Most sorbents are general-purpose. Polyamide is not, and that is its strength. Before you add it to a method, it helps to be clear about the jobs it does well.
Examine: what the material is good at
Polyamide 6 retains compounds mainly through hydrogen bonding between their hydroxyl groups and the amide groups of the polymer. That gives it a clear profile: it has a strong affinity for phenolic compounds, and the affinity generally grows with the number of phenolic OH groups. Compounds without hydrogen-bond donors pass through comparatively easily.
Diagnose: the typical applications
These are the well-established uses we see described in the literature and in our customers' methods:
- Flavonoids and other polyphenols from plant extracts. Polyamide is a classic choice for fractionating flavonoid glycosides and aglycones. Elution usually starts in water and moves to increasing proportions of methanol or ethanol.
- Tannins and phenolic acids. Their many hydroxyl groups make them bind strongly. That is useful when you want to isolate them and equally useful when you want to remove them.
- Clean-up of natural-product extracts. Where polyphenols interfere with the analysis of other constituents, a polyamide step can hold them back while the compounds of interest pass through.
- Anthraquinones, coumarins and similar phenolic natural products. These appear regularly in phytochemistry protocols that call for polyamide columns.
Polyamide is often used alongside TLC on polyamide layers. Running a plate first, for example on POLYGRAM POLYAMID-6 UV254, 20x20 (SKU 803023), shows how your fractions will behave before you commit material to a column. Readers searching for "polymid CC" or "polyamid CC" are looking for the same column material.
Prescribe: matching grade to the job
- Analytical-scale clean-up and finer separations: Polyamide-CC 6, below 0,07 mm, 5 kg (SKU 8156105) or Polyamide-CC 6 (0,05-0,16 mm), 5 kg (SKU 8156205).
- Preparative gravity columns where flow rate matters: Polyamide-CC (0,10-0,30 mm), 5 kg (SKU 8156005).
Pack the material as a slurry in the starting eluent, as with other sorbents. Let it swell and settle before you load the sample. A plain gravity column such as the Chromatography-column 70 ml (SKU 2131003) from Witeg is enough for many method-development runs. You'll find larger formats in our glass and flash chromatography columns. The bench work around the column is ordinary lab practice: weighing the sorbent on a balance, preparing extracts in Erlenmeyer flasks, and stirring the slurry.
Where polyamide is the wrong choice
If your targets lack hydrogen-bond donors, or your method is built on normal-phase silica, polyamide will add a step without improving the separation. In that case, look at our sorbents, silica gel and ion exchangers instead.
Luminix Health supplies Macherey-Nagel polyamide grades as a distributor. If you want a second opinion on the grade or the pack size, send your method or the compound class you are working with to sales@luminixhealth.com and we will come back with a quote. We are ready to help.