I am testing an immunostaining protocol that requires 4% PFA in 0.1 M Millonig’s Phosphate Buffer. I only need a small amount of this buffer, so I tried to search for a way to make the phosphate buffer in the lab. However, I could not find a recipe, except one listed on a commercial microscopy website (https://www.deltamicroscopies.com/en/products/millonigs-phosphate-buffer/). I also cannot find Millonig’s original paper.

This is the recipe from the microscopy website:

Phosphate buffer (1964)

In 500 ml dH2O:

Monobasic sodium phosphate 1.8 g

Dibasic sodium phosphate 23.25 g

NaCl 5 g

Ph to desired value then add

d H2O to make 1,000 ml

My chemistry is bad. I would highly appreciate it if anyone could tell me whether this is 0.2 M Millonig’s Phosphate Buffer. If this is not, how do I make a 0.2 or 0.1 M Millonig’s Phosphate Buffer?

Thank you in advance!