Parameters 

CHIRALPAK ^® QN-AX / CHIRALPAK ^® the QD-AX

A CHIRALPAK ^® QN of-AX and a CHIRALPAK ^® the QD-AX is a weak anion exchange chiral column, can be used for separation of chiral acidic compounds, particularly suitable for containing a carbonyl group split, a phosphoric acid group or an acidic compound phosphonic acid group.

The elution order of QN-AX and QD-AX is opposite.

Commonly used reverse phase elution mode, can also use pure polar organic solvent as the mobile phase (containing acid or alkali anhydrous organic solvent)

All chromatographic solvents are suitable, such as methanol, acetonitrile, THF, dioxane, chloroform and the like.

Acetic acid, formic acid, phosphoric acid can be used as the buffer in the reverse phase mobile phase. 

CHIRALPAK ^® QN-AX: silica surface is covalently bonded to -O-9- (t-butyl carbamoyl) quinine

CHIRALPAK ^® the QD-AX: silica surface is covalently bonded to -O-9- (t-butyl carbamoyl) quinidine

These columns are enatioselective weak anion-exchange (AX) HPLC columns. They were developed by Prof. W. Kindber's group in Vuena and are designed specifically for enantioselective HPLC of chiral acids and possess exceptional enantiomer separation capabilities for acidic chiral compounds containing carboxylic, phosphoric, phosphoric or sulfonic acid groups. In some cases, weakly acidic compounds such as phenols can also be separated.

Operating Procedures

CHIRALPAK ® QN-AX and CHIRALPAK ®

QD-AX have been developed as enantioselective weak anion-exchange (AX) HPLC columns most useful for the separation of acidic chiral compounds, based on two complementary stereoisomeric quinine (QN) and quinidine (QD) derivatives. Owing to their pseudo-enantiomeric character they usually reveal reversed elution order for opposite enantiomers

They can be used in polar organic mode (non-aqueous, polar organic solvents containing organic acids and bases as buffer constituents) or in reversed-phase (RP) mode. CHIRALPAK ® QN-AX and CHIRALPAK QD-AX are designed specifically for enantioselective HPLC of chiral acids and possess exceptional enantiomer separation capabilities for acidic chiral compounds containing carboxylic, phosphonic, phosphinic, phosphoric or sulfonic acid groups. In some cases, weakly acidic compounds such as phenols (e.g. coumarols) can also be separated.

They are compatible with all common HPLC solvents (e.g. methanol, acetonitrile, tetrahydrofuran, dioxane or chloroform) as well as in a wide pH range spanning from pH 2 to 8. Typical buffers used in hydro-organic mode are acetate, formate, citrate and phosphate. They are capable for use in LC-MS detection of chiral acids with compatible mobile phases and buffers (e.g. ammonium acetate, ammonium formate).

In addition, the separation of chiral basic and neutral compounds may also be possible, but usually under normal phase (NP) conditions or if preferred in RP-mode with higher aqueous content. In NP-mode, CHIRALPAK QN-AX and CHIRALPAK ® QD-AX behave like a standard Pirkle type chiral stationary phase. 

Column Care/Maintenance

Before initial use, the column should be flushed with at least 20 column volumes (ca. 30 ml for a 150 x 4.6 mm i.d. column) of 1% (v/v) acetic acid in methanol. The column should then be equilibrated in 20 column volumes of the initial mobile phase.