摘要:

AbstractMethods available for the determination of low concentrations (of the order of 0·01 p.p.m.) of dissolved oxygen in water are critically reviewed and methods of assessing their accuracy are discussed. The Winkler method with an amperometric finish for the iodimetric titration is advocated with amendments to avoid errors caused by the presence of interfering substances in the water sample and in the reagents used

ISSN:0021-8871    

DOI:10.1002/jctb.5010070602

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

摘要:

AbstractThe errors introduced by the use of the McLean sampling vessel for determination of the dissolved oxygen content of water up to 0·1 p.p.m. are discussed. A new apparatus is developed by means of which a precision of ± 0·0007 p.p.m. in the determination may be obtained. A modification for use with warm water‐samples is descr

ISSN:0021-8871    

DOI:10.1002/jctb.5010070603

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

摘要:

AbstractA sensitive electrical circuit is described for use with all‐platinum or tungsten/platinum electrodes in the amperometric titration of iodine. The procedure described is sensitive to 0·01 μg. of iodine in 100 ml. of solution. The presence of up to at least 2 p.p.m. of ferrous, ferric and cupric ions causes no interference.Thiosulphate and iodate solutions of concentration 10−5Ncan be accurately prepared by successive dilution of 0·1N solutions. Titration of 100 ml. of 10−7N‐thiosulphate with 10−5N‐iodate is reproducible a

ISSN:0021-8871    

DOI:10.1002/jctb.5010070604

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

摘要:

AbstractAn experimental test is described of the analytical efficiency of Winkler's reaction, for the determination of dissolved oxygen in water at concentrations in the range 0·0007−0·0544 mg./1. No bias exceeding 0·0002 mg./1. was obtained by using the reaction as described, the analytical procedure giving a precision for a single estimate is ±0·0006

ISSN:0021-8871    

DOI:10.1002/jctb.5010070605

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

摘要:

AbstractA chromatographic method has been developed for the separation and determination of adipic and sebacic acids in mixtures of phthalic, adipic and sebacic acids. The separation is effected on a silicic acid column buffered to pH 4·30 and the appropriaten‐butanol/chloroform eluates are titrated with standard alkali. The behaviour of other dicarboxylic acids under the same conditions is briefly consider

ISSN:0021-8871    

DOI:10.1002/jctb.5010070606

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

摘要:

AbstractDeterminations of the volumes of different precipitants required just to cause precipitation of cellulose nitrate, cellulose acetate and ethyl cellulose from dilute solutions in representative solvents are made and the values compared with those of the polymer‐solvent interaction parameter μ. Estimates are made of the solubility parameters of the polymers precipitated and a qualitative interpretation of the variation of volume of precipitant with solvent is attempted. In certain cases, enhancement of solvent power on addition of precipitant is suggested and confirmed by osmotic pressure studies using solvent—precipitant mixtures as solvents. Criteria for the use of the dilution ratio method as a means of assessing thermodynamic solvent power are suggested. In the cases of ethyl cellulose and cellulose acetate, a quantitative treatment predicts conditions under which precipitation and enhanced solvent power may occur fairly

ISSN:0021-8871    

DOI:10.1002/jctb.5010070607

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

摘要:

AbstractA study has been made of the desorption and absorption of gases by liquid drops during the period of their impact on various types of surfaces, following previous work on absorption during formation and during flight of drops. On impinging on a surface, drops form spray, and ‘residual liquid’ which is not detached from the surface and ultimately drains away. The amount of desorption in the spray does not vary greatly with either the height of fall of the drops or the type of surface. In the residual liquid, poor desorption is obtained with ‘dry’ surfaces, i.e. well‐drained surfaces with an average liquid depth of less than 0·1 mm., and relatively good desorption with ‘wet’ surfaces. Desorption in the residual liquid increases to a moderate extent with the velocity of drops before impact, but appears to be little affected by the nature or the contour of the surfaces tested. The process of absorption or desorption is interpreted in terms of the dynamics of the impinging drop. For desorption measurements, water drops containing carbon dioxide were used; as far as could be judged by a limited number of experiments, absorption of oxygen by drops of sodium dithionite or sulphite solution appeared to be affected by factors similar to those found

ISSN:0021-8871    

DOI:10.1002/jctb.5010070608

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

ISSN:0021-8871    

DOI:10.1002/jctb.5010070601

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY