achem

Calibration curve

A graph showing the value of some property versus concentration of analyte.

Standard solutions

A solution whose composition is known by virtue of the way that it was made from a reagent of known purity or by its reaction with a known quantity of a standard reagent.

Blank solution

Solutions containing all reagents and solvents used in the analysis, but no deliberately added analyte.

Linear range

Concentration range over which the change in detector response is proportional to the change in analyte concentration.

Dynamic range

Range of analyte concentration over which a change in concentration gives a change in detector response.

Standard operating procedures (SOP)

Statement of what steps will be taken and how they will be carried out.

Accuracy

Nearness to the 'truth'.

Precision

How well replicate measurements agree with one another.

Range

The concentration interval over which linearity, accuracy, and precision are all acceptable.

Selectivity

Extent to which a method can distinguish an analyte from everything else in the sample.

Matrix

Everything in the unknown, other than the analyte.

Matrix effects

Interference of the matrix in analytical measurements.

Sensitivity

Capability of responding reliably and measurably to changes in analyte concentration.

Limit of detection (LOD)

The smallest quantity of analyte that is significantly different from the blank.

Limit of quantitation (LOQ)

The smallest amount that can be measured with reasonable accuracy.

Repeatability

Describes how well one person can obtain the same results when analyzing the same sample.

Reproducibility

Describes how well different people in different laboratories can get the same results when analyzing equivalent samples.

Robustness

The ability of an analytical method to be unaffected by small, deliberate changes in operating parameter.