Ammonia Buffer Solution Research Articles

A.C. Polarographic Determination of Lanthanum(III), Nickel(II), Calcium(II), and Magnesium(II) by Using Diethylenetriaminepentaacetic Acid as a Titrant

Abstract The a.c. polarographic determination of lanthanum(III), nickel(II), calcium (II), and magnesium(II) with diethylenetriaminepentaacetic acid was studied by using a dropping mercury electrode and a hanging mercury drop electrode as indicator electrodes. Lanthanum(III) and nickel(II) in an acetate buffer solution and calcium(II) and magnesium(II) in an ammonia buffer solution could be titrated with diethylenetriaminepentaacetic acid in the concentration range from 5×10−5 to 1×10−3 m by measuring the height of the a.c. polarographic wave of diethylenetriaminepentaacetic acid after the end point. The effect of the presence of calcium-(II) ions on the a.c. polarographic determination of lanthanum(III) in an acetate buffer solution of pH 4.0 was also examined and discussed thermodynamically.

A Study of Lipoprotein Lipase Produced by Perfusion of Isolated Rabbit Heart with Heparin.

SummaryWith a perfused, isolated rabbit heart LPL activity appeared in the perfusion solution of bicarbonate buffer in the presence of 5 mg % heparin and 5 to 10% serum. However, under the same conditions, LPL did not appear with phosphate buffer. The LPL produced was inhibited by protamine sulfate, CaCl2 and NaCl. Optimum pH of enzymatic activity was at pH 8.2, and 80% of the activity was lost by heating at 50°C for 2 min and 70°C for 30 sec. After perfusion, LPL activity in the heart disappeared. Total activity appearing in the circulating solution was nearly equal to total activity of heart tissue which was extractable with ammonium buffer solution.

Knorre氏法<SUP>1)</SUP>の適用性について

Recently, in order to improve hot workability of high grade stainless steel, adding rare earth metals in a bath have been widely taken in stainless-steel melting practice. As regards determination of Ce in steels, W. Westwood and A. Mayer2) reported in their paper that Ce in cast iron was separated from iron by using citric acid ammonia buffer solution, then extracted with chloroform and at last determined by oxine colorimetry.To determinate Ce in stainless steel which was treated with misch-metal, the author made some experiments concerning the following matters:(i) Separability of all rare earth metals from the steel using HF solution.(ii) Applicability of Knorre's method to Ce in separated rare earth metals.As a result of experiments, the author ascertained applicability of Knorre's method to determine the Ce in steel.

A Chemical Method for the Rating of Agricultural Limestones Used as Soil Amendments

AbstractA method for the calibration of the efficiency of both calcitic and dolomitic limestone in relation to their rapidity in correcting acidity in soils is proposed. The procedure is as follows:Exactly 1.0 gm. of the limestone to be tested is added to 250 ml. of boiling 0.07 N disodium ethylene‐diaminetetraacetate which is contained in a 500‐ml. Erlenmeyer flask connected to a reflux condenser. After refluxing 20 minutes, 10 ml. of ammonia buffer solution (pH 10) is rapidly added. The solution is immediately titrated with 1.0 N magnesium sulphate solution using Eriochrome black T as indicator. The end point is attained when the color of the indicator changes from blue to wine red. Time and rate of heating must be controlled precisely.Limestone samples are calibrated from these titration results by comparing them to the reaction of calcite under identical conditions.When the results of this test for 19 commercial limestone samples were compared with the pH change of soil suspensions treated with the same materials, a correlation of 0.96 was obtained. A field test of nine commercial samples showed a correlation with this test of 0.79.

Etude polarographique de la salive

AbstractDiluted human saliva in an ammonia buffer solution and in presence of CoII gives three catalytic waves, whilst blood serum, under the same conditions, gives only two waves. Saliva presents the first two waves only in the presence of CoII, but the third wave appears in buffer solution with or without CoII. After denaturation with potassium hydroxyde under the given conditions the third wave disappears completely, whilst the first and the second waves augment. Saliva changes its properties when kept; the stability of the waves is diminished in regressive order from h, to h,. After simple dialysis the second and third waves disappear, whilst the first wave does not change. After electrodialysis during two and a half hours, the first wave disappears, but the third wave is hardly changed. The water used for the simple dialysis has also been examined under the polarograph; this gave only the second and the third waves, but the behaviour of the third wave with or without CoII is quite different from the behaviour of h, taken from a saliva which has not been dialysed. By addition of cystine or cysteine to the saliva, the third wave increases when CoII is present, but it decreases in the absence of this ion.

Etude polarographique de la salive

AbstractL'étude du comportement de la salive à la polarographie est poursuivie. On constate la présence de 3 sauts catalytiques; les divers potentiels de ces sauts sont pratiquement constants pour les salives examinées. Puis on étudie le comportement de la salive à la dénaturation par la chaleur et par la potasse caustique. Une étude systématique de l'évolution des sauts a été faite, conduisant à un certain nombre de remarques; on signale, entre autres, la disparition complète du 3e saut lors de la dénaturation à la potasse caustique.