摘要:

Early work on use of carbons for liquid chromatography shows that special carbons must be developed if carbon is to be useful in HPLC. The processes used to make carbons, the properties of such carbons and the requirements for HPLC carbons are discussed. The preparation of HPLC carbons is reviewed in detail and the results which have been obtained are assessed in terms of their kinetic and thermodynamic performance. Applications are reviewed.

ISSN:0148-3919    

DOI:10.1080/01483918308067647

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Designs of post-column reaction detection systems for HPLC are discussed with respect to their effect on sensitivity and resolution on the basis of systems theory. The most promising post-column reactor types are the packed-bed reactor and the electronically desegmented liquid-segmented reactor. No experimental data on the latter are available, however.

ISSN:0148-3919    

DOI:10.1080/01483918308067648

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A method of instrumental spreading correction in sizeexclusion chromatography is described, which is simple, precise, and easy to calculate with a simple desk-top calculator. A Gaussian-type instrumental spreading function with variable or fixed Tung's constants is assumed. No assumption of any functions for uncorrected (observed) and corrected chromatograms for polymers is made in advance, instead, these chromatograms are assumed to be the assembly of several Gaussian distributions. After an uncorrected chromatogram being devided into several Gaussian distributions correction of instrumental spreading is made on each Gaussian function and then the corrected Gaussian distributions are assembled into the corrected chromatogram. Examples for correction are demonstrated. Even in high performance SEC, this correction is still needed.

ISSN:0148-3919    

DOI:10.1080/01483918308067649

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

HPLC optical detector advances are reviewed in the field of absorbance, fluorescence, phosphorescence, and elemental emission detection. The development of UV-doped silicon photodiodes having excellent response throughout the UV, miniature gas discharge lamps (Hg, Zn, Cd) with high output UV lines, and high throughput UV interference filters allow optical systems with shot noise levels below 10−5au. However, the fundamental noise limitations in such systems are now thermal changes in the optoelectronic components and flow cells. Future absorbance detectors may require thermostatting to achieve the minimal noise and drift performance inherent in the optical design. The emerging development of UV-doped photodiode arrays at reasonable cost offers multichannel absorbance detection and on-the-fly spectral information. Data system design for processing the multichannel data is critical in this field. On-column absorbance detection using packed microbore fused silica columns has been demonstrated, allowing a flow cell volume of <10 nanoliters, compatible with micro HPLC. In a similar development, on column fluorescence detection using an open tubular glass capillary column has been demonstrated in zone electrophoresis. A significant amount of research in fluorescence detection using laser sources is now underway. Sensitivity advantages of approximately 10-fold have been demonstrated due to high laser output and another 10-fold improvement for detecting long radiative lifetime molecules due to pulsed laser/temporal discrimination. Dual photon excited fluorescence, offering unique selectivities, has been demonstrated. This technique requires the high output power of the laser source. Room temperature phosphorescence HPLC detection has been demonstrated, utilizing triplet → triplet energy transfer from a donor solute molecule to a mobile phase acceptor additive (e.g., biacetyl). This energy transfer technique offers the expansion of the emission technique to phosphorescent molecules at nanogram sensitivities. Finally, the development of micro HPLC columns operating at 1–10 μl/min offers potential compatibility with element specific GC detectors such as the flame photometric detector (S, P specific).

ISSN:0148-3919    

DOI:10.1080/01483918308067650

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

During the past ten years there has been a dramatic increase of interest in the field of flavonoid chemistry. This was mainly due to the application of HPLC to the study of flavonoids. These compounds, natural plant constituents with a structure based on the aromatic heterocycle, 3-phenylbenzopyrone, are ideally suited for analysis by HPLC. The basic complex structure can be varied by the number and position of hydroxyl substituents and other derivatives (sugars, methyl). These variations cause changes in the way the compounds react to solvents and columns commonly used in HPLC allowing separation and identification.

ISSN:0148-3919    

DOI:10.1080/01483918308067651

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

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

ISSN:0148-3919    

DOI:10.1080/01483918308067646

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor