Fluorescence Detection System

B. Schmidt and D. Riesner, A fluorescence detection system for the analytical ultracentrifuge and its application to proteins, nucleic acids, viroids and viruses (in Ref. [77]). 

Chabinyc M.L., Chiu D.T., McDonald J.C., Stroock A.D., Christian J.F., Karger A.M., Whitesides G.M., An integrated fluorescence detection system in poly(dimethylsiloxane) for microfluidic applications, Anal. Chem. 2001 73 4491-4498. 

Recent developments in the determination of elements in this group have been very much linked to the use of atomic fluorescence detection systems rather than AAS (see section 8.7). ICP-AES and ICP-MS can also be used but they are generally inferior in sensitivity. Best sensitivity is obtained from AFS detection. It should also be noted that the analysis may also be required to detect and measure organic compounds of these elements because of the toxicity in the organic form. Separation by one of the methods reviewed in Chapter 4 may thus be used in sample processing prior to analysis. 

Godden and Stockwell [11] have described a specific fluorescence detection system to provide fully supported analytical systems for routine analysis of mercury at low levels. The fluorescence approach provides a wide linear dynamic range and extremely low detection limits. P.S. Analytical s Merlin Plus System provides a fuUy automated system which will produce results at a rate of around 40 per hour. This is due to the optimization of the optical design of the detector, coupled to the inherent features of the fluorescence technique. 

In any application the fluorescence detection systems must have four compatible elements ... 

Weinberger, . M. Wiedenmann, E. Bohm, S. Jilg, W. Sensitive and accurate quantitation of hepatitis virus DNA using a kinetic fluorescence detection system (TaqMan PCR). J Virol Methods 2000, 35(1-2), 75-82. 

K. M. Walsh, and R. S. Keynton, Fully Integrated On-Chip Electrochemical Detection for Capillary Electrophoresis in a Microfabricated Device, Anal. Chem. 2002, 74, 3690 M. L. Chabinyc, D. T. Chiu, J. C. McDonald, A. D. Strook, J. F. Christian, A. M. Karger, and G. M. Whitesides, An Integrated Fluorescence Detection System in Poly(dimethylsiloxane) for Microfluidic Applications, Anal. Chem 2001, 73, 4491. 

FIGURE 7.1 Schematic of the laser-induced fluorescence detection system. Excitation was provided by an argon ion laser light. It was focused with a lens (1) onto the separation channel in a microchip. The chip was held in place with a Plexiglas holder (2). Fluorescence emission (3) was collected with a microscope objective (4), focused onto a spatial filter (5), emission filter (6), and then detected with a photomultiplier tube [550]. Reprinted with permission from the American Chemical Society. 

Experimental. The experimental set up consisted of a -pum-ped-dye laser (Molectron UV-14, DL-400), spatial filters to isolate the central part of the dye laser beam, a H2 02-Ar or N2 flame supported by a capillary burner with Ar or N2 sheath, and a fluorescence detection system at right angles (a JY-H-10 monochromator, a photomultiplier, and a PAR 162-164 boxcar averager). All measurements were taken 1 cm above the burner top the concentration of Ca, Sr, In, and Na was low ( 1 yg/ml). The fluorescence waveform was monitored with a 75 ps sampling head (PAR 163). The laser spectral bandwidth was also measured with a JY-HR-1000 monochromator (6AS < 0.1 ). 

Figure 1. Multiphoton UV-photolysis-laser fluorescence detection system...

The principle of fluorescent detection systems is that an organic molecule, or in some cases a metal complex, can absorb photons in a particular range and then reemit them at a longer wavelength, illustrated by a Jablonski diagram in Fig. 6.4. For this to be used as a detection method the fluorescent species must have an affinity for a specified target or be attached to a molecule that does. 

In microarray analysis, detection is the step in which the signal for each spot is revealed and quantified, giving an image that is like photography of the microarray. In the following paragraphs we shall provide basic information on the currently used fluorescence detection systems for microarrays and the characteristics of corresponding detection devices. 

Nishino, N., Makinose, Y., and Fujimoto, T. 1992. 2-Aminobenzoyl-peptide-2,4-dinitroanilinoethylamides facile fluorescent detection system for sequence specific proteases. Chem. Lett. 1, 77-80. 

Sample preparation is critical to the success of any spectrophotometric experiment whether using absorbance or fluorescence detection systems. Even the rapid mixing of two samples of buffer in a sensitive instrument can result in what appears to be a reaction curve. This may be caused by simple effects such as the rapid compression and decompression of an air bubble in the flow path, the nuxing of two solutions at different temperatures or the effect of the stopping process upon small dust particles present in the solution. Therefore it is essential that solutions be prepared thoroughly before use. Sometimes it is necessary to degas buffers to remove dissolved air that may otherwise come out of solution following rapid decompression of the reaction solutions. In practice, it is... 

Portable X-ray fluorescence detection system. Identification of different non-nuclear materials under field conditions. 

Fig. 3 Schematic representation of a 1000-capillary rotary scanner and a four-color confocal fluorescence detection system. (From Ref. [10].)...

Examples for the fluorescence detection system are the determination of quinine in soft drinks and the important quantification of benzo[a]pyrene and other polycyclic hydrocarbons (PAH) in smoke flavourings or smoke preparations [13-14]... 

Figure 33F-1 On-column laser fluorescence detection system for capillary array electrophoresis. A laser is focused as a line onto the array of capillaries at a 45° angle. The fluorescence is filtered and detected by a CCD camera through a wide-angle lens. (Reprinted with permission from K. Ueno and E. S. Yeung, Anal. Chem., 1994,66. 1424. Copyright 1994 American Chemical Society.)...

The fluorescence detection system employed is shown in Figure 29.3. Both the IR and visible light ( 3 ps, 15 cm-1) generated by the picosecond laser system were introduced into a home-made laser fluorescence microscope [29, 30]. For the measurement of both solutions and fluorescent beads, both beams were adjusted onto a co-linear path by a beam-combiner and focused into the sample by an objective... 

For methanol sensing, a simple vapor generation and fluorescence detection system was utilized. A diagram of this system is presented in Fig. 2. The generation of methanol vapor was accomplished by flowing a carrier gas, in this case dry air, through a 20 ml... 

A number of common TWA samples were analysed in the participating laboratories. The results of these analyses are given in Table 6. Good agreement in the results for the analysis of these samples was obtained in view of their nature and the different detection systems employed. These data emphasise the superior specificity of the fluorescence detection system. 

For FIPLC, advantage may be taken of the high sensitivity of fluorescent detection systems. 

Just as in the computer and Internet revolution, other successful technologies, such as capillary electrophoresis, offer proven and open solutions, deliver robust results, are cost effective and easy to implement, and yield high value. Currently, capillary electrophoresis can quantitate concentration detection limits in the range of 1 ng/mL to 1 pg/mL using on-line immunoaffinity preconcentration with UV or conventional laser-induced fluorescence detection systems (58,... 

Fig. 3. Schematic view of a beam line in a synchrotron radiation facility for x-ray absorption experiments using a wiggler as x-ray source and a fluorescence detection system. The incident radiationJlux is measured usually by a ionization chamber. The absorption is measured by the ratio of the x-ray fluorescence I detected by the photomultipliers and...

Bouchard, A., Hannes, B., Krawczyk, S., A novel concept of the integrated fluorescence detection system and its application in a lab-on-a-chip microdevice. Sens. Actuators, B 2006,118(1-2),... 

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