Emission spectrum & λem
Wavelength and intensity of the emitted light.
Useful forDyes, quantum dots, phosphorsSpectroscopy
Fluorescence Spectroscopy
Excitation and emission spectra of fluorescent samples
Fluorescence spectroscopy measures the light a sample emits after absorbing light at a chosen wavelength. It is highly sensitive and suits dyes, quantum dots, proteins and other luminescent materials.
1 test optionExcitation & emission spectraRange typically ~200–850 nmTypical turnaround 3–5 working days
Fluorescence Spectroscopy measurement principleIllustrative
01 / Overview
What is Fluorescence Spectroscopy?
A spectrofluorometer excites the sample with light of one wavelength, selected from a xenon lamp by a monochromator. The emitted light is collected at 90° to the beam, passed through a second monochromator and recorded as an emission spectrum; scanning the excitation side instead gives an excitation spectrum.
Because emission is measured against a dark background rather than as a small drop in transmitted light, fluorescence is often far more sensitive than UV–Vis absorbance. It also shows emission maxima, Stokes shifts and quenching, which absorbance alone cannot.
02 / How it works
How it works
- 01
Sample is placed
A dilute solution goes into a quartz cuvette; solids and films sit in a front-face holder.
- 02
Light excites the sample
A monochromator selects one excitation wavelength from the lamp and directs it into the sample.
- 03
Sample emits light
Excited molecules relax and emit light at longer wavelengths, collected at 90° to the beam.
- 04
Spectrum is recorded
The emission monochromator scans wavelengths and the detector records intensity at each one.
03 / What it measures
What it measures
Excitation spectrum
Which wavelengths excite the emission most efficiently.
Useful forChoosing excitation, identifying emittersStokes shift
Gap between the excitation and emission maxima.
Useful forProbe, label and sensor designQuenching & binding
Changes in intensity as a quencher or binding partner is added.
Useful forSensing, protein–ligand studiesRelative quantum yield
Emission efficiency against a reference dye, on request.
Useful forNew fluorophores and nanomaterials04 / Test options
Choose the Fluorescence Spectroscopy options you need
1 option · none added yet
05 / Sample requirements
Sample requirements
- Accepted forms
- Solutions, dispersions, films on quartz or glass, powders
- Liquids
- About 3–5 mL, plus 5–10 mL of the pure solvent for the blank
- Concentration
- Dilute; absorbance ideally below ~0.1 at the excitation wavelength
- Solids
- Around 100–200 mg powder, or films about 10 × 10 to 25 × 25 mm
- Wavelengths
- Give the excitation wavelength, or the absorption peak if known
- Dissolve in a clean, non-fluorescent solvent
- Send the pure solvent separately for the blank
- Mention the absorption maximum or expected emission range
- No turbid or strongly coloured solutions; dilute them first
- No light-sensitive samples left unwrapped; use amber vials or foil
Hazardous or air-sensitive samples: mention it in your request, and attach the MSDS if you have one.
06 / Results & turnaround
Results & turnaround
What you receive
- Emission and/or excitation spectra
- Peak wavelengths (λex, λem)
- Relative intensities under stated settings
- Raw data files
- Report PDF
Turnaround & pricing
Typically 3–5 working days after samples reach the lab.
Price confirmed in your quotation, depending on user type, options and number of samples.
07 / Limitations
When Fluorescence Spectroscopy isn't the right fit
Non-fluorescent samples or absorbance checks
Identifying an unknown compound
Crystal structure of solid phosphors
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