Which practice minimizes contamination during sample preparation?

• A. Carryover of previous sample due to uncleaned apparatus.
• B. Relying on proper method blanks.
• C. Using clean apparatus.
• D. Ignoring cleaning protocols.

Answer: (A)

Preventing cross-contamination during sample prep hinges on using clean apparatus. When equipment isn’t cleaned, residues from a previous sample can transfer to the next one, causing carryover that skews results. Clean apparatus removes these residues so the current sample is analyzed without interference. Relying on method blanks helps detect contamination after the fact, but it doesn’t stop it from occurring. Ignoring cleaning protocols obviously increases contamination risk.