摘要:

The glycerol is quantitatively oxidized to formaldehyde by periodic acid, using a five minute oxidation period to minimize oxidation of glucose. The iodate and periodate are reduced to iodide by a large excess of sodium arsenite and the formaldehyde then determined directly in the oxidation mixture, by the color reaction with chromotropic acid. The precision of the method is about ± 2% in the range 2 to 8 p.p.m. of glycerol. The error due to glucose, in quantity equal to the glycerol, is only 2.5 to 5.0% and can be easily corrected for when the glucose content of the solution is known. One worker can analyze 40 to 60 samples per day.

ISSN:1923-4287    

DOI:10.1139/cjr50b-013

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

A mercury resonance lamp is described whose output is 6 × 1013quanta per second of radiation of wave length 1850 Å. The radiation is emitted through a window of synthetic sapphire. The lamp is of simple construction and gives consistent and trouble free operation. A xenon lamp is also described which emits 1 × 1015quanta per second of radiation below 1470 Å. The construction, method of calibration, and some of the operating characteristics of the lamp are given.

ISSN:1923-4287    

DOI:10.1139/cjr50b-014

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

The scattering of light by aqueous solutions of three different samples of sodium thymonucleate has been investigated. It was found that one sample in water consisted of randomly coiled molecules of molecular weight greater than 24 × 106. A second sample gave a less viscous solution in water and was only partially coiled, the coiling of the molecules being increased by the addition of a small amount of sodium chloride. In dilute salt solution the molecular weights of all three samples were greater than 3.7 × 106. Two samples of nucleate were degraded in solution by irradiation with ultraviolet light in the presence of hydrogen peroxide. In both cases the nucleate was converted into material consisting of rodlike molecules, 2400 Å in length and having a molecular weight of 750,000.

ISSN:1923-4287    

DOI:10.1139/cjr50b-015

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

This work shows how the molecular weight of sodium alginate can be determined by measuring the values of the osmotic pressure,P, in the presence of low concentrations of sodium chloride, and extrapolation ofP/CtoC = 0, whereCis the concentration of sodium alginate. For different samples of sodium alginate the slope of the curveP/CagainstCwas independent of the molecular weight. Molecular weight values from 48,000 to 186,000 were obtained. The intrinsic viscosity of the different samples were linearly related to the degree of polymerization.

ISSN:1923-4287    

DOI:10.1139/cjr50b-016

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

not available

ISSN:1923-4287    

DOI:10.1139/cjr50b-017

出版商:NRC Research Press    

年代:1950

数据来源: NRC