Systematic Evaluation of Chromatographic Parameters for Isoquinoline Alkaloids on XB-C18 Core-Shell Column Using Different Mobile Phase Compositions

Figure 2

Exemplary chromatograms of the standard mixture obtained at (a) acetonitrile and 10 mM water solution of ammonium formate adjusted to pH 4 with formic acid (20 : 80, v/v), (b) acetonitrile and 20 mM water solution of ammonium acetate adjusted to pH 4 with acetic acid (20 : 80, v/v), and (c) acetonitrile and 10 mM water solution of ammonium acetate adjusted to pH 4 with acetic acid (20 : 80, v/v). (1) protopine, (2) allocryptopine, (3) chelidonine, (4) coptisine, (5) sanguinarine, (6) berberine, and (7) chelerythrine.