Polar-modified bonded phase materials for chromatographic separations

• US 20060207923A1
• Filed: 05/22/2006
• Published: 09/21/2006
• Est. Priority Date: 02/12/2004
• Status: Active Grant

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Li, Guang Q.
• Granted Patent: US 8,702,988 B2
• Time in Patent Office: Days
• US Class Current: 210/198.200
• CPC Class Codes: B01J 20/288 Polar phases
• CPC Class Codes: B01J 20/3227 by end-capping, i.e. with or after the introduction of functional or ligand groups

Abstract

Novel compositions are disclosed for use as a stationary phase in chromatography comprising an inorganic substrate that is modified with at least one silane having the formula R¹_δ-Q_α-(CH₂)_βSiR²_γX_3-γ. In a preferred embodiment, the inorganic substrate is silica gel and is modified with at least two silanes. Methods of preparation and use in chromatographic applications are disclosed. The novel compositions provide superior chromatographic performance, reduced silanol activity, enhanced stability, and reproducibility in preparation and performance.

Claims

1-24. -24. (canceled)

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

(a) equilibrating the inorganic substrate in an atmosphere having a defined relative humidity to provide a controlled amount of water on the surface of the inorganic substrate;

(b) modifying the inorganic substrate with at least one silane; and

(c) further modifying the inorganic substrate with an endcapping silane.

26. The method of claim 25, wherein the silane has the formula:

R¹_δ

-Q_α

-(CH₂)_β

SiR²_γ

X_3-γ

,

wherein R¹ is hydrogen, C₁-C₁₀₀ substituted or unsubstituted hydrocarbyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl;

wherein the substituents are selected from C₁-C₁₂ 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;

R² is C₁-C₁₀₀ substituted or unsubstituted hydrocarbyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl;

wherein the substituents are selected from C₁-C₁₂ 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—

, CH₂OCHCH₂O—

, —

(CH₂CH₂O)_n—

, —

(CH₂CH₂CH₂O)_n—

, —

C(O)—

, —

C(O)O—

, —

OC(O)—

, CH₃C(O)CH₂—

, —

S—

, —

SS—

, —

CHOH—

, —

O—

, —

SO—

, —

SO₂—

, —

SO₃—

, —

OSO₃—

, —

SO₂NH—

, —

SO₂NMe-, —

NH—

, —

NMe-, —

NMe₂⁺-, —

N[(CH₂)_n]₂⁺-, —

CN, —

NC, —

CHOCH—

, —

NHC(NH)NH—

, —

NO₂, —

NO, —

OPO₃—

, where n is 1-30; and

X is a leaving group.

27. The method of claim 25, further comprising the step of modifying the inorganic substrate with a second silane, wherein δ

for the second silane is from 0-3.

28. The method of claim 27, wherein the modification step with the second silane is performed at the same time as the modification step with the first silane.

29. The method of claim 27, wherein the modification step with the second silane is performed after the modification step with the first silane.

30. The method of claim 25, wherein the atmosphere having a defined relative humidity is provided by hydrated salts or saturated salt solutions.

31. The method of claim 30, wherein the defined relative humidity is less than 50%.

32. The method of claim 30, wherein the relative humidity is from about 0% to about 10%, from about 10% to about 20%, from about 20% to about 30%, from about 40% to about 50%, from about 50% to about 60%, from about 60% to about 70%, from about 70% to about 80%, from about 80% to about 90% or from about 90% to about 100%.

33. The method of claim 30, 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.

34. The method of claim 25, wherein the inorganic substrate is a metal or metalloid oxide substrate.

35. The method of claim 34, wherein the metal or metalloid oxide comprises silica, alumina, zeolite, mullite, zirconia, vanadia or titania, or mixtures thereof.