Absolute calibration method (external standard) and internal standard method are used for quantitative determination in chromatography.
External standard method is based on drawing a calibration graph using standard solutions of substances that are being analysed.
Internal standard method is based on adding of a known quantity of ethalon compound inth the solution that is being analysed. The etalon compound is known to be absent from the sample before.
Currently for analysis of spirit drinks
- the countries of Customs union use the external standard method,
- coutries, which have harmonised their laws in accordance with recommendations of OIV, use internal standard method.
Aforementioned methods have several advantages and drawbacks. For elimination of the latter, staff of BSU developed an innovation method of analysis of spirit drinks using ethanol as an internal standard.
See more info at project page.