Abstract
The fact that generalized infections are more common in patients with a low tissue ascorbic acid content and that ascorbic acid may be related to this and other tissue phenomena have led to the suggestion that the determination of the ascorbic acid content of blood might be of diagnostic value. 1 We wish to report some values obtained in normal and pathologic patients by a method slightly modified from that of Emmerie and Van Eekelen. 2 This method determines the total content of ascorbic acid present in the reduced form, any oxidized material being converted to the reduced form by the procedure. We used 5 cc. instead of 10 cc. of blood and were able to increase the ease of obtaining satisfactory duplicate determinations by using acetic instead of trichloracetic acid for the final titration.
Our procedure is as follows: To 5 cc. of oxalated whole blood in a 50 cc. Erlenmeyer flask, add 5 cc. of 10% trichloracetic acid, shake and then add 5 cc. of 16.6% mercuric acetate; mix thoroughly and allow to stand for 5 minutes. Then add about 0.25 gm. calcium carbonate and mix until neutral to Congo Red. Transfer to a 15 cc. test-tube and centrifuge. Without decanting, allow H2S to bubble through the supernatant solution for a few minutes and then filter into another 15 cc. test-tube. Through this filtrate again bubble H2S until all the air in the tube is displaced; then stopper the tube and allow the solution to remain overnight in contact with the gas in the tube. On the following day bubble nitrogen through the solution for 15 minutes in order to remove the H2S.
The 2:6 sodium dichlorphenolindophenol used for titration of the ascorbic acid is extracted with hot water (about 25 mg. in 50 cc.) and diluted until 12 cc. of this solution is equivalent to 1 mg. ascorbic acid as determined by standardization with a solution of pure ascorbic acid.
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