Aromatic interactions in gas chromatography: the use of 2,4,6-trinitrophenetole as a column liquid

Abstract

Retention times measured on a column containing 2,4,6-trinitrophenetole show that this substrate possesses considerable aromatic selectivity. On 2,4,6-trinitrophenetole, benzene emerges between n-undecane and n-dodecane, and m-xylene precedes p-xylene, which is the reverse of the usual order. The major part of the difference in the retention of aliphatic and aromatic compounds appears to act by a mechanism which rejects aliphatics rather than one which preferentially retains aromatics. However, an analysis of the results using a R ohrschneider plot shows that this substrate is nevertheless specifically selective towards aromatic compounds. Moreover, compared with tritolyl phosphate, 2,4,6-trinitrophenetole strongly retards o- and p-xylene and retards methyl substituted aromatic hydrocarbons significantly more than it retards those substituted with more bulky groups.