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If the contents of the square bracket are denoted by — K\ the solution to Eq. 23) is simply: x= (2 24) wr + κ"' · where K" is another constant. 25) P = P0) when x = I. Substituting these in Eq. 26) 26 2. RETENTION VOLUME AND COLUMN VARIABLES When these are substituted back in Eq. 24), the result is an equation for the pressure at any point in the column, x T P? 27) The other quantities in the equation, P0, P{, and I, are all easily measurable. 3 shows a plot of P\P0 as a function of xjl for various values of the pressure ratio across the column, PiJP0.

47), and substituting the result into Eq. 50), R * = (a + mß) ri ! + * [ ! 51) If tR is the retention time for the case of limitingly small vapour concentration, then: *Ä* — ^Ä( 1 k 2c' Ämax ^ ^ Ι . 02 mole fraction. Also, the term in k is usually close to unity. It is thus possible for this effect to produce definite errors in retentions of several percent. In the case of a mixture with components in very unequal proportions, it is clear that the effect can also influence relative retentions. 9 shows a set of peaks of different samples of chloroform chromatographed in dinonyl phthalate (18), and illustrates a case in which retention decreases with sample size.

During its passage through the column, the gas acquires the temperature of the column, and thus, by a simple extension of Charles' law, if the flowmeter is calibrated at Tf°K, and the column is at TC°K, VTo = VTf X A . 39) In Eq. 38), the quantity V0 pertains to column temperature, and therefore must be calculated from the flow rate measured by a flowmeter calibrated at Tfhy Eq. 39). Note in this connection that T^is the temperature of the gas by which the flowmeter is calibrated, and not necessarily the temperature of the flowmeter.