FCCP (Carbonyl cyanide p-trifluoro-methoxyphenyl hydrazone, C10H5F3N4O) is a protonophore or uncoupler: added at uncoupler concentration Uc; c is the optimum uncoupler concentration in titrations to obtain maximum mitochondrial respiration in the noncoupled state of ET-capacity.
MitoPedia topics: Uncoupler
CCCP versus FCCP
Application in HRR
- FCCP (Carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone, C10H5F3N4O); Sigma C 2920, 10 mg, store at 4 °C: FW = 254.17)
- Caution: Toxic!
- Preparation of 1 mM stock solution (dissolved in 99.9% ethanol):
- 1. Weigh 1.27 mg of FCCP into a glass vial.
- 2. Dissolve in 5 ml ethanol.
- 3. Divide into 0.2 ml portions, or store in 5 ml glass vial and use subsamples during experiments to avoid contamination of the storage solution.
- 4. Store in glass vials at -20 °C.
- Caution: Chemicals stored in the fridge or freezer should be allowed to reach room temperature before opening.
- O2k manual titrations MiPNet09.12 O2k-Titrations
- Titration volume: 1 µl (or 0.5 µl) steps using a 10 µl syringe (2 ml O2k-Chamber).
- Final concentration: 0.5 µM (or 0.25 µM) steps.
- Frequently, a more diluted FCCP stock is necessary for reducing the concentration steps in manual titrations. In this case prepare more diluted stocksolution (ditution 2-10x) from your storage solution. The highest accuracy of uncoupler titrations is achieved by titrations with the TIP2k at high concentrations of the stock solution. 
- Gnaiger E (2008) Polarographic oxygen sensors, the oxygraph and high-resolution respirometry to assess mitochondrial function. In: Mitochondrial dysfunction in drug-induced toxicity (Dykens JA, Will Y, eds) John Wiley:327-52. »Bioblast link«