>Hello, >Does anyone have any experience with the storage of unconjugated FITC >(isomer 1, Sigma, F7250) ? I have dissolved it in PBS, pH8, 0.1mg/ml >and I keep it in the dark at 3-4°C. Does anyone know something about >the stability in this form and how long it can be stored like this ? > >Thanks >Isabel About 30 minutes. FITC reacts with water quite rapidly... never store it in water! Since the cost of FITC is so low compared to the cost of everything else associated with the reaction, you should always use a freshly-opened vial when you are about to use it; discard the rest. Also, dissolve the FITC in DMSO and then add it to your reaction. Make sure that your DMSO is the highest-grade possible, and keep the DMSO in a dessicator to make sure it has no water. Note that you cannot use pipetteman to accurately pipet DMSO--you have to use glass (not plastic!) pipettes. Typically, we break the ampule, and add 1.0 mL of DMSO from a glass pipet. This results in 10mg/ml solution, which is great for most reactions. (Then you will have to add the small amount you need using a pipettman; using yellow tips works reasonably well but you have to operate quickly: the DMSO does not hold well inside the tip and leaks out). FITC in DMSO is relatively stable (i.e., hours... not days), when kept unexposed to air & water. mr -- End --
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