# Turkevich citrate reduction of gold nanoparticles

> Trisodium citrate is added to a boiling solution of chloroauric acid. Citrate reduces Au(III) to gold atoms, which form nuclei that grow into spherical nanoparticles, and the adsorbed citrate gives them a negative charge that keeps the colloid stable. The pale yellow solution turns wine red. Frens showed that the citrate-to-gold ratio sets the particle size.

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- Open in the LabCanvas editor (LabCanvas account): https://www.labcanvas.com/editor.html?template=turkevich-citrate-gold
- Updated: 2026-10-14
- Category: Nanomaterial synthesis
- Method: Citrate reduction, bottom-up
- Starting materials: HAuCl₄ in water and trisodium citrate
- Product: Citrate-capped spherical gold nanoparticles (wine-red colloid)
- Typical size: Tens of nanometres for the classic recipe; tunable by the citrate-to-gold ratio (Frens)
- Key result: Near-spherical, fairly monodisperse particles at the usual ratios; broader distributions for large sizes
- Scalability: High: one pot, water, simple reagents
- Figure: 1920 × 1080 px, 76 editable layers (20 generated objects with settings)

## Steps

1. **Boil the gold salt**: Aqueous HAuCl₄ (pale yellow AuCl₄⁻) is brought to the boil with stirring
2. **Add citrate**: Trisodium citrate is added quickly; it reduces Au(III) to Au(0)
3. **Nucleation and growth**: Gold atoms form nuclei, which grow as more gold is reduced on them
4. **Colloid**: The solution turns wine red; adsorbed citrate makes the particles negatively charged so they repel
5. **Size control (Frens)**: Less citrate per gold gives fewer nuclei and larger particles; more citrate gives smaller ones

## Strengths

- Simple, fast and reproducible
- Water-based; citrate is easy to replace with thiols or polymers
- Size tunable through one parameter

## Limitations

- Large particles become polydisperse
- Weakly bound citrate: colloids aggregate in salt
- Needs boiling and quick mixing

## Uses

- Colorimetric sensing and lateral-flow assays
- SERS substrates
- Seeds for larger or anisotropic particles
- Bioconjugation

## References

1. Turkevich, Stevenson & Hillier, “A study of the nucleation and growth processes in the synthesis of colloidal gold”, Discuss. Faraday Soc. 1951. https://doi.org/10.1039/DF9511100055 (method origin)
2. Frens, “Controlled nucleation for the regulation of the particle size in monodisperse gold suspensions”, Nature Phys. Sci. 1973. https://doi.org/10.1038/physci241020a0 (primary)

Credit: Redrawn and simplified after Turkevich, Stevenson & Hillier, Discuss. Faraday Soc. 1951 (doi:10.1039/DF9511100055) and Frens, Nature Phys. Sci. 1973 (doi:10.1038/physci241020a0).

## Questions

**What does the “Turkevich citrate reduction of gold nanoparticles” template show?** Trisodium citrate is added to a boiling solution of chloroauric acid. Citrate reduces Au(III) to gold atoms, which form nuclei that grow into spherical nanoparticles, and the adsorbed citrate gives them a negative charge that keeps the colloid stable. The pale yellow solution turns wine red. Frens showed that the citrate-to-gold ratio sets the particle size.

**What are the steps shown in “Turkevich citrate reduction of gold nanoparticles”?** 1. Boil the gold salt: Aqueous HAuCl₄ (pale yellow AuCl₄⁻) is brought to the boil with stirring. 2. Add citrate: Trisodium citrate is added quickly; it reduces Au(III) to Au(0). 3. Nucleation and growth: Gold atoms form nuclei, which grow as more gold is reduced on them. 4. Colloid: The solution turns wine red; adsorbed citrate makes the particles negatively charged so they repel. 5. Size control (Frens): Less citrate per gold gives fewer nuclei and larger particles; more citrate gives smaller ones.

**What are the starting materials and the product?** Starting materials: HAuCl₄ in water and trisodium citrate. Product: Citrate-capped spherical gold nanoparticles (wine-red colloid).

**Which papers is “Turkevich citrate reduction of gold nanoparticles” based on?** Turkevich, Stevenson & Hillier, “A study of the nucleation and growth processes in the synthesis of colloidal gold”, Discuss. Faraday Soc. 1951 (doi:10.1039/DF9511100055); Frens, “Controlled nucleation for the regulation of the particle size in monodisperse gold suspensions”, Nature Phys. Sci. 1973 (doi:10.1038/physci241020a0).

**Can I edit the “Turkevich citrate reduction of gold nanoparticles” template?** Yes. Open it in the LabCanvas editor: all 76 layers are editable, including 20 generated objects (structures, plots, equipment) with their own settings. Change the text, colours and layout, then export PNG, TIFF, SVG or PDF.

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