Each instrument used in analytical chemistry

Analytical chemistry

Analytical chemistry is the study of the separation, identification, and quantification of the chemical components of natural and artificial materials. Qualitative analysis gives an indication of the identity of the chemical species in the sample and quantitative analysis determines the amount of...

 has a useful working range. This is the range of concentration (or mass) that can be adequately determined by the instrument, where the instrument provides a useful signal that can be related to the concentration of the analyte

Analyte

An analyte, or component , is a substance or chemical constituent that is of interest in an analytical procedure. Grammatically, it is important to note that experiments always seek to measure properties of analytes—and that analytes themselves can never be measured. For instance, one cannot...

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All instruments have an upper and a lower working limit. Concentrations below the working limit do not provide enough signal to be useful, and concentrations above the working limit provide too much signal to be useful. When calibrating an instrument for use, the experimenter must be familiar with both the lower and upper working range of the chosen instrument.