Inorganic salts as hold-up time markers in C18 columns

Effect of temperature on the chromatographic retention of ionizable compounds. III. Modeling retention of pharmaceuticals as a function of eluent pH and column temperature in RPLC

“…This behavior has also been observed previously [16,42,43]. Due to these differences found in the hold-up time measurements, the values obtained with all the mobile phases at a given temperature were averaged.…”

New insights on the retention mechanism of non-polar solutes in reversed-phase liquid chromatographic columns

“…The obtained experimental data corrected for the extra-column volume and in terms of ln k versus ϕ are shown in Tables 1-4. The hold-up time, t 0 , was measured by injection of 0.01% KBr [27,28]. These values of t 0 were further verified by indicative measurements using water instead of KBr as the t 0 marker [22].…”

Prediction of the chromatographic retention of acid–base compounds in pH buffered methanol–water mobile phases in gradient mode by a simplified model

“…The hold-up time of the chromatographic system, including the precolumn, was determined by means of a solution of KBr as unretained solute at a concentration of 100 ppm and detected at 190 nm [39]. The dwell time of the system was determined with methanol and acetone as described [40].…”