100 ml solution
19g EGTA (MW 380g/mol) ddH2O to 90ml adjust pH 7.5/8.0 with solid NaOH (>4g) adjust volume to 100ml
Note: EGTA will not go into solution without NaOH. Once the pH has been raised sufficiently it dissolves quickly. For pH 7.5 the exact amount required is slightly above 4g. Add 3.5-4g immediately, then proceed carefully not to overshoot the desired pH.