Abstract: A solvent delivery subsystem for a chromatography device performs relatively low pressure, high flow mixing of solvents to form a gradient and subsequent high pressure, low flow delivery of the gradient to the separation column. The mixing of the gradient is independent and does not interfere with the gradient delivery. To form the gradient, the outputs of an aqueous pump and an organic pump are mixed to fill a storage capillary while a downstream point from the storage capillary is vented to atmosphere. After gradient formation, the vent to atmosphere is closed, the solvent delivery system rises to high pressure, and only the aqueous pump runs for gradient delivery. To maintain integrity of the fluid stream, the solvent delivery system uses feed forward compensation and controls at least one parameter selected from the group consisting of pressure and flow in the conduit means to follow a gradual ramp.

Abstract: The invention provides a method for removing multimers from a preparation of recombinant polyclonal antibodies (rpAbs) while maintaining the ratio of monomers within a narrow range. The invention provides a method of separating recombinant polyclonal antibody multimers with minimal separation of monomers comprising subjecting a mixture comprising a plurality of monoclonal antibodies to at least one separation process selected from the group consisting of multi-modal chromatography, apatite chromatography, and hydrophobic interaction chromatography thereby producing an antibody monomer preparation that is substantially free of multimers.

Abstract: Embodiments of the present invention feature methods and apparatus for performing chromatographic separations. The invention feature methods and control means in the form of computer programs and software that control the formation of a concentration gradient at two or more total flow rates, with an elution period occurring in a slow flow rate and at least other portions of the gradient occurring during a fast total flow rate.

Abstract: The present invention relates to a supported polyolefin catalyst and its preparation and application. Its main catalyst is composed of a support and a transition metal halide; the support is composed of a magnesium halide compound, a silicon halide compound, an alcohol compound having 5 carbon atoms or less, an alcohol compound having carbon atom number of 6-20 in a molar ratio of 1:(0.1 to 20):(0.1 to 5):(0.01 to 10); the molar ratio of the magnesium halide compound and the transition metal halide is 1:(0.1 to 30); during the preparation process of the main catalyst, an organic alcohol ether compound is added, the mass ratio of the magnesium halide compound and the organic alcohol ether compound is 100:(0.1 to 20); and the molar ratio of the transition metal halide in the main catalyst and the co-catalyst is 1:(30 to 500).

Abstract: A solvent delivery subsystem for a chromatography device performs relatively low pressure, high flow mixing of solvents to form a gradient and subsequent high pressure, low flow delivery of the gradient to the separation column. The mixing of the gradient is independent and does not interfere with the gradient delivery. To form the gradient, the outputs of an aqueous pump and an organic pump are mixed to fill a storage capillary while a downstream point from the storage capillary is vented to atmosphere. After gradient formation, the vent to atmosphere is closed, the solvent delivery system rises to high pressure, and only the aqueous pump runs for gradient delivery. To maintain integrity of the fluid stream, the solvent delivery system uses feed forward compensation and controls at least one parameter selected from the group consisting of pressure and flow in the conduit means to follow a gradual ramp.

Abstract: A solvent delivery subsystem for a chromatography device performs relatively low pressure, high flow mixing of solvents to form a gradient and subsequent high pressure, low flow delivery of the gradient to the separation column. The mixing of the gradient is independent and does not interfere with the gradient delivery. To form the gradient, the outputs of an aqueous pump and an organic pump are mixed to fill a storage capillary while a downstream point from the storage capillary is vented to atmosphere. After gradient formation, the vent to atmosphere is closed, the solvent delivery system rises to high pressure, and only the aqueous pump runs for gradient delivery. To maintain integrity of the fluid stream, the solvent delivery system uses feed forward compensation and controls at least one parameter selected from the group consisting of pressure and flow in the conduit means to follow a gradual ramp.

Abstract: Embodiments of the present invention feature methods and apparatus for performing chromatographic separations. The invention feature methods and control means in the form of computer programs and software that control the formation of a concentration gradient at two or more total flow rates, with an elution period occurring in a slow flow rate and at least other portions of the gradient occurring during a fast total flow rate.

Abstract: Embodiments of the present invention feature methods and apparatus for performing chromatographic separations. The invention feature methods and control means in the form of computer programs and software that control the formation of a concentration gradient at two or more total flow rates, with an elution period occurring in a slow flow rate and at least other portions of the gradient occurring during a fast total flow rate.

Abstract: The invention provides improved methods and apparatus for fluid chromatography, and is particularly appropriate to high-pressure liquid chromatography carried out using eluent flow rates less than 1 ?l/minute, for example on nanoflow columns. In both single- and multi-dimensional chromatography systems, especially those comprising trapping media to facilitate injection of relatively large volumes of sample on to nanoflow columns, the on-line addition of a diluting solvent enables stronger eluents and sample solvents to be employed without causing premature release of analytes from the trapping media or the degradation of the second dimension chromatographic separation. The invention may be advantageously used for two-dimension reverse phase/reverse phase separations, especially for the separation of complex mixtures of peptides.

Abstract: The invention provides improved methods and apparatus for multidimensional analysis, especially for multidimensional liquid chromatography. Methods and apparatus for the quantitative determination of one or more components comprised in a sample mixture are described. Methods and apparatus of the invention typically allow accurate quantitative determination of more components of the mixture than prior multidimensional methods. The invention is particularly useful for, but is not limited to the analysis of complex mixtures of peptides and proteins.

Abstract: The invention provides improved methods and apparatus for multidimensional analysis, especially for multidimensional liquid chromatography. Methods and apparatus for the quantitative determination of one or more components comprised in a sample mixture are described. Methods and apparatus of the invention typically allow accurate quantitative determination of more components of the mixture than prior multidimensional methods. The invention is particularly useful for, but is not limited to the analysis of complex mixtures of peptides and proteins.

Abstract: The invention provides improved methods and apparatus for fluid chromatography, and is particularly appropriate to high-pressure liquid chromatography carried out using eluent flow rates less than 1 ?l/minute, for example on nanoflow columns. In both single- and multi-dimensional chromatography systems, especially those comprising trapping media to facilitate injection of relatively large volumes of sample on to nanoflow columns, the on-line addition of a diluting solvent enables stronger eluents and sample solvents to be employed without causing premature release of analytes from the trapping media or the degradation of the second dimension chromatographic separation. The invention may be advantageously used for two-dimension reverse phase/reverse phase separations, especially for the separation of complex mixtures of peptides.

Abstract: Embodiments of the present invention feature methods and apparatus for performing chromatographic separations. The invention feature methods and control means in the form of computer programs and software that control the formation of a concentration gradient at two or more total flow rates, with an elution period occurring in a slow flow rate and at least other portions of the gradient occurring during a fast total flow rate.

Abstract: A solvent delivery subsystem for a chromatography device performs relatively low pressure, high flow mixing of solvents to form a gradient and subsequent high pressure, low flow delivery of the gradient to the separation column. The mixing of the gradient is independent and does not interfere with the gradient delivery. To form the gradient, the outputs of an aqueous pump and an organic pump are mixed to fill a storage capillary while a downstream point from the storage capillary is vented to atmosphere. After gradient formation, the vent to atmosphere is closed, the solvent delivery system rises to high pressure, and only the aqueous pump runs for gradient delivery. To maintain integrity of the fluid stream, the solvent delivery system uses feed forward compensation and controls at least one parameter selected from the group consisting of pressure and flow in the conduit means to follow a gradual ramp.