A note on urea estimation by diacetyl monoxime.
نویسنده
چکیده
Rosenthal (1955) has described in great detail a method using diacetyl monoxime which is generally satisfactory for the routine estimation of urea in blood and urine except that complete colour development requires prolonged heating in boiling water. This disadvantage can be overcome by the use of a pressure cooker. The tubes of reaction mixture are immersed in a beaker filled with hot water to a level above that of the liquid in the tubes. The beaker is placed in a domestic pressure cooker which has been warmed during the preparation of the reaction tubes, heated until all air is expelled, and heating continued for 10 minutes at 15 lb. steam pressure. Heating is then stopped, the pressure allowed to fall to zero, and the tubes removed and cooled. Further heating produced no increase of colour. The colour produced appears more stable. There was approximately 3% fading in one hour under fluorescent light and 12% on standing for two days. One of the reagents (arsenic acid in concentrated hydrochloric acid) is unpleasant and difficult to dispense accurately and the final reaction mixture has a sickly smell. The range, for 0.1 ml. of blood and 10 ml. final volume, is 0-200 mg. urea/100 ml. On the credit side, in comparison with the usual urease-nesslerization methods are greater sensitivity and colour stability as well as greater reagent stability and a shorter time for the analysis.
منابع مشابه
Determination of Urea in Blood and Urine with Diacetyl Monoxime-glucuronolactone Reagent.
N UMEROUS STUDIES have been reported in the literature on the photometric determination of urea in biological fluids with diacetyl monoxime as the color-developing agent. The reaction is photosensitive, does not follow Beer’s law, and requires special precautions for reproducible results. In many proposed procedures, oxidants were added in the reaction mixture to destroy hydroxylamine which mig...
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A rapid and reproducible method is described for measurement of urea in biological materials (after deproteinisation) and in serum (without deproteinisation). Urea is colorimetrically determined with diacetyl monoxime and thiosemicarbazide in the presence of sulphuric acid, phosphoric acid and ferric chloride. The sensitivity of the colorimetric reaction and stability of the colour are enhanced...
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IN RECENT YEARS the automated diacetyl monoxime (DAM) reaction as adapted to the AutoAnalyzer has become the method of choice in many clinical laboratories for the determination of urea in biologic fluids. The method is based on the condensation of urea with diacetyl, the latter usually being liberated from the monoxime in the presence of one of various acid reagents (1, 2). The reaction, howev...
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Methods for the determination of urea in biological fluids have passed through an interesting cycle (cf. Peters and Van Slyke (3) pp. 539-544). The earliest procedures were strictly chemical ones, involving precipitation of the urea as an insoluble mercury complex or decomposition of the urea by means of heat or hypobromite. The use of the highly specific enzyme urease occurring in the jack and...
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عنوان ژورنال:
- Journal of clinical pathology
دوره 11 4 شماره
صفحات -
تاریخ انتشار 1958