The only company to produce a combined CD & CPL spectrophotometer now introduces a CPL only model

OLIS: Your exclusive source for Circularly Polarized Luminescence (CPL) acquisition on a CD spectrometer. OLIS DSM 172 for CPL &CD Additional measurements include absorbance, fluorescence, and polarization of fluorescence

OLIS DSM 172 for CPL &CD

Why one instrument for both CD and CPL Why one instrument for both CD and CPL? If your only interest is CPL for OLED development and lanthides studies, CD might hold no interest. But, for protein labs, both CD and CPL are useful: “The signal of circular polarization of luminescence is sensitive to fine conformational transitions because of its susceptibility to changes in the environmental asymmetry of fluorescent chromophores in their excited electronic state… Therefore, the CPL signal is expected to reflect conformational transitions in a structural subdomain close to a fluorescent probe. The CPL spectroscopy is thus expected to be a sensitive technique for the detection of the folding-unfolding transitions in proteins.”1   Two Steps in the Transition between the native and acid states of bovine alpha-lactalbumin detected by circular polarization of luminescence: Evidence for a premolten globule state? Protein Science, 1995 Vol 4, 11 (2319-2326).

CD is the measure of the chirality of molecules in their ground state CD = abs (L) – abs (R) The measurement light is polarized The polarizer is positioned before the sample The fast response PMT is used for detection directly at the sample Snap-in positioning of the polarizer, PEM, and detector make configuration changes easy and perfect

CPL is the measure of the chirality of molecules in their excited state CPL = fluor (L) – fluor (R) The emitted light is polarized The polarizer is positioned after the sample The high sensitivity photon counting PMT is used for detection directly at the sample (fixed wavelength emission) or after the emission monochromator (scanning emission)

Components: Light Source: 150 watt xenon arc lamp CPL excitation & CD measurement wavelength selection: Premier double monochromator Sample compartment: Polarization Toolbox with positionable polarizer and PEM CD detection: Hamamatsu photomultiplier tube CPL detection: Single scanning emission monochromator and Hamamatsu photon counting detector Computerization: OLIS electronics & SpectralWorks software

Polarization Toolbox with positionable polarizers and PEM light source PEM Sample Emission Monochromator Photon Counter Polarizer

Specifications of the OLIS DSM 172 One optical bench configurable for many experiments Wavelength Ranges Absorbance = 185 to 800 nm or dual beam 185-2600 nm with secondary enhancement Excitation = 185-2600 nm Fluorescence emission = 230-870 nm or 700-1700 nm with optional NIR enhancement Polarization of fluorescence = 230-870 nm or 700-1700 nm with optional NIR enhancement Circular Dichroism = 185-800 nm, extendible to 1700 nm Circularly Polarized Luminescence = 230-870 nm

Specifications, page 2 Spectral Resolution - 0.1 nm to 20 nm Optics - Prism-grating double monochromator and single grating emission monochromator Detector - Photomultiplier tube for UV/Vis absorbance; photon counting detector for UV/Vis emission; optional InGaAs(s) for NIR Light Source - 150 W xenon arc lamp, non-ozone producing unless CD below 200 nm is required Scanning Speed - up to 40 nm/sec Wavelength Accuracy - better than 0.1 nm Dynamic Range - 0.001 to 3 AU Linearity - over at least six orders of magnitude Spectral Bandwidth - down to 0.3 nm Calibration – Factory set and permanent Lock-in amplifier – None. No decoupling or amplification of polarization signal is required

Newest Publications https://pubs.acs.org/doi/pdf/10.1021/acs.joc.8b00162 Publication Date (Web): March 26, 2018 Pyrene-Containing ortho-Oligo(phenylene)ethynylene Foldamer as Ratiometric Probe Based on Circularly Polarized Luminescence Circular Dichroism and Circularly Polarized Luminiscence Measurements CD titrations were performed in an Olis DSM 172 spectrophotometer with a xenon lamp of 150 W with a 1.0 cm path-length quartz cell. In all the cases a fixed slit-width of 1 mm and 0.2 s of integration time were selected. Titrations of compounds (P,1S,2S)-2-3 were carried out by addition of progressive quantities of a 2.5x10-4 M solution of AgBF4 salt, which was commercially available, to a 2.5x10-5 M solution of the corresponding compound in 95:5 mixture of CH2Cl2:acetone. To make the fitting of the kinetic constant easier, concentration of ligands (P,1S,2S)-2-3 was kept constant during the titration. To ensure this, 2.5x10-5 M solution of these compounds was used as solvent to prepare the AgBF4 solution. Circularly polarized luminiscence (CPL) measurements were recorded in an Olis DSM 172 spectrophotometer. The spectra were recorded at 1×10-5 M concentrations in HPLC grade solvents. A fixed wavelength LED (372 nm) as the excitation source was used.

And from the same instrument and same research group in Granada, Spain: http://pubs.rsc.org/en/content/articlelanding/2018/sc/c8sc00427g#!divAbstract published on 14 Mar 2018 Enantiopure distorted ribbon-shaped nanographene combining two-photon absorption-based upconversion and circularly polarized luminescence The strong bands in the 350–400 nm region in the CD spectrum (calculated at 397 nm and 380 nm) involve the charge transfer between the helicene and the heptagon units (see ESI, Table S5 and Fig. S30†)…We also recorded the circularly polarized luminescence (CPL) spectra of M-1 and P-1 (Fig. 5b) at 105 M in CH2Cl2, thus discarding the formation of aggregates that would lead to artifact signals due to photoselection.25 As expected, the CPL spectrum showed an emission maxima at 560 nm upon irradiation with UV light (lexc 372 nm) whose sign correlates with the lowest energy CD sign (band at 555 nm).

OLIS DSM 172 at Univ of Granada, Spain with authors of the two papers and Dr. Richard De Sa

Perhaps you noticed? In both cited papers: “A fixed wavelength LED (372 nm) as the excitation source was used [for the CPL measurement]” Circular dichroism spectroscopy demands a premier optical system for stray light rejection, photometric precision, and deep UV use. CPL does not.

Much greater excitation intensity is available from a well-selected LED than from a xenon arc lamp and double monochromator Thus, for CPL without CD, it is better to use wavelength specific and intensity appropriate LEDs as the light source. The OLIS CPL Solo is the OLIS DSM 172 with an LED source replacing the excitation hardware required for CD.

You choose. CD & CPL Or CPL Solo

You choose. OLIS DSM 172 For CD & CPL Or CPL Solo (shown with optional Automatic Titrator)

OLIS CPL Solo: small, simple, extremely affordable (pictured with optional Automatic Titrator)

Publications by Dr. Richard J. De Sa, founder of OLIS, Inc Publications by Dr. Richard J. De Sa, founder of OLIS, Inc., which describe technology used in the Polarization Toolbox and resulting spectrophotometers and fluorimeters: Device for enabling slow and direct measurement of fluorescence polarization, August 2004, US Patent: US6970241 B1 Recording polarization of fluorescence spectrometer. Unique application of piezoelectric birefringence modulation, 1974 Analytical Chemistry 46(4) See these and other publications 1969 to present on https://www.researchgate.net/profile/Richard_Desa2/publications