Micro-spectrophotometry
Microspectrophotometry is the measure of the spectra of microscopic samples using different wavelengths of electromagnetic radiation (e.g. ultraviolet, visible and near infrared, etc.) It is accomplished with microspectrophotometers, cytospectrophotometers, microfluorometers, Raman microspectrophotometers, etc. A microspectrophotometer can be configured to measure transmittance, absorbance, reflectance, light polarization, fluorescence or luminescence of sample areas less than a micrometer in diameter through a modified optical microscope.
Applications
One reason microspectrophotometry is useful is that measurements are made without destroying the samples. This is important when dealing with stained/unstained histological or cytochemical biological sections, when measuring film thickness in semi-conductor integrated circuits, when matching paints and fibers (forensic science), when studying gems and coal (geology), and in paint/ink/color analysis in paint chemistry or art-work.
Variations
An advantage of the 'microscope spectrometer' is its ability to use microscope apertures to precisely control the area of sample analysis. Flat capillaries can be used for analyzing small liquid samples, up to about 10 micro-liters in volume. Quartz optics can be used for studying samples in the ultraviolet (UV) range down to wavelengths of about 200 nm. Samples that emit fluorescence or delayed fluorescence (phosphorescence) when exposed to UV light, can be quantitatively investigated using a variety of excitation and barrier filters. A variety of observations can be made on samples of interest by using different illumination sources such as halogen, xenon, deuterium and mercury illuminators. Plane polarized light can also be used for studying birefringent samples.
See also
- Fluorescence spectroscopy
- Infrared spectroscopy
- Microfluorimetry
- Raman spectroscopy#Microspectroscopy
- Spectrophotometry
- Ultraviolet-visible spectroscopy
- Ultraviolet