Longpass Filters
CRi offers a variety of microscope filter cubes and longpass filters to optimize the use of the Nuance Multispectral Imaging System on your fluorescent microscope or macroscope. For optimal performance using the Nuance system in fluorescence, longpass emission filters are recommended where the cut-on parameter of the emission filter is 5 – 10 nm or more after the excitation filter peak and 10-20 nm or more before the fluorophore’s emission peak. The longpass emission filter allows for further rejection of excitation wavelength light to the Nuance Imaging System and allows for all emission wavelength information to be captured by Nuance. The optimum longpass filter will cut-on just after the excitation fluorophore peak and before the emission peak. However, this is not always possible due to available filters and small Stoke shift fluorophores. Therefore, some filter cubes may have excitation or emission filters that might not be at peak absorption or emission wavelengths. Depending on the shape of the absorption and emission spectra, and on the quantum efficiency of individual fluorophores, excitation and emission filter selection may not be optimum but still effective. In general, these are the longpass filters used for common fluorescent filter cubes:
| General Cube Description | Longpass Filter CRi |
|---|---|
| DAPI Cube | 420 nm Longpass |
| Quantum Dot Cube | 475 nm Longpass |
| FITC Cube | 515 nm Longpass |
| TRITC Cube | 590 nm Longpass |
This downloadable table is a more extensive guide for which a particular longpass filter can be used with different fluorphores. These are only suggested filters and results may vary.
Since many Leica microscopes and macroscopes are equipped with filter cubes that have aligned and epoxied in-place emission filters (thus not allowing users to replace the bandpass emission filters with longpass emission filters), CRi offers a limited number of full cubes for the Leica DMI microscope family of products. These are filter cubes with bandpass excitation filters, dichroic mirrors and longpass emission filters optimized for the Nuance Multispectral Imaging System. Filters are loaded into filter cube holder to fit Leica DMI series microscopes.
Specifications: 22x29 mm dichroic mirror, 21.9 mm diameter excitation filter and 23.4 mm diameter emission filter in filter cube for Leica DMI Series.
| Description | Fluorophores |
|---|---|
| UV Excitation; 350 nm +/- 25 nm 420 nm Longpass emission filter |
DAPI, Hoecsht, Alex Fluor 350, AMCA |
| Blue/Violet Excitation; 425 nm +/- 20 nm 475 nm Longpass emission filter |
Q Dots and Q_dots with DAPI |
| Blue Excitation; 470 nm +/- 20 nm 515 nm Longpass emission filter |
FITC, Alexa Fluor 488, GFP |
| Green Excitation; 535 nm +/- 25 nm 590 nm Longpass emission filter |
TRITC, Cy3, Alexa Fluor 546, Ds Red |
| Yellow Excitation; 560 nm +/- 20 nm 610 nm Longpass emission filter |
Texas Red, Alexa Fluor 568 |
