Parameters:
(1) The injection point is the time when material is entered into the system. This is the reference time from which other points are measured (t = 0).
(2) The height of the compound peak and preferably the area under the curve for the compound peak are used to measure the amount of that compound present.
(3) The capacity factor is a measure of the amount of time that a solute molecule spends in the stationary phase relative to the time it spends in the mobile phase. It is related to the retention time of the compound. The retention of a solute can be increased by increasing the amount of the stationary phase relative to that of the mobile phase.
capacity factor = retention factor =
= ((time in seconds to peak height for the compound of interest) - (time in seconds to peak height for a nonretained compound)) / (time in seconds to peak height for a nonretained compound)
corrected retention time =
= ((time in seconds to peak height for the compound of interest) - (time in seconds to peak height for a nonretained compound))
where:
• Optimal values for the capacity factor is between 2 and 6. Values between 1 and 10 can be used in actual practice.
• If the capacity factor is too small, then resolution of compound from others with similar characteristics may be poor. If the capacity is too high, then the width of the compound's peak may be too broad.
