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| There are at least three fundamentally different kind of contaminations that can accumulate in the measuring chamber of the oxygraph and cause problems. All of them have to be treated in different ways:
| | #REDIRECT [[MiPNet19.03 O2k-cleaning and ISS]] |
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| * [[Biological Contamination]] is caused by the growing of biological material (originating from samples or otherwise). Biological contamination of the chamber is typically detected by a high O2 flux at closed chamber near air saturation. It is detected by a sensor test, an instrumental background test or by observing the flux at closed chamber for a short time routinely before any experiment. In the later two cases the high flux contamination may be caused by biological contamination of the chamber itself or by a contaminated medium. This can be tested by observing the flux in pure water. The ideal counter agent is 70% Ethanol with 30% water (NOT 100% Ethanol). Prevention of biological contamination of the chamber is primarily by [[storage under 70% ethanol]]. If repeated washing with 70% Ethanol does nor remove a already present biological contamination, the glass chamber has to be cleaned as described for Protein contamination
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| * Protein contamination and other macroscopic deposits. After long use a whitish deposit can form at the glass walls of the chamber. Additionally, small glass splinters (difficult to see) may become embedded in such a deposit. This will be detected by a jumping stirring bar or a stirring bar getting stuck. In this case the glass chamber should be removed from the oxygraph and treated with concentrated hydrochloric acid at least over night. Additionally the stirring bar should be cleaned.
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| * [[Contamination by hydrophobic inhibitors]]: The ideal counter agent for this case is pure Ethanol (NOT 70% ethanol). Follow the Contamination by hydrophobic inhibitors link for a discussion of the problem and a suggested cleaning protocol.
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| {{#set: Technical service = chamber | Technical service = contamination}}
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| {{Technical service}}
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| __SHOWFACTBOX__
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