Limit of oxalate
Dissolve 1.0 g of Sodium Tartrate in 10 mL of water, then add 5 drops of diluted acetic acid and 2 mL of calcium chloride TS
: no turbidity develops within 1 hour. Not more than 0.1% is found.
Transfer about 250 mg of Sodium Tartrate, accurately weighed and previously dried at 150
for 3 hours, to a 250-mL beaker, and dissolve by stirring and heating to near the boiling point in 150 mL of acetic acid. Cool the solution to room temperature. Titrate with 0.1 N perchloric acid VS (in glacial acetic acid), determining the endpoint potentiometrically. Perform a blank determination, and make any necessary adjustments (see Titrimetry 541
). Each mL of 0.1 N perchloric acid is equivalent to 9.703 mg of C4