The YSI 8500 CO2 monitor measures dissolved carbon dioxide in bioprocess development applications. Engineered to fit within a variety of bioreactors, the unit delivers precise, real-time data that increases an understanding of critical fermentation and cell culture processes. This data can help in gaining insight into cell metabolism, cell culture productivity, and other changes within bioreactors.
The monitor is based on the reliable opto-chemical technology that was developed by Tufts University and YSI Incorporated. The technology involves the use of a CO2 sensor capsule consisting of a small reservoir of bicarbonate buffer covered by a gas permeable silicone membrane. The buffer contains HPTS (hydroxypyrene trisulfonic acid), a pH-sensitive fluorescent dye.
CO2 diffuses through the membrane into the buffer, changing its pH. As the pH changes, the fluorescence of the dye changes. The 8500 monitor compares the fluorescence of the dye at two different wavelengths to determine the CO2 concentration of the sample medium.
The sensor can be autoclaved multiple times. It will measure dissolved CO2 over the range of 1 to 25 per cent, with an accuracy of 5 per cent of the reading, or 0.2 per cent absolute. The sensor drift is 2 per cent of the reading, over a seven day period. Response time is seven minutes for T90. Sensor longevity is over 45 days of continuous use, depending upon application.
Moreover, the unit allows dissolved CO2 to be monitored digitally via real-time display or graphically, with users able to upload the data on to a computer or integrate the output signal into existing control processes. Frequency of data point logging is highly flexible down to a minimum interval of 15 seconds which allows the user to accommodate specific applications.
Previously, CO2 was measured either in the exit gases from the fermentation process or by taking a manual sample. The new opto-chemical technology uses a fibre-optic cable transfer light through a stainless-steel probe into a disposable sensor capsule, which contains a pH sensitive dye.
The dissolved carbon dioxide diffuses through a polymer membrane to change the colour of the dye which is then relayed by fibre optic cable back to a rack-mounted monitor which determines and displays the dissolved the CO2 level.
Versatile and easy to use, the robust and reliable stainless steel probe is available in four different styles to fit a range of fermentation vessels. For added convenience, it can be autoclaved in situ before each fermentation run. The YSI 8500 is currently in use internationally at over 30 major Biotechnology companies.
ENQUIRY No 97
YSI is based in Yellow Springs, OH, USA. www.ysi.com
