Conventional wide-field microscopy

Confocal Laser Scanning Microscopy (CLSM). Prior to the invention of confo-cal microscopy, conventional wide-field microscopy has a fundamental limitation for providing three-dimensional imaging due to blurring of the image caused by... 

Usually, in conventional wide-field microscopy the images from the focal plane and out-of-focus parts of the sample are superimposed. This problem can be overcome in different ways ... 

Conventionally, wide-field Raman microprobes are applied for such mappings, but, recently, confocal microscope systems have also been used (Bridges et al., 2004 Puppels et al., 1990, 1991 Schliicker et al., 2003). Confocal microscopy originated from biological applications with the goal of analysis of the insides of cells without destruction of the cell membrane. Confocal microscopy selectively rejects any information from planes closer or further from the focal plane. Confocal microscopy is a... 

A nondestructive method may be applied to a sample with relatively simple composition, but for a more complex sample, digestion processes are recommended, which are destructive. Beam analysis is recommended as a nondestructive method for samples with simple composition. The reliability of the analytical information for the beam analysis technique is assured by reproducibility and homogeneity of surfaces. It is necessary to clean the surfaces before the analytical process. Also, there are mechanical steps used for sample preparation to assure surface homogeneity. Conventional scanning election microscopy (SEM) is widely used as an analytical tool.38 4(1 Variable pressure scanning electron microscopy (VP-SEM) opens new opportunities in the field of materials science. Samples such as liquids can be analyzed using the VP-SEM technique without any prior preparation method (e.g., the characterization of two-phase crude petroleum from the... 

At the moment, LEDs are constantly being improved in terms of efficiency, output power, and available wavelength. If developments continue, it could very well be that, in time, LEDs are the hght source of choice, not only for wide-field FLIM, but also for conventional steady-state wide-field fluorescence microscopy. 

There arc various techniques for recording luminescence microscopy images and for improving the contrast and/or the resolution. Their description is out of the scope of this chapter. It is howevCT worth mentioning confocal microscopy. In this technique, conventional illumination in which the observed object is completely and evaily irradiated by a light source (wide field illumination) is replaced by point laser illumination. A scanning unit is inserted... 

Identifying pharmaceuticals, whether APIs or excipients used to manufacture products, and the end products themselves is among the routine tests needed to control pharmaceutical manufacturing processes. Pharmacopoeias have compiled a wide range of analytical methods for the identification of pharmaceutical APIs and usually several tests for a product are recommended. The process can be labor-intensive and time-consuming with these conventional methods. This has raised the need for alternative, faster methods also ensuring reliable identification. Of the four spectroscopic techniques reviewed in this book, IR and Raman spectroscopy are suitable for the unequivocal identification of pharmaceuticals as their spectra are compound-specific no two compounds other than pairs of enantiomers or oligomers possess the same IR spectrum. However, IR spectrometry is confronted with some practical constraints such as the need to pretreat the sample. The introduction of substantial instrumental improvements and the spread of attenuated total reflectance (ATR) and IR microscopy techniques have considerably expanded the scope of IR spectroscopy in the pharmaceutical field. Raman spectroscopy,... 

A recent introduction of scanning electrochemical microscopy (SECM) to this field [16-23] has revitalized the study of ET at the OAV interface. In contrast to the conventional, four-electrode cyclic voltammetry at externally polarized OAV interfaces, the SECM measurements not necessarily require supporting electrolytes, and thus can be carried out over a wide range of driving forces without the limitation of the potential window. This advantage of SECM allowed for an experimental verification of the Marcus theory in the driving-force dependence of the ET rate constant [18,21]. 

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