PROPERTIES OF THE TOCOPHEROLS 



815 



same group in the aliphatic hnkages causes an absorption at 3.41 n. A 

 series of bands centering around 7 n (6.7 to 7.15) can Hkewise be ascribed to 

 the angular vibration of the C — H linkages. Finally, there are a number 

 of "unassigned" bands between 10 and 12 /x, some of which arise from C — C 

 vibrations. Both Stern et al.^^ and Rosenkrantz^''^ consider that the infrared 



9.50 9 8.50 



WAVE LENGTH. MICRONS 



Fig. 5. Infrared transmission spectra of natural tocopherols." 'i"* 



spectrum offers much promise for the detection and determination of the 

 indi\adual tocopherols. Figure 5 illustrates the infrared absolution pat- 

 tern of the four common tocopherols. 



Table 6 records the absorption maxima of some of the tocopherols and 

 their derivatives as determined in the infrared area of the spectrum. 



All natural tocopherols have been sho\Mi to be optically active. They 

 have three centers of asymmetry ,^2 ^yhich are on carbons 2, 4', and 8'. 

 Thus, 8 potential isomers of each are possible. Stem et a/.'* have reported 

 that, when dissolved in ethyl alcohol, all natural tocopherols show a dextro- 



