Detects contamination from reagents, sample handling, and the entire measurement process.

• A. Solvent blank
• B. Matched-matrix blank
• C. Method blank
• D. Calibration blank

Answer: (C)

A method blank reveals contamination introduced anywhere along the analytical workflow—from reagents and containers to sample handling and the measurement itself. It’s prepared in the same way as real samples but contains no analyte, so any signal indicates carryover or interference from the reagents, labware, or steps in the process. This makes it the best choice for detecting contamination across the entire method. A solvent blank only checks solvent purity, a matched-matrix blank focuses on matrix effects, and a calibration blank is used to establish instrument response for calibration, not to monitor the full workflow for contamination.