Polar-modified bonded phase materials for chromatographic separations

1. A method for covalently modifying an inorganic substrate, comprising the steps of:

(a) equilibrating the inorganic substrate in an atmosphere having a defined relative humidity of less than 40% to provide a controlled amount of water on the surface of the inorganic substrate, thereby enhancing batch to batch reproducibility;

(b) covalently modifying the inorganic substrate with at least one silane in the presence of an inert solvent; and

(c) further covalently modifying the inorganic substrate with an endcapping silane, wherein the silane has the formula:

R 1 δ -Q α -(CH 2 ) β SiR 2 γ X 3-γ ,

wherein R 1 is hydrogen, C 1 -C 100 substituted or unsubstituted hydrocarbyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl; wherein the substituents are selected from C 1 -C 12 hydrocarbyl, hydroxyl, alkoxy, halogen, amino, nitro, sulfo, and carbonyl;

α is 0 or 1;

β is 0-30;

γ is 0, 1 or 2;

δ is 0-3;

R 2 is C 1 -C 100 substituted or unsubstituted hydrocarbyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl; wherein the substituents are selected from C 1 -C 12 hydrocarbyl, hydroxyl, alkoxy, halogen, amino, nitro, sulfo, and carbonyl;

Q is independently selected from —NHC(O)—, —C(O)NH—, —OC(O)NH—, —NHC(O)O—, —NHC(O)NH—, —NCO, —CHOHCHOH—, —CH 2 OCHCH 2 O—, —(CH 2 CH 2 O) n —, —(CH 2 CH 2 CH 2 O) n —, —C(O)—, —C(O)O—, —OC(O)—, CH 3 C(O)CH 2 —, —S—, —SS—, —CHOH—, —O—, —SO—, —SO 2 —, —SO 3 —, —OSO 3 —, —SO 2 NH—, —SO 2 NMe-, —NH—, —NMe-, —NMe 2 + -, —N[(CH 2 ) n ] 2 + -, —CN, —NC, —CHOCH—, —NHC(NH)NH—, —NO 2 , —NO, —OPO 3 —, where n is 1-30; and

X is a leaving group.

2. The method of claim 1 , further comprising the step of modifying the inorganic substrate with a second silane, wherein δ for the second silane is from 0-3.

3. The method of claim 2 , wherein the first silane has a value for δ of 1, α is 0, β is 8-30, γ is 0, 1 or 2, R 1 is H, and the second silane has a value for δ of 1, R 1 is a substituted or unsubstituted C 1 -C 6 hydrocarbyl, and Q is amido, cyano or glycidoxy.

4. The method of claim 2 , wherein the first silane has a value for δ of 1, α is 0, β is 8-30, γ is 0, 1 or 2, R 1 is H, and the second silane has a value for δ of 1, R 1 is a substituted or unsubstituted C 1 -C 6 hydrocarbyl, and Q is thio, dithio, ether, sulfinyl, sulfonyl, sulfonic acid, sulfate, sulfonamido, amino, nitrile, isonitrile, epoxy, guanidino, nitro, nitroso, or phosphate.

5. The method of claim 2 , wherein the first silane has a value for δ of 1, α is 1, β is 1-30, γ is 0, 1, or 2, R 1 is a substituted or unsubstituted C 1 -C 30 hydrocarbyl, Q is amido or carbamyl, and the second silane has a value for δ of 1, α is 1, β is 1-30, γ is 0, 1, or 2, R 1 is a substituted or unsubstituted C 1 -C 6 hydrocarbyl, and Q is amido, carbamyl, cyano or glycidoxy.

6. The method of claim 2 , wherein the modification step with the second silane is performed at the same time as the modification step with the first silane.

7. The method of claim 2 , wherein the modification step with the second silane is performed after the modification step with the first silane.

8. The method of claim 1 , wherein the atmosphere having a defined relative humidity is provided by hydrated salts or saturated salt solutions.

9. The method of claim 8 , wherein the relative humidity is from about 0% to about 10%, from about 10% to about 20%, from about 20% to about 30%, or from about 30% to about 40%.

10. The method of claim 8 , wherein the hydrated salts or saturated salt solutions comprise cesium fluoride, lithium bromide, zinc bromide, potassium hydroxide, sodium hydroxide, lithium chloride, calcium bromide, potassium acetate, potassium fluoride, magnesium chloride, sodium iodide, potassium carbonate, magnesium nitrate, sodium bromide, cobalt chloride, sodium nitrite, potassium iodide, strontium chloride, sodium nitrate, sodium chloride, ammonium chloride, potassium bromide, ammonium sulfate, potassium chloride, strontium nitrate, barium chloride, potassium nitrate, or potassium sulfate.

11. The method of claim 1 , wherein the inorganic substrate is a metal or metalloid oxide substrate.

12. The method of claim 11 , wherein the metal or metalloid oxide comprises silica, alumina, zeolite, mullite, zirconia, vanadia or titania, or mixtures thereof.

13. The method of claim 1 , wherein the inorganic substrate is in the form of a monolith or porous particles.

14. The method of claim 1 , wherein the inorganic substrate comprises silica.

15. The method of claim 5 , wherein the first or second silane or both the first and the second silanes comprises a mixture of silanes.

16. The method of claim 5 , wherein the silica gel substrate is modified with at least one silane wherein δ is from 0 to 3, and at least one additional silane wherein δ is 0 or 1.

17. The method of claim 1 , wherein the endcapping silane is a monosilane, disilane, trisilane or tetrasilane, or a combination thereof.

18. The method of claim 1 , wherein Q, R 1 or R 2 is a chiral recognition ligand.

19. The method of claim 18 , wherein the chiral recognition ligand is optically active.