ABSTRACT
Alkaloids ...................................................................................... 642 25.2 Sample Preparation for TLC Analysis....................................................... 648
25.2.1 Different Methods of Extraction.................................................. 649 25.2.2 Sample Purification and Concentration ....................................... 649
25.3 Systems and TLC Techniques Used in the Isoquinoline Alkaloids.......... 650 25.3.1 Normal Phase Systems ................................................................ 650 25.3.2 RP Systems .................................................................................. 660 25.3.3 Pseudo-RP Systems ..................................................................... 664 25.3.4 Special Techniques Used in TLC of Isoquinoline Alkaloids...... 665
25.3.4.1 Multidimensional TLC ............................................... 665 25.3.4.3 Forced-Flow Techniques ............................................ 672
25.4 Quantitative Determination by TLC and Densitometry ............................ 672 25.5 TLC of Isoquinoline Alkaloids in Preparative Scale................................. 674
25.5.1 Mode of Overloading................................................................... 674 25.5.2 Mode of Development ................................................................. 678
References ............................................................................................................. 679
To the isoquinoline group belongs numerous alkaloids having as main element molecule isoquinoline or tetrahydroisoquinoline ring. Among isoquinoline alkaloids
eight main types (groups) of compounds are distinguished (see Table 25.1). There are following groups of alkaloids: benzylisoquinoline and benzyltetraisoquinoline group, aporphine group, protoberberine group, benzophenantridine group, protopine group, phthalideisoquinoline group, morphinane group, and emetine group. Moreover special group of isoquinoline alkaloids of dimeric structure-bis-benzyloisoquinoline alkaloids-is also included into isoquinoline group.
