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Did You Know That?

Featuring tips, tools, explanations, and information about things that are not quite microscopes, but might be of use to our users. Is there something you would like to see here? Contact us and let us know.

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That many of our core facility instruments are equipped for spectroscopy? 

Spectroscopy can provide additional scientific information about a sample that may not be apparent from more routine imaging.

Spectral confocal microscopes can be used to determine the emission spectrum of fluorophores. If two fluorophores with previously measured spectra are in one sample and their emission spectra overlap, the overlapped spectra can be measured and then "unmixed" to determine the location of the individual fluorophores. (Instruments: Zeiss LSM880 inverted, Zeiss LSM 880 upright multiphoton) In addition, the computer-controlled multiphoton laser on the Zeiss LSM 880 upright multiphoton can be scanned through a range of excitation wavelengths and the emission spectra measured.

Raman spectroscopy uses the inelastic scattering of monochromatic light to determine a molecular fingerprint in a sample. (Instruments: Renishaw Reflex, Hitachi S-3400N with Renishaw attachment)

Energy dispersive X-ray microanalysis looks at the spectra of characteristic X-rays that are given off when an electron beam interacts with a sample. This type of elemental analysis requires an electron microscope. Small atomic number elements can be difficult to detect and this is somewhat dependent on the type of detector being used, the element of interest, and how abundant the element is in the sample. (Instruments: Hitachi S-3400N, Hitachi S-4800, FEI Helios Dualbeam, Hitachi HF5000, FEI Inspec-S, Hitachi 3400N, JEOL 6010LA). Please note that the FEI Inspec-S is the only one of these instruments that can be used for biological samples.

Wavelength dispersive spectroscopy has better spectral resolution and sensitivity than energy dispersive X-ray microanalysis, but it can be slower to perform. There is considerable expertise with this technique in LPL's Michael J. Drake Electron Microprobe Laboratory (two SEMs with multiple WDS detectors). These instruments are for materials only, no biological samples.

Electron energy loss spectroscopy looks at energy loss in electrons that are in-elastically scattered. (Instrument: Hitachi HF5000).