Which practice helps prevent contamination when aliquoting reagents for storage?

• A. Use sterile tubes and tips.
• B. Reuse contaminated tips.
• C. Pipette with wet hands.
• D. Store reagents in unsealed containers.

Answer: (A)

Maintaining aseptic technique during aliquoting is essential to prevent contamination. Using sterile tubes and sterile pipette tips ensures that no microorganisms, dust, or residues are introduced during each transfer, keeping stored reagents pure and stable for future use. By starting with clean vessels and tips, you minimize carryover from one aliquot to another and protect the integrity of the reagent. Reusing contaminated tips allows microbes or residues to be transferred between samples; pipetting with wet hands can deposit moisture, oils, or microbes; storing reagents in unsealed containers leaves them exposed to air, dust, and potential contaminants. Thus, using sterile tubes and tips is the best practice to prevent contamination when aliquoting reagents for storage.