J.R. S. answered 11/17/21
Ph.D. University Professor with 10+ years Tutoring Experience
Not sure what McIlvaine buffer is without looking it up, but to make a buffer with salicylic acid, you would use salicylic acid and a salt of that acid, such as sodium salicylate. If you don't have sodium salicylate, you can make it by simply adding NaOH to a solution of salicylic acid. So you'd have your solution of salicylic acid (0.1M say) and you'd add NaOH until the pH was at the desired pH (be sure it is close to the pKa of the salicylic acid). Not sure what else I can tell you about making this buffer.