Linoleyl groups

From the results of Figure 14.3, interestingly, the protein extraction behaviour by dilinoleyl phosphoric acid (DLIPA) is distinct from the result obtained by DOLPA, in spite of the similar hydrophobic chain. The oleyl and linoleyl groups are unsaturated C18 chains. The former has one unsaturated cis-double bond at the position between C9 and CIO, while the latter has two at the position between C9 and CIO and between C12 and Cl 3. The two double bonds in the hydrophobic part of the surfactant DLIPA provide some inflexibility in the chain, which can lead to steric hindrance and to solvation by the organic phase (Figure 14.5). 

Remarkably, the effectiveness of separation (the criteria being the number of protein peaks, the separation of heme- from non-heme-containing proteins, and the separation of cytochrome b from cytochrome aa depends on the length and degree of unsaturation of the resin-bound aliphatic chain.The separation efficiency first increases with increasing chain length, reaches an optimum with the capryl chain, and then decreases from lauryl to palmityl to stearyl. Within the Cig group, the separation efficiency increases from the stearyl to the oleyl to the linoleyl chain. 

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