Rapid scanning spectroscopy instrumentation

Ori ally ai lied jH edominantly as an analytical tool in the field of polymer characterization infrared spectroscopy has bem increasingly utilized in the last decades for the ducidation of the diysical structure of polymers. However, with the advent of rapid-scanning FTIR instruments and the development of the iheo-optical FTIR technique infrared spectro py has been launched into a completely new ex of polymer ph ical applications. 

FTIR spectroscopy to a particular pesticide, the methods have general applications to numerous compounds. Most of these utilize the high sensitivity of FTIR, and the data manipulation capability of the system. In several of the gas evolution studies, spectra were acquired at less than one-minute intervals. While this is not really "rapid scanning," the high resolution required for vapor phase spectra would not have been possible with a normal dispersive instrument. Several other techniques using FTIR show promise in the area of pesticide analysis. 

The last quantity to be discussed in this section is maximum path of the movable mirrors. In the slow-scan instruments, usually a lead-screw is employed to drive the mirror with the synchronous motor. And a maximum scan length of the movable mirror of 5—10 cm is achieved without any problems. In the case of rapid-scan instruments however, the customer has to pay for a larger maximum scan length. From a comparison of this quantity for various instruments in Table 3 e.g. No. 4a—d and No. 5a, b) with the prices of the instruments in Table 2, we learn that with increasing prices also the maximum mirror path is increased which determines maximum resolution of the instruments as limited by the mechanics of the interferometer. We recall from our considerations in Sections 2.3, 3.2, 4.6 and 5.1 that, in Fourier spectroscopy, the resolution width is... 

The limited availability of affordable commercial RSSF instruments has been an important factor that has prevented the widespread application of RSSF spectroscopy to the study of biological systems. However, in the past year, a significant change in the availability of commercial instrumentation hats come about. There currently are at least five manufacturers of computerized rapid-scanning detector systems. The choices in commercial instrumentation range from a mechanically scanned system with a single photomultiplier detector to photodiode array detector systems. This review includes descriptions of the currently available commercial systems. Because the authors experience in the field of RSSF spectroscopy is limited to the use of diode array detector systems and because most of the commercial instruments have appeared on the market just within the past 12 months, it has not been possible to make detailed performance evaluations and comparisons of the new commercial systems. 

A polymeric material coated onto, for example, aluminum is easily measured by an attenuated total reflectance attachment. Vibrational spectroscopy, IR, or NIR may be used for this application. A possible postproduction reaction, polymerization, or coating each may be followed by a surface probe. The reaction requires only a moderately fast instrument, such as a rapid scanning IR or NIR. Monitoring a continuous process, e.g., a lamination of two or more layers, requires a rapidly scanning device. In this case, an interferometric IR/NIR or accoustooptic device is able to scan hundreds to thousands of sample points per minute. 

An alternative technique for time-resolved infrared measurements on a rapidscanning FT-IR spectrometer that not only overcomes the limitations of stroboscopic spectroscopy described in Section 19.3 but under certain circumstances appears to have better time resolution than measurements made on a step-scan interferometer has been developed by Masutani et al. [22-25]. In this technique, the sample perturbation is not timed to coincide with the scanning and data acquisition of the spectrometer, (i.e., the two are asynchronous). The basic instrument used for asynchronous time-resolved FT-IR spectrometry is a standard rapid-scanning FT-IR spectrometer to which is added a boxcar integrator and some timing circuitry. The instrumental setup is shown in Figure 19.8. 

One of the major advantages of FTIR spectroscopy is its rapid scanning capability, which has opened new applications of IR spectroscopy. These new applications require continuous monitoring in short time intervals and extremely small differences between spectra. With currently available commercial instrumentation, inter-... 

Both instrument design and capabilities of fluorescence spectroscopy have greatly advanced over the last several decades. Advancements include solid-state excitation sources, integration of fiber optic technology, highly sensitive multichannel detectors, rapid-scan monochromators, sensitive spectral correction techniques, and improved data manipulation software (Christian et al., 1981 Lochmuller and Saavedra, 1986 Cabaniss and Shuman, 1987 Lakowicz, 2006 Hudson et al., 2(X)7). The cumulative effect of these improvements have pushed the limits and expanded the application of fluorescence techniques to numerous scientific research fields. One of the more powerful advancements is the ability to obtain in situ fluorescence measurements of natural waters (Moore, 1994). 

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