| Pelleting cells | Holds a suspension while centrifugal force separates cells from the surrounding liquid. | Bacterial cultures, mammalian cells, yeast, algae, and other cell suspensions. | Conical tubes, commonly 15 mL or 50 mL; smaller samples may use microcentrifuge tubes. | A compact cell pellet at the bottom of the tube and a liquid supernatant above it. | Resuspend the pellet gently when cell damage or clumping could affect the experiment. |
| Clarifying liquids | Separates suspended particles, cell debris, or precipitates from a liquid sample. | Cell lysates, tissue homogenates, culture media, and chemical solutions. | Microcentrifuge tubes for small volumes or conical tubes for larger volumes. | A clearer supernatant with unwanted solid material concentrated at the bottom. | Tube material must be compatible with the sample solvent, temperature, and centrifugal force. |
| Separating phases | Uses differences in density to separate immiscible liquid layers or solid and liquid phases. | Organic extraction mixtures, blood components, and multiphase laboratory samples. | Conical tubes or specialized tubes with suitable chemical resistance. | Distinct layers or an interface that can be transferred separately. | Allow the layers to settle and use care when removing the desired phase to avoid cross-contamination. |
| Nucleic acid extraction | Supports lysis, binding, washing, and elution steps during DNA or RNA purification. | Blood, saliva, cultured cells, plant tissue, bacteria, and purified nucleic acids. | Usually 1.5 mL or 2.0 mL microcentrifuge tubes; larger starting volumes may require conical tubes. | Purified DNA or RNA collected in a small final liquid volume. | Use nuclease-free tubes when required and avoid disturbing the pellet or purification membrane. |
| Washing precipitates | Retains a solid precipitate while the liquid wash is removed after centrifugation. | Precipitated proteins, nucleic acids, salts, and other laboratory precipitates. | Microcentrifuge tubes or conical tubes, depending on sample volume. | A washed pellet with reduced residual contaminants. | Balance tubes carefully and remove the wash liquid without loosening the pellet. |
| Density-gradient separation | Holds layered solutions while particles migrate to positions determined by density. | Organelles, viruses, lipoproteins, nucleic acids, and subcellular particles. | Specialized thin-wall or ultracentrifuge tubes selected for the rotor and gradient medium. | Separated bands or layers containing particles with different densities. | Tube type, fill volume, sealing method, and rotor compatibility must match the centrifuge protocol. |
| Protein precipitation | Contains a sample while centrifugation collects proteins or removes insoluble material. | Cell extracts, serum, plasma, and purified protein solutions. | Microcentrifuge tubes for routine small-scale workflows; larger conical tubes for bulk samples. | A protein pellet or a clarified protein-containing supernatant. | Temperature control may be important because protein solubility and stability can change with temperature. |
| Blood component separation | Separates blood cells from plasma or serum and can support further fractionation. | Whole blood, plasma, serum, and prepared blood fractions. | Tube size and additives depend on the collection and testing procedure. | Separated cellular and liquid fractions, often visible as distinct layers. | Follow the required collection, anticoagulant, clotting, time, and handling procedures for the test. |
| Sample storage after processing | Provides a closed container for temporary or long-term storage of separated fractions. | Cell pellets, supernatants, extracted DNA or RNA, proteins, and prepared aliquots. | Sealable microcentrifuge tubes or conical tubes with appropriate temperature ratings. | Organized aliquots that can be retrieved without repeatedly exposing the entire sample. | Check leak resistance, low-temperature suitability, chemical compatibility, and labeling requirements. |