Which technique uses zinc sulfate or saturated NaCl?

The flotation technique utilizes substances like zinc sulfate or saturated sodium chloride (NaCl) primarily due to their specific gravity properties. In this technique, a sample, often containing parasites or other lighter components, is mixed with a solution that has a higher specific gravity than the target organisms or components. The use of zinc sulfate or saturated NaCl allows these lighter entities to float to the surface, forming a distinct layer that can be collected for further examination.

This method is particularly advantageous in the identification of certain parasites in fecal samples, as it increases the concentration and visibility of these organisms compared to other techniques. The buoyant properties of the solutions enable effectively separating the targets from heavier debris or sediment.

The other techniques mentioned have different applications: the sedimentation technique relies on gravity to separate particles based on size and weight, the filtration technique physically strains out particles using a filter, and the dehydration technique involves removing moisture from samples, which does not directly relate to using zinc sulfate or sodium chloride solutions.