Check https://www.researchgate.net/publication/229809636_Anthocyanins_of_Tradescantia_pallida_Potential_Food_Colorants

https://www.mdpi.com/1424-8220/21/9/3078/htm

A simple method is spectroscopy approach at pH 1 and 4.5. The protocol is simple and readily available in the net.

The precise method is HPLC assay

Interesting topic

Kindly check on this paper

https://www.semanticscholar.org/paper/Extraction-of-Eco-friendly-Natural-Dyes-from-and-in-Jabli/b7570338fdc04dcb3f6364f28fa20342c48ed699

Dear Dr Ammar Mahmood Zalzala . To measure anthocyanin according to Krizek et al (1993), 0.2g of leaves will homogenized with 3ml 1% HCL-methanol (99:1), the extract will be centrifuged at 18000 g for 30 min, at 4°C, the supernatant will leave overnight in dark place at 5°C. Anthocyanin content will measure at 550nm using spectrophotometer.

See the following useful RG link:

https://www.researchgate.net/post/Does_anyone_know_a_reliable_method_to_measure_anthocyanin_content_with_spectrophotometer#:~:text=To%20measure%20anthocyanin%20according%20to,measure%20at%20550nm%20using%20spectrophotometer.

Kindly see also the following useful RG link: Article Solvent extractions and spectrophotometric protocols for mea...

Also check please the following good RG link: Article Total anthocyanin content determination in intact acai (Eute...

The following RG link is also very useful: https://www.academia.edu/10825938/Spectrophotometric_Determination_of_Anthocyanin_Content_in_Six_Common_Vegetables

Hope this will help ...

... and this.

I want to sincerely thank all of you for your various contributions. Thank you once again 🙏.