PBS buffer pH value is about 7.4 and Now a days the biologists use PBS buffer tablets which have a concentration of 0.1M and pH 7.4.Although PBS is made up of four constituents ( NaCl, KCl, Na2HPO4 and KH2PO4 ) can we make it the pH changes to 5,6,7,8,9 by adding acids and bases like NaOH and HCl/H3PO4 ?
I diluted 1x and 10x PBS in 0.2 M H2SO4 (1:1). The pH dropped from ~ 7 to ~ 1.
On sodium phosphate buffer solutions ― You may want to check my post at this related query:
https://www.researchgate.net/post/Why_do_I_struggle_to_adjust_lower_pH_of_my_phosphate_buffer_at_a_certain_pH_point_even_though_I_add_too_much_acidic_solution
On potassium phosphate buffer solutions ― You may check my post at:
https://www.researchgate.net/post/How-can-I-prepare-1M-of-Potassium-phosphate-buffer-with-pH-of-68
We can predict the pH of mixed Na/K monobasic and dibasic phosphate solutions after the following 'adapted' Henderson–Hasselbalch equation, within the effective buffer range pH = pKa2 ± 1 (6.2―8.2):
pH = pKa2 + log10{(CNa2HPO4 + CK2HPO4)/(CNaH2PO4 + CKH2PO4)}
Here C refers to nominal (formal) concentrations of the salts in the mixed solution. Ka2 is the second dissociation constant of phosphoric acid.
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