Cavitand Sorbents for the Selective Adsorption of Organic Compounds by the Purge-and-trap Technique

Two cavitand sorbents were tested for the selective adsorption of different analytes by using the purge-and-trap technique. Model mixtures of esters and ketones covering a wide range of volatilities were used; the trapped compounds were thermally desorbed and analyzed by GC–MS. Diazanaphthalene-bridged cavitand proved to be highly selective toward aliphatic ketones with respect to aliphatic esters. Among ketones selectivity differences were observed depending both on the position of the carbonyl group and on the length of the alkyl residues. The discrimination of structural isomers belonging to the same class was also demonstrated for this receptor. The methylene-bridged cavitand having a much reduced cavity was capable of efficiently trapping small organic molecules such as acetonitrile.