Experiment 32 Gas Chromatographic Analysis of a Tertiary Mixture

A mixture of pentane, hexane, and heptane is separated by gas chromatography. A number of different types of colutrms can be used, and a simple thermal conductivity or hot wire detector is satisfactory. The instrument response for each compound is calibrated by running a standard mixture of the compounds. The order of separation is determined by miming the individual compounds. 

An alternative experiment is to analyze a two-component mixture of n-hexane and n-heptane, and use n-pentane as an internal standard. 

To prepare. Standard mixture. Prepare the following standard mixture re-pentane (5.00 mL), re-hexane (10.00 mL), re-heptane (15.00 mL). All mixtures 

Obtain an unknown mixture from the instructor. Check the instrument instructions and your instructor regarding the operation of the chromatograph. Do not make any temperature adjustments. Using the appropriate syringe for the instrument, obtain chromatograms of each separate component of the mixture, three chromatograms of your standard mixture, and three chromatograms of your unknown. 

Having obtained the necessary data, leave the instrument in the manner prescribed by the instructor. Especially important is the decrease in gas flow and adjustment of filament conditions to a stand-by state. Also, clean, rinse, and dry with acetone all syringes and vials. 

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