The following issues are commonly observed during acid-base extraction and typically have simple solutions
* Only one layer is observed in the separatory funnel.
** This is due to using an organic solvent with significant miscibility with water (e.g. acetonitrile). The organic solvent used must be water-insoluble to observe phase separation and perform an acid-base extraction.
* Three layers form in the separatory funnel.
** Often this is a result of insufficient mixing, and light stirring will solve the issue.
* The boundary between the organic layer and aqueous layer is not observed.
** Ice can be used to identify the boundary as it will float between the two layers.
* An emulsion forms and one layer is suspended in the other as tiny droplets.
** This can be solved by using a glass stirring rod to gently "push" the tiny droplets into each other, eventually resulting in separation and causing the two layers to appear. Adding a small amount of brine solution can also be used to break up the emulsion; this process is termed "salting out". Emulsions can be prevented by mixing the solutions gently rather than vigorously.
* The relative positions of the aqueous/organic layers are unknown.
** A small amount of water can be added to the separatory funnel. Whichever layer these droplets go into is identified as the aqueous layer.