Biomolecular absorption

Measuring concentration of biomolecules

Biomolecular absorption is a process in which light energy with certain wavelength is absorbed by a molecule during the interaction with light, promoting the molecule from ground state to higher energy excited states. It is widely used to measure concentration.

We can measure, analyse and consult on the light absorption (UV-visible and mid-IR) and emission (UV and visible) properties of biomolecules and bioactive molecules in solution. Our capabilities include tuneable one and two photon excitation sources (lamps, lasers, LEDs) and analysis techniques for pure, complex and reacting (or kinetic) samples.  

Standard measurements and consultancy services include:

• UV-visible absorption spectroscopy (190 – 1100 nm)
• Mid-FTIR absorption spectroscopy (900 – 4000 cm^-1)
• UV-visible emission (200-900 nm) and excitation (200-800 nm) spectroscopy
• Extinction coefficient determination
• Fluorescence quantum yield determination
• Two photon absorption cross section determination (340 – 1300 nm) and power dependence
• Spectral fingerprinting
• (Bio)molecular conformation and stability measurements
• Characterisation of engineered biomolecules and optogenetic tools (including under illumination)
• Spectrometer validation
• Multivariant analysis of complex mixtures
• Global analysis of kinetic data (single colour and spectral
• Consultancy and technical support for time-resolved measurement, including: laser spectroscopy, stopped-flow spectroscopy, magnetic perturbation and instrument development

Depending on the measurement, usually only low volumes (< 2 mL) of samples in the nM-mM range are required. We have a strong track record of measuring proteins (native and therapeutic) and work closely with the NPL’s Protein Metrology Facility, which has dedicated protein expression, purification and characterisation capabilities.

Our equipment includes:

• Agilent Cary 60 UV-Visible Spectrophotometer
• Bruker Tensor 27 FTIR Spectrometer
• Perkin Elmer LS55 Luminescence Spectrometer
• Ocean Optics QEPRO Spectrometer
• Spectra-Physics InSight X3 80 MHz Ultrafast Dual Beam Laser System (680 – 1300 nm tuneable, < 120 fs; 1045 nm fixed, < 200 fs) and Ultrafast Harmonic Generator (340 – 650 nm)
• Bespoke, automated laser beam attenuation system

Don’t see what you are looking for? Our diverse skill set enables us to provide bespoke solutions. Please contact us to discuss your requirements.

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