Duplicate Analysis

Duplicate Analysis - A measure of precision determined by analyzing samples twice or by analyzing a second sample taken from the same source at the same time and analyzed under identical conditions. There are several different types of duplicate samples that provide information on the precision of specific types of environmental data operations

Field Duplicates - Independent samples that are collected as close as possible to the same point in time and space. They are two separate samples taken from the same source, stored in separate containers and analyzed independently. These types of duplicates are useful in characterizing the precision of the sampling process.

Matrix Duplicates - An intralaboratory split sample that is used to document the precision of a method in a given sample matrix.

Split Samples - Two or more representative portions taken from one sample in the field or in the laboratory and analyzed by different analysts or laboratories. Split samples are quality control (QC) samples that are used to assess analytical variability and comparability.

[Category=Quality Assurance ]

Source: Massachusetts Department of Environmental Protection, 19 March 2011 07:30:59, http://www.mass.gov/dep/cleanup/laws/glossa01.htm