Limit of Detection (LOD) 2
Limit of Detection (LOD) 2 : Chemistry and Chemical Disasters. (a) The lowest concentration of a substance that can reliably measured. [CARB, 2000: Glossary of Air Pollution Terms]; (b) [Limit of Determination] The LOD is the lowest concentration of a pesticide residue or contaminant that can be identified and quantitatively measured in a specified food, agricultural commodity, or animal feed with an acceptable degree of certainty by a regulatory method of analysis. The LOD is considered synonymous with the limit of quantitation/quantification. [FAO/WHO, 1997: Food Consumption & Exp. Assessment of Chemicals]; (c) The level at which a pesticide can be detected but not quantified for a given analytical procedure. [OECD, 1997: Occupational Exposure to Pesticides]; (d) [also, Method Detection Limit (MDL)] The minimum concentration of an analyte that, in a given matrix and with a specific method, has a 99% probability of being identified, qualitatively or quantitatively measured, and reported to be greater than zero. [USEPA, 1992: GL for Exposure Assessment]; (e) The minimum concentration of a substance being analyzed test that has a 99 percent probability of being identified. [USEPA, 1997a: EPA Terms of Environment]; (f) LOD is the point at which "a measured value becomes...larger than the uncertainty associated with it" (Taylor, 1987). The LOD can be defined in a number of ways, such as the background response plus three times the standard deviation of the lowest measurable concentration, three times the signal-to-noise ratio of baseline noise, three times the standard deviation of the lowest measurable concentration, etc. [USEPA, 1998: Postapp. Exposure Test GL.]
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