摘要:

The analytical reagent dithizone has now been used in analytical chemistry for just over 50 years, and forms the subject of an extensive literature comprising well over 2200 papers. Research work on this reagent was first carried out by Hellmuth Fischer, originally as a purely personal interest — virtually a hobby. However, the Siemens organization at Erlangen, Germany, was fortunate indeed to be able to employ his expertise when they were faced with the problems of determining small amounts of metallic impurities in certain highly purified metals.1,2In this field, its great sensitivity and considerable selectivity made an immediate impact. The intense color of the reagent itself — and that of each of its metal complexes, their sparing solubility in water, but considerable solubility in organic solvents — led Hellmuth Fischer, and later many others, to elaborate liquid-liquid extraction procedures for concentrating and separating desired metals and to devise a whole variety of absorptiometric finishes. Selectivity was enhanced by a careful control of the pH employed in extractions, and by the use of masking agents.

ISSN:0007-8980    

DOI:10.1080/10408348008542714

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Luminescence derivatization procedures convert non- or weakly luminescent sample molecules to highly luminescent products. The usual motivation for forming luminescent derivatives is to increase the sensitivity with which samples can be detected. Analytical methods based on luminescence generally have detection limits from one to four orders of magnitude lower than corresponding methods based on absorption. Other advantages of luminescence methods relative to absorption include greater linear dynamic response ranges and greater selectivity, since both excitation and emission wavelengths can be chosen to maximize selectivity. The required instrumentation is relatively simple. More information on luminescence can be obtained from basic texts on this subject.1-5While luminescence includes fluorescence, phosphorescence, and chemiluminescence, most of the applications involve fluorescence. This review will be devoted exclusively to fluorescence. Applications of phosphorescence are limited, because phosphorescence is rarely observed from solution. Chemiluminescence is restricted in scope, because relatively few reactions give yield to efficient light production.

ISSN:0007-8980    

DOI:10.1080/10408348008542715

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor