Abstract
Some time ago in a study in this laboratory 1 dealing with the influence of ether anesthesia on the acid-base balance in dogs it was noted that when silver nitrate was added to urine collected following the anesthesia for the chloride estimation, the silver was reduced and a black precipitate formed before the acid indicator was added. This observation led us to investigate the influence of the ether anesthesia on the excretion of ascorbic acid as determined by titration with 2:6-dichlorophenolindophenol.
Female dogs were employed. The urine was collected by catheterization into a bottle containing a few drops of glacial acetic acid, after which sufficient 20% trichloracetic acid was added to give a 5% trichloracetic acid concentration. This was then titrated into a known amount of 2:6-dichlorophenolindophenol. The dye was standardized with crystalline ascorbic acid (Merck) according to the procedure of Birch, Harris and Ray. 2 It was found, however, that when urine was allowed to stand even for short periods the reducing value decreased appreciably. Consequently it was thought necessary to perform a preliminary step of bubbling hydrogen sulfide through the urine for ten minutes and then allowing it to stand over night under an atmosphere of hydrogen sulfide, after which the H2S was driven off by bubbling nitrogen through the urine for 15 minutes (or until no nitroprusside test was obtained). The trichloracetic acid was then added and the titration carried out immediately.
Table I presents the results of one of a number of experiments which have been performed.
From these results it is observed that the urinary excretion of ascorbic acid as determined by titration with 2:6-dichlorophenolindophenol is markedly increased in the dog following ether anesthesia.
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