摘要:

The development of a rapid and a simple “Weisz ring-oven” method is described for the semiquantative determination of diquat and paraquat. In this method column chromatography is used for the separation of herbicides from water and soil samples. Further evidence of the identity of individual residues is provided by thin layer chromatography.

ISSN:0003-2719    

DOI:10.1080/00032716908051338

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

A method for the determination of beryllium oxide in glasses and in the presence of other metal oxides is described. Beryllium oxide has been separated from commonly associated metal oxides and gravimetrically determined using CDTA (1,2-cyclohexylenedinitrilo-tetraacetic acid). Using this method, separations and recovery of beryllium oxide were excellent.

ISSN:0003-2719    

DOI:10.1080/00032716908051339

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The reaction of testosterone with heptafluorobutyric anhydride, in the presence of pyridine or collidine, leads to two diheptafluorobutyrate (HFB) derivatives. These compounds are believed to be the di-HFB esters of 2,4-androstadien-3, 17β-diol (A) and 3, 5-androstadien-3, 17β-diol (B), withAas the major product. This is similar to the reaction with silylating reagents which leads to two isomeric enol ethers. In benzene or acetone solution, and in the absence of an organic base, the same two isomers are formed, but withBas the major product. Although the latter reaction has been recommended for quantitative work, the formation of isomeric enol esters has not been noted. Since the products are not stable in the reaction medium, the method is not entirely satisfactory. The reaction in pyridine solution should be suitable for quantitative work; the products are stable in solution and can be detected in subnanogram amounts.

ISSN:0003-2719    

DOI:10.1080/00032716908051340

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The method involves the addition of chromium as an internal standard and requires no other chemical pretreatment. Samples are spotted directly onto chromatographic paper discs and analyzed by x-ray fluorescence spectrometry. The method is rapid, and is best in the concentration range 5–400 p.p.m.

ISSN:0003-2719    

DOI:10.1080/00032716908051341

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The polarographic behavior of a number of metal-N-benzoyl-N-phenylhydroxylamine complexes extracted into chloroform is presented. Lithium chloride in methanol is used as the supporting electrolyte. Half-wave potentials for the seven elements producing reducible complexes are reported.

ISSN:0003-2719    

DOI:10.1080/00032716908051342

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The performance of a new liquid-membrane electrode using valinomycin as membrane component is described with respect to selectivity, working range, speed of response and accuracy. The electrode makes possible the measurement of potassium ion activities in the range of 10−1Mto at least 10−6Min unbuffered systems with a selectivity of potassium over sodium ions of more than 4,000. The electrode was used for the direct titration of potassium ions.

ISSN:0003-2719    

DOI:10.1080/00032716908051343

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0003-2719    

DOI:10.1080/00032716908051337

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor