Circular Dichroism Spectrophotometers
Whether you are doing protein denaturation studies 260-190 nm or MCD 1100-2700 nm, you
want the right answer. And you want it quickly, easily, perfectly.
Design advances by OLIS make these instruments as easy to use correctly as a UV/Vis
spectrometer. After all: CD is abs(L) minus abs(R).
These advances simplify all instrument settings and eliminate all potential for incorrect answers.
Non-OLIS CDs
calculate the answer as
decoupled AC and DC intensities,
times a calibration constant k,
Should you care? Yes! if you want to eliminate as many routes to problems as possible. Yes! If you want the peace of mind that comes from knowing that the answer can only be correct. Yes! If you want best results with least waste.
Did you notice another attribute of the OLIS CDs? They utilize all of the light, collecting and averaging two CD scans simultaneously.
All OLIS DSM CDs
collect the answer as
CD = abs(L) - abs(R)
There are five OLIS CDs, three for dual beam CD and two for single beam CD plus single beam CPL.
OLIS DSM 20 CD UV/Vis
Perfect for most CD labs, 170-700 nm
Commonly equipped with Peltier thermal control
Smallest CD on market
Exclusive OLIS Hummingbird monochromator
OLIS DSM 1000 CD UV/Vis
Highest sensitivity DSM CD
167-540 nm
Exclusive OLIS RSM 1000 monochromator
Optional millisecond spectral scanning during ABS (not CD)
DSM 17 CD UV/Vis/NIR
Full scanning range of 185-1700 nm, optionally extended to 2600 nm
Useful for nearly all CD studies, including MCD
Prism-grating CARY monochromator with
all the outstandingperformance characteristics of the original classic.
OLIS DSM 172 UV/Vis/NIR
CD and absorbance 185-1700 nm;
extendible to 2600 nmCPL, fluorescence, and anisotropy, 230-870 nm
Polarization Toolbox sample compartment
for tool-free positioning of polarizers and PEMLED source provided for select CPL excitation
Prism-grating CARY monochromator with all the outstanding performance characteristics of the original classic
OLIS DSM 245
CD and absorbance 170-700 nm;
CPL, fluorescence and anisotropy 230 - 870 nm
Physically small with two OLIS monochromators, including the subtractive double grating OLIS Hummingbird
Polarization Toolbox sample compartment
for tool-free positioning of polarizers and PEM
LED source provided for select CPL excitation
Phosphorescence Lifetime PLT3
Direct alternative to time correlated single photon counting
Fast & flexible...collect a decay curve up to 4,000 times per second
You can purchase this as a free-standing system or purchase the hardware/ software for seamless integration of phosphorescence lifetime into a OLIS spectrophotometer, where the sample compartment and computerization come from the host instrument.
Practical Considerations when comparing “170 nm” (OLIS) with “163 nm” (APP and Jasco):
Our competition in the UK, Applied Photophysics, has produced a nice document reminding everyone that “170 nm is the lower wavelength limit for benchtop CD instruments, and is only achievable with experimental conditions that are not really feasible for every-day work.” The document ends with “As with other technical specifications, comparisons of different instruments against each other should be based on sensible, applicable requirements rather than numbers that lack relation to real-life situations. Unfortunately, a technical specification sheet is not designed to include comprehensive and intricate considerations such as those above. Fortunately though, there are avid users such as yourself who take the time to learn and understand them!” Read the full document here:
Resources
Linearity of the OLIS DSM CDs
Numerous advantages come from the direct subtractive method (DSM) which was pioneered by Dr. Richard J. DeSa in the 1990s and made possible by the brilliant software developed by Denghui Cheng, including perfect linearity as far as you will ever need.
