Simultaneous multiple sample light

MCF McFaul, C.A., Alb, A M., Drenski, M.F., and Reed, W.F., Simultaneous multiple sample light scattering detection of LCST during copolymer synthesis, Polymer, 52, 4825, 2011. 

FIGURE 13.16 Second generation ACOMP used to determine how much composition of anionic SS a copolymer with NIPAM can have and still exhibit an LCST (at lOmM ionic strength) fractional conversion of SS and total comonomers and average instantaneous SS composition (top). LS at 90° (log scale) for three detectors at different temperatures increases abruptly at the LCST when there is only about 4% SS in the copolymer (bottom). Adapted with permission from McFaul CA, Alb AM, Drenski MF, Reed WF. Simultaneous multiple sample light scattering detection of LCSTduring copolymer synthesis. Polymer 2011 52 4825 833. 

Drenski MF, Reed WF. Simultaneous multiple sample light scattering for characterization of polymer solutions. J Appl Polym Sci 2004 92 2724-2732. 

FIGURE 14.3 The decrease in light scattering intensity in time as hyaluronate is hydrolyzed by hyaluronidase. Results are shown for various concentrations of hyaluronate. Reprinted with permission from Drenski MF, Reed WF. Simultaneous multiple sample light scattering for characterization of polymer solutions. J Appl Polym Sci 2004 92 2724-2732. 

Over the past decade, there has been considerable development in imaging type detectors for the measurement of ultraviolet (UV) and visible light. These new detectors have attracted the interest of a number of analytical spectroscopists. For absorption spectroscopy, analytical chemists have traditionally used such instruments as the photometer, which uses a narrow-band light source (for example the 254 nm emission line from a low pressure Hg lamp or a continuous source with a filter), a sample cell and a photomultiplier tube (FMT) as the detector. While useful for many specific applications, the single-wavelength photometer cannot determine multiple sample components simultaneously or provide a general absorbance characterization of the system. When information at multiple wavelengths is desired,... 

Reed WF, Device and method of simultaneously measuring the light scattering from multiple hquid samples containing polymers and/or coUoids. US Patent 6,618,144. 2003. 

The above-mentioned method is effective in identifying the molecules of detected ions. However, because PVDF film is not permeable to light, it is difficult to observe tissue sections. To resolve this problem, we developed a method to fix tissue sections on transparent film, and then performed MS on those sections.6 We used a conductive film because we expected the ionization efficiency would increase when the electric charge accumulation on the sample was reduced. The film used for this purpose was a polyethylene terephthalate (PET) film with a thickness of 75-125 pm, having a 5 15-nm-thick layer of evaporated oxidation indium tin (ITO) upon it (ITO film). This film is used in touch-panel displays because of its high transparency and superior conductivity. We used it to perform MS/MS for tissue sections and succeeded in identifying multiple proteins from mass spectra.6 Therefore, the further development of this method will enable the application of the mass-microscopic method to observe tissue by optical microscope and to perform tandem mass spectrometry (MSn) at the observation part, simultaneously, enabling the identification of molecules included the part. 

Analogous to the principal concept of multiplex CARS microspectroscopy (cf. Sect. 6.3.5), in multiplex SRS detection a pair of a broad-bandwidth pulse, eg., white-light femtosecond pulse, and a narrow-bandwidth picosecond pulse that determine the spectral width of the SRS spectrum and its inherent spectral resolution, respectively, is used to simultaneously excite multiple Raman resonances in the sample. Due to SRS, modulations appear in the spectrum of the transmitted broad-bandwidth pulse, which are read out using a photodiode array detector. Unlike SRS imaging, it is difficult to integrate phase-sensitive lock-in detection with a multiplex detector in order to directly retrieve the Raman spectrum from these modulations. Instead, two consecutive spectra, i.e., one with the narrow-bandwidth picosecond beam present and one with that beam blocked, are recorded. Their ratio allows the computation of the linear Raman spectrum that can readily be interpreted in a quantitative manner [49]. Unlike the spectral analysis of a multiplex CARS spectrum, no retrieval of hidden phase information is required to obtain the spontaneous Raman response in multiplex SRS microspectroscopy. 

The cuvette rotor receives the reagent preparations of the samples, rotates the cuvettes for light measurements and places them under the washing station. The rotor is furnished with 45 semi-micro cuvettes —the odd number allows for simultaneous filling, measurement and aspiration. Only every second cuvette is filled. Every 8 s, each cuvette returns to its initial position after two turns. The minimum analysis time is therefore 6 min or a multiple of this. 

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