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Sept. 13, 2006 The Perkin Elmer LS 55 luminescence spectrometer is a very versatile instrument that allows measurement of fluorescence, phosphorescence, and chemiluminescence or bioluminescence of a liquid, solid, powder, or thin film sample. The instrument is simple to operate and is controlled by easy-to-use software. The sample is illuminated in the wavelength range of 200 to 800 nm and the emission spectra recorded from 200 to 900 nm. Excitation and emission monochromators can be independently or synchronously scanned, while the Prescan mode is ideal for method development and locating of peak excitation and emission maxima.  The Model LS 55 Series uses a pulsed Xenon lamp as a source of excitation. Fluorescence data are collected at the instant of the flash while phosphorescence data are collected in the dark period between each flash. The use of the pulsed Xenon lamp obviates the need for a mechanical means of chopping the excitation and emission beams, thus leading to improved precision and speed of analysis. The instrument software includes application programs for observing short (msec) and long (seconds) phosphorescence decay curves in addition to spectra. Measurement Modes for the LS 55
Standard Accessories The LS 55 includes a single cell sample holder that can accommodate 1 cm path length cells as well as semi-micro cuvettes. Semi-micro cuvettes are particularly useful where the sample is precious or volume is limited. They only require 0.3mL of sample but offer a 5 mm path length. Most operators will use standard inexpensive plastic cuvettes. The system also includes an automated polarizer that consists of 2 filter wheels; each wheel containing a horizontal and vertical polarizing element. Polarizer positions are software controlled and can be manually set or automatically controlled for polarization, anisotropy or G-factor. Other Accessories for the LS 55 @ MRL Front Surface Accessory for Solid Samples While some highly emitting powders may be used in standard cuvette cells, many solids need a specific measurement geometry to get sufficient signal. The Front Surface Accessory was created for this application and is useful for analyzing powders, films, papers, and other flat samples. The sample may be placed in the accessory directly or held in the powder holder that has a synthetic fused silica window. Ultra small volumes or viscous samples such as oils, opaque and turbid samples may be measured via the holder or cuvette. Remote Fiber Optic accessory The Remote Fiber Optic accessory allows the user to take the measurement at the sample rather than taking the sample to the instrument. It is ideal for remote, non-destructive testing of fluorescent papers and fabrics as well as the sampling of hazardous materials such as radioactive sources. Total Emission Accessory The Total Emission Accessory uses a plane mirror that swings into place in front of the emission monochromator grating so that the total fluorescence of the sample can be measured. This accessory is often used with long pass emission filters to restrict the wavelengths. This accessory is built into the Spectrometer and is controlled via software. Low Temperature Luminescence Accessory Samples can be measured at the temperature of liquid nitrogen by placing them in synthetic fused silican tubes which have an internal diameter of 2mm, an outer diameter of 4mm, and a length of 75mm. The tubes are cooled by conduction by placing them in contact with the end of a high-purity copper rod which itself is immersed in liquid nitrogen. The position of the tube is reporducible and the samples cool rapidly. Frosting of the cell is minimized by purging the sample compartment with a flow of dry nitrogen gas. Easily installs in the standard sample compartment for the analysis of samples at the temperature of liquid nitrogen.
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