Micro-Diffusion Analysis and Volumetric Error (Conway, E. J.)

Abstract

This useful book describes procedures developed by the author and others for the determination of small quantities of ammonia, urea, adenylpyrophosphoric acid, adenylic acid, adenosine, volatile amines, chlorides, bromides, C02, acetone, and alcohol. The "Conway Unit" is used in all of these determinations. This unit consists of a pyrex glass container resembling a small Petri dish with thick glass walls, within which a second chamber is formed by a circular wall of glass arising from the floor. The wall of the inner chamber is about one-half the height of the outer. The sample to be analyzed is placed in the outer chamber and the volatile substances arising therefrom are absorbed by means of appropriate reagents in the inner chamber. By this means, extremely small quantities can be analyzed with an accuracy comparing favorably with that of macro methods.Students and biochemists will find the discussion of the design and use of micro glassware very helpful. The accuracy of micro methods is limited largely by the accuracy of measurement of the sample and volumetric reagents and by the limitations inherent in the chemical reactions involved in the determinations. The author discusses fully the many sources of error and gives methods for their evaluation.

Studies on functions of reductones. XX. Effect of reductones on glyoxalase I.

“…The following chemicals were obtained from the suppliers indicated and were used without further purification: reduced glutathione (Koh jin); ascorbic acid, hydroquinone, catechol and resorcinol (wako), p-Benzo quinone (wako) was recrystallized from ethanol. Ascorbic acid 3-phosphate was kindly supplied by Takeda Pharmaceutical Industry Co. Methylglyoxal (40% in water) (Nakarai) was distilled before use and the distillate was standardized according to FRIEDEMANN (6). Dehydroascorbic acid was synthesized from ascorbic acid by oxidation with p-benzoquinone according to the method de scribed by von EULER (7) and was recrystallized from acetone based on the method of KENVON and MUNRO (8).…”

The respiration of Mycobacterium phlei

“…An amount of 80 ml. was used for the determination of lactic acid by the method of Friedemann & Graeser (1933).…”

Potential transition-state inhibitors of glyoxalase. I

“…MeG was steam distilled and its concentration determined by the method of Friedemann [25]. GSH 3.46 m M and MeG 2.07 mM in phosphate buffer, pH 6.8, was incubated 1-2 h at 24OC giving approximately 1 mM hemimercaptal.…”