A chromatography column has a retaining plug permanently fixed to an upstream end of the column and blocks one end of the bore through the column. The plug has a fluid passage therethrough. An upstream end of the passage is preferably but optionally larger in diameter than a downstream end of the passage. An upstream porous member upstream of the retaining plug is held by an upstream end cap and urged toward the plug. Chromatographic media extends from the upstream porous member, through the passage in the retaining plug, to a downstream porous member held by a downstream end cap. The media between the retaining plug and the downstream porous member are under compression to form a bed of packed media.

Provided is a supercritical fluid chromatography method, system, and components comprising such a system wherein a non-polar solvent may replace a portion or all of a polar solvent for the purpose of separating or extracting desired sample molecules from a combined sample/solvent stream. The method and system are designed to eliminate or reduce the amount of polar solvent necessary for chromatographic separation and/or extraction of desired samples to less than or equal to twenty percent polar solvent within the total volume concentration of the total solvents used, and the technique may include one or more of a supercritical fluid chiller, a supercritical fluid pressure-equalizing vessel, and a supercritical fluid cyclonic separator. The supercritical fluid chiller and the use of the chiller allow efficient and consistent pumping of liquid-phase gases employing off-the-shelf HPLC pumps in the supercritical chromatography system using liquid-phase gas mobile phase. The pressure equalizing vessel allows the use of off the shelf HPLC column cartridges in the supercritical chromatography system. The cyclonic separator efficiently and effectively allows for separation of sample molecules from a liquid phase or gas phase stream of a supercritical fluid. The technique may further incorporate the use of one or more disposable cartridges containing silica gel or other suitable medium for use as a chromatographic separation column. The technique may also utilize an open loop cooling circuit using fluids with a positive Joule-Thompson coefficient.

The subject invention provides chemical compositions and synthesis strategies to create molecularly imprinted polymers (MIPs) via sol-gel processes. In a specific embodiment, the subject invention utilizes a(n) organic, inorganic, or metallic template analyte to create a hybrid organic-inorganic or inorganic three-dimensional network possessing cavities complementary to the shape, size, and functional orientation of the template molecule or ions. The subject invention further pertains to the use of the novel MIPs as selective solid phase extraction (SPE) sorbents for pre-concentration and clean-up of trace substances in biological and environmental samples. Synthesis of other molecularly imprinted polymers with environmental, pharmaceutical, chemical, clinical, toxicological, and national security implications can be conducted in accordance with the teachings of the subject invention.

The subject invention provides chemical compositions and synthesis strategies to create molecularly imprinted polymers (MIPs) via sol-gel processes. In a specific embodiment, the subject invention utilizes a(n) organic, inorganic, or metallic template analyte to create a hybrid organic-inorganic or inorganic three-dimensional network possessing cavities complementary to the shape, size, and functional orientation of the template molecule or ions. The subject invention further pertains to the use of the novel MIPs as selective solid phase extraction (SPE) sorbents for pre-concentration and clean-up of trace substances in biological and environmental samples. Synthesis of other molecularly imprinted polymers with environmental, pharmaceutical, chemical, clinical, toxicological, and national security implications can be conducted in accordance with the teachings of the subject invention.

The invention relates to a curable composition, containing (A) at least one polyorganosiloxane, which has at least one hydroxy group bound to a silicon atom, (B) at least one silane of the formula (1):
Si(R.sup.1).sub.m(R.sup.2).sub.n(R.sup.3).sub.4-(m+n)(1), as defined herein, (C) at least one aminosilane, and (D) at least one tin compound,
whereby the molar ratio of the aminosilane to the tin compound is 1:1 to 50:1, as well as to the preparation and use thereof.

A method of analyzing a multi-component polymer comprising: (a) dissolving an multi-component polymer having a primary monomer and primary comonomer to form a first volume (soluble portion of multi-component polymer); (b) injecting a portion of the first volume into a chromatographic column to get elution first slices, leaving a second volume behind; (c) filtering the second volume to isolate multi-component polymer solids; (d) dissolving solids to form solution third solution (insoluble portion of multi-component polymer); (e) injecting a portion of third solution into the chromatographic column to get elution second slices; (f) obtain infra-red spectra at wavelengths suitable for the primary monomer and the primary comonomer of first and second elution slices, separately; and (g) for each elution slice, separately calculate: (i) the different polymer components (soluble and insoluble); and (ii) the comonomer content of each component (soluble and insoluble).

A method of analyzing a multi-component polymer comprising: (a) dissolving an multi-component polymer having a primary monomer and primary comonomer to form a first volume (soluble portion of multi-component polymer); (b) injecting a portion of the first volume into a chromatographic column to get elution first slices, leaving a second volume behind; (c) filtering the second volume to isolate multi-component polymer solids; (d) dissolving solids to form solution third solution (insoluble portion of multi-component polymer); (e) injecting a portion of third solution into the chromatographic column to get elution second slices; (f) obtain infra-red spectra at wavelengths suitable for the primary monomer and the primary comonomer of first and second elution slices, separately; and (g) for each elution slice, separately calculate: (i) the different polymer components (soluble and insoluble); and (ii) the comonomer content of each component (soluble and insoluble).

Yttria containing hybrid organic-inorganic sol-gels may be used in coatings for capillary microextraction, optionally hyphenated to online HPLC analysis. The sol-gel reaction mixture can use an yttrium trialkoxyalkoxide, such as yttrium trimethoxyethoxide, and a [bis(hydroxyalkyl)-amino-alkyl]-terminated polydialkyl/arylsiloxane, such as [bis(hydroxyethyl)-amine] (BHEA)-terminated polydimethylsiloxane, that can undergo hydrolysis and polycondensation, to form coating materials. Capillaries coated with such sol-gels can have improved extraction efficiency compared, e.g., to pure yttria-based coatings. The CME-HPLC can analyze water samples containing analytes of varied polarity, with excellent extraction of amides, phenols, alcohols, ketones, aldehydes, and polyaromatic hydrocarbons and detection limits ranging from 0.18 to 7.35 ng/mL (S/N=3). Such capillaries can exhibit solvent stability at pH 0 to 14, RSD % between 0.6 to 6.8% (n=3), at a preparative reproducibility RSD between 4.1 and 9.9%.

A method to form mesoporous silica by a sol-gel process that has an acid catalyzed hydrolysis and the base catalyzed condensation of one or more tetraalkoxysilane that gives mesoporous silica and larger pores and high pore volumes. The mesoporous silica is surface modified by a sol-gel process that has an acid catalyzed hydrolysis and condensation of a methyltrialkoxysilane and a substituted trialkoxysilane and/or a hydroxy substituted inorganic or organic polymer to form gel coated mesoporous silica particles having functionality for use as chromatographic supports or a solid phase sorbent.

A method to form mesoporous silica by a sol-gel process that has an acid catalyzed hydrolysis and the base catalyzed condensation of one or more tetraalkoxysilane that gives mesoporous silica and larger pores and high pore volumes. The mesoporous silica is surface modified by a sol-gel process that has an acid catalyzed hydrolysis and condensation of a methyltrialkoxysilane and a substituted trialkoxysilane and/or a hydroxy substituted inorganic or organic polymer to form gel coated mesoporous silica particles having functionality for use as chromatographic supports or a solid phase sorbent.