What is meant by 'Limit of Detection' in analytical chemistry?

The term 'Limit of Detection' (LOD) in analytical chemistry refers specifically to the lowest concentration of an analyte that can be reliably detected, even though it may not be quantifiable with precision. This threshold indicates the minimal level at which a signal can be distinguished from the noise present in the experimental system.

Choosing the lowest concentration that results in a detectable signal is crucial in various applications, as it helps in validating methods and ensuring that even trace amounts of substances can be identified, which is particularly important in fields like environmental monitoring, pharmacokinetics, and food safety. Establishing the LOD allows analysts to determine the capability of a method to detect specific contaminants or substances at very low levels, thereby influencing the overall sensitivity and reliability of the analytical procedure.