A
gradient elution program was applied for chromatographic analysis (Table 1).
In the findings of a published study by Geng in the Journal of Science China Chemistry on the two variable-theory of peptides under
gradient elution in 2017, a dynamic separation method for the rapid identification and improvement of the selectivity of peptides achieved by simply changing the mobile phase flow-rate (MPF-R).
Initially, a gradient run from 2% to 92% was achieved to determine whether isocratic or
gradient elution was appropriate [9].
speciosum extract from three different batches was performed using a rapid high-performance liquid chromatography method under the conditions using
gradient elution with a mobile phase of acetonitrile-water, as previous described by our group [8].
The water (containing 0.1% formic acid and solvent A) and acetonitrile (solvent B) was used as mobile phase with
gradient elution. The gradient was as follows: 0 min 5% B, 0.5 min 5% B, 2.0 min 80% B, 2.1 min 5% B, and 3.0 min 5% B, and then stopped.
The four synthetic food dyes are efficiently separated using an optimized
gradient elution in a single run within 15.1 min.
Gradient elution was performed with (A) 80% methanol and (B) 20% water (pH 3.5 modified by o-phosphoric acid) at flow rate of 1.0 mL min-1 after filtration through 0.45 um pore size.
The fractionation of the ethyl acetate extract was done through a series of
gradient elution normal phase gravity column chromatography (GCC) on a 60 - 230 mesh silica gel stationary phase [11].
Recommendations are made concerning initial column selection and the choice of isocratic or
gradient elution approaches.
The described method of the prediction of retention time can substantially reduce the time required to find optimal conditions in
gradient elution.