The cerimetric determination of glucuronic acid, using the Conway burette

Abstract

To 0.8 ml. of soln. containing not more than 300 [gamma] glucuronic acid, in a 10 ml. centrifuge tube, add 0.6 ml. 2.5% CuSO4 soln. and, after mixing, 0.6 ml. 2.5% Na2SO4 in 0.5% Na2CO3 soln. After shaking add about 10 mg. BaCO3 and let stand for 10 min. The tube is again shaken and centrifuged for 5 min. One ml. of supernatant is transferred to a fresh tube. After addition of 0.25 ml. of K3Fe(CN)6 in Na2CO3 soln., a glass bulb is inserted in the mouth of the tube, which is placed in a boiling water bath for 15 min., and then cooled in running water for 3 min. Immediately before titrating 0.2-0.25 ml. of 11N-H2SO4 is added, followed by 1-2 drops of indicator. Titration is carried out with a Conway burette using 0.012 [image]-Ce(SO4)2 to an endpoint stable for 30 sec. The microburette was fitted with ground glass joint and the reservoir shielded from light. No change in titre of Ce(SO4)2 was observed in a year under these conditions.