Sensitivity in metrology is the change in instrument response per unit change in the measured quantity — mathematically the slope of the calibration curve ($partial Signal / partial Concentration$), sensitivity determines how much the instrument's output changes for a given change in the measurand.

Sensitivity Details

• Calibration Slope: For linear calibration: $Sensitivity = m$ where $Signal = m imes Concentration + b$.
• Units: Signal units per concentration unit — e.g., counts per ppb, mV per nm.
• Element-Dependent: In ICP-MS, sensitivity varies by element — Au has different sensitivity than Fe.
• Matrix-Dependent: The sample matrix can affect sensitivity — matrix effects change the slope.

Why It Matters

• Detection: Higher sensitivity enables lower detection limits — more signal per unit analyte.
• Precision: Higher sensitivity means better signal-to-noise ratio — more precise measurements.
• Optimization: Sensitivity can be improved by optimizing instrument parameters (wavelength, power, geometry).

Sensitivity is how responsive the instrument is — the magnitude of signal change per unit change in the measured quantity, determining the instrument's ability to detect small differences.