Perkin-Elmer LS 55 Luminescence Spectrometer -- This luminescence spectrometer is a very versatile instrument that allows measurement of fluorescence, phosphorescence, and chemi- or bio-luminescence. Brief details on its operation and on software with various applications are given. The following are specifications for the LS 55.
Sample Detector: Gated photomultiplier with modified S5 response for operation to about 650 nm. Red-sensitivity R928 photomultiplier is not installed at NMSU but will operate up to 900 nm.
Reference detector: Photodiode for operations up to around 900 nm.
Monochromators: The separate Monk-Gillieson excitation (An optical arrangement utilizing a plane grating in a converging or diverging light beams. a wide slit is used. It obtains better dispersion than prisms and produces more uniform linear dispersion and with a stigmatic spectrum, with smaller aberrations such as coma, and the extremely small variations in magnification were of no consequence for fluorescence applications.) covers the wavelength range 200–800 nm with zero order selectable. Emissions from 200-650 nm with the standard photomultipher or with the R928 photomultiplier from 200-900 nm
Wavelength accuracy of ± 1.0 nm and reproducibility of ± 0.5 nm. Both monochromators have slit widths that can be varied over the range 2.5–20 nm in 0.1 nm increments.
Synchrounous scanning is available with constant wavelength or constant energy differences. Scanning speed: Scanning speed can be selected in increments of 1 nm for 10-1500 nm/minute. Time dependent data can also be selected.
Spectral bandpass: The excitation slits (2.5-15.0 nm) and emission slits (2.5-20.0 nm) can be varied and selected in 0.1 nm increments.
Phosphorescence mode: Delay and gate times can be varied to measure phosphorescence. Minimum total period 13.0 ms (50 Hz).
Emision filters: Computer selectable cut-off (high-pass) filters at 290, 350, 390, 430, and 515 nm, a blank (to act as a shutter), a 1%T attenuator, and clear beam position.
All excitation spectra are corrected using an internal Rhodamine cell. Instrument control and data acquisition is performed by the FL WinLab software loaded on the adjacent computers.
Sensitivity: Signal to noise is 500:1 RMS, using the Raman band of water with excitation at 350 nm, excitation and emission bandpass 10 nm.
Cell Holder: A single position standard cell holder for 10-mm pathlength fluorescence cells, having windows on all four sides. Do not use cells with two sides made of frosted glass. Cells are expensive: handle with care!
An interchangeable well-plate accessory allows the user to measure samples in 6-96 well-plates, cuvettes, TLC plates, electrophoresis gels, or any other flat sample type The photo at the right show the instrument with a plate reader. The LS 55 spectrometer includes a host of automated accessories and software for a range of bio- research applications. These applications are currently not available at NMSU.
* Developed for a wide range of bioanalytical applications * Holographic gratings for reduced stray light * Versatility, reliability and ease-of-use * Large sample compartment * Easy-to-use FL WinLab software * Includes automated polarizers
Optical performance -- The monochromator based LS 55 uses a high energy pulsed Xenon source for excitation. The pulsed Xenon sources minimizes photo bleaching of samples and provide a long-lived excitation source. The variable slit and holographic gratings provide flexibility with very low stray radiation. A holographic gratings on both the excitation and emission monochromators further reduces stray light and improve the systems performance. A reference signal system has been added to provide control over signal dynamics. This is particularly useful for samples with widely differing intra-sample signal size. For example, the LS 55 signal system has reduced noise by a factor of about 5 for intracellular ion analyses, and increased data transfer rates by a factor of 10.
Software controls the entire analyses -- The FL WinLab™ software is designed for all laboratories. Specific modes of instrument operation such as Scan, Time Drive, and Ratio Data Collection can be easily accessed from the Applications Menu. 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. FL WinLab includes a validation protocol that automatically checks the instrument performance to ensure that it is operating within specification. With its unique set of accessories and software applications, the LS 55 offers powerful and flexible system for data collection and analysis. The Expert mode in FL WinLab 4.0 allows control of all the instrument parameters. The Graphical User Interface uses point and click to change any of the instrument operation parameters. The creation of methods for any applications has never been easier! And these methods can be saved and used in GLP mode for routine analysis.
# 420 to 600 nm (ovalene)
# 300 to 400 nm (p-terphenyl)
# 400 to 600 nm (tetraphenyl/butadiene)
# 600 to 640 nm (Compound 610 --European)
# 540 to 640 nm (Rhodamine B)
A 10-mm cell with high-purity water is used for checking instrument sensitivity. It provides a constant sample to reproducibly measure signal-to-noise using the Raman band of water.
