UV-Vis spectrophotometer for polymer characterization

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How a molecule absorbs and emits light provides an unequivocal signature of that molecule. This observation led to the design of instruments such as spectrophotometers and time-resolved fluorometers to characterizehow molecules absorb and emit light, respectively. Light can be characterized in terms of its wavelength, the blue, green, and red colours corresponding to wavelengths of 475 nm, 510 nm, and 650 nm, respectively. The ability of a given instrument at characterizing a molecule with light is characterized by its "spectral bandwidth" or wavelength resolution. The smaller the spectral bandwidth and the more accurate is the characterization of the molecule. My laboratory is currently equipped with a 20 year-old spectrophotometer which was generouslydonated by my department 10 years ago. The spectral bandwidth of the spectrophotometer equals 2 nm. In the "old days", the typical light source of a time-resolved fluorometer was a hydrogen lamp. The hydrogen lampsemitted weakly so that the spectral bandwidth of the fluorometer needed to be broadened, sometimes up to 16 nm in order to obtain sufficient light into the fluorometer. The advent of relatively cheap, powerful laser sources for time-resolved fluorometers enables fluorescence measurements to be done with a spectral bandwidth of 1 nm, smaller than that afforded by our 20 year-old spectrophotometer. Consequently our ability to characterize molecules by the light they emit with the fluorometer is now better than that of our spectrophotometer. This situation is unfortunate because modern spectrophotometers can easily achieve a spectral bandwidth as good as, and even much better than 1 nm. It is for this reason that we request funds to purchase a newer, better spectrophotometer whose capabilities will be on a par with our newly upgradedtime-resolved fluorometer.