5. Calibration

Atomic absorption spectrometry is a comparative analytical method; it involves calibration, and the quality of the results depends on the representativeness of the standards in relation to the samples. Many factors can affect this quality, so great care must be taken when selecting and preparing standards.

The most common calibration is obtained by measuring the absorbance of synthetic solutions with progressive concentrations of analyte. The concentration of the unknown solution is then directly deduced by plotting its absorbance value against a previously established calibration line. This method, known as direct calibration, applies to relatively simple media, with a sufficiently constant matrix and negligible interference.

For complex media with a known matrix that is relatively constant from one sample to the next, and if this matrix...