Uniqueness of the RSM 1000

Based on the unique technology and patented DeSa subtractive double grating monochromator, an Olis RSM 1000 spectrophotometer is capable of remarkable and routine performance.

  1. The RSM 1000 spectrophotometer uses a double grating monochromator with a scan rate of 1,000 scans/second. In nanometers per second, that comes to 75,000 to 500,000 nm, depending upon component selection (normally, resolution is 0.2 to 10 nm, the range of 0.1 to 20 nm is also available). In nanometers per minute, the scan rate come to more than 107nanometers! The millisecond scan rate is perfect for stopped-flow speed studies.
  2. For laser/flash studies, one uses the Olis RSM 1000 with the fixed slit cartridge rather than the ScanDisk cartridge, to achieve data acquisition speeds of 2 MHz. Or, with an optional enhancement, choose to collect up to 20,000 points per millisecond!
  3. Detection is achieved with pairs of photomultiplier tubes, UV or red optimized, or InGaAs detectors, depending on wavelength range needed. Detectors are easily accessed and exchangeable for optimization for response time, gain settings, and spectral ranges. The standard detectors support submicrosecond detection rates, fully computerized gain settings, and spectral utility from 190-800 nm. Other detectors are used to extend into the deep UV, down to 167 nm, and into the NIR, up to 2600 nm. For NIR rapid-scanning applications from 900-2600 nm, InGaAs detectors are used; for 700-2600 nm, PbS are available.
  4. Gratings are a matched pair of 50 mm2 holographically blazed gratings. The number of lines per millimeter and the blaze wavelength are chosen for the experimental case at hand. Gratings are easily accessed and exchanged between measurements for optimization within the UV, Visible, and NIR spectral ranges. As of 2005, the available entire range available for millisecond spectral scanning is 190-2500 nm; in conventional scanning applications, the UV can be extended to 167 nm and the NIR to 2600 nm. 
  5. During both conventional speed scanning and millisecond spectral scanning, “dark” readings are made between every scan, such that correct readings can be made even on samples with fortuitous fluorescence induced by the (absorbance) measuring beam.
  6. The spectrophotometer’s sample compartment supports use of water jacketed cuvettes, Peltier cells, cryogenic flasks, magnets, stopped-flow mixing system, and/or other sample holders either directly or with available customization.
  7. The double grating monochromator is a “subtractive,” which differs from the more common “additive” in producing a homogeneous output beam, particularly desirable when non-homogeneous samples such as solids, crystals, films, powders, and other heterogeneous samples are studied.
  8. As a pre-dispersive monochromator system, the spectrophotometer does not cause photolysis on even photolabile samples such as vitamins or visual pigments, since the sample sees only rapidly varying monochromatic light during the measurement. And, the measuring beam can be blocked from reaching the sample between measurements with a manual or computerized shutter.
  9. No optical components move during rapid-scanning. All rapid-scanning is achieved by a moving aperture in the midplane of the double monochromator. Thus, during millisecond spectral scanning, the only moving component in the instrument is a thin metal disk with 16 radially dispersed slits (apertures) being spun by a synchronous motor at 62.5 Hz.
  10. The spectrophotometer is used in conventional speed scanning after the replacement of the moving intermediate slit wheel (“ScanDisk”) with a fixed intermediate slit cartridge. Now, the two gratings, under computer control, move in lock-step for conventional slow scanning.
  11. The spectrophotometer is fitted with a 75 watt xenon arc lamp when configured for absorbance spectroscopy. The identical lamp housing supports use of ozone producing and non-ozone producing 150 watt xenon arc lamps, which are preferred for excitation sources and for deep UV CD work. These light sources are easily accessible for quick and fail-safe exchanges.
  12. All components are mounted for precise positioning and perfect alignment on custom optical plates, rendering the components easily accessible and removable to support the modularity needed to realize luminescence, fluorescence emission and excitation, anisotropy, polarization of fluorescence, circular and linear dichroism, optical rotary dispersion, and variations on a theme, all on one optical bench.
  13. An optional computer-controlled shutter for protection of photolabile samples between measurements can also be opened and closed quickly, effectively producing an “actinic flash” from an otherwise steady-state measuring beam.
  14. All electronics to control the optical bench and accessories are external to the spectrophotometer, rendering diagnosis and repair as simple and economical as possible. Only the free-standing box needs be returned to Olis, if the repair must be done by Olis personnel; otherwise, the box can be opened by laboratory personnel under Olis direction to access and repair/ replace any faulty power supply, amplifier, or circuitry.
  15. All software for collecting and analyzing data as a function of wavelength, time, temperature, concentration, and other processes is provided as part of the comprehensive Olis SpectralWorks software package.
  16. The software supports signal averaging capabilities for effectively ‘slowing’ acquisition during rapid-scanning (fixed at 1000, 62, 31, 15, 10, 5, 2, or 1 scan per second) and during fixed wavelength (arbitrary from 0.5 microseconds per datum).
  17. The 3D data analysis software includes the “Simplex Method,” a linear fitting procedure which is applicable to linear and non-linear problems using linear optimization of the parameters until some convergence criterion is met. (The Simplex Method differs from the widely known and widely used Levenberg-Marquardt and Gauss-Newton methods in that it does not use derivatives of the function with respect to the parameters, and thus, is much less prone to find false minima.) In addition, the software includes the exact “Matrix Exponential Solution” method in kinetic analysis, which is markedly more precise than numerical integration methods and which does not have Runga-Kutta’s stiffness.
  18. The software includes data compression algorithms which reduce the size of the raw data files by 40 fold while losing none of the information in the data files.
  19. The software includes Singular Value Decomposition (“SVD”) to calculate the number of components which caused the data and to reduce random noise by three-fold.
  20. The software supports a dynamic, interactive 3D display of the data for graphical interpretation of the kinetic process.
  21. The software supports extraction of kinetics from any wavelength.
  22. The software supports ASCII file creation of any selected scans or kinetic traces; large 3D file storage is binary.
  23. The controlling computer is a Pentium-4, 2.4 GHz processor or faster.
  24. The software is Windows 2000/XP compatible with fast, modern, menu-driven features to support all instrument control, data analysis, data presentation, and data storage and handling.
  25. The stopped-flow provides anaerobic performance with gas purging (for oxygen binding) available in three positions.
  26. The stopped-flow has ceramic valve blocks for durability against all corrosive solutions, temperature ranges, and gas exchange. The novel development is unique to Olis and has significant consequences for the robustness and longevity of the flow system, rendering it imperious to abuse which renders other stopped-flows useless.
  27. The stopped-flow has a deadtime of approximately one or two milliseconds, adjustable to longer times.
  28. The stopped-flow is fitted with five sensors to provide 100% security against misfiring, premixing, and damage to the hardware and operator. Feedback from these sensors will come from both the trigger box (LED display) and/or Olis control software. This novel advance is unique to Olis and has significant consequences for the security of the hardware and the operator.
  29. The stopped-flow uses syringes from 0.5 to 5 mL, matched or mixed, so that 1:1 up to 1:11 mixing can be achieved (unit will be delivered with one pair of 2.5 mL syringe unless prior arrangements are made).
  30. The stopped-flow is useable over a temperature range of 10°C to 100°C, extendible with additional hardware to -30°C.
  31. The stopped-flow is pneumatically driven for reliable performance, even when solutions of different viscosities are used.
  32. The stopped-flow is useable with an optional Auxiliary Mixer for preparation of an unstable A + B mixture that will subsequently be one of the reagents used during stopped-flow.
  33. The stopped-flow mixing apparatus remove easily from the Olis RSM 1000, so that the Olis RSM 1000 can be used as a research grade scanning absorbance, fluorescence, or circular dichroism spectrophotometer when stopped-flow mixing is not required.
  34. The Olis method of “Digital Subtractive Method” (“DSM”) is for the direct acquisition of absolute CD results. “DSM” detection is exclusive to OLIS and is the means to directly collect (not calculate) circular dichroism (“CD”).
  35. The DSM CD spectrophotometer requires no calibration, since CD data are acquired by definition (CD = abs(L) -abs(R)), instead of as a ratio of decoupled AC and DC intensities multiplied by a calibration constant.
  36. Use of the CD spectrophotometer does not presume any prior knowledge about the sample by the operator, as there are no amplitude, sensitivity, or time constant settings to make prior to scanning the sample.
  37. The resulting CD spectrophotometer supports variable data collection rates such that each datum is acquired over the exact length of time necessary to reach a user specified noise level. Using this optional variable data collection rate feature ensures that the best data are obtained in the least amount of time, saving time, nitrogen, and the need for repetitive scanning.
  38. The resulting CD spectrophotometer provides useful light to 167 nm, with scanning to 450 nm standard and scanning extendible to 800, 1100, 1700, or 2600 nm without optical realignment or use of tools.
  39. The CD spectrophotometer uses a dual beam phase coherent detection system, in which 100% of the light from the lamp is used, providing 100% more light for the measurement than a single beam, “modulation method” CD spectrometer.
  40. The CD spectrophotometer supports read rates of 1000 readings per second in dual (or single) beam mode. Scan rates up to 200 nm/minute are supported in both dual (or single) absorbance and dual (or single) CD.
  41. The CD spectrophotometer supports the option of rapid-scanning to rates of 62 CD scans per second.
  42. The CD spectrophotometer is a dual beam, double monochromator based instrument which is fully usable as a research grade dual beam absorbance spectrophotometer.
  43. The CD spectrophotometer supports the simultaneous detection of CD/2 with absorbance from 1 cm² and microvolume cells, as well as option of single beam fluorescence emission (photon counting) concurrent with CD and CD/2 detection.
  44. The CD spectrophotometer sample compartment includes up to three jacketed cuvette holders, one for cylindrical and rectangular dual beam CD cuvette use and two for 1 cm² and microvolume single beam CD and dual beam absorbance cuvette use. Alternatively, and at higher cost, the CD spectrophotometer sample compartment can be fitted with a single thermoelectric heating/ cooling Peltier cells for electronic temperature ramping.
  45. The CD spectrophotometer is installed with software for collecting and analyzing data as a function of wavelength, time, concentration, and/or temperature (3D global analysis, as well as 2D fits). This software uses the modern and correct methods of SVD, Downhill Simplex, and Matrix Exponentiation for fitting of changing (‘kinetic’) and non-changing (“equilibrium”) samples.
  46. All tools for realizing the modularity are provided at installation.

There is no other spectrophotometer manufactured in any country, by any company, with all these unique and non-unique attributes. The easily implemented modularity allows one optical bench to be used among a large group with many needs, easily replacing the need for two, three, four, even five lesser spectrophotometers.