Obtaining a pure sample for testing, whether it is DNA, RNA or protein usually comprises of two parts: extraction followed by cleanup. Common technologies used include silica membrane spin columns, magnetic beads and solutions such as Trizol and TRI Reagent.
Extraction to Preservation
Extraction initially isolates the nucleic acid or peptide of interest from its source; this can be tissue, cells or a lysate, but to name a few. Check out our protein purification or plasmid purification troubleshooting guides for guidance.
Cleanup is then employed to remove any remaining contaminants from the final sample, therefore increasing the concentration of the molecule of interest. Cleanup is of particular importance for electrophoresis and PCR. Our DNA Gel Cleanup troubleshoot can provide you with solutions to any problems you encounter.
Enrichment aims to amplify the concentration of a small subset of the target molecule, usually a species which is difficult to acquire in significant volume. Don’t be afraid to make use of our sample enrichment troubleshoot when problems arise. Also, see our RNA enrichment troubleshooting guide, when attempting to deplete ribosomal RNA or enrich mRNA, (through poly-A enrichment).
Preservation is usually a final step of sample purification, used to maintain the activity and structure of the sample for future testing. Any technique used needs to prevent degradation, especially from enzymes such as RNase or DNase.