The volume of mobile phase passing through the column in unit time. The flow rate is usually measured at column outlet, at ambient pressure (\(p_{\text{a}}\)) and temperature (\(T_{\text{a}}\), in \(\text{K}\)); this value is indicated with the symbol \(F\). If a water-containing flowmeter was used for the measurement (e.g. the so-called @S05721@ bubble flowmeter) then \(F\) must be corrected to dry gas conditions in order to obtain the mobile phase flow rate at ambient temperature (\(F_{\text{a}}\)): \[F_{\text{a}}=F\ (1- \frac{p_{\text{w}}}{p_{\text{a}}})\] where \(p_{\text{w}}\) is the @P04420@ of water vapour at ambient temperature. In order to specify chromatographic conditions in @C01182@, the flow-rate (mobile phase flow rate at column temperature, \(F_{\text{c}}\)) must be expressed at \(T_{\text{c}}\) (@K03374@), the column temperature: \[F_{\text{c}}=F_{\text{a}}\ \frac{T_{\text{c}}}{T_{\text{a}}}\]