Mixed-mode chromatography allows to separate various hydrophobic and hydrophilic drugs in one HPLC method. Presence of at least two mechanism of retention allows adjust selectivity of separation by changing three parameters: amount of acetonitrile, buffer concentration and buffer pH. Seven common drugs are separated on a Primesep C trimodal HPLC column in gradient method. Method provides alternative selectivity to traditional reversed-phase chromatography. Operational range in which basic compounds are retained the most is from pH 3 to 5. At higher pH, longer retention can be achieved. Mixed-mode chromatography provides longer retention and better peak shapes for basic and acidic analytes. Method can be used in analysis of drugs and pharmaceuticals.
Comparison of the Separation of Polar Drugs on Obelisc R and Zorbax SB-AQ
Common hydrophobic basic and hydrophilic basic drugs are separated by mixed-mode chromatography with greater selectivity and resolution than traditional reversed-phase column. Drugs are retained by combination of reversed-phase and cation-exchange mechanisms. Retention time is controlled by amount of acetonitrile, buffer concentration and buffer pH. Available detection techniques are based on buffer selection and include UV, Evaporative Light-Scattering Detector (ELSD), Corona (CAD), LC/MS, etc. This HPLC method can be adopted as general approach for analysis of drugs and pharmaceuticals.
HPLC Separation of Pseudoephedrine, Norephedrine, Phenylephrine, and Norphenylephrine Using Hydrogen Bonding Mode
Application Notes: Neurotransmitters are polar basic compounds. Several HPLC techniques are used to analyze these hydrophilic molecules. The most common techniques are reversed-phase with ion-pairing reagents chromatography, ion chromatography, HILIC, and mixed-mode chromatography. SIELC developed a new approach of analysis, which is based on hydrogen bond interactions. Hydrogen-bonding offers unique and alternative selectivity to traditional approaches like reversed-phase, HILIC, ion-exchange, and mixed-mode chromatography. Our methods are fully compatible with ELSD, LC/MS and prep chromatography.
Application Columns: SHARC 1, 3.2x100 mm, 5 um, 100A. To learn more about SHARC 1 columns click here. To order this column click here. To see more chromatographic separations check our web site.
Application compounds: Pseudoephedrine, norephedrine, phenylephrine and norphenylephrine
HPLC Separation of Norepinephrine on Legacy L1 Column
Norepinephrine was analyzed based on the United States Pharmacopeia. The Legacy L1 HPLC column is classified as a reversed-phase column according to USP manual. This column can be used for other methods which require this type of column. Legacy L1 can also be used instead of columns from other column manufacturers.