Abstract: A sample pre-separation and concentration system for detecting low levels of analytes in highly complex mixtures includes a plurality of trapping columns having a high selectivity for classes of compounds of interest, upstream of a standard separation column. The system may be used, for example, to measure urinary 8 hydroxy 2′ deoxyguanoisine.

Abstract: The present invention generally relates to a microcolumn capable of separating an analyte from a sample in the millisecond time domain. The microcolumn is capable of such rapid separation by employing small column volumes that can tolerate medium to high flow rates. The invention also relates to a method of loading a microcolumn capable of separating an analyte from a sample in the millisecond time domain.

Abstract: Methods and apparatus are disclosed which are useful for detecting the presence of various pesticides, including aryl pyrazoles such as fipronil. Pesticide residues are extracted from a variety of samples, including soil and/or water samples using techniques well known to those of skill in the art. The samples are then concentrated, and transferred to an solid phase extraction cartridge. The SPE cartridge includes activated charcoal, silica gel, magnesium-silica gel and an amino-functional silica sorbent, or suitable equivalents thereof. After cleanup, the eluate containing the analyte of interest can be concentrated to a standard sample size and the amount of pesticide residues quantitated. In a preferred embodiment, the column chromatography materials are assembled in a solid phase extraction cartridge with frits between the chromatography materials. This facilitates the use of the cartridge in standard automated analytical equipment, for example, robotic equipment.

Abstract: Laminates having microfluidic structures disposed between sheets of the laminate are provided. The microfluidic structures are raised on a sheet of laminate, typically by printing the structure on the sheet. Printing methods include Serigraph, ink-jet, intaligo, offset printing and thermal laser printing.

Abstract: The present invention generally relates to a microcolumn capable of separating an analyte from a sample in the millisecond time domain. The microcolumn is capable of such rapid separation by employing small column volumes that can tolerate medium to high flow rates. The invention also relates to a method of loading a microcolumn capable of separating an analyte from a sample in the millisecond time domain using plural injections of the packing material.

Abstract: Method and apparatus for generating an acid or base, e.g. for chromatographic analysis of anions. For generating a base the method includes the steps of providing a cation source in a cation source reservoir, flowing an aqueous liquid stream through a base generation chamber separated from the cation source reservoir by a barrier (e.g. a charged membrane) substantially preventing liquid flow while providing a cation transport bridge, applying an electric potential between an anode cation source reservoir and a cathode in the base generation chamber to electrolytically generate hydroxide ions therein and to cause cations in the cation source reservoir to electromigrate and to be transported across the barrier toward the cathode to combine with the transported cations to form cation hydroxide, and removing the cation hydroxide in an aqueous liquid stream as an effluent from the first base generation chamber. Suitable cation sources include a salt solution, a cation hydroxide solution or cation exchange resin.

Abstract: A thermostat array including an array of two or more capillary columns (10) or two or more channels in a microfabricated device is disclosed. A heat conductive material (12) surrounded each individual column or channel in array, each individual column or channel being thermally insulated from every other individual column or channel. One or more independently controlled heating or cooling elements (14) is positioned adjacent to individual columns or channels within the heat conductive material, each heating or cooling element being connected to a source of heating or cooling, and one or more independently controlled temperature sensing elements (16) is positioned adjacent to the individual columns or channels within the heat conductive material. Each temperature sensing element is connected to a temperature controller.

Abstract: The present invention relates in general to the preparation and use of matrices having solid spaces, interstitial spaces and interstitial polymer networks. In particular, the interstitial polymer networks have utility in chemical and biochemical separations, solid phase synthesis, catalysis of chemical reactions, and immobilized enzyme reactors. The interstitial polymer networks in one embodiment comprise crosslinked polymers suspended in the interstitial spaces from and/or between solid particles. The matrices are characterized by high ligand and functional group density and by reversible high sorptive and binding capacity, and are substantially accompanied by a very low nonspecific adsorption or interaction with molecules such as proteins. Moreover, the matrices of the invention exhibit other characteristics highly desirable in chromatographic and catalytic applications, such as high physical rigidity, high ligand density, chemical stability, high ligand reactivity, and rapid exchange and reaction kinetics.

Abstract: A method for generating high purity acid or base in an aqueous stream for use as an eluent for chromatography and, particularly, ion chromatography. For generating a base for anion chromatography, the aqueous stream is directed through a cation exchange bed having a first strongly acidic and a second weakly acidic portions. An electrical potential is applied to the bed. Cations on the bed electromigrate into the aqueous stream while hydroxide ions are electrolytically generated to form a base-containing eluent. Anions to be detected and the generated eluent flow through a chromatographic separator. The chromatographic effluent flows past a detector.

Abstract: An electrophoretic device and method for focusing a charged solute is disclosed. The device includes a first chamber for receiving a fluid medium, the first chamber having an inlet for introducing a first liquid to the chamber and an outlet for exiting the first liquid from the chamber; a second chamber comprising an electrode array, the second chamber having an inlet for introducing a second liquid to the chamber and an outlet for exiting the second liquid from the chamber; and a porous material separating the first and second chambers. The device's electrode array includes a plurality of electrodes and generates an electric field gradient profile which can be dynamically controlled. In the method, a charged solute is introduced into a fluid medium followed by the application of a hydrodynamic force. Opposing the hydrodynamic force with an electric field gradient results in solute focusing in the fluid medium.

Abstract: Method and apparatus for generating an acid or base, e.g. for chromatographic analysis of anions. For generating a base the method includes the steps of providing a cation source in a cation source reservoir, flowing an aqueous liquid stream through a base generation chamber separated from the cation source reservoir by a barrier (e.g. a charged membrane) substantially preventing liquid flow while providing a cation transport bridge, applying an electric potential between an anode cation source reservoir and a cathode in the base generation chamber to electrolytically generate hydroxide ions therein and to cause cations in the cation source reservoir to electromigrate and to be transported across the barrier toward the cathode to combine with the transported cations to form cation hydroxide, and removing the cation hydroxide in an aqueous liquid stream as an effluent from the first base generation chamber. Suitable cation sources include a salt solution, a cation hydroxide solution or cation exchange resin.