Amine-bonded chromatography columns

Nikolov, Z., Meagher, M., and Reilly, P., High-performance liquid chromatography of trisaccharides on amine-bonded silica columns, J. Chromatogr., 321, 393, 1985. 

A short column packed with an amine bonded polymer (weak anion exchange material) connected prior to the anion separation column was found to be very effective for the selective removal of humic substances prior to anion separation by ion chromatography. About 500 sample injections could be performed before breakthrough of humic substances occurred as indicated by ultraviolet measurements made on the eluate at 225nm. 

Hydrophilic interaction chromatography on Asahipak NH2P or Excel-pak CHA-P44 with pulsed amperometric detection has been used to fractionate malto-oligosaccharides.266 The Asahipak NH2P is a polyvinyl alcohol support with a polyamine bonded phase, and the Excelpak is a sulfonated polystyrene in the Zn+2 form. Amine adsorption of sialic acid-containing oligosaccharides was performed on a Micropak AX-5 column (Varian) using acetonitrile-water-acetic acid-triethylamine.267... 

The TLC process is an off-line process. A number of samples are chromatographed simultaneously, side-by-side. HPTLC is fast (5 min), allows simultaneous separation and can be carried out with the same carrier materials as HPLC. Silica gel and chemically bonded silica gel sorbents are used predominantly in HPTLC other stationary phases are cellulose-based [393]. Separation mechanisms are either NPC (normal-phase chromatography), RPC (reversed-phase chromatography) or IEC (ion-exchange chromatography). RPC on hydrophobic layers is not as widely used in TLC as it is in column chromatography. The resolution capabilities of TLC using silica gel absorbent as compared to C S reversed-phase absorbent have been compared for 18 commercially available plasticisers, and 52 amine and 36 phenolic AOs [394]. 

As shown by mass spectrometry and NMR spectroscopy, these amine derivatives of Cgfl, after work up, are dehydrogenated adducts [81]. After nucleophilic addition, the H atoms brought in by the diamines were oxidatively eliminated. The final adduct formation of the secondary diamines proceeds exclusively at [6,6] bonds. Besides the monoadduct, most of the regioisomeric bisadducts of piperazine or N,N -dimefhylethylenediamine and Cjq could be separated by column chromatography. The structure of the monoadduct and some of these bis-adducts were proven by X-ray crystal-structure analysis [90]. 

Figure 15. Open tubular liquid chromatography of amine-NBD derivatives using on-column fluorescence detection. Peaks correspond from left to right to ethylamine, n-propylamine, n-butylamine, cyclohexylamine, and n-hexylamine. Conditions 20-p.m X 8.3-m column with C-18 bonded phase 20% acetonitrile and 80% water (v/v) mobile phase at a linear velocity of 0.50 cm/s on-column injection of 5 nL. (Reproduced from reference 59. Copyright 1984 American Chemical Society.)...

In some cases of gas-liquid partition chromatography, as well as in the solid-liquid type just discussed, H bonds have been proposed as an important factor in achieving some separations. James (1031) describes successive passage through columns having stationary phases of differing H bond properties to separate 15 aliphatic amines. James, Martin, and Smith (1033) also effected separation of some amines by changing the liquid composition. Bradford, Harvey, and Chalkley (257, 884) used a similar method to separate unsaturated hydrocarbons. In this case, the... 

A dual column system has been described in which a complex mixture of saccharides from cell wall hydrolysates were separated on a chemically bonded amine colunm (Blaschek, 1983). The saccharides in the unresolved peaks were then further resolved by using cation-exchange chromatography which facilitated a baseline separation of all the carbohydrate components present in the extract. 

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