Vibrational Circular Dichroism (VCD) spectroscopy is a method where the difference in attenuation of left and right circularly polarized light is detected as it traverses through a sample. This method differs from classical IR spectroscopy, where the adsorption spectra are detected as a result of vibrational excitation with non-polarized IR radiation.
Being a very powerful method, VCD can provide 3D structural information owing to its sensitivity to the orientation of diverse functional groups in a molecule. As a result, absolute configurations of small molecules in solutions can be categorized, which is very helpful in pharmaceutical quality control.
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VCD Spectroscopy Applications in Pharmaceutical Quality Control
VCD Spectroscopy is a highly versatile tool for pharmaceutical quality control applications, as it can perform several different tasks during the entire drug production process.
The method can be employed for raw material identification of drugs to guarantee that there are no impurities which could lower efficiency and increase potential health hazards.
VCD can also be employed for reaction monitoring of new pharmaceuticals. It enables Chemists to see the reaction taking place in real time and confirm that it is continuing as expected.
VCD Spectroscopy Instrumentation
The PMA 50 module is a very flexible module that has been built for circular dichroitic experiments, such as VCD spectroscopy, and for polarization modulation (PM) measurements, such as PM infrared reflection absorption (PM-IRRAS).
The module has a photoelastic modulator (PEM) consisting of a nominal modulation frequency of 42 kHz. The sum and the difference signals are gathered concurrently with the maximum sensitivity with the assistance of the 24-bit dual-channel data acquisition technology. The detector compartment has a high precision rail to allow the quick switching between PM-IRRAS and VCD modes of operation.
Optimal S/N ratios and stability are provided by the short beam path displayed by the PMA 50 and the system provides unparalleled sensitivity and flexibility.
The PMA 50 can be incorporated into Bruker Optics’ INVENIO and VERTEX spectrometers and is regulated using Bruker’s user-friendly OPUS software.
The PMA can be used for peptides and protein characterization during the PAT process and purity control of pharmaceuticals. To acquire optimal VCD spectra, Bruker Optics offers a number of liquid cells and a range of window materials and spacers for transmission data collection from solids and liquids.
If the application necessitates temperature induced changes to be witnessed in the conformation of proteins, temperature controlled liquid cells can also be purchased from Bruker. These temperature controlled measurements can be regulated in OPUS with the ability to automate decreasing and increasing temperature ramp data acquisitions.
Bruker Optics offers a wide range of products that cover the complete pharmaceutical quality control process.
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This information has been sourced, reviewed and adapted from materials provided by Bruker Optics.
For more information on this source, please visit Bruker Optics.