What is the Technology Behind Monipa?
Spectroscopy enables real-time and online monitoring of several parameters in parallel. For bioprocesses, typical wavelengths range from UV to mid-infrared. Infrared spectroscopy is usually divided into far infrared, mid infrared and near infrared. Monipas’ technology is based on mid-infrared spectroscopy.
In Infrared Spectroscopy there are different measurement methods such as Transmission, Reflection, and Attenuated Total Reflection (ATR). The advantages of ATR spectroscopy compared to other methods are that no sample preparation is required but also the ability to measure a broad concentration range also high concentrated samples.
What is ATR Spectroscopy?
The attenuated total reflection (ATR) technique has become established as an alternative to transmission measurements. The infrared beam passes through a material with a high refractive index at an angle that leads to total internal reflection at the interface. Due to physical boundary conditions, a small part of the beam penetrates into the sample and gets absorbed, which is called an evanescent field. The penetration depth of the radiation into the measurement medium is a few µm, depending on the wavelength, material and angle. You can determine the penetration depth for your sample and learn more about our crystals using our very own calculator!
What Makes the IRUBIS ATR Crystal Special?
One important factor of the ATR crystal is the refractive index. Only materials with a high refractive index can be used, such as diamond, zinc selenide, etc. These materials are expensive and not suitable for single-use application, such as for bioprocess monitoring. By using silicon material and well-known semiconductor manufacturing processes, large quantities of ATR crystals can be fabricated, reducing the price. This makes them suitable for single-use application.
Microstructured Bottom and Single Reflection
During the manufacturing process, our crystals receive a special MEMS (Microelectromechanical Structuring) on the underside. This makes them an ideal IRE (Internal Reflection Element) for Single Reflection ATR.
In comparism to Multi-Bounce ATR, where multiple internal reflections occur, the microstructures serve as individual prisms in which single internal reflections occur.
The advantage compared to other Single-Bounce ATRs is the large coupling area. The light can be coupled into each of the single prisms, so exact positioning is not necessary.
How Does Monipa Work?
Monipa is our mid-infrared spectroscopy system with a single use flow cell that is specifically designed for bioprocessing. The ATR crystal is integrated into the flow cells, and can be easily attached to the Monipa, which houses the spectrometer with a click-mechanism.
As the flow cell is a demountable component, it is autoclavable and suitable as a disposable element. Alternatively, it can also be gamma sterilized if necessary. Monipa is an online monitoring system and can be used in different steps of bioprocessing, like for Downstream and Upstream Applications.
How can I integrate Monipa with my bioreactor?
The Monipa can be connected to your bioreactor via the perfusion or harvest stream as well as via loop in fed-batch processes. Compared to inline probes, the external flow cell provides a constant measurement environment, without influences by gas bubbles or the stirrer in the bioreactor.