The present disclosure pertains to methods of separating nucleic acid component compounds from one another. In some embodiments, the methods comprise: (a) loading a sample fluid comprising a plurality of nucleic acid component compounds onto a chromatographic column comprising a zwitterionic stationary phase contained inside the column; (b) flowing a mobile phase through the chromatographic column over a time period thereby forming an eluent in which at least some of the plurality of the nucleic acid component compounds are separated from each other, the mobile phase comprising a polar aprotic solvent, a protic solvent, and a volatile buffer salt, wherein flowing the mobile phase comprises varying a ratio of the protic solvent to the polar aprotic solvent over at least a portion of the time period and varying an ionic strength of the volatile buffer salt over at least a portion of the time period.

A method and an apparatus suitable for a continuous chromatography process which only needs three separation columns, and a two-step process containing two chromatographic steps, in which the first chromatographic step (capture) is performed alternating and sequentially on two separation columns, the second chromatographic step (polishing) is performed, also sequentially, on the third column.

The present invention relates to a method for detecting a pathogenic strain having resistance to carbapenem antibiotics in a biological sample. According to the present invention, it is possible to directly identify carbapenemases, specifically KPC, OXA, NDM, IMP, VIM and/or GES protein, by mass spectrometry, thereby making it possible to quickly determine not only whether a pathogenic strain has resistance to antibiotics, but also the type of protein involved in the resistance. According to the present invention, the physical and chemical properties of each carbapenemase in vivo, such as the unique N-terminal truncation length, methionine residue oxidation and disulfide bond formation in each type of carbapenemase, are identified and are reflected on reference mass values. Accordingly, it is possible to more closely detect the presence of an antibiotic-resistant strain with high reliability, and thus the present invention may be advantageously used to establish an appropriate strategy for antibiotic administration at an early stage of infection.

The present invention relates to a method for detecting a pathogenic strain having resistance to carbapenem antibiotics in a biological sample. According to the present invention, it is possible to directly identify carbapenemases, specifically KPC, OXA, NDM, IMP, VIM and/or GES protein, by mass spectrometry, thereby making it possible to quickly determine not only whether a pathogenic strain has resistance to antibiotics, but also the type of protein involved in the resistance. According to the present invention, the physical and chemical properties of each carbapenemase in vivo, such as the unique N-terminal truncation length, methionine residue oxidation and disulfide bond formation in each type of carbapenemase, are identified and are reflected on reference mass values. Accordingly, it is possible to more closely detect the presence of an antibiotic-resistant strain with high reliability, and thus the present invention may be advantageously used to establish an appropriate strategy for antibiotic administration at an early stage of infection.

An electrolytic eluent generator includes an electrolyte reservoir, an eluent generation chamber, and an ion exchange membrane stack. The electrolyte reservoir includes a chamber containing an aqueous electrolyte solution including an electrolyte; and a first electrode. The eluent generation chamber including a second electrode. The ion exchange connector includes an ion exchange membrane stack, and a compression block.

An electrolytic eluent generator includes an electrolyte reservoir, an eluent generation chamber, and an ion exchange membrane stack. The electrolyte reservoir includes a chamber containing an aqueous electrolyte solution including an electrolyte; and a first electrode. The eluent generation chamber including a second electrode. The ion exchange connector includes an ion exchange membrane stack, and a compression block.

An electrolytic eluent generator includes an electrolyte reservoir, an eluent generation chamber, and an ion exchange membrane stack. The electrolyte reservoir includes a chamber containing an aqueous electrolyte solution including an electrolyte; and a first electrode. The eluent generation chamber including a second electrode. The ion exchange connector includes an ion exchange membrane stack, and a compression block.

A method for determining properties of different cation exchange sites in a rock core sample, at a preserved state of the rock core sample may include providing a rock core sample that includes a plurality of indigenous exchangeable cations adsorbed onto the cation exchange sites, a plurality of cation exchange sites occupied by a crude oil, and one or more fluids occupying pore spaces in the rock core sample; subjecting the rock core sample to a plurality of coreflooding steps, the plurality of coreflooding step displacing the plurality of indigenous exchangeable cations, the crude oil, and the one or more fluids in at least three separate coreflooding steps to render the rock core sample clean of native components; determining an amount of indigenous exchangeable cations adsorbed onto the cation exchange sites; subjecting the rock core sample clean of native components to a plurality of coreflooding steps to determine a total amount of exchangeable cations adsorbed onto the cation exchange sites when the rock core sample is clean of native components; and determining at least one property of different cation exchange sites in the rock core sample at the preserved state based on the amount of indigenous exchangeable cations and the total amount of exchangeable cations.

A method for determining properties of different cation exchange sites in a rock core sample, at a preserved state of the rock core sample may include providing a rock core sample that includes a plurality of indigenous exchangeable cations adsorbed onto the cation exchange sites, a plurality of cation exchange sites occupied by a crude oil, and one or more fluids occupying pore spaces in the rock core sample; subjecting the rock core sample to a plurality of coreflooding steps, the plurality of coreflooding step displacing the plurality of indigenous exchangeable cations, the crude oil, and the one or more fluids in at least three separate coreflooding steps to render the rock core sample clean of native components; determining an amount of indigenous exchangeable cations adsorbed onto the cation exchange sites; subjecting the rock core sample clean of native components to a plurality of coreflooding steps to determine a total amount of exchangeable cations adsorbed onto the cation exchange sites when the rock core sample is clean of native components; and determining at least one property of different cation exchange sites in the rock core sample at the preserved state based on the amount of indigenous exchangeable cations and the total amount of exchangeable cations.

The present disclosure relates to methods, compositions and kits useful for the enhanced pH gradient cation exchange chromatography of a variety of analytes. In various aspects, the present disclosure pertains to chromatographic elution buffer solutions that comprise a first buffer salt, a second buffer salt, a third buffer salt, and fourth buffer salt. The first buffer salt may be, for example, a diprotic acid buffer salt, the second buffer salt may be, for example, a divalent buffer salt with two amine groups, the third buffer salt may be, for example, a monovalent buffer salt comprising a single amine group, and the fourth buffer salt may be, for example, a zwitterionic buffer salt. Moreover, the buffer solution has a pH ranging from 3 to 11.