Lab.1. Thin-layer chromatography REPORT NAME………………………………………….. FIRST NAME:……………………………………………. STUDENT GROUP…………………………………….. DATE OF LABORATORY……………………………… PART I ELUOTROPIC SERIES OF SOLVENTS IN SYSTEM WITH SILICA GEL Table.1. The values of migration distance (mm) and retardation factor, RF, of solutes in systems with silica gel and different solvents, is the elution strength Hexane Toluene Acetone Solute = 0.00 = 0.22 = 0.56 The solvent front migration distance, start – finish (b) Migration RF Migration RF Migration RF Colour of the distance distance distance dye (a) (a) (a) Dye 1 Colour ……. Dye 2 Colour……. Dye 3 Colour ……. Dye 4 Colour …… Mixture 1 Lab.1. Thin-layer chromatography Formula to use: RF = a/b, RF – retardation factor Answer the questions: Which solvent is characterized by the highest elution strength? Arrange the eluotropic series for solvents/eluents used. What components comprise the investigated sample mixture? Table 2. The values of separation factor, α, of solutes chromatographed in systems with silica gel and different solvents, is the elution strength Hexane Toluene Acetone Solute = 0.00 = 0.22 = 0.53 Separation factor Separation factor Separation factor Dye 1/ Dye 2 Dye 2/ Dye 3 Dye 3/ Dye 4 Formulas to use: Place for calculations: 2 Lab.1. Thin-layer chromatography Answer the questions: Indicate chromatographic system, which is characterized by the highest values of separation factor? Indicate the chromatographic system, which facilitates good separation of all investigated mixture components. PART II. ELUOTROPIC SERIES OF SOLVENTS IN TLC SYSTEMS WITH ALUMINUM OXIDE Use the procedure from PART I, steps 1- 6, for aluminium oxide plates. Table.3. Migration distance (mm) and retardation factor, RF, values of solutes in systems with aluminium oxide and different solvents; is the elution strength Hexane Toluene Acetone Solute = 0.00 = 0.29 = 0.56 The distance of solvent front migration, start – finish (b) Migration RF Migration R Migration R Colour of the F F distance distance distance dye (a) (a) (a) Dye 1 Colour ……. Dye 2 Colour……. Dye 3 Colour ……. Dye 4 Colour …… Mixture 3 Lab.1. Thin-layer chromatography Answer the questions: Which solvent has the highest elution strength? Arrange the eluotropic series of solvents for chromatographic systems with aluminium oxide. Table 4. Separation factor, α, values of solutes in systems with aluminium oxide and solvents/eluents specified Formulas to use: Hexane Toluene Acetone Solute = 0.00 = 0.29 = 0.56 Separation factor Separation factor Separation (α) (α) factor (α) Dye 1/ Dye 2 Dye 2/ Dye 3 Dye 3/ Dye 4 Answer the question: For which solvent the separation factor shows the highest values? 4 Lab.1. Thin-layer chromatography PART III COMPARISON OF ELUTION STRENGTH OF SOLVENTS IN SYSTEMS WITH SILICA AND ALUMINA Table.5. The values of retardation factor, RF, obtained for the systems with silica gel and aluminium oxide Hexane Toluene Acetone Silica Aluminium Silica Aluminium Silica Aluminium Solute oxide gel gel gel oxide oxide Dye 1 Colour ……. Dye 2 Colour……. Dye 3 Colour ……. Dye 4 Colour …… Mixture Answer the question: Have you obtained the same results for the systems with silica gel and aluminium oxide ? If not then try to explain the difference/s? 5 Lab.1. Thin-layer chromatography PART IV ELUTION STRENGTH OF MIXED SOLVENTS IN SYSTEMS WITH SILICA GEL Table 6. Migration distance (mm) and retardation factor values of investigated solutes in the systems with silica gel and acetone + hexane Eluent 5% acetone in hexane 10 % acetone in hexane 40% acetone in hexane The migration distance of solvent front (start – finish) (b) Migration RF Migration RF Migration RF Colour of the dye distance (a) distance (a) distance (a) Dye 1 Colour ……. Dye 2 Colour……. Dye 3 Colour ……. Dye 4 Colour …… Colour of the dye Answer the question: Does composition of the mobile phase influence on migration distance of solute zone/s? Arrange the solvent mixtures/solutions in respect of their elution strength in silica gel system 6 .