The determination of ergotamine in preparations containing ergotamine tartrate and cyclizine hydrochloride.

A simple and rapid method was developed for determining L-glutaminase and L-asparaginase activities in soils. It involved colorimetric estimation of NH4 + released by the activity of L-glutaminase and L-asparaginase when soil was incubated with 0.25 M L-glutamine or L-asparagine in 0.1 M phosphate buffer (pH 7.6) and toluene used as a germicide. The indophenol method was applied to the assay of NH4 + for soil L-glutaminase and L-asparaginase activities. Color development in the indophenol method required one hour. The color development was stable for 2 d and was not appreciably affected by the presence of L-glutamine, L-glutamic acid, L-asparagine, and L-aspartic acid. In addition, no turbidity nor precipitate appeared in the presence of a high concentration (10 μg) of NH4 +-N. The L-glutaminase activity was estimated in three soil samples differing in pH, organic-C content, and land use. The L-glutaminase activity in the three soils ranged from 28 to 1,470 mU (10-9 mol min-1 g-1 of dry soil at 3...

Colorimetric Estimation of Lactose and Its Hydrolytic Products

Methods for the estimation of guanidine and its methyl derivatives have been subject to considerable criticism. A study of the color reaction for guanidines recently described by Marston1 was undertaken in order to determine its biochemical applicability. Although Marston specifically states that his reagent will keep indefinitely, in our hands deterioration and precipitation invariably set in shortly after mixing the three ingredients, sodium nitroprusside, potassium ferrocyanide and sodium hydroxide.A reagent has been developed, which, although it contains the same ingredients as employed by Marston, has the advantage that it keeps well and gives within five minutes a full color development which does not fade or become turbid for more than an hour, thus allowing ample time for color comparison.The reagent we now employ is prepared as follows: 6 gm. sodium nitroprusside and 8.5 gm. potassium ferrocyanide are dissolved in water and made up to 100 cc. About 15 to 20 minutes before using, one volume of thi...