Ministry of Education, Culture and Sport funded the FPU Fellow of M.T. (FPU16/05452). The Argentine National Scientific and Technical Research Council (CONICET) is acknowledged for funding G.A.P. fellowship. Generalitat of Catalunya is acknowledged for the project 2017SGR765. A.R. is grateful for the financial support of Grifols SA with the 2017 Albus Award.

Author information



Corresponding author

Correspondence to Carlos Moya.

Ethics declarations

Conflict of interest

The authors declare that they have no conflict of interest.

Additional information

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Electronic supplementary material


(DOCX 1410 kb).

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Torras, M., Moya, C., Pasquevich, G.A. et al. Accurate iron quantification in colloids and nanocomposites by a simple UV-Vis protocol. Microchim Acta 187, 488 (2020).

Download citation


  • Iron quantification
  • Iron oxide nanoparticles
  • Iron (III) chloride complexes
  • Ultraviolet–visible spectroscopy
  • Inductively coupled plasma optical emission