0.5M EDTA

for 500mL

93.6g EDTA (MW=372.24g/mol)

in 400mL ddH2O

stir and heat slightly (setting 2)

add 25mL 10N NaOH and allow solution to clear

add 10N NaOH dropwise as needed to reach pH 8.0

pour into graduated cylindar and add ddH20 to 500mL

autoclave to sterilize

10N NaOH

for 50mL

20g sodium hydroxide (MW=40g/mol) in a 50mL tube

add ddH2O to 50mL

careful – the tube will get very hot

shake gently to mix and put on ice

shake occasionally until dissolved

vortex if necessary to get residual pellets off tube bottom