Limit of Detection
The smallest concentration of analyte that can be reliably distinguished from the blank.
Formula / equation
LOD = 3σ_blank / m
Unit
Various
In depth
Conventionally defined as the concentration giving a signal three standard deviations above the mean blank, the limit of detection establishes only that the analyte is present, not how much. It improves with a lower blank noise and a steeper calibration slope.
Examples in the real world
An ICP-MS reaching detection limits below one part per trillion for many heavy metals.