Reagent	Final concentration	Amount (50 mL)
Glycolic acid (GA)	0.1 M	0.38 g
MeCN	80% (v/v)	40 mL
TFA	5% (v/v) aqueous solution	2.5 mL
MilliQ water		7.5 mL
Prepare freshly before each use. ∼1.2 mL of Phosphopeptide Bind buffer (Zr-IMAC) is needed for each sample