Syringe filters are small, single-use disc filters attached to the tip of a syringe to remove particulates, bacteria, or other contaminants from a liquid or gas sample as it's pushed through. They're typically made from materials like PES, PTFE, nylon, or cellulose acetate, with pore sizes (commonly 0.22 or 0.45 µm) chosen based on the application. In the lab, they're essential for sample preparation prior to HPLC and other chromatography techniques, sterilizing solutions, and clarifying samples before analysis, since even small particulates can clog instruments or skew results.