Multichannel fluorescence systems

Schuderer J, Akkoyun A, Brandenburg A et al (2000) Development of a multichannel fluorescence affinity sensor system. Anal Chem 72 3942-3948... 

Saito, M. Ohi, A. Matsuoka, H. Microinjection of fluorescent dye in a plant cell and its intercellular translocation using a multichannel microelectrode system. Biochim. Biophys. Acta, Gen. Sub. 1996, 1289, l-Ar. 

Some commercially available detectors have a number of detection modes built into a single unit. Fig. 2.4o is a diagram of the detector used in the Perkin Elmer 3D system, which combines uv absorption, fluorescence and conductivity detection. The uv function is a fixed wavelength (254 nm) detector, and the fluorescence function can monitor emission above 280 nm, based on excitation at 254 nm. The metal inlet and outlet tubes act as the electrodes in the conductance cell. The detection modes can be operated independently or simultaneously, using a multichannel recorder. In the conductivity mode, using NaCl, a linear range of 103 and a noise equivalent concentration of 5 x 10 8 g cm-3 have been obtained. 

The //PLC system described in this chapter is equipped with 24 parallel columns for liquid chromatography, each with its own sample introduction port and exit port for connection to detectors of choice (UV absorbance and/ or fluorescence). Flow from a binary solvent delivery system is divided evenly across 24 channels and results in 1/24 of the programmed pump flow rate through each column (i.e., total flow of 300 /zL/ min will produce a flow of 12.5 /zL/ min in each column). Samples are introduced to the columns by a multichannel autosampler configured to sample from either 96-or 384-well SBS standard plates. Figure 6.2 depicts a general view of the system. 

With single-photon exposure, excitations may decay either through a variety of processes including chain scission and fluorescence (47). We would therefore expect to observe fluorescence from two-photon excitation as well. To observe the fluorescence, we used a Spectra Physics mode locked dye laser system, operating with Rhodamine 560 dye. This was focused onto the polymer film, and the emitted light collected into a spectrometer with a Princeton Instruments Optical Multichannel Analyzer (OMA) attachment. 

Multichannel HPLC—HPLC system designed to run parallel HPLC columns into a multi-flow cell UV or fluorescent detector. Designed for production laboratories to speed QA/QC monitoring (see Chapter 16). 

This report will discuss the results of a study in which an optical multichannel analyzer (OMA) was coupled to standard spectrometers to record both the UV/VIS absorption and fluorescence emission spectra of complex mixtures of PAH s separated by HPLC techniques "on-the-fly" (i.e., one second spectral scans of the HPLC effluent stream) and stored on a floppy disc for subsequent retrieval and data analysis. The system described has the capability of storing 250 (500 point) spectra and can readily be used to increase the effectiveness of HPLC analysis by allowing both quantitative and qualitative data to be obtained. 

The fluorescence light is observed at right angles to the laser beam by an optical system and a small monochromator followed by a RCA Quantacon photomultiplier, the signal of which is sent to an amplifier and a chart recorder when the cell is continuously irradiated or to a photon counting system and a multichannel analyser when transient effects are studied. 

After consideration of the properties of dispersive/CCD Raman spectroscopy and FT-Raman, questions about alternative approaches to conventional FT-Raman often arise. First, can fluorescence be further reduced by using still longer laser wavelengths Second, wouldn t the best solution be a shot-noise-limited multichannel system operating above 1000 nm Both of these questions have been addressed experimentally, but given current technology the associated hardware developments are not yet ready for widespread use. 

As manual, multichannel pipeting devices and plate-based detection systems became staple tools in the modem discovery laboratory, bioassays for moderate throughput have been developed in a wide variety of formats. The flexibility of these detection devices allowed assays that utilize visible-, fluorescence-, luminescence-, and radioactive-based readouts. Manual pi-... 

A multichannel detector for In-situ analysis of fluorescent materials on TLC plates was investigated (26). The optical system was designed to obtain a fluorescence spectrum from each position along the elution axis of a one-dimensional plate without the mechanical scanning. By use of tetraphenylporphlne and octaethylporphine it can be shown how overlapping spots can be resolved into their components. 

In the past, molecular luminescence spectrometry was always conducted with single channel systems involving a photomultiplier tube (PMT) as the detector. The availability of multichannel detectors with internal gain has provided a new powerful tool for luminescence measurements, and several types of applications have been reported (1-15). This paper is concerned with the application of an intensified diode array dynamic molecular fluorescence and chemiluminescence measurements. In this paper the types of measurements and analytical systems for which multichannel detectors are used in our laboratory are introduced. Next the specific IDA system used is presented along with important hardware and software considerations. Third, the characteristics of the IDA detector are reviewed to give some perspective about its influence on the quality of measurements. Finally, some typical applications to chemical systems are presented to illustrate the advantages of multichannel detection. 

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