Spectroscopic Determination of Gum Acacia in Blood. Rate of Disappearance in Normal Dogs

Abstract

In the use of gum acacia in the treatment of nephrosis it is important to maintain a definite minimum concentration in the blood stream in order to derive satisfactory results. There is, therefore, need of a method for an accurate quantitative estimation of acacia on a sufficiently small sample of blood so that the test may be frequently repeated, especially when small children are involved. Acacia is a pentosan and all the methods now employed are based on the production of furfural by heating with dilute acid, steam distilling the furfural and determining it either by weighing as the phloroglucide 1 or by forming a color-complex between furfural and analine acetate. 2 Both methods require samples too large to make them practical for this purpose. Another method based on the Shaffer-Hartmann procedure for the determination of reducing sugars freed by hydrolysis of the Folin-Wu filtrate, as suggested in a personal communication from Dr. Hartmann, is some improvement. We have used this procedure on duplicate samples for comparison with a new spectroscopic method which we present herewith.

Our method is essentially a reversal of the Pettenkofer test for bile salts, with conditions so arranged as to make it quantitative for furfural. The details are as follows: 0.5 to 1.0 cc., of blood is precipitated according to the standard Folin-Wu technic. Five-tenths to 2 cc. of the filtrate, sufficient to contain 0.5 to 1.0 mg. of acacia, is pipetted into a 10 cc. volumetric flask with enough distilled water added to give a total volume of 2 cc.; and then 2 cc. of 80% sulfuric acid are added. The contents are mixed and heated in a 100° C. water-bath for exactly 30 minutes (to assure complete hydrolysis) and are promptly cooled to room temperature in running water. Five cc. of 80% sulfuric acid and 1 cc. of 1% bile salts in 70% alcohol are added, mixed, and to bring out the color, the flask is placed in a 57°C. water bath for 20 minutes. The contents are immediately cooled to room temperature and after standing at least 10 minutes and not over 40 minutes are read in a spectrometer.