Hello Ibrahim,

many thanks for sharing this very interesting technical question with the RG community. Although we frequently worked with gold nanoparticles in the past, we never considered citrate-cappe Au NPs ourselves. However, there are several relevant articles about this topic available in the chemical literature. For example, please have a look at the following potentially useful papers:

Structural Study of Citrate Layers on Gold Nanoparticles: Role of Intermolecular Interactions in Stabilizing Nanoparticles

Article Structural Study of Citrate Layers on Gold Nanoparticles: Ro...

and

Continuous flow synthesis of citrate capped gold nanoparticles using UV induced nucleation

Article Continuous flow synthesis of citrate capped gold nanoparticl...

The second article is freely avaliable as public full text on RG. If you are interested in the first one, you can request the full text directly from the corresponding author via RG at https://www.researchgate.net/profile/Jennifer-Shumaker-Parry.

Good luck with your research and best wishes, Frank Edelmann

Thank you for your help

Uttam Pal thank you sir for sharing this article