Combining chromatographic separation system on-line with a spectroscopic detector in order to obtain structural information on the analyses present in a sample has become the most important approach for the identification and/for confirmation of the identity of target and unknown chemical compounds. For most (trace-level) analytical problems in research field of food products, the combination of column liquid chromatography or capillary gas chromatography with a mass spectrophotometer has become the preferred approach for the analysis of food products. Two very important examples of hyphenated procedures that are used in food analysis are GC-MS and LC-MS. The information obtained from GC-MS or LC-MS is not only useful for quantitation but also provide confirmation of the analytic, especially if the residue is present at trace level. In GC and HPLC analysis, the results sometimes might be misleading as compounds having similar chemical nature often elute at approximately the same retention time.

Mass spectrometry is an analytical technique that identifies the chemical composition of a sample on the basis of the mass to charge ratio of charged particles. The technique has both qualitative and quantitative uses, including:

• Identifying unknown compounds by the mass and mass fragmentation