What is a duplicate sample?
A sample collected concurrently, i.e. in the course of the same sample survey under comparable conditions, with a first sample. It acts in much the same way as a replication except that in some cases the only thing which can be replicated is the act of taking a second independent sample.
What is a laboratory control sample?
Laboratory Control Samples (LCS): The Laboratory Control Sample (LCS) is analyzed to assess the laboratory performance to successfully recover target analytes from a control matrix on a purified sample material, like homogenous sand or deionized water.
What is an LCS sample?
Laboratory Control Samples and Sample Duplicates (LCS/LCSD) are samples prepared in the laboratory that contain analytes that are representative of the analytes of interest in client submitted samples.
What is replicate testing in laboratory?
Laboratory replicate sample means a sub-sample taken of the representative sample used for laboratory quality control purposes to demonstrate reproducibility. It is prepared and analyzed in the identical manner as the representative sample. The results from replicate analyses are used to evaluate analytical precision.
What is the difference between a duplicate and replicate sample?
Duplicate – Two samples are taken side by side using the same procedures and tested separately. Duplicate samples used to evaluate analytical or measurement precision. Replicate – A single sample that is tested twice within the batch. The results indicate precision.
What are control samples?
Control samples are reference materials with a matrix composition close to that of the analyzed samples, and which elemental mass fractions are close to the expected ones in the unknown samples. They should also be stable over time, and be available in sufficient amount as to be used for years.
What is a control specimen?
Control samples are any type of well-known forensic samples used to assure analyses are properly performed so that results are reliable. Also called controls, known samples, and knowns, these control samples are fully known to the forensic community with respect to composition, identification, source, and type.
What is a spike sample?
Spike sample – A sample to which known concentrations of specific analytes have been added in such a manner as to minimize the change in the matrix of the original sample. Every spiked sample analyzed should have an associated reference to the spike solution and the volume added.
What is matrix in lab?
From Wikipedia, the free encyclopedia. In chemical analysis, matrix refers to the components of a sample other than the analyte of interest. The matrix can have a considerable effect on the way the analysis is conducted and the quality of the results are obtained; such effects are called matrix effects.
What are replicate samples in analytical chemistry?
Replicate samples: two or more samples representing the same population characteristic, time, and place, which are independently carried through all steps of the sampling and measurement process in an identical manner. Replicate samples are used to assess total (sampling and analysis) method variance.
What are the benefits of replicate sample in analytical chemistry?
Using replicates offers three major advantages: Replicates can be used to measure variation in the experiment so that statistical tests can be applied to evaluate differences. Averaging across replicates increases the precision of gene expression measurements and allows smaller changes to be detected.