Methyl iodide, identification

GC separation of the isolated phenolic compounds occurs prior to identification and quantification using ECD- and MS-coupled detectors (Sect. 4.3). However, phenolic compounds are polar, and derivatization gives better GC peak shapes in the most commonly used types of GC columns. Hitherto the standard method of derivatization of OH-PCBs retained in blood has been methylation by diazomethane to form the corresponding methoxy-PCB (MeO-PCB) [39,43, 135]. OH-PCB methylation by ion-pair alkylation with methyl iodide is an alternative to the diazomethane technique [43,140]. Acetylation has been shown to give comparable recoveries of OH-PCB derivatization as the methyl iodide and diazomethane approaches to OH-PCB methylation [139]. Silylation reactions have also been applied for the derivatization of various OH-PCBs [137]. 

Evodia elleryana also contains evellerine (165), a derivative of 7-hy-droxydictamnine. Evellerine was shown to be a 4-methoxyfuroquinoline by conversion into the isoalkaloid isoevellerine (166) by heating with methyl iodide. Isoevellerine furnished a monoacetyl derivative, and yielded 7-methoxyisodictamnine when heated with sodium hydroxide and dimethyl-sulfate. The structure of the side chain in evellerine was established by reaction of isoevellerine with periodate and the identification of acetone... 

If nitrogen heterocycles have basic properties, the preparation of picrates, chloroplatinates, or the quaternization of the heterocyclic nitrogen with methyl iodide (see p. 326) is recommended this is true especially for pyridine-, pyrroline-, and quinoline-type bases. Tetraphenylboranates (111) are also suitable for the identification of nitrogen heterocycles. For their preparation see p. 331. The preparation of quinoline picrate is described on p. 330. 

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