Column chromatography

Column chromatography is the separation technique in which a column or tube holds the stationary phase while the sample flows through it. Components partition between the moving mobile phase and the stationary packing, emerging at different times according to their affinities. From glass gravity columns in teaching labs to high-pressure steel columns in HPLC systems, the principle scales from milligrams to tonnes. Food analysts use it to isolate flavours, pigments, vitamins, contaminants, and adulterants — the purification step that makes accurate measurement possible.