摘要:

Gas diffusion/permeation techniques involving different membrane interphases or an open fluid/fluid interface are presented as powerful tools for separation and/or preconcentration of a variety of classes of analytes, i.e., gases, gas-evolving species, volatile inorganic and organic substances, etc., from gaseous, aquatic, or organic sample matrices. Principles of the techniques and factors influencing transmembrane transport, such as acidity of the donor and the acceptor streams, their flow rates, membrane characteristics, temperature, pressure, etc., are described. Different configurations of FIA manifolds for stopped-flow, closed-loop, and continuous flow arrangements, designs of principal instrumental modules, characteristics of different semipermeable membranes, and special arrangements of detection systems are outlined.

ISSN:1040-8347    

DOI:10.1080/10408349208051649

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Present-day inductively coupled plasma-mass spectrometry (ICP-MS) instrumentation is described briefly. Emphasis is placed on performance characteristics for geoanalysis, geochemistry, and hydrology. Applications where ICP-MS would be indispensable are indicated. Determination of geochemically diagnostic trace elements (such as the rare earth elements [REE], U and Th), of isotope ratios for fingerprinting, tracer and other geo-isotope applications, and benchmark isotope dilution determinations are considered to be typical priority applications for ICP-MS. It is concluded that ICP-MS furnishes unique geoanalytical and environmental data that are not readily provided by conventional spectroscopic (emission and absorption) techniques.

ISSN:1040-8347    

DOI:10.1080/10408349208051650

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The new and novel techniques of fluorescence lifetime imaging (FLI)** and fluorescence lifetime imaging microscopy (FLIM) provide the investigator with the capacity to quantitate two-dimensional fluorescence intensity distributions and lifetimes. The concept, theory, and instrumentation of FLI and FLIM are reviewed in this paper. The implementation of FLIM instrumentation with conventional and confocal microscopic systems is discussed. These instruments permit the quantitative measurement of molecular interactions and chemical environment from samples in biological, physical, and environmental sciences. Numerous applications in the biomedical sciences for FLIM instrumentation are also discussed.

ISSN:1040-8347    

DOI:10.1080/10408349208051651

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Electrothermal vaporization (ETV) as a sample introduction technique for plasma source spectrometry offers several advantages over traditional solution nebulization sample introduction methods. Because volatilization of the analyte occurs in the ETV device, the plasma is not required to desolvate the sample and, therefore, the plasma has greater energy available for atomization, ionization, and excitation. The furnace also offers the ability to separate sample matrix components from the analyte of interest, which causes a reduction in interferences in the emission or mass spectrum. Both of these advantages allow for improved detectability for most elements. ETV also allows for the analysis of solid samples with minimum sample pretreatment, which broadens the numbers of samples amenable to analysis by plasma spectrometry. In the nearly 20 years that have followed the first report of ETV as a sample introduction method for plasma sources, there has been extensive research improving the design of the vaporization device, investigating matrix effects using ETV, analyzing solid samples, and coupling the devices to alternate plasma sources (other than inductively coupled plasma [ICP]). This review discusses the current state of electrothermal sample introduction for plasma source spectrometry and possible future directions of the technique.

ISSN:1040-8347    

DOI:10.1080/10408349208051652

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:1040-8347    

DOI:10.1080/10408349208051648

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor