Thin-layer chromatography has become so widely known in the space of a few years that it has proved necessary to gather into book form and thus make generally accessible the experimental material previously only available in isolated publications. As thin-layer chromatography can be used both for organic and inorganic matter as well as on quantities ranging from the nanogram to the microgram, it is impossible for anyone individual to possess sufficient laboratory experience or overall knowledge to produce a practical handbook that will be of real assistance to be­ ginner and specialist alike. For this reason, an international group was formed, who made it their task to produce the best possible treatise. In view of the present stage of development reached by thin-Iaycr chromatography, it seems specially apt that the authors should include yet unpublished work of their own. As thin-layer chromatography is used in many different fields in natural science and medicine, the kind of brief description of materials intelligible only to the expert has been avoided. The short guides to the chemical properties of the groups to be separated, their names, and relevant bibliographic details should facilitate introductory studies arid make possible a close acquaintance with the material in hand. It also seemed advisable to give brief details of the analytical classification of material, which is so often necessary. Although the classification used may appear unusual, it is in fact pre-eminently suitable to thin-layer chromatography.

General Section.- A. History of the Development of Thin-Layer Chromatography.- B. Instruments used in Thin-Layer Chromatography and their Operation.- I. The application of thin layers to carrier plates.- Thin-layer spreader.- a) Aligning tray.- b) Positioning of the spreader.- c) Adjustment of layer thickness.- d) Filling of spreader and application.- e) Cleaning and storage of spreader.- II. Drying, storage and handling of TLC-plates.- III. Preparation of TLC-plates for use in chromatography.- a) Checking dried thin layers.- b) Stripping of thin-layer edge.- c) Marking the layer.- d) Instruments for application of spots.- e) Streak application of larger quantities of mixture for micro-preparative thin-layer chromatography.- IV. Separation chambers and conditions of saturation.- 1. Saturation and edge effects.- 2. Assembly of chambers (temperature, light, protection against oxidation).- 3. Chambers for ascending development.- a) Rectangular trough chamber.- b) S-Chamber system.- 4. Equipment for descending development.- 5. Equipment for horizontal development.- a) Circular technique.- b) Horizontal method in closed tank.- c) Continuous flow technique (BN-Chamber).- 6. Apparatus for electrophoresis and ionophoresis in thin layers of adsorbent.- V. Spraying equipment and fume hoods.- VI. Standard conditions in thin-layer chromatography.- VII. Basic equipment for use in thin-layer chromatography.- C. Coating Materials for Thin-Layer Chromatography.- Further properties of adsorbents.- Additional adsorbents and adsorbent combinations.- Storage and treatment of adsorbents.- D. Special Techniques.- 1. Continuous flow, and multiple development techniques.- 2. Wedged-tip technique.- 3. Two-dimensional separation, SRS-technique.- 4. Variation in the separation characteristics of a layer.- Bibliography to Chapters A-D, General Section.- E. Documentation of Thin-Layer Chromatograms.- F. Quantitative Evaluation of Thin-Layer Chromatograms.- I. Determination without extraction of separated substances from the chromatogram (Method I).- 1. Method of visual comparison.- 2. Evaluation by photographic methods.- 3. Photo-densitometric determination after staining.- 4. Autoradiographic evaluation.- II. Determination of separated substances after extraction (Method II).- 1. Location by color or fluorescence.- 2. Use of fluorescent layers.- 3. Staining of separated substances before extraction.- 4. Other methods of locating separated substances.- Bibliography to Chapters E and F, General Section.- G. Isotope Techniques.- I. Layers, solvents, and chemical methods of detection.- II. Methods of detecting radiation.- 1. Autoradiography.- 2. Counting tubes and scintillation counters.- III. Preparation of radioactively labelled substances.- IV. Isolation of radioactive compounds by thin-layer chromatography.- V. Analysis by means of radioisotopes.- 1. Indicator analysis.- 2. Isotope dilution analysis.- 3. Activation analysis.- 4. Isotopic derivative method.- a) Fractionation before radioactive labelling.- b) Separation of radioactive derivatives.- c) Fractionation after adding a radioactive derivative to the mixture of non-labelled derivatives.- d) Separation after adding an inactive derivative to the mixture of radioactively labelled derivatives of the compound to be determined.- e) Application of two different radioactive isotopes.- VI. Procedures for radioactive labelling.- 1. Esterification of acids with diazomethane, C14H2N2.- 2. Acetylation of alcohols with acetic anhydride (C14H3CO)2O or (CH33CO)2O.- VII. Application of thin-layer chromatography in chemical and biochemical investigations with radioisotopes.- Bibliography to Chapter G, Isotope Techniques.- H. Theoretical Aspects of Thin-Layer Chromatography.- General Remarks.- I. General theory of chromatography.- 1. An introductory experiment.- 2. Another experiment.- 3. The model.- 4. The chromatographic column.- a) Comparison with the model.- b) Developing a chromatogram.- c) Elution.- d) Estimation of the number of theoretical plates and of the height equivalent to a theoretical plate (HETP).- e) Gross deviations from ideal behavior.- 5. Summary and concluding remarks.- II. Chromatographic behavior and chemical structure.- 1. Relations of the partition coefficient and phase ratio to the Rf-value and retention volume.- 2. Qualitative rules.- 3. Quantitative relations: the Martin-relation.- a) Definition of the Rm-value.- b) Application of the Rm-value.- c) Exceptions.- III. Particularities of thin-layer chromatography.- 1. Features analogous to paper chromatography.- a) Migration and distribution of the solvent, Rf and Rm values.- ?) Single component solvents.- ?) Multicomponent solvents; chromatographic demixing of the solvent.- b) Quantitative evaluation of thin-layer chromatograms.- 2. Differences between thin-layer chromatography and paper chromatography.- 3. Relations to column chromatography.- Addendum: Displacement and ion exchange on thin-layer chromatograms.- List of symbols.- Bibliography to Chapter H, Theoretical Aspects of Thin-Layer Chromatography.- Special Section.- Mixture to be separated.- Solvent.- Adsorbent.- A. Aliphatic Lipids.- I. Introduction.- 1. Neutral lipids and their hydrolysis products.- 2. Phospholipids, sulpholipids, and glycolipids.- 3. Older methods of lipid analysis.- 4. New procedures for the fractionation of lipids.- 5. Preparation of the sample for analysis.- a) Homogenization and extraction.- Preparation of vegetable lipids.- Extraction of animal lipids.- b) Saponification and esterification.- II. Thin-layer chromatography of lipids.- 1. Separation of lipids according to classes of compounds.- a) Neutral lipids and their hydrolysis products.- Experimental conditions.- Applications and results.- ?) Fats, oils, and waxes.- ?) Free fatty acids and simple fatty acid derivatives.- b) Phospholipids, sulpholipids, and glycolipids.- Experimental conditions.- Applications and results.- c) Applications of thin-layer chromatography for structural analysis of lipids.- 2. Fractionation of homologous series.- a) Procedures for fractionating short-chain compounds.- Experimental conditions.- b) Procedures for separating long-chain compounds.- Experimental conditions.- Applications and results.- 3. Separation of lipids according to their degree of unsaturation.- a) Preparation of mercuric acetate derivatives.- b) Experimental conditions.- c) Rec…