DVDs and Videos > Chemistry

Prog07- Chromatographic Techniques Age: 16 Years-Adult; Time: 30 mins; Year: 1995 Format code; R = DVD, V = VHS, C = CD-ROM

Program Description

THIN LAYER CHROMATOGRAPHY Running time: 6:42 mins. Introduction to thin layer chromatography: the chromatography plate and choice of eluting solvent; carrying out the TLC process including: marking the plate, using a capillary tube to spot the plate, using a filter paper to saturate the atmos phere in the "tank" with solvent, adding solvent and plate to the "tank", the separation, removal of plate from the "tank" and subsequent drying; detecting spots using the naked eye, ultraviolet light, staining with iodine or dipping and spraying; interpreting the results; monitoring reactions; calculating Rf values. COLUMN CHROMATOGRAPHY Running time: 6:36 mins. Introduction to column chromatography with the use of TLC to pre-select the solvent system; selection and preparation of columns including: using a column with a frit or a glass wool plug, adding solvent/silica gel slurry to a column followed by recycling of solvent and elimination of air bubbles, using compressed air to force fresh solvent through ready for adding sample, adding sample; chromatography process: collection of eluent, analysis of eluent fractions by TLC, combination of eluent fractions and subsequent concentration by evaporation using a rotary evaporator. ION EXCHANGE CHROMATOGRAPHY Running time: 8:15 mins. Introduction to ion exchange chromatography; preparation of ion exchange resin by suspension in deionised water; preparation of an ion exchange column; addition of resin slurry to column; draining off excess water; regeneration of old exchange resin by adding 6M hydrochloric acid followed by addition of deionised water and testing of washings with an indicator; ion exchange chromatography: addition of sample, eluting and testing eluent with indicator, and titrating the acid eluent with standard alkali using an indicator. GAS CHROMATOGRAPHY Running time: 7:43 mins. Introduction to the gas chromatograph: packed and capillary columns, ovens, mobile phase/carrier gas e.g. nitrogen or helium; operating the gas chromatograph: setting the injector- port and oven temperatures, dissolving the sample in a solvent(diethyl ether), injecting the sample onto column, using a gas syringe and loop to present gaseous samples; detection of eluents and brief description of detectors available; discussion of retention times and their signifi cance; identification of unknown compounds.