BOOKS However, some difficult chromato graphic separations are greatly facil itated by EDA-type interactions, and the use of such interactions in con junction with efficient columns may permit the rapid separation of spe cies t h a t cannot readily be separated by any other means. In C h a p t e r 1, " C o m p l e x a t i o n in Chromatography," L. Nondek gives a general overview of the applications of EDA interactions in chromatogra phy. Nondek notes t h a t only weak labile EDA complexes with interac tion energies of a few kilocalories per mole are useful in chromatography. EDA interactions are classified with respect to the type of donor and ac ceptor orbitals involved, u s i n g t h e h a r d - s o f t a c i d - b a s e theory to esti m a t e which type of a c i d - b a s e reac tion will be facile. General examples of EDA complexes in GC and LC are presented, as are t h e use of linear free energy relationships and simple quantum mechanical models to pre dict selectivity in EDA interactions. The use of metal complexes in chro m a t o g r a p h y , including m e t a l che l a t e s a n d silver s a l t s , is also d i s cussed briefly.
A concise source for argentation and complexation methods should prove useful to chromatograpners· Chapter 2, with 54 tables, surveys s t a t i o n a r y phases t h a t are used as packings in EDA chromatography. G. Felix discusses the use of silver salts, other metals, other elements such as I 2 , and organic acceptors (e.g., tetrachlorophthalates and 2,4,7-trinitro-
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798 A · ANALYTICAL CHEMISTRY, VOL. 65, NO. 18, SEPTEMBER 15, 1993
fluorenone) as stationary phases for GC. He also reviews the use of simi lar compounds and chiral ligands as packings for thin-layer chromatogra phy (TLC) and metals coated or che lated onto supports as packings for LEC. Felix discusses organic donoracceptor species a n d describes t h e many chiral stationary phases pro posed by Pirkle and co-workers and by M a t l i n a n d c o - w o r k e r s . Refer e n c e s for 596 p a p e r s a r e g i v e n through 1987. In Chapter 3 Cagniant covers c h a r g e - t r a n s f e r (CT) a b s o r p t i o n chromatography or EDA with appli cations for determining polycyclic ar omatic compounds, aromatic amines, azaarenes, and biological compounds. He notes t h a t no fundamental new work h a s b e e n p u b l i s h e d on EDA c o m p l e x e s a p p l i e d to TLC p l a t e s since 1974, and he briefly presents older work in this area. His review of CT i n t e r a c t i o n s in LC i n c l u d e s a brief coverage of pre-1982 papers on bonded phases for HPLC separation of polycyclic aromatic hydrocarbons (PAHs) as well as a more compre h e n s i v e look a t l a t e r p a p e r s on bonded nitroderivatives and on other bonded EDA compounds. Applica t i o n s of CT i n t e r a c t i o n s to g a s liquid chromatography (GLC) and to the separation of racemic polycyclic aromatic compounds by LC are also described; a similar discussion of ar omatic amines and azaarenes covers TLC, LC, and GLC methods. Separa tion of biological compounds, proba bly the most important topic in the chapter, is covered from research by P o r a t h ' s g r o u p in t h e early 1970s through work reported in 1987. In Chapter 4 Cagniant reviews argentation chromatography. He notes t h a t it is difficult to decide whether s e p a r a t i o n s based on complexes of metal ions with organic compounds should be considered as CT complex chromatography or LEC. He then fo cuses on the separation of olefins by argentation chromatography, includ ing classic examples of steric effects on the stability of olefin-Ag + com plexes as well as less familiar cases in which argentation chromatogra phy gives unique separations. Com plexation of olefins with other metals is discussed briefly. Covered in con siderable detail are the application of argentation chromatography to the separation of lipids, fatty acids, and their methyl esters as well as sepa r a t i o n s of p r o s t a g l a n d i n s , l e u k o trienes, neutral and polar lipids, ster oids, and N- and S - s u b s t i t u t e d heterocyclic compounds. V. A. Davankov describes LEC of
