Aminex HPLC columns are packed with a polymer-based matrix (polystyrene divinylbenzene). They separate compounds using the ion-moderated partition chromatography technique.
HPLC separations using Aminex columns employ the mechanisms of ion exclusion, ion exchange, ligand exchange, size exclusion, reversed phase, and normal phase partitioning. These multiple modes of interaction offer a unique ability to separate compounds. Several Aminex columns are available for small acidic and polar molecule analysis.
Aminex columns allow the use of simple isocratic methods, eluting with water or dilute acid. There is minimal sample preparation, usually just filtering through a 0.45 μm filter with no derivatization necessary. Aminex media have a high pressure stability, wide pH stability, and high column efficiency and selectivity.
Aminex columns are an industry standard for the analysis of organic acids and alcohols.Bio-Rad offers organic acid columns for simple, yet specific methods of food and beverage analysis. Use our selection guide to choose the column that fits your application needs.
Aminex HPX-87H Column
This hydrogen-form, 300 x 7.8 mm column performs most analyses in about 20 minutes, with sensitivity to the nanogram level. A simple isocratic elution with slightly acidified water is all that it takes to analyze organic acids in most samples, and filtration is the only sample preparation required before injection. Separations can be performed from ambient temperature to 60°C at flow rates of 0.4–1.0 ml/min. When many compounds in a formulation must be analyzed, or when high-resolution separations are required, this is the column of choice.
Fast Acid Analysis Column
This hydrogen-form, 100 x 7.8 mm column is optimized for the analysis of alcohols, glycols, and hydrophobic organic acids. Typically, analyses can be shortened 4-fold over those obtained with research-length columns. Because the fast acid column is shorter, components elute as taller, narrower peaks. Detection limits are improved, and smaller sample loads can be used. This column provides fast separations of specific organic acids in samples where only certain components are of interest. With these columns, analyses can be completed in 3–5 minutes. As with the Aminex HPX-87H column, dilute sulfuric acid is the only eluent used, and filtering is generally the only sample preparation required.
Fermentation Monitoring Column
This hydrogen-form, 150 x 7.8 mm column is optimized to resolve maltotriose, maltose, glucose, and fructose while also resolving acids and alcohols. When analysis of sugars in a fermentation broth is required, this is the column of choice. Dilute sulfuric acid is the only eluent used, and filtering is generally the only sample preparation required.
Aminex HPX-87C Column
This calcium-form, 300 x 7.8 mm column can be fine-tuned for organic acid analysis by using an eluent that contains a mixture of water, calcium sulfate, sulfuric acid, and acetonitrile. It is also suited for analyzing organic acids in combination with carbohydrates.