Which HPLC column should be used to separate a mixture of amino acids?

Reversed phase HPLC, where the column material is hydrophopic. The amino acids are eluted by a gradiend of increasing amounts of an organic solvents, such as acetonitrile

I would use a reverse phase column, i.e. a column with some sort of organic stationary phase e.g. stationary phase containing methyl group coated or bonded onto the main frame of the column. This type of column should retain my hydrophobic groups thus resulting in an effective separation.

SUPELCOSIL .

Particles size 3 microns As well as eclipse xDB-C18

Use TLC/ Column is best method to separate bulk amino acid.  and exactly you want to do means now HPLC - C2 column and oversize also available for separation,

For a separated, identify, and quantify each component in a mixture. Is being used technique in analytical chemistry, which is high-performance liquid chromatography (HPLC; formerly referred to as high-pressure liquid chromatography). It has the operational pressures that are significantly higher (50 –350 bar) compared with traditional ("low pressure") liquid chromatography, which depends on the force of gravity to pass mobile phase through the column. Typical column dimensions are 2.1–4.6 mm diameter, and 30–250 mm length. Also HPLC columns are made with smaller sorbent particles (2–50 micrometer in average particle size). This gives HPLC superior resolving power (the ability to distinguish between compounds) when separating mixtures, which makes it a popular chromatographic technique.  The basis of her work as an HPLC instrument , typically includes a sampler, pumps, and a detector. The sampler brings the sample mixture into the mobile phase stream which carries it into the column. The pumps deliver the desired flow and composition of the mobile phase through the column. The detector generates a signal proportional to the amount of sample component emerging from the column, hence allowing for quantitative analysis of the sample components. Some HPLC techniques use water-free mobile phases. The aqueous component of the mobile phase may contain acids (such as formic, phosphoric or tri fluoro acetic acid) or salts to assist in the separation of the sample components. The composition of the mobile phase may be kept constant ("isocratic elution mode") or varied ("gradient elution mode") during the chromatographic analysis.

Reveased phase HPLC with hydrophobic stationary phase.

phenyl isothiocyanate, o-phthalaldehyde and dansyl chloride columns are suitable.

RP-HPLC we can use to seperate amino acis 

REVERSE PHASE COLUMN CHROMATOGRAPHY

Amino acids can be separated using either a reversed phase column or an ion exchange column. The method almost always requires a gradient, and usually some form of derivatisation to enable detection with a UV or fluorescence detector. Shodex offer two columns for amino acid analysis. The first is the Shodex CXpak P-421S (4.6mmID*150mm), a cation exchange column, which is suitable for a broad spectrum of amino acids. Under most circumstances, this is the column of choice. Analysis times are around 50 minutes, using a citrate buffer gradient. There is also RSpak NN-814, a polymer-based reversed phase column packed with polyhydroxymethacrylate bonded with trace amounts of sulfo groups. This gives a mixed mode separation, which can be used to separate certain amino acids which are not easily separable using the CXpak column. The elution order is different. Acidic amino acids, such as aspartic acid, are separated by ion exclusion mode and elute faster. Neutral substances are separated by reversed phase and alkaline amino acids are separated by a mixture of reversed phase (in case of hydrophobic structure) and ion exchange mode. Therefore, amino acids basically elute in the following order: first the acidic amino acids, second the neutral amino acids and finally the alkaline amino acids.

Reversed phase HPLC column, where the column material is hydrophopic.