An open tubular gas chromatography column is 35.7 m long and has an inner diameter of 0.250 mm. It is coated on the inside wall with a layer of stationary phase that is 1.8 µm (0.0018 mm) thick. Unretained solute, methane, passes through in 6.39 min, whereas toluene has a retention time of 16.35 min. Calculate the retention factor for toluene.

The retention factor, k is 2.49

Explanation:

According to the theory of High-Performance Liquid Chromatography (HPLC), the retention factor (or capacity), k, of a column is the ratio of the retention time of a retained analyte (toluene) to that of the  un-retained solute (methane).

This implies that:

k =  =  

 retention factor, k  = 2.49.

Note that there is no unit for retention factor, as it is a ratio.

answer : (a) volume of the gas = 8.67 ×   l

                (b) second virial coefficient b = -1.21226 l/mole

solution :   given,     t = 300k

                                p = 20atm

                                z = 0.86

                                n = 8.2 mmoles = 8.2 × moles

                                r =   0.082 l atm/k/mol

        find,     (a) volume of gas   and (b) second virial coefficient b at 300k.

formula used :            

                          and            

(a)            

                    = \times 0.082\times 300}{20}[/tex]

                    = 8.67 ×   l

(b)      

                    = (0.00867-1) × 8.659

                    = - 8.5839 l/mole