On the value of Brücke's method for the removal of interfering substances from urine in testing for glucose / by Edgar Moore Green.

  • Edgar Moore Green
Date:
[1886]
Catalogue details

Licence: Public Domain Mark

Credit: On the value of Brücke's method for the removal of interfering substances from urine in testing for glucose / by Edgar Moore Green. 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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    In several cases, both neutral plumbic acetate and plumbic tribasic acetate were added before filtration, and the proportion of glucose present then determined, after which the process was carried on as before described. In a few instances one or more of the determinations were made by Fehling's solution instead of by the saccharimeter. In some of the solutions the quantity of glucose was not esti- mated until after the completion of the whole process. Frequently, however, an estimation was also made of the glucose lost in the nitrate after precipitation by ammonium hydroxide. By these different methods almost all possible conditions of working the original process were obtained, and it was possible to ascertain not only the whole amount of loss caused by the process, but also the steps which involved a loss, and the amount of each. The saccharimeter used in these experiments was one of the latest Laurent shadow instruments of the largest size. The 200 mm. tube was frequently used, but when testing a weak solution the 400 mm. tube was used. In every case at least ten observations were made, and the average of these was adopted as showing the amount of glucose present. The glucose was perfectly pure, crystallised and anhydrous, polarising 99.850 to the right as shown by previous experiment. In two solutions containing 0.05 per cent, of glucose, the average loss caused by the process was found to be41.00 percent., the tests being made by Fehling's solution.1 A solution containing 0.1 per cent, of glucose showed a loss of 52.60 per cent, by the neutral plumbic acetate and plumbic tribasic acetate, when both were added before the first filtration, and a loss of 66.80 per cent, by the whole process, leaving 14.20 per cent, as the loss caused by the precipitations by ammonium hydroxide and by hydrogen sulphide. However, as only a trace of glucose was found in the filtrate and washings obtained after the precipitation by ammonium hydroxide, this loss must have been caused almost entirely by the precipitation by hydrogen sulphide. In one solu- tion containing the same amount of glucose, only 2.60 per cent, was lost as determined by Fehling's solution in employing the method, and only a trace of glucose was found in the filtrate and washings obtained after precipitation by ammonium hydroxide. In four solutions of the above strength, no glucose was found in the 1 In the estimations following, the saccharimeter was invariably used, unless Fehling's solu- tion is specially mentioned as having been employed.
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