摘要:

The dominant noises present in sequential, two-photon photoionization, in polar solvent systems under HPLC conditions, are discussed. Several representative chromatograms for the separation and detection of five benzodiazepines are exhibited, showing the effectiveness of a baseline restorer preamplifier relative to an ordinary, low-noise, AC-coupled preamplifier. It is found that there isnooptimum preamplifier, particularly where solvent programming applications are necessary. The observed dominant noises in polar solvents are related to the leakage currents that result when high voltages are impressed across the polar solvent systems, but the precise nature of the relationship is unknown.

ISSN:1073-9149    

DOI:10.1080/10739149008543714

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A pulsed laser excited fluorescence detector is described for the quantitative analysis of DNA and RNA components separated by electrophoresis. The system is based on measurement of the fluorescence from ethidium bromide complexed with DNA where the fluorescence is excited by a nitrogen laser. In principal the method should work for any fluorescing stain.

ISSN:1073-9149    

DOI:10.1080/10739149008543715

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A near-infrared laser diode excitation source for effectively increasing the near-infrared performance of an SLM/Aminco 8000C fluorometer is described. This laser diode excitation source provides high power monochromatic excitation for extremely low detection limits. Evaluation of the laser diode excitation source and stability is monitored by a series of calibration curves. The paper presents the advantages of laser diode excitation sources in spectroscopic applications. The laser diode described can also be used for simultaneous absorbance measurements if laser diode intracavity effect is utilized. The design and implementation of a simple controlling circuit for accurately maintaining the laser power of the laser diode are also described.

ISSN:1073-9149    

DOI:10.1080/10739149008543716

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The versatility and ease of operation of a video densitometer system for the analysis of thin-layer chromatographic (TLC) plates is described. In that no such device is currently available commercially, a suitable system was configured utilizing commercially available components. Three characteristic detection modes commonly used in TLC are illustrated using the new system. Detection limits, dynamic range, and resolution well within acceptable limits are indicated. Comparison with a conventional scanning densitometer reveals a more rapid analysis without significant loss of precision or resolution.

ISSN:1073-9149    

DOI:10.1080/10739149008543717

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:1073-9149    

DOI:10.1080/10739149008543718

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:1073-9149    

DOI:10.1080/10739149008543719

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:1073-9149    

DOI:10.1080/10739149008543720

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor