Introdcution to Detection Limits
Detection limit is commonly understood to be the smallest concentration we can measure with a particular technique. In fact it is the point at which we can make a decision whether the element or compound is present or not. To be able to measure it we need at least three times the detection limit. Three times the detection limit is often called the limit of determination. A different term used for detection limits is "Limits of Detection" with the abbreviation LoD.
By convention and from statistics, detection limit (DL) is defined as the concentration corresponding to a signal three times the noise level of the background.