Antioxidants chromatogram, examples

Fig. 2. Examples of HPLC chromatograms using the methods described in the text. Solid lines show the UV absorbance at 351 nm, and dotted lines the cpm measured with an on-line radioactivity detector. (A) A mixture of six retinoid standards separated out into individual peaks with different elusion times. Peak 1 = retinal, peak 2 = tRA, peak 3 = retinol, peak 4 = 13-cis-RA, peak 5 = didehydroretinol, peak 6 = 4-oxo-RA. The dotted line marks the cpm of [ H] tRA, which was also added to the mixture and this coeluted with the cold tRA. (B) The retinoid extracted from a whole 10.5-d mouse embryo. The same six peaks of known standards are marked. Only retinol (peak 3) and tRA (peak 4) are clearly identifiable. Peak 2 coelutes with authentic [ H] tRA, suggesting that the mouse embryo contains significant quantities of tRA and a good deal of retinol. The peak on the extreme right of the chromatogram is an unknown, and the peak to the left of arrow 5 is butylated hydroxy-toluene, the antioxidant added to the extraction solvent.

The schematic separation shown in Fig. 2 represents the molecular-weight (MW) distribution of the polymeric gum base used in chewing gum, followed by the lower-MW components in decreasing order of size. A similar example could be a chromatogram of PVC with a mixture of plasticizers, antioxidants, and UV stabilizers. 

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