Eluent conditions forODP, C8P, C4P:
Asahipak ODP, C8P and C4P columns can be used with eluents containing water, methanol and acetonitrile. In general, acetonitrile aqueous solutions provide greater efficiency, especially for compounds containing an aromatic ring.
For control of pH within the range of pH 2 to 13, phosphate, acetate, tris-HCl, NaCl, KCl, Na2SO4, and trifluoroacetic acid buffers can be used. Please consult your Asahipak representative if you have questions about buffering agents not listed above. It is important to note that the mobile phase should be filtered before use.
Adding organic solvents to salt and buffer solutions can lead to precipitation of the salt. Precipitation can occur in the column, which will often cause a catastrophic rise in the pressure across the column. If this does occur, try washing out the precipitate by reversing the flow on the column with distilled water. Use a slow flow rate initially to keep the back pressure low, below 15 MPa.
It is important to check the solubility of mixed solvent buffers before running a solvent program. This can be done by making a quick scouting run in a test tube. Slowly add the strong eluent to a small quantity of the starting eluent. If the solution turns cloudy or white, this means a precipitate is forming. Other buffer combinations should be tried. If in doubt, consult your representative.
Eluent Conditions for NH2P:
(1) Water, acetonitrile, and ethanol, either singly or in mixtures of any ratio, may be used as eluent. With aqueous ethanol solutions, the flow rate should be lower than normal, because of their relatively high viscosity.
(2) Various types of buffers soluble in acetonitrile or ethanol (such as tetrapropyl-ammonium acetate or sodium acetate) may be used together with the above components, so long as no observable precipitation occurs in the eluent.
(3) Eluents of pH 2.0 to 13.0 can be used.
(1) Buffer solutions such as phosphate, acetate, and tris, with or without NaCl, KCl, or Na2SO4, may be used.
(2) Eluents of pH 2.0 to 13.0 can be used.