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A variety of volatile metal halides were used in the gas phase to produce layers with thicknesses in the monomolecular range on Chromosorb W. The final layers result from subsequent treatment with H 2 O, NH 3 or H 2 . They could be considered to be of the “oxide”, “nitride” or “reduced” type, although no evidence for particular surface structures has been obtained. Layers were tested by gas chromatography directly and after attempted synthesis of an additional “bonded” Carbowax 20M layer. These procedures were successful (in terms of achieving inorganic layers in the monomolecular range and good chromatography with Carbowax 20M) in some but not all cases. The best materials were about equal in chromatographic performance to the best comparable phases containing no metals. “Bonding” of Carbowax could be achieved on several types of layers. For example, those containing Fe or Cr performed noticeably better than those containing Al or B. General uses of such materials are suggested.

The treatment of chromatographic supports with acid is of crucial importance for the subsequent bonding of polymers, as well as for certain types of analysis on conventional gas-liquid chromatographic coatings. This paper reports on the efficiency of treatments with acid for the removal of various cations from the silicic surfaces of Chromosorb W. G and P. While the commercial acid-washing process removes only negligible amounts of iron, the procedure reported here can remove over 95% of the iron initially present.

Normal and branched mercaptans containing up to eight carbon atoms and their 2,4- and 2,5-dinitrophenylalkylthioether and thioalkylbenzoate derivatives have been analyzed by gas-liquid chromatography (GLC). The most suitable derivatives for GLC separation appeared to be the thioalkylbenzoates, which enabled all of the normal and branched mercaptans studied to be resolved on an SE-30 column. Two methods of preparation of thioalkylbenzoates with benzoyl chloride were compared: (1) derivatization with pyridine under anhydrous conditions and (2) derivatization in aqueous solution with sodium hydroxide as acceptor of hydrochloric acid. The method was faster and more effective when aqueous alkaline solution was used.

Modified gas chromatographic supports based on very thin, non-extractable layers of Carbowax 20M on Chromosorv W have become popular phases, and other polymer—support combinations may follow. It is therefore desirable for the practitioner of gas chromatography to know something about the “polarity” of these phases. The available polarity scales predicated on gas—liquid partition involving heavy loads of liquid phase. Thus they are not, in principle, applicable to very thin, bonded layers. In practice, however, it is helpful to know that supports modified by pola materials such as Carbowax 20M or polyethylene glycol adipate appear much less polar than their regular gas—liquid chromatographic counterparts, i.e., packings with heavy loads of Carbowax 20M or polyethylene glycol adipate: the retention indices for typical probes differ by ca. 100–400. Phases based on non polar materials, e.g., Apiezon L, can show the opposite effect.