Chromatographic Methods

Chromatographic Methods (HPLC-DAD, GC-MS, GC-ECD, GC-NPD)

Generally Chromatography works on a similar principle. Chromatography is a method of separation. The unit that does the separation is the column. It comprises of a mobile phase (The analyte and carrier fluid) and a stationary phase (The ‘Separator’ which will interact with the analyte which will cause separation of the mixture of compound). The separation of compounds is base on the affinity of analyte with the stationary phase. The higher the affinity, the longer the compound will interact with the stationary phase, therefore achieving separation. The time that the compound interacts with the stationary phase is termed as the retention time. The chromatogram that comes out will produce the intensity of analyte signal with reference to retention time.

Intensity of signal can be correlated with the amount of analyte present.

Specific analyte will interact differently with the different types of stationary phase. Therefore for different types of compound of interest, one may use specific types of column. All these are subjected to the chemical engineer and manufacturer’s recommendation and advisory.

With a group specific retention time of analyte on specific column, one can zoom down a group of compound. A spectroscopic method or detector needs to determine and confirm the identity of compound.