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Retention Characteristics of Betaine in Mixed-Mode HPLC |
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Application Notes:
The retention of the zwitterion betaine on Primesep 200 demonstrates the tunability of Primesep columns. Retention of betaine is altered by acid type, amount of acid in the mobile phase, and the amount of organic solvent. Typical reversed-phase columns do not show this tunability with simple mass spec compatible mobile phases of water, acetonitrile (MeCN, ACN) and trifluoracetic acid (TFA) with evaporative light scattering detection (ELSD).
Application Columns:
- Primesep® 200 is a mixed-mode HPLC column with general hydrophobic and ion-exchange properties. The Primesep 200 stationary phase combines a hydrophobic chain and a weakly acidic functional group as a cation exchanger. Acids, bases, zwitterions and neutrals can be retained and separated by Primesep 200 columns. Primesep 200 retains hydrophobic compounds by reversed-phase retention alone or a combination of reversed-phase and ion-exchange retention. Primesep 200 separates underivatized amino acids, amines, isomers and structurally related compounds by combining reversed phase and ion exchange. In this case the acidic functional group acts as an embedded ion-pairing reagent. Organic acids and diacids are separated by reversed phase and ion exclusion. Methods can be developed on Primesep columns that are fully compatible with detectors such as UV, RI, conductivity, fluorescence, evaporative light scattering (ELSD) as well as mass spectrometers (LC/MS) and preparative chromatography (prep HPLC) systems.
Application Analytes:
Application Detection:
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HILIC Separation of Carboxymethylcysteine and Betaine |
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Application Notes:
Application Columns:
- Obelisc N columns are the first commercially available columns with Liquid Separation Cell technology (LiSC). With multiple patents pending, LiSC technology is based on a new chemical modification of silica gel pores that creates a liquid separation cell with its own charge characteristics, ionic strength, and hydrophobic properties. Like living cells which exist in equilibrium with the outside environment, liquid separation cells exist in constant equilibrium with the mobile phase. Obelisc N, for normal phase, has very polar characteristics and works well for polar and charged analytes. In ion-exchange mode, charged analytes interact with oppositely charged groups on the stationary phase. In traditional HILIC mode, a charged or neutral polar analyte interacts with a water layer on the polar stationary phase surface. On Obelisc N the charges are greatly separated and independently accessible which results in different selectivity compared to traditional HILIC and silica columns. Mobile phase composition changes the conformation of the long hydrophilic chain. This affects the properties of the liquid separation cell and changes separation selectivity. Typical mobile phases used with Obelisc N columns are based on acetonitrile, water, and the mass spec compatible buffers ammonium formate (pH 3) and ammonium acetate (pH 5). If it is necessary to detect in low UV (<220 nm) then phosphate buffer is recommended. Obelisc N columns are compatible with mass spectrometers (LC/MS), evaporative light scattering detectors and preparative chromatography (prep HPLC) system.
Application Analytes:
Application Detection:
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