An accurate microchemical method of estimating sugar in the blood / Albert A. Epstein.

  • Epstein, Albert Arthur, 1880-1965.
Date:
1914
Catalogue details

Licence: In copyright

Credit: An accurate microchemical method of estimating sugar in the blood / Albert A. Epstein. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    reaction, stays in solution. The tube is finally shaken vigor- ously (covering the end of the tube with the finger) and the contents filtered through a small filter, or, better still, centri- fuged for one or two minutes. One cubic centimeter of the filtrate or the clear supernatant fluid obtained on centrifugalization is withdrawn, put into the boiling tube, 5, and heated carefully over the naked flame. The contents of the tube are boiled until all but 2 or 3 drops of the solution is evaporated. One-half cubic centimeter of the 10 per cent, soda solution .is then added and the tube heated again until the contents are concentrated to a small volume equal to about two or three drops. The color of the fluid changes from yellow to deep red or reddish brown and the reaction is completed. Three or four drops of distilled water are added and the tube warmed gently. The contents are then transferred to the graduated tube, 1. The boiling tube is rinsed several times with water (using only three or four drops at time). The tube is warmed with each rinsing before transferring the contents to the graduated tube. The volume is then made up to the mark 50 on the scale. The color of the resulting solution is compared with that of the two standard tubes, A and B. If it is darker than standard A (representing 0.05 per cent, of sugar) and lighter than standard B (representing 0.1 per cent.), the first stand- ard is used for comparison. In either case the solution in the graduated tube is diluted gradually with water (just as is usually done in hemoglobin estimations) until the colors match. The percentage of sug^r in the blood is then computed thus: Using the lighter standard A the figure on the scale, divided by 1,000 represents the percentage of sugar in the blood. For example, the tube reads 86; then the result is 86 —.,0.086 per cent. 1000 When Standard B is used for comparison, the figure on the scale is multiplied by 2 and divided by 1,000. For example, the tube reads 73; then the percentage of sugar is 73 X 2 =0.146 per cent. 1000 With the instructions given, the above formulas may be used for direct computation of the percentage of sugar only, when 0.2 c.c. of blood is used in the determination. When, however, only 0.1 c.c. of blood is used, the formulas apply as well, but the value obtained must be multiplied by 2. In developing this method I at first used three standard tubes representing 0.05 per cent., 0.10 per cent., and 0 20 per cent., respectively, so as to meet all likely percentages of