High-sensitivity, bench-friendly spectrofluorometer at an accessible price
Measure absorption, transmission, fluorescence emission and fluorescence excitation
Overview | How Does a Spectrofluorometer Work | Specifications | Spectrofluorometer vs. Spectrophotometer
Measurements | Understanding the Components | Gallery | Resources and Support
Spectrofluorometers are essential measurement instruments that can take fluorescence (or photoluminescence), absorbance, and transmission measurements. They can do this with a high level of accuracy and repeatability by selecting wavelengths with nanometer resolution using either a dual-monochromator set-up, or a single monochromator with a dedicated single-wavelength UV light source. The ability to select both the excitation and detection wavelength gives spectrofluorometers their flexibility, allowing them to accurately conduct a range of spectroscopy measurements.
The Ossila Spectrofluorometer is a complete fluorescence spectroscopy system that includes:
- A hyperspectral 380nm – 1000nm white LED
- A high-power 365nm UV light source
- 2 silicon photomultiplier detectors
- 2 ultra-fast monochromators
- A sample chamber with integrated filter holders
- Sample holders for both solutions and thin films
How Does a Spectrofluorometer Work?
The Ossila spectrofluorometer works by combining different spectrophotometry components in various orientations to enable different measurements.
For fluorescence measurements, a single wavelength light source is directed towards the sample to excite any fluorophores. This can use the UV light source or combine the broadband light source and excitation monochromator to create a variable light source. Which source is best depends on the measurement you are taking. Any emitted light from the sample enters the detection monochromator. This monochromator either selects a specific emission wavelength, or scans through various wavelengths before intensity is measured by the detector.
For absorbance measurements, the broadband light source travels through the excitation monochromator, which again selects a specific wavelength or scans through a wavelength range. This monochromatic light is directed straight through the sample, where transmission is measured by a separate detector
Ossila Spectrofluorometer Specifications
| Spectral Range (Broadband) | 380 – 1000 nm |
|---|---|
| Wavelength Accuracy | <1 nm (in calibrated range) |
| Wavelength Repeatability | <0.1 nm |
| UV Source Wavelength | 365±15 nm |
| Spectral Resolution | Slit width dependent |
| Slit Type | Manual – micrometer driven with 10 μm resolution |
| Slit Size | 50 μm – 6 mm (W) x 10 mm (H) |
| Maximum Sample Size | 75 (W) x 50 (H) x 5 (D) mm |
| Cuvette Size | 10 x 10 mm; maximum height 52 mm |
| Dimensions | 280 x 260 x 100 mm |
| Weight | 4.2 kg |
Spectrofluorometers vs. Spectrophotometers
As with most measurement equipment, choosing the right spectroscopy system for you comes down to your experimental needs, lab space and budget. Simple spectrometers can be incorporated into modular optical systems, and are a cost-effective way to take simple optical spectroscopy measurements. However, they lack the resolution and accuracy of most spectrofluorometers.
Spectrofluorometers are versatile pieces of equipment. They are more costly than modular spectrometers but provide higher resolution, accuracy and consistency in all measurements.
Reliable and calibrated optical measurementsNon-invasive molecular probingAll-in-one systemWide range of measurementsNo complex optical alignmentMeasure live dynamic reactions
Spectrofluorometers are similar to spectrophotometers, and often the terms are used interchangeably. They use the same components, and they build a spectrum in the same way. However, there are a few key differences between spectrofluorometers and spectrophotometers.
| Spectrofluorometers | Spectrophotometers | |
|---|---|---|
| Number of Monochromators | 2 | 1 |
| Number of Detectors | 2 | 1 |
| Broadband Light Source |  |
|
| UV Light Source | |
 |
| Suitable for Absorbance Measurements? | |
|
| Suitable for Fluorescence Measurements? |
(Both emission and excitation spectra) |
|
Spectrofluorometer Measurements
A major benefit of a spectrofluorometer is that you can take different types of measurements with one instrument. The main measurements they are used for are:
- Fluorescence spectroscopy
- Emission spectra: Spectrofluorometers can measure the emission spectrum of a fluorophore, where the excitation wavelength is fixed and the emission wavelength is varied. These measurements tell you about the light a fluorophore emits.
- Excitation spectra: Where the measured emission wavelength remains the same (ideally where emission is strongest) but the excitation wavelength is varied. These measurements will tell you which wavelengths of light stimulate the most fluorescence.
- Absorbance spectroscopy
- Spectrofluorometers can also measure absorbance, much like a spectrophotometer. Measuring absorbance with a spectrophotometer takes longer than with a USB spectrometer but will have higher sensitivity and resolution as you can measure transmission intensity 1 nm at a time.
Which Setup for Which Measurements?
To efficiently use a spectrofluorometer, ensure that you are using the correct combination of spectrofluorometer components.
| Excitation Fluorescence Measurements | Emission Fluorescence Measurements | Absorbance/Transmission Measurements | |
|---|---|---|---|
| Light Source Required | Broadband light source | Single wavelength light source | Broadband light source |
|
Number of Monochromators |
Two required:
|
One required, between the sample and detector | One required, between the light source and sample |
More on Fluorescence Spectroscopy
Fluorescence spectroscopy is the study of fluorophores, either for use in fluorescent applications such as in LEDs, or as a marker to study biological processes or chemical reactions.
Fluorescence spectroscopy analyzes light emitted from a sample due to an excited electron relaxing from the first electronic state into the ground state. There are two types of fluorescence measurement: steady state fluorescence and time resolved fluorescence. Time resolved PL measurements are used to measure dynamic processes like fluorescence lifetime. Steady state fluorescence can be used to probe the molecular structure of a material and is measured using a spectrofluorometer.
Fluorescence spectroscopy is often used alongside absorbance spectroscopy, as absorbance measures the excited state of a molecule whereas fluorescence measurements probe the ground state.
Understanding Spectrofluorometer Components
Excitation Sources
Single wavelength light sources, such as the UV light source, provide a high energy excitation source with a narrow wavelength range to selectively excite fluorophores for fluorescence measurements. However, absorbance measurements and excitation fluorescence measurements require a broadband light source so spectrofluorometers also need a broadband light source.
In most spectrofluorometers, the broadband light source is passed through a scanning monochromator, where wavelengths are selected individually and an absorbance spectrum is built wavelength by wavelength.
This variable light source can also be used as a narrow wavelength excitation source for fluorescence measurements. Therefore, spectrofluorometers, like the Ossila Spectrofluorometer, often have both a high energy UV light source and a variable light source, allowing users to conduct a wider range of measurements with just one instrument.
Sample Holder
The sample holder is a straight-forward but vital part of the system. It ensures consistency between measurements and holds the sample steady. There are sample holders designed to measure substrates for thin film measurement. Additionally, many samples measure fluorescence within solution, usually in a quartz cuvette. Using ultra-flat quartz cuvettes or substrates helps to reduce reflection, scattering and absorbance of light. This ensures that the maximum possible light is transmitted through the holder without interaction.
Detectors
Spectrofluorometers use single pixel detectors, unlike spectrometers which use array detectors. Single pixel detectors can only measure intensity and have no way to decipher between different wavelengths of light. This makes spectrofluorometers more sensitive to smaller signals, but means that wavelength selection must take place before or after interacting with the sample. Often photomultipliers are used as these detectors, with the type determining the spectral range and sensitivity of the spectrofluorometer.
For fluorescence measurements, the light needs to pass through a monochromator before it hits the detector. This isolates the emission wavelength and crucially reducing the intensity of the excitation wavelength in the transmitted signal.
For absorbance measurements, the light source must be able to pass through the sample directly into the detector. Therefore, for maximum versatility, some spectrofluorometers, such as the Ossila Spectrofluorometer, come with multiple detectors in different locations to facilitate both absorbance and fluorescence measurements.
Gallery
Resources and Support
Fluorescence Spectroscopy
Fluorescence spectroscopy is used to measure fluorescence. The technique often used together with absorbance spectroscopy. Fluorescence is a type of photoluminescence where light is quickly reemitted from a material after incident photons are absorbed. This is different to phosphorescence where there is a delay between photon absorption and emission. The term fluorescence is often used interchangeably with photoluminescence.
Read more...
What Is Spectrophotometry?
Spectrophotometry examines the interactions between visible light and matter through measurements like absorbance, transmission, and reflectance spectroscopy.
Read more...